United States Department of Agriculture

Forest 

Service

Pacific Northwest 

Research Station

General Technical Report

PNW-GTR-917 January 

2016

A Climate Adaptation Strategy for 

Conservation and Management of 

Yellow-Cedar in Alaska

Paul E. Hennon, Carol M. McKenzie, David V. D’Amore, Dustin T. Wittwer, 

Robin L. Mulvey, Melinda S. Lamb, Frances E. Biles, Rich C. Cronn
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Authors

Paul E. Hennon is a research plant pathologist, David V. D’Amore is a research 

soil scientist, and Frances E. Biles is a geographer, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Forestry Sciences 

Laboratory, 11175 Auke Lake Way, Juneau, AK 99802. Carol M. McKenzie was 

the regional silviculturalist and Dustin T. Wittwer is a geospatial specialist, U.S. 

Department of Agriculture, Forest Service, Alaska Region, P.O. Box 21628, Juneau, 

AK 99801. Robin L. Mulvey is a plant pathologist and Melinda S. Lamb is a biological technician, U.S. Department of Agriculture, Forest Service, Alaska Region, 

State and Private Forestry, Forest Health Protection, 11175 Auke Lake Way, Juneau, 

AK 99802. Rich C. Cronn is a research geneticist, U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station, Forestry Sciences Laboratory, 

3200 Jefferson Way, Corvallis, OR 97331. Carol McKenzie is the vegetation staff 

officer, U.S. Department of Agriculture, Forest Service, Idaho Panhandle National 

Forest, 3815 Schreiber Way, Coeur d’Alene, ID 83815.

Cover: The scalelike foliage of yellow-cedar. (Photo by USDA Forest Service.)
Abstract

Hennon, Paul E.; McKenzie, Carol M.; D’Amore, David V.; Wittwer, Dustin 

T.; Mulvey, Robin L.; Lamb, Melinda S.; Biles, Frances E.; Cronn, Rich C. 

2016. A climate adaptation strategy for conservation and management of yellowcedar in Alaska. Gen. Tech. Rep. PNW-GTR-917. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 382 p.

A conservation and management strategy for yellow-cedar in Alaska is presented 

in the context of climate change. This document has four sections. Section 1 covers 

the ecology and silvics of yellow-cedar, as well as other background information. 

Section 2 outlines knowledge on the extensive mortality to yellow-cedar, including 

the role of climate. Section 3 describes opportunities for the conservation and active 

management of yellow-cedar on lands that are considered either suitable or unsuitable for yellow-cedar. Section 4 uses risk models and yellow-cedar distribution data 

to evaluate, quantify, and map areas of habitat suitability for yellow-cedar, both now 

and predicted through the year 2100. Yellow-cedar at risk of forest decline by the 

end of the century varies considerably by geography in coastal Alaska. Some areas 

are already heavily affected by decline, and risk is not expected to increase appreciably. Other areas are currently unaffected but are expected to develop decline. 

Still other areas are expected to remain healthy. This report provides a vulnerability 

assessment and the scientific foundation for conservation and active management of 

yellow-cedar on suitable and vulnerable lands. Specific management considerations 

are presented regionally and for 33 separate geographic zones where yellow-cedar 

grows in coastal Alaska. 

Keywords: Alaska-cedar, Alaska yellow-cedar, Callitropsis nootkatensis, 

Chamaecyparis nootkatensis, climate adaptation. 
ii

Summary

In 2011, the Alaska Region of the U.S. Department of Agriculture, Forest Service 

identified the need to develop a conservation and management strategy for yellowcedar. Forest Service specialists would synthesize what was known about the 

species in terms of best available science, evaluate the current and future condition 

and vulnerability of the species, and recommend conservation and management 

strategies that would address these vulnerabilities. This report is the product of a 

collaborative team: Alaska Region land managers and specialists, State and Private Forestry forest health professionals, and Pacific Northwest Research Station 

scientists. 

The report contains four sections and four appendixes. Section 1 provides 

background on the values, distribution, natural history, ecology, genetics, silvics, 

and management experience for yellow-cedar to serve as a general reference for 

the species. Section 2 describes the extent and causes of the widespread decline 

and mortality of yellow-cedar, with emphasis on the historical and anticipated role 

of climate. Section 3 offers management considerations on lands in protection and 

active management status that have current mortality (e.g., succession to other tree 

species and salvage potential) or in areas of current and future favorable habitat 

(e.g., favoring yellow-cedar through active management such as planting and thinning). Section 4 quantifies and maps the risk of yellow-cedar decline through time 

as the basis for determining yellow-cedar habitat suitability. The complex cause 

of yellow-cedar decline is reduced to two risk factors (drainage and snow) that 

are used to model habitat suitability for yellow-cedar forests in Alaska. Snow is a 

dynamic risk factor and it is modeled in three time steps to predict future conditions 

in yellow-cedar forests. Models suggest that risk to yellow-cedar decline in Alaska

by the end of the century varies considerably by geography and elevation with some 

forests already affected, some forests expected to develop mortality, and still others 

expected to remain healthy.

Appendix 1 provides a detailed risk assessment for 33 geographic units in 

coastal Alaska on the extent of (a) yellow-cedar populations, (b) forests with current 

and expected future mortality, and (c) current and expected future risk of yellowcedar decline. Appendix 2 summarizes information gaps and research needs. 

Appendix 3 documents known young-growth stands on Tongass National Forest 

land with a yellow-cedar component. Last, appendix 4 lists common and scientific 

names of plants, mammals, insects, and fungi mentioned in the report. This document may serve as a scientific foundation for developing adaptation strategies in 

other forests affected by climate change. 
iii

Contents

1 Section 1: Background on Yellow-Cedar 

1 Introduction

1 Values

2 Cultural Values

5 Economic Values

8 Ecological Values

11 General Information on Yellow-Cedar

11 Taxonomy and Scientific Names

12 Native Names and Common Names

13 Yellow-Cedar Distribution

27 Tree Morphology

28 Wood Properties and Chemistry

33 Foliage Morphology and Chemistry

34 Distinguishing Yellow-Cedar From Western Redcedar

36 Reproduction and Regeneration

40 Genetics

55 Paleoecology

58 Dendrochronology

59 Ecology and Silvics

59 General Habitat Characteristics

60 Forest Types and Plant Communities

63 Geology and Soils

64 Adaptations to Wet Soils and Related Nutrient Cycling

65 Rooting Habits

66 Adaptations to Drought

67 Shade Tolerance

67 Cold Tolerance

69 Damage Agents

69 Wind
iv

70 Fire

71 Insects

74 Diseases

75 Wood Decays

77 Potential Invasive Species

77 Animal Damage

78 Climate 

79 Commercial Use and Forest Management

79 Logging History

83 Silvicultural Systems

85 Reforestation

86 Natural Regeneration

88 Artificial Regeneration

93 Control of Animal Damage

96 Precommercial Thinning

97 Section 2: Climate and Yellow-Cedar Decline

97 Yellow-Cedar Decline

97 Extent and Intensity of Decline

103 Epidemiology, Timing, and Pulses of Mortality

106 Causes of Extensive Tree Death

106 Early Studies on Symptoms and Biotic Agents

109 Abiotic Factors and the Complex Cause: Freezing Injury

116 Relationship of Snow and Yellow-Cedar Decline at Different 

Spatial Scales

119 Climate Interactions With Yellow-Cedar

121 Conclusions

123 Section 3: Opportunities for Conservation and Management of 

Yellow-Cedar On Vulnerable and Suitable Habitats 

123 Impacts and Considerations for Management Within the Maladaptation 

Zone: Species Conversions, Timber Salvage, and Conservation on 

Vulnerable Habitats
v

124 Transition in Overstory Trees and Understory Plants

127 Potential for Salvaging Dead Yellow-Cedar

142 Biogeochemical Implications for the Dead and Dying Yellow-Cedar 

Component of Forests

143 Changes in Lands Under Protection Status 

144 Considerations for Conservation and Management on Suitable Habitat

146 Monitoring Yellow-Cedar Life Stages in Unmanaged Forests

148 Yellow-Cedar Natural Regeneration in Harvested Forests

150 Success of Yellow-Cedar Planting in Harvested Forests

150 Applied Genetics

157 Thinning to Favor Yellow-Cedar in Managed Forests

158 Longer Term Young-Growth Management

159 Special Case of Forest Management: Yellow-Cedar’s Role in the Transition 

to a Young-Growth Utilization Program

161 Dispersal of Yellow-Cedar to New Habitat Areas With Suitable Climates

163 Section 4: Modeling Future Vulnerability of Yellow-Cedar Forests to 

Climate Change for Conservation and Management Planning 

163 Introduction and Conceptual Basis

165 Modeling of Suitable and Vulnerable Areas for Yellow-Cedar Based On 

Risk of Decline

167 Yellow-Cedar Distribution

170 Yellow-Cedar Decline

171 Predicting Future Yellow-Cedar Decline With Two Risk Factors: 

Soil Drainage and Snow 

176 Delineating 33 Yellow-Cedar Management Zones in Coastal Alaska 

for Assessment

178 Challenges in Using Different Scales for Geographic Information 

Systems Layers

180 Final Risk Assessment Summary

182 Yellow-Cedar Forest Distribution and Decline

185 Projection of Risk of Yellow-Cedar Decline
vi

188 Implications of Risk Models for the Conservation and Management of 

Yellow-Cedar

188 Lands Under Conservation or Protection Status

189 Lands Under Active Management Status: Intervention Activities

193 Conclusions

194 Acknowledgments

195 Metric Equivalents

195 Literature Cited

227 Appendix 1: Local Assessments of Yellow-Cedar in Alaska

361 Appendix 2: Information Gaps, Needed Research, and Technology 

Transfer

369 Appendix 3: Yellow-Cedar Occurrence in Young-Growth Stands 

in Alaska

380 Appendix 4: Common and Scientific Names of Plants, Mammals, Insects,

and Fungi Mentioned in This Report
1

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Introduction

Yellow-cedar (Callitropsis nootkatensis) is a unique tree species with an ancient 

lineage and a rich cultural history. A comprehensive science synthesis is needed 

to combine various sources of information on the species. Section 1 is divided as 

follows: cultural, economic, and ecological values; geographic, physical, chemical, 

and genetic characteristics; ecology and silvics; damage agents; and commercial use 

and management of yellow-cedar. Many of these subjects are treated as a review 

of literature and management experience. Topics in this section with considerable 

new information include a description of recent genetic research, and a new map 

of yellow-cedar’s rangewide distribution. The new information on distribution of 

yellow-cedar is a key component of the vulnerability assessment in section 4. Many 

aspects of yellow-cedar’s ecology and silvics presented here are important factors in 

yellow-cedar decline (section 2), conservation and management (section 3), and the 

construction and interpretation of landscape models (section 4). Note that factors for 

converting from English measurements to metric units are given before the “Literature Cited” section.

Values

Yellow-cedar is an important forest tree in coastal Alaska due to its cultural, 

economic, and ecological values. We treat each of these values separately in this 

document, but several values are intertwined. For example, Alaskan Native people 

have long known the strength of yellow-cedar wood, and selected it for use as canoe 

paddles because of the potentially dire consequences if a paddle broke while canoeing. The same wood properties make yellow-cedar a desirable engineered wood 

product for bridges and other applications where strength is needed. The unique 

chemistry of yellow-cedar’s heartwood allows the tree to live for >1,000 yr and persist long after death as sequestered carbon and durable wood products. John Muir 

(1882: 192) summarized the species’ remarkable qualities in the following way:

The most important of Alaska trees measured by the value of its timber 

is the yellow cedar or cypress (Cupressus nutkatensis), a truly noble tree, 

attaining a height of 150 feet and a diameter of 3 to 5 feet. The wood of 

this tree is undoubtedly the best the country affords, and one of the most 

valuable to be found on the Pacific coast; it is pale yellow, close grained, 

tough, durable, and takes a good polish, and has a pleasant fragrance, like 

that of sandal wood. The durability of this timber is forcibly illustrated by 

the fallen trunks lying in the damp woods. Many of the largest of these last 

Section 1: Background on Yellow-Cedar
2

GENERAL TECHNICAL REPORT PNW-GTR-917

for centuries, retaining the delicate color and fragrance unimpaired. Soon 

after falling they become overgrown with moss, in which seeds lodge and 

germinate and grow up into vigorous saplings, and as these grow larger 

they stand astride the parent trunk, their roots stretching to the ground on 

either side, and when these have reached the age of several hundred years 

the down-trodden trunk, when cut into, will be found as fresh at the heart 

as when it fell.

Gifford Pinchot commented on yellow-cedar in a brief silvics guide (Pinchot 

1907) by saying that it had valuable, fine-grained, and exceedingly durable wood 

but that it was one of the least known tree species in western forests. Pinchot also 

mentioned that yellow-cedar grows in areas where temperature changes are gradual, 

the climate is especially mild and uniform, and winters are not severe. He continued 

by stating that the root system is shallow, but more so in wet situations than dry 

ones. These insightful observations are closely related to our current understanding 

of the factors that cause the widespread yellow-cedar mortality described in section 

2 of this report. 

Cultural Values

Yellow-cedar has both spiritual and practical significance to Native peoples in 

Alaska and British Columbia. There are uses for nearly every part of the tree, but it 

is the wood and bark of cedars that are extensively used. Alaska Natives and First 

Nations People of British Columbia have used the wood for canoe paddles, totem 

poles, chests, dishes, and tool handles (Turner 1979). Today, yellow-cedar continues 

to be an important wood for carving (fig. 1). The unusual similarity in density 

Figure 1—“The raven 

and the first men” carved 

by Bill Reid in 1980 and 

in the collection of the 

University of British 

Columbia Museum of 

Anthropology. Linda Stanfield 
3

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

between springwood and summerwood (the two parts of an annual growth ring) 

allows for especially smooth carved surfaces, whether these are for utilitarian or 

artistic purposes. 

The inner bark (phloem tissue) is an important source of fiber. After the outer 

bark is stripped and removed, the inner bark is sometimes soaked in saltwater and 

pounded, or often just dried, and then cut into thin strips. These strips are woven 

into mats, hats, or decorations for masks, or prepared with mountain goat wool and 

woven into blankets or clothing (Turner 1979). The inner bark has been known to 

be eaten (Petrof 1880). Where there is access to both western redcedar and yellowcedar, the bark is collected from each tree for specific types of weaving because of 

differences in bark texture between the species. 

Mature trees with bark sections removed are fairly common in southeast Alaska 

(fig. 2). These are called culturally modified trees (CMTs). Our own observations 

indicate that some CMTs appear to have had their bark removed long ago, whereas 

others have had their bark removed more recently. Bark stripping, once a common 

practice, was abandoned during most of the 1900s, and is now frequent again with 

a resurgence of interest in the cultural art of weaving. Cedar trees can survive long 

after having a section of their bark removed. The traditional practice is to remove 

only a fraction of the bole’s circumference, typically less than one-quarter or 

one-third, so as not to cause undue injury. Horizontal cuts are made at the bottom 

of the tree to initiate bark removal. Cuts are sometimes made to mark the top of the 

removed bark, but in other cases the bark is simply pulled from the bottom until the 

sheet breaks free from the top. 

Bark is collected in the spring, generally in May, when wood growth is occurring and the bark is more easily removed (i.e., “the bark slips”). Cedar trees have 

several defenses that limit internal wood decay, mainly caused by fungi, which 

would otherwise develop in the wood around these large wounds. The biologically active compounds in the heartwood greatly reduce fungal growth toward the 

middle of the tree. Surviving sapwood surrounding the wound also fills with these 

same compounds as an active response. The adjacent sapwood takes on rich colors 

similar to the heartwood, an indication that high concentrations of defensive compounds are present. These same biological responses have been reported in Alaska 

in yellow-cedars with lower-bole injuries caused by brown bears (Hennon et al. 

1990a). See “Wood properties and chemistry” for more information on the chemical 

defenses in cedar wood and foliage. 

Although yellow-cedar and western redcedar sometimes grow together, they 

have distinct distributions in coastal Alaska, with yellow-cedar extending farther 

north and westward around the Gulf of Alaska. Redcedar grows only as far north 
4

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 2—Culturally modified cedars with the bark removed, recently (left) and long ago (right).

as 57° N and has a preference for lower elevations; yellow-cedar is more common at 

middle and higher elevations in Alaska. The proximity and availability of yellowcedar and redcedar trees for cultural use vary throughout southeast Alaska due to 

differences in the species’ latitudinal and elevational distributions. Trees of both 

species may be available in southern southeast Alaska, yellow-cedar is the only 

cedar found to the north of the Petersburg and Kake area, and there are some places 

in coastal Alaska with no cedar present. Historically, where neither cedar species 

was accessible, bark acquired through trading, or spruce roots were used as an 

alternative source of fiber for weaving (Harris 1995).

Native people have a keen awareness of where yellow-cedar occurs on the landscape. The following Haida story, “The Legend of the Yellow Cedar” (Turner and 

Efrat 1992), indicates knowledge that yellow-cedar is abundant at mid-elevation, a 

fact later confirmed by analyzing forest inventory data. 
5

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Long ago, when the world was not as it is now, Raven, the great creator and 

trickster[,] came across three young women who were drying salmon on the 

beach. Ever hungry, the wily bird approached the women and asked. “Are 

you not afraid of bears?” And again they replied. “No.” Persistent, Raven 

asked if they were afraid of wolves, marten and various other creatures. 

Each time they answered no, until he mentioned owls, at which time the 

three women confessed their terrible fear of owls.

Raven went off and quickly hid himself in some nearby bushes, where he 

began making owl calls. Terrified, the women fled, running and running 

until they were halfway up the mountain. They stopped, finally, out of 

breath. Standing together on the mountainside, the three of them turned 

into yellow-cedar trees. That is why yellow-cedars are always found on 

high slopes and why they are so beautiful; their long graceful branches 

and silky inner bark resemble the women’s hair and their young trunks are 

smooth to the touch1

 [fig. 3].

Economic Values

Yellow-cedar has long been recognized as Alaska’s most economically valued tree 

species. As early as 1886, the species was documented as the most valuable timber 

“found on some of the islands in the Alexander Archipelago and in the neighborhood of Sitka, and frequently attains a height of one hundred feet, with diameter 

of five or six feet” (Bancroft 1886). Today, yellow-cedar continues to be the most 

valued of all tree species commercially harvested in Alaska (table 1). Figure 3—Three graceful yellow-cedar trees, a reminder 

of the legend on the origins of 

yellow-cedar. 

Table 1—Recent values for foreign market 

sales of old-growth logs, by commercial 

species in southeast Alaska

Species 

2012 value/1,000

board feeta

Yellow-cedar $974

Western redcedar $800

Sitka spruce $596

Western hemlock $540

a

 Values from USDA FS (2014).

1

 Story as told by Alice Paul in Hesquiat, reproduced with permission.
6

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 4—Vertical section of a small yellow-cedar tree. The 

name “yellow-cedar” comes from the distinctively colored yellow heartwood, which contrasts with the creamy white sapwood. 

The wood has many favorable characteristics that make it a high-valued 

commodity. It is fine textured, straight grained, easily workable, and moderately 

heavy, and has moderate strength, stiffness, hardness, and shock resistance (Forest Products Laboratory 1963, Harris 1984). The wood has a large sulfur-yellow 

heartwood core with a narrow band of sapwood (fig. 4). A combination of chemical 

extractives gives the wood its distinctive yellow color and aromatic odor, and, most 

importantly, makes the wood highly resistant to fungal decay and attack by marine 

borers, termites, and other insects (Forest Products Laboratory 1963, Harris 1984, 

Morales-Ramos et al. 2003). Bannan (1950, 1951) described the microscopic wood 

anatomy of yellow-cedar.
7

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Yellow-cedar wood has a variety of commercial uses that arise from its desirable traits, especially its durability, structural integrity, and resistance to rot. Ship 

and boat building with yellow-cedar has a history that dates back to the early 1800s. 

From 1804 to 1863, the Russian American Company operated a shipyard in 

Sitka, Alaska, and launched some 22 vessels made primarily from yellow-cedar 

(Andrews 1934). In today’s markets, yellow-cedar wood continues to be sought for 

the construction of canoes, racing shells, fishing boats, and yachts. 

Yellow-cedar is suitable for many types of standard construction, carpentry, 

joinery, and exterior applications (fig. 5), such as bridge and dock decking, patio 

decking, sill plates, door paneling, park benches, and play structures. The natural decay resistance of the wood means that it is seldom treated with chemical 

preservatives, so yellow-cedar is sought after for applications for which chemical 

treatment is undesirable. Donovan and Hesseln (2004) found that consumers were 

willing to pay twice as much for play structures made with yellow-cedar as for play 

structures made from wood treated with chemical preservatives. 

Yellow-cedar in Alaska was undervalued during much of the 20th century. Production and export volumes increased in about 1970 (Hutchison and LaBau 1975: 

fig. 13). Before the 1970s, yellow-cedar values were low because they were based 

on sawn values. In 1969, both yellow-cedar and western redcedar were declared 

Figure 5—Bus stop shelter in Ketchikan, Alaska made from yellow-cedar. 
8

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 6—Export log selling value (unadjusted for inflation) of yellow-cedar in Alaska from 1980 to 

2012, courtesy of Inga Petaisto, U.S. Forest Service, Alaska Region. 

surplus to Alaska domestic manufacturing needs and both were freely exportable 

from federal lands. In 1976, western redcedar was no longer surplus and could be 

exported only if the Alaska sawmills did not need it (e.g., poor sawn lumber markets due to low U.S. housing construction). Yellow-cedar has continued to remain 

surplus (i.e., uneconomical to saw) and since 1999, the Alaska Region’s appraisal 

system has appraised yellow-cedar as export (fig. 6). 

Asian markets, especially Japan, pay premium prices for yellow-cedar lumber. 

Most high-quality yellow-cedar logs are exported to Japan. The wood is also a 

popular material for dimensional lumber; glue-laminated beams; and rough, green 

or planed lumber for shoji manufacturing (Gaston and Eastin 2010). The light 

yellow color and pleasant aroma of yellow-cedar are comparable to the relatively 

unavailable hinoki cypress, native to Japan, where yellow-cedar is used as an 

alternative for specialty construction of marinas, temples, and shrines. 

Ecological Values

The most notable traits of yellow-cedar trees are their longevity and unique chemistry; these characteristics influence stand structure and nutrient cycling in forests 

that contain yellow-cedar. Forests of the northern Pacific Northwest coast have 
9

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

relatively limited coniferous species diversity. There are six main tree species that 

coexist in forested areas of southeast Alaska: Sitka spruce, mountain hemlock, 

western hemlock, western redcedar, shore pine, and yellow-cedar. Yellow-cedar is 

not as common on some landforms, such as alluvial terraces and recently deglaciated, early-seral environments. Yellow-cedar frequently grows in wet forests, but 

can also occur in comparatively drier mixed-conifer forests. 

Yellow-cedar is typified by its longevity; once established, it represents an 

important long-term component of structure and diversity in forested stands (Capp 

et al. 1992, McClellan 2004). On average, yellow-cedar lives for about 500 to 750 

yr (Laroque and Smith 1999), nearly twice as long as the spruce and hemlock trees 

that dominate most forest stands of southeast Alaska. In addition, many yellowcedar trees die standing and persist as snags for 80 to 100 yr after death (Hennon 

et al. 1990b), providing structural diversity in mixed-species stands. The presence 

of yellow-cedar mixed with other conifers in a stand can be viewed as a two-tiered 

woody debris system: spruce and hemlock provide downed woody debris and logs 

in various stages of decay, while yellow-cedar provides standing, relatively undecayed snags. This heterogeneity adds diversity for species of wildlife that occupy 

different strata in the forest. Cedar snags leave areas of forest floor open to light, 

but unfettered with decaying wood, creating space for forbs to flourish. 

Yellow-cedar also provides a unique chemical signature in forests due to the 

sequestration of abundant calcium in foliage (D’Amore et al. 2009, Kranabetter et al. 2003). The store of calcium is transferred to the forest floor during leaf 

senescence (Alban 1969), altering the chemical balance and microorganism communities in the soil (Turner and Franz 1985). Soil and litter layers in yellow-cedar 

stands tend toward bacterial communities rather than fungal communities, which 

diversifies the ecosystem at a very fine scale. The nutrient diversity also creates 

the potential for niche complementarity. This is the process where plants coexist by 

using different nutrient pools and occupying smaller spaces based on their relative 

competitive ability (McKane et al. 2002).

The populations of yellow-cedar in Prince William Sound add species diversity 

to an ecosystem with few tree species. The yellow-cedar populations there are 

generally small and fragmented, and are thought to have originated from different 

glacial refugia than populations farther to the southeast. Yellow-cedar forests in 

Prince William Sound appear healthy and are regenerating well, probably because 

heavy annual snow accumulation protects yellow-cedar roots from freezing and 

seedlings from being consumed by deer. Deer were introduced to Prince William 

Sound, but are locally scarce. Permanent plots installed on Hawkins Island and 

western Prince William Sound document the growth, regeneration, age structure, 
10

GENERAL TECHNICAL REPORT PNW-GTR-917

and community relationships in these yellow-cedar forests (Hennon and Trummer 2001). Yellow-cedar trees show rapid growth on these plots; they tend to 

be larger and younger than co-occurring Sitka spruce, western hemlock, and 

mountain hemlock. This is in marked contrast to conditions in southeast Alaska, 

where yellow-cedar can be a slow-growing tree. It is not known if the full crowns 

and vigorous growth (fig. 7) are due to a favorable climate (e.g., heavy snow that 

promotes yellow-cedar and slows the growth of other tree species) or genetic factors. Research has not yet detected genetic differences between the Prince William 

Sound populations of yellow-cedar and those that are farther south (see “Genetics,” 

this section). It is possible that yellow-cedars from Prince William Sound possess 

the trait of rapid growth, however, and this hypothesis could be tested in any future 

common garden trials. Common garden studies help determine which characteristics are under genetic control by growing seedlings from different seedlots in 

similar environments.

Figure 7—Vigorous, full-crowned 

yellow-cedar in Prince William Sound, 

Alaska.
11

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

General Information on Yellow-Cedar

Taxonomy and Scientific Names

Yellow-cedar is a member of the Cupressaceae, the cypress family of conifers that 

includes junipers, cypresses, and false-cedars, which are found in many parts of the 

world. This family of trees and shrubs is both large and ancient. Almost all species 

in the Cupressaceae have small, scalelike foliage, and lack distinct buds enclosed 

by bud scales (Hultén 1968, Owens and Molder 1984). Other fairly close relatives 

such as redwoods and yews once placed in the Taxodiaceae have been merged into 

a larger family of Cupressaceae based on genetic similarities (Gadek et al. 2000).

There are three abundant Cupressaceae species in Alaska: yellow-cedar, 

western redcedar (Thuja plicata Donn), and common juniper (Juniperus communis

L.) (Viereck and Little 2007). A fourth species, creeping juniper (J. horizontalis

Moench), has a limited range around the Wrangell Mountains. Of these species, the 

junipers generally have a low-growing or shrublike form; only yellow-cedar and 

western redcedar attain a tree form. 

Botanists have had substantial interest in the phylogeny and taxonomy of 

the Cupressaceae due to the antiquity of the family, and its unusual geographic 

distribution, which is an outcome of the breakup of the Pangean supercontinent 

into Laurasia and Gondwana nearly 150 million yr ago (Mao et al. 2012, Yang et 

al. 2012). Historically, yellow-cedar was first described by the botanist David Don 

as a member of the genus Cupressus, but later classifications transferred the taxon 

to the genus Chamaecyparis (Spach 1842) and Callitropsis (Oersted 1864). Recent 

attention to yellow-cedar’s taxonomic status and scientific name intensified with 

the discovery of a new cypress in northern Vietnam, golden Vietnamese cypress 

(Xanthocyparis vietnamensis Farjon & Hiep) (Farjon et al. 2002). Based on morphology and genetics, yellow-cedar and the newly discovered tree are considered 

to be closely related and possibly belong to the same genus (Farjon et al. 2002). A 

recommendation was made for yellow-cedar to join the Vietnamese tree as the only 

other member of this genus, and for the scientific name of yellow-cedar to change 

to Xanthocyparis nootkatensis Farjon & Hiep. In 2004, Damon Little contended 

that an older name for yellow-cedar, Callitropsis nootkatensis (D. Don) Örest., be 

used, and that the two species should reside in the genus Callitropsis (Little et al. 

2004). A debate ensued in the literature about the validity of the older genus name 

Callitropsis, which would ordinarily take precedence following botanical rules of 

nomenclature. Farjon asserted that this name was published in an obscure source 

in the 1800s, and the newer genus name Xanthocyparis should be used (Mill and 

Farjon 2006). The situation was finally resolved in the summer of 2011 at the International Botanical Congress in Australia, where the proposal to use Xanthocyparis 
12

GENERAL TECHNICAL REPORT PNW-GTR-917

was not brought to committee, leaving Callitropsis as the accepted genus (personal 

communication, Damon Little, New York Botanical Gardens, 2013). 

It is worth noting that there is growing awareness that species in the genera 

Xanthocyparis, Callitropsis, and western North American Cupressus (e.g., Baker 

cypress and Monterey cypress) all share a common lineage, and may trace to a 

common ancestor that dates to 30–50 million yr ago (Adams et al. 2009, Little 

2006), a time of expansive radiation for many conifer lineages (Leslie et al. 2012, 

Mao et al. 2010, Willyard et al. 2007). These species show similar traits in leaf 

dimorphism, seed and cone morphology, and the age of cone maturation, and 

researchers continue to discuss revising these groups to reflect their common 

ancestry. At present, the names Cupressus and Hesperocyparis are both being used 

to describe this group; one of these names may replace Callitropsis in the future. 

For now, we use the genus name Callitropsis, and follow the currently accepted 

scientific name for yellow-cedar as Callitropsis nootkatensis (D. Don) D.P. Little. 

Native Names and Common Names

The scientific name for yellow-cedar is not the only naming controversy. There is 

also uncertainty about the spelling of Native American names and disagreement 

about which common names to use for this tree species. With assistance from ethnobotanist Nancy Turner (University of Victoria, Victoria, BC) and review by local 

elders in Alaska facilitated by Lillian Petershoare (U.S. Forest Service, Juneau, 

Alaska), we compiled the names for yellow-cedar and western redcedar used by 

Native people in Alaska. Because these were historically unwritten languages, we 

encountered multiple spellings for several of these words, but found general agreement with those in table 2. 

Table 2—Alaska Native names for western 

redcedar and yellow-cedar

Tribe Western redcedar Yellow-cedar

Tlingit laax xáay

Haida ts’úu sgahláan

Tsimshian smgán walh
13

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

A number of other common names (e.g., Nootka cypress, canoe-cedar) applied 

to the tree that we call yellow-cedar. The commonly used names draw on various combinations of “Alaska” or “yellow,” followed by “cedar” or, in some cases, 

“cypress.” “Alaska-cedar” is the common name accepted by the U.S. Forest Service 

(Little 1979). Our Canadian colleagues disagree with this name and do not use it. 

Note that the species was first discovered by Archibald Menzies on the Vancouver 

expedition in British Columbia and named for the Nootka Sound area (hence 

“nootkatensis”) of western Vancouver Island. The greater acreage and volume of 

this tree exist in British Columbia, not Alaska, supporting Canadians’ objection to 

the use of names such as Alaska-cedar or Alaska yellow-cedar. The word “yellow” 

is a descriptive reference to the distinctive color of the heartwood.

Because this species is not taxonomically a true cedar, there is a convention that 

a hyphen must be used with the word “cedar,” as in yellow-cedar. True cedars are in 

the pine family (Pinaceae) and are represented by Old World species with needles 

in the genus Cedrus (e.g., deodar cedar). Use of the hyphen follows the same logic 

as with Douglas-fir, which is not a true fir.

“Yellow-cedar” and “yellow cypress,” or sometimes just “cypress,” are used in 

Canada. We use the name “yellow-cedar” in this document because of its historical 

use; however, especially in light of new phylogenetic analysis that links yellowcedar and the New World cypresses (Little 2006), “yellow cypress” would probably 

be a suitable common name, as would “Nootka cypress” to honor the location of its 

discovery. 

Yellow-Cedar Distribution

Nearly every form of resource management relies on an accurate account of the spatial distribution of important species. Modeling the likely responses of forest species 

to climate change (i.e., bioclimatic envelopes or geographic shifts in potential habitat) 

or to disease, insect, or abiotic factors requires a complete species distribution map. 

Until recently, only a coarse range map (fig. 8) was available for yellow-cedar. This 

is surprising given the importance and value of this species. Yellow-cedar is known 

to occur from the northern tip of California (Griffin and Critchfield 1972), through 

the Siskiyou and Cascade Mountains in Oregon and Washington, and north into 

coastal areas of British Columbia and Alaska to Prince William Sound (Little 1971). 

Two well-known small, disjunct populations of yellow-cedar occur farther east in the 

Aldrich Mountains of Oregon (Frenkel 1974) and near Slocan Lake and Evans Lake, 

north of Nelson in interior British Columbia (Perry 1954). 
14

GENERAL TECHNICAL REPORT PNW-GTR-917

Higher resolution distribution maps or geographic information systems (GIS) 

layers are now available for yellow-cedar. These are derived from a combination 

of species distribution models and direct observation during surveys from aircraft 

or boats. In the following pages we describe these sources of information below, 

and we integrate them into a new, improved rangewide distribution layer (fig. 9) 

intended to replace the Little (1972) map. This layer covers area from 41 to 61° 

latitude and is based on a 240 m × 240 m (800 ft × 800 ft) pixel size. This is a 

distribution GIS layer (or map) and does not necessarily display the locations where 

yellow-cedar would be considered the dominant species. Section 4 of this report 

discusses differences between occurrence and cover type maps. 

Figure 8—The Little Atlas distribution for yellow-cedar (Little 1972). Projection is North 

American Albers.
15

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 9—New yellow-cedar range map. Projection is North American Albers.

California— 

Several small populations in northern California were mapped and discussed briefly 

by Griffin and Critchfield (1972). These are an extension of nearby populations in 

the Siskiyou Mountains of southern Oregon. We created small polygons for each of 

the California populations (fig. 10) in our new composite rangewide layer. 

Oregon and Washington— 

In Oregon and Washington, yellow-cedar is most common in the Pacific silver fir 

and mountain hemlock zones, growing at higher elevations approaching timberline, 

especially in open-canopy forests near meadows, streams, or avalanche chutes. The 

ecology of yellow-cedar in the Cascade and Siskiyou Mountains is well documented 

by Antos and Zobel (1986).
16

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 10—Occurrence of yellow-cedar (yellow shading) in California, Oregon, and Washington. 

This map was derived from specific locations in California given by Griffin and Critchfield (1972) 

and using a layer created by nearest neighbor imputation (Ohmann and Gregory 2002) that we 

modified. Ground observations of yellow-cedar by Murray (a subset of these were reported by 

Murray (2010)) are shown as dots and were independent from these sources.
17

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

The distribution of yellow-cedar in Oregon and Washington (fig. 10) has been 

predicted at a fine scale through a modeling process known as nearest ecological neighbor imputation (Ohmann and Gregory 2002). This technique integrates 

presence/absence data from forest inventory plots with many landscape, climate, 

and remotely sensed values to display a predicted species occurrence. It was necessary to remove some suspicious modeled locations for yellow-cedar in southwest 

Oregon. To verify this decision, we consulted with Mike Simpson (U.S. Forest 

Service, Bend, OR), who checked inventory data for the occurrence of yellow-cedar 

and found it to be absent from southwest Oregon and from portions of northwest 

Oregon where Little (1971) had shown it to occur. We then added the known location of yellow-cedar near Mount Aldrich in eastern Oregon (Frenkel 1974). Figure 

10 shows the yellow-cedar locations documented on the ground (Murray 2010).

British Columbia— 

Yellow-cedar is more widespread and abundant in British Columbia than in parts 

of its range farther south, where it is an important timber resource and is highly 

valued by First Nations people. The known distribution of yellow-cedar in British 

Columbia (fig. 11) was provided by Todd Davis (British Columbia Ministry of 

Forests, Lands and Natural Resource Operations, Nanaimo, B.C.). We consulted 

with Stefan Zeglen (British Columbia Ministry of Forests, Lands and Natural 

Resource Operations, Nanaimo, B.C.), who supported deleting from the model 

several populations outside of the range that were mapped in error, or that represented locations where yellow-cedar was artificially planted. The British Columbia 

yellow-cedar model was created primarily by photo interpretation, but also includes 

inputs such as stereograms, ground calibration points, ecological site descriptions, 

and local knowledge. These interpretations are tempered by knowledge of species 

heights, crown shapes, and other factors. Pat Martin (British Columbia Ministry of 

Forests, Lands and Natural Resource Operations), provided details about development of this model; more information can be found at http://www.for.gov.bc.ca/hts/

vri/standards/photo.html. 

In British Columbia, yellow-cedar commonly occurs in the windward portions 

of high-elevation Mountain Hemlock (MHmm1 and MHwh1) subzones. It is also 

widely distributed throughout the Coastal Western Hemlock zone at low elevations 

in the Very Wet Hypermaritime (CWHvh2) and Very Wet Maritime (CWHvm1) 

subzones, and at higher elevations in the CWHvm2 subzone (Klinka et al. 2000, 

Pojar et al. 1987). These areas encompass much of the outer coast of British Columbia, including the Queen Charlotte Islands, the western side of the Coast Mountains, and the Hecate Strait. Yellow-cedar can be found down to sea level north of 

Knight Inlet (Whitford and Craig 1918). The unusual populations in eastern British 
18

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 11—Distribution of yellow-cedar in British Columbia, produced by the Ministry of Forests, 

Lands and Natural Resource Operations in British Columbia. The projection is Canada Albers Equal 

Area Conic.
19

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Columbia near Slocan Lake and Evans Lake are disjunct from the main range to 

the west (Perry 1954). There is an unconfirmed third small population in eastern 

British Columbia near Trout Lake.

Alaska— 

In Alaska, the broad range map by Little (1971) has been the main source of distribution information for yellow-cedar. The map scale is too coarse for forest planning 

uses and it is known to contain inaccuracies. Beyond the Little map, forest type and 

plant association GIS layers and maps (e.g., timber classification cover type) were 

developed for the panhandle of Alaska, especially for the Tongass National Forest, 

but are incomplete for yellow-cedar because they exclude some forest types and 

plant communities in which yellow-cedar is present but not the dominant species. 

Also, because these layers and maps were derived from aerial photograph interpretations, difficulties in distinguishing yellow-cedar in mixed-species stands led to 

products that could not reliably display yellow-cedar occurrence. 

An interim yellow-cedar occurrence layer and map for southeast Alaska was 

produced by Dustin Wittwer, who used presence/absence data from U.S. Forest Service, Forest Inventory and Analysis (FIA) forest inventory plots and some Tongass 

National Forest inventory plots. Groups of watersheds that contained yellow-cedar 

in forest inventory plots were displayed as containing yellow-cedar. This map 

provided the context for a coarse map of yellow-cedar distribution that was needed 

to determine the portion of yellow-cedar’s range affected by yellow-cedar decline 

(e.g., see Hennon et al. 2006). 

The Forest Service’s Forest Health Technology Enterprise Team in Fort Collins, 

Colorado, has created species distribution layers and maps for important tree species in the United States as an initial step in predicting insect and disease risk over 

the next 15 yr (USDA FS 2014). These “host” maps represent the most advanced 

tree distribution maps in Alaska. The layers are derived from landscape, site, and 

climate variables correlated with presence or absence of the host tree species in 

inventory plots. The remote sensing inputs (i.e., reflectance values) allow for the 

production of high-resolution (30-m [100-ft] pixel) forest parameter GIS raster surface layers, including presence, basal area (BA), and stand density index (SDI). The 

chief remote sensing analyst producing these maps is Jim Ellenwood, so we call this 

the Ellenwood layer (fig. 12). Ellenwood (2015) produced aggregated companion 

data for broad-scale applications at a resolution of 240 m. From the 240-m resolution layers, we produced an index representing yellow-cedar BA as the percentage 

of the total BA, and used all pixels >1 percent yellow-cedar to represent the entire 

distribution of yellow-cedar in southeast Alaska (Krist et al. 2014).
20

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 12—Distribution of yellow-cedar in southeast Alaska, derived from the “Ellenwood” forest 

parameter models for most of the panhandle and aerial surveys for Glacier Bay National Park. See 

text. Projection is Alaska state plane.
21

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

The 2012 tree species parameter data or Ellenwood tree species layers were 

derived from statistical models. The modeling technique used data mining software and ancillary geospatial data to build the statistical relationships to predict 

occurrence and location of individual tree species and associated density metrics, 

BA, and SDI. Existing national datasets were used where available, including the 

National Land Cover Database (NLCD); the state Soil Survey Geographic Database 

(STATSGO2) of the USDA Natural Resources Conservation Service (NRCS); FIA 

forest inventory; the National Elevation Dataset of the Department of the Interior, 

U.S. Geological Survey; and the National Oceanic and Atmospheric Administration’s National Climatic Data Center U.S. normal data (Krist et al. 2014). 

Climate data in southeast Alaska were derived from Rehfeldt’s original spline 

models for western North America. Forest Inventory and Analysis data were 

extracted from FIADB version 4.0 (Woudenberg et al. 2010) for plot and tree data. 

Plot data were limited to those that closely aligned with the imagery dates and 

used live tree data ≥5 in diameter at breast height (d.b.h.) on the main plots, and <5 

in, but >1 in d.b.h. on the nested subplots. Coastal Alaska inventories were from a 

10-yr annualized scheme and were collected from 2004 through 2009. Imagery data 

from coastal Alaska were collected in early and late summer from 1994 through 

2006 (Krist et al. 2014).

Tree species’ presence/absence, BA, and SDI were constructed from the predictor layers listed above by using a classification regression tree modeling method. 

Subsequently, the presence/absence of the total BA >1 in d.b.h. was modeled by 

using See5TM version 2.062. These results represent the forested or “treed” area and 

are shown as the forested area in appendix 1 tables (Krist et al. 2014). 

The outputs were then adjusted to ensure the sum of the individual species’ 

density metric at each location did not exceed a separately modeled total for all species. Because the vintage of the Landsat satellite imagery used was roughly 2002, 

growth and mortality adjustments were applied to account for growth from 2002 

through 2012. In Alaska, only burned areas were adjusted for growth and mortality; 

therefore, little to no adjustment was applied in southeast Alaska and on the yellowcedar layer (Krist et al. 2014). 

For yellow-cedar populations in Prince William Sound and extending down 

through Glacier Bay National Park, other mapping efforts were used rather than 

the Ellenwood method. For Prince William Sound, too few inventory plots with 

2

 The use of trade or firm names in this publication is for reader information and does not 

imply endorsement by the U.S. Department of Agriculture of any product or service.
22

GENERAL TECHNICAL REPORT PNW-GTR-917

yellow-cedar were available. In Glacier Bay, a specific field mapping mission was 

conducted to delineate yellow-cedar distribution. Mapping in these two locations 

will be discussed further in the following pages. 

The Ellenwood yellow-cedar layer reveals the broad-scale pattern in southeast 

Alaska that we have described previously (e.g., Hennon 2012); that is, the tree is 

well distributed in most areas of the panhandle, except to the northeast around 

Hoonah, Admiralty Island, the Juneau area, and Lynn Canal. Yellow-cedar occurs 

sparsely in these areas, but is absent or rare over large portions of the landscape that 

appear to represent suitable habitat. We hypothesize that this incomplete colonization can be attributed to the past and current yellow-cedar migration from the outer 

coastal Pleistocene refugia towards the northeast (see “Paleoecology,” this section). The rarity of yellow-cedar in the Juneau area may indicate that yellow-cedar 

is just now arriving via this easterly or northeasterly migration. We have found 

several locations with very small populations, including one lone yellow-cedar tree 

on Douglas Island. The unique stand of yellow-cedar near Haines found by Roy 

Josephson (Alaska Department of Natural Resources, Haines, Alaska), may be an 

example of a founder population that is ahead of the main migration. Josephson 

estimates the size of this small population to be 30 ac. 

There is also new knowledge of yellow-cedar’s occurrence by elevation in 

southeast Alaska that comes from analysis of forest inventory plot data. This project 

was begun by the late John Caouette (The Nature Conservancy, Juneau, Alaska). 

Yellow-cedar was found to have peak abundance at mid-elevations, whereas 

western redcedar was more common at lower elevations and mountain hemlock 

preferred higher elevations (Caouette et al. 2016). These patterns can be observed 

from analysis of all available plot inventories, but only results from FIA analysis 

in the lower and upper panhandle of Alaska are shown here (fig. 13). By combining all plots where yellow-cedar occurred in southeast Alaska, Jovan (2011) found 

live yellow-cedar to have a mean elevation of 973 ft (standard error, 109 ft). Only 

mountain hemlock had a higher mean elevation in the region.

These patterns of occurrence are shifted to relatively lower elevations with 

increasing latitude (moving north). Soil hydrology is also known to modify the elevation at which species occur, especially those found at middle and high elevations, such 

as yellow-cedar and mountain hemlock, respectively. These species are competitive at 

lower elevations in the marginal environment of saturated peatland soils. 

The distribution of yellow-cedar in Glacier Bay National Park has been a gap 

in our knowledge. With few reported observations and inventory plots, Little (1971) 

did not know how to portray this portion of the range. This is an important area, as 

it marks the northwest extent of the main yellow-cedar range in southeast Alaska. 
23

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 13—Percent presence of yellow-cedar and associated tree species by elevation classes in 

the southeast (lower panhandle) and middle (upper panhandle) regions of coastal Alaska. Modified 

from Caouette et al. 2016. TSME=mountain hemlock, PISI=Sitka spruce, CANO=yellow-cedar, 

PICO=shore pine, THPL=western redcedar, and TSHE=western hemlock.

A photograph from 1918 shows William Weigle, U.S. Forest Service forest supervisor in Alaska, in a stand of yellow-cedar trees near Lituya Bay (fig. 14). 

Although difficult, it is possible to distinguish yellow-cedar from co-occurring 

tree species during aerial surveys. In June 2012, we attempted to map the entire 

distribution of yellow-cedar in Glacier Bay National Park, where a relatively narrow 
24

GENERAL TECHNICAL REPORT PNW-GTR-917

forested strip is wedged between large mountains and the ocean. A 200-m (700-ft) 

point grid, derived from polygons collected during the aerial surveys, was used to 

produce the presence/absence layer. The output was linked to existing and continuous conifer vegetation classes (Boggs et al. 2008) to improve polygon boundaries 

and to exclude locations where yellow-cedar would be very unlikely to occur, but 

was also constrained by the distance from the survey flight line. Greg Streveler, 

an ecologist from Gustavus, Alaska, with extensive knowledge of the vegetation 

at Glacier Bay, examined our map for accuracy. We made several changes and 

remapped portions of the park in July 2012 based on his advice. The final map from 

these surveys is shown in figure 15. Yellow-cedar does not grow in the central portion of Glacier Bay, where extensive even-aged Sitka spruce forests have colonized 

as glaciers receded from their maximum advances in the Little Ice Age. Yellowcedar is rare on the older forested wetland benches below Excursion Ridge in the 

eastern portion of the park (not shown in figure 15). Some of these trees were used 

in a recent dendrochronology study of yellow-cedar (Wiles et al. 2012). This large 

forested wetland complex is another example of suitable habitat that is not widely 

colonized by yellow-cedar, probably because of incomplete migration. 

Figure 14—Photograph taken in 1918 showing William Weigle (forest supervisor in Alaska) and 

yellow-cedar trees. The back of the photo has the inscription, “in the vicinity of Lituya Bay,” a 

location which is now part of Glacier Bay National Park, Alaska.
25

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 15—Occurrence of yellow-cedar in Glacier Bay National Park, Alaska. 

Yellow-cedar is abundant along the west coast of Glacier Bay extending to an 

area just northwest of Cape Fairweather (fig. 15). We searched for and did not detect 

yellow-cedar along the coast as far as the southeastern portion of Icy Bay. Except 

for the population west of Icy Bay (see below), we believe yellow-cedar is absent 

from the Cape Fairweather area to about 300 mi along the outer coast near the 

Cordova-Hawkins Island area, which marks the beginning of the Prince William 

Sound populations. Another exception is the trial planting of yellow-cedar by the 

U.S. Forest Service near Yakutat established in 2009. 

Joel Nudelman (personal communication, Alaska Department of Natural 

Resources, Juneau, 2013) discovered another small population of yellow-cedar near 

Icy Bay just west of Lawrence Creek (60.03335° N, 142.05346° W). Icy Bay is in the 

large expanse between Glacier Bay and Prince William Sound with no previously 

documented yellow-cedar. The stand was harvested in 2002, and it is not clear if any 

yellow-cedar seedlings might be present among the natural regeneration growing 

after the harvest. In 2014, Josephson (personal communication, 2014) observed live 

yellow-cedar trees (60.004951° N, 141.731458° W) just east of Big Sandy Creek and 

west of Priest River in a natural stand upslope from a harvested area. He saw numerous yellow-cedar trees with 20- to 24-in diameters. These two areas are separated by 
26

GENERAL TECHNICAL REPORT PNW-GTR-917

about 11 mi of harvested areas in the lowlands and intact hillside forests. It would be 

worthwhile to visit this part of Icy Bay to search for other yellow-cedar populations 

and determine their size, health status, and genetic and age structure, as well as to 

examine the harvested units for yellow-cedar stumps and yellow-cedar regeneration. 

Sudworth (1908) mentioned yellow-cedar occurrence near Icy Cape, but he may have 

been referring to Icy Point near Palma Bay in Glacier Bay (where yellow-cedar is 

common) because he indicated that it was just north of Cross Sound.

The occurrence of yellow-cedar in Prince William Sound has been described 

as a phytogeographical problem (Cooper 1942) because the origins of these populations are unclear owing to their considerable geographic isolation from the more 

contiguous range farther south. Botanical texts and other literature have given 

conflicting accounts of where yellow-cedar grows in Prince William Sound. Hennon and Trummer (2001) outlined the history of these reports. 

The combination of boat surveys and local knowledge of yellow-cedar is 

believed to have captured nearly all of the distribution of the species in Prince William Sound (Hennon and Trummer 2001), where we now know there are two main 

populations (fig. 16). The smaller eastern yellow-cedar population near Cordova 

includes stands at Windy Bay and Mud Bay on Hawkins Island; Point Gravina, 

Bomb Point, and Alice Cove on the mainland; and Yelper Cove on Hinchinbrook 

Island. We have not confirmed the presence of yellow-cedar at Cedar Bay on 

Hawkins Island. This location is not to be confused with Cedar Bay mentioned 

below (fig. 16). Yellow-cedar is not known to occur between this eastern population 

and the larger western population that begins on Glacier Island about 40 mi to the 

northwest. Yellow-cedar is common on the western portion of Glacier Island and 

continues, in patches, from Eickelberg Bay around to Granite Bay. The largest, most 

contiguous yellow-cedar forest in this population occurs in Cedar Bay from sea 

level to near timberline. Yellow-cedar stands are also common in Wells Bay and in 

small patches along both sides of the peninsula on the east side of Unakwik Inlet. A 

large stand (about 100 ac), and some smaller scattered stands at Winter Anchorage, 

mark the western extent of yellow-cedar’s natural range (147.5472° W). Populations 

along the eastern arm of Wells Bay represent the northernmost extent of yellowcedar (61.0136° N), but several trees just north of Winter Anchorage extend almost 

as far north. 

The locations of yellow-cedar occurrence in Prince William Sound suggest 

a different historical origin for these populations, possibly on Hinchinbrook and 

Montague Islands, which may have been ice-free during parts of the Pleistocene 

and served as refugia (Lance and Cook 1998). Yellow-cedar may have more distant 

origins, perhaps being transported by Alaska Natives or by tsunamis to these areas. 
27

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 16—General location of the two populations of yellow-cedar in Prince William Sound, and closer views of these populations 

around the Cordova-Hawkins Island area of the eastern sound and the Cedar Bay-Unakwik Inlet area of the western sound. Projection 

is Alaska Albers NAD83.

The phytogeographical problem of yellow-cedar in Prince William Sound considered by Cooper (1942) remains unresolved.

Section 4 of this report describes the development of a GIS layer and map for 

the distribution of yellow-cedar in Alaska through the integration of the sources of 

information presented above. The yellow-cedar layer serves as the foundation for 

distinguishing current and future suitable and unsuitable habitat by overlaying risk 

factors for yellow-cedar decline. 

Tree Morphology

Yellow-cedar is a long-lived medium-sized tree that usually ranges from 66 to 115 ft 

tall at maturity. Heights of 170 ft and diameters of 6.6 ft have been reported (Owens 
28

GENERAL TECHNICAL REPORT PNW-GTR-917

Table 3—Strength values for yellow-cedar wood (Forest 

Products Laboratory 1987)

Wood property Green wood Dry wood

Specific gravity 0.42 0.44

Modulus of rupture (lbs/in2

) 6,400 11,100

Modulus of elasticity (million lbs/in2

) 1.14 1.42

Work to max load (in-lb/in3

) 9.2 10.4

and Molder 1984). Trees have drooping, loosely hanging branches and a narrow, 

conical crown. The grayish-brown bark of young trees is thin and scaly, and the 

silvery bark of mature trees is fibrous and leathery, composed of narrow, intersecting ridges (fig. 17). For unknown reasons, some mature yellow-cedar trees retain 

the smooth brownish bark of young trees. The bark of yellow-cedar contains resin 

ducts (fig. 18), another trait that can be used to distinguish it from western redcedar, 

which lacks this feature. 

Wood Properties and Chemistry

Yellow-cedar, named for its yellow heartwood, is known for its extraordinary 

strength and decay resistance. These properties make it ideal for building in the 

outdoor environment, and more information on wood uses can be found under 

“Economic Values.” The heartwood is considered moderately heavy, hard, strong, 

and stiff, and it has moderately high resistance to shock (Forest Products Laboratory 1987) (table 3). The sapwood is narrow, with a creamy-white color, making it 

easily distinguished from the yellow heartwood. 

Perry (1954) documents wood properties for yellow-cedar in British Columbia. 

These species-wide values were recently updated for yellow-cedar growing in 

Alaska in tests at the Ketchikan Wood Technology Center (Bannister et al. 2007). 

This was an effort to separate wood strength values of yellow-cedar in Alaska from 

values reported elsewhere for the species and also from other western cedars. The 

authors concluded that yellow-cedar in Alaska has uniquely strong wood relative to 

other cedar species for engineering design purposes. The Western Wood Products 

Association recognizes yellow-cedar grown in Alaska as a separate grade mark 

known as Alaska Yellow Cedar, with wood property values reported for different 

yellow-cedar lumber grades from select structural to stud (Western Wood Products 

Association 2005). 
29

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 17—Silvery gray bark common on mature yellow-cedar trees. 
30

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 18—Old resin ducts (white vertical tissue) in the bark of yellow-cedar. 

Resin ducts are active when they occur in phloem tissue, before being incorporated 

into the outer bark as in this picture. The presence of resin ducts in bark can be 

used to distinguish the two cedars in Alaska because western redcedar lacks them 

in the outer bark. 

Yellow-cedar heartwood is known for its bright-yellow color, pleasant aroma, 

and exceptional decay resistance. These characteristics are derived directly from 

its biochemical composition. The heartwood contains phenolic compounds with 

antimicrobial and antifungal properties that afford protection from fungi, insects, 

and other organisms (Barton 1976) (fig. 19). The high concentration of heartwood 

defense compounds is an adaptation that allows yellow-cedar trees to survive for 

>1,000 yr, far exceeding the longevity of most associated tree species. A yellowcedar tree near Campbell River, B.C., was documented to be 1,600 yr old (Jozsa 

1991), and yellow-cedar may reach 3,500 yr of age (Owens and Molder 1984). We 
31

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 19—Chemical structure of several important compounds in the heartwood of 

yellow-cedar. 

are unaware of any attempts to document the oldest yellow-cedar in Alaska. Some 

specialized stain and decay fungi are able to invade the heartwood of live yellowcedar trees (De Groot et al. 1999, Hennon 1990). Colonization by stain fungi leads 

to reduced concentrations of defense compounds in yellow-cedar wood, making 

it vulnerable to further degradation by fungi and insects (Morales-Ramos et al. 

2003). Unlike its heartwood, yellow-cedar sapwood contains lower concentrations 

of defense compounds and is not resistant to decay once the tree is dead because 

compounds from the heartwood cannot be mobilized to the sapwood. 

Extractable bioactive compounds of yellow-cedar heartwood include alaskene, 

carvacrol, chamic acid, chaminic acid, chanootin, isochamic acid, nootkatene, 

nootkatin, nootkatone, valerianol, and vetivone (Barton 1976). Table 4 lists many of 
32

GENERAL TECHNICAL REPORT PNW-GTR-917

Table 4—Known heartwood constituents of yellow-cedar

Compound Identification, conformation, synthesis, or assay

Alaskene Marx and Norman (1973)

Carvacrol Carlsson et al. (1952), Erdtman (1952), Kelsey et al. (2005), Voda et al. 

(2003)

Chamic acida Carlsson et al. (1952), Erdtman (1955), Erdtman et al. (1956), Gensler 

and Soloman (1973), Norin (1964), Norin et al. (1982), Rennerfelt and 

Nacht (1955)

Chaminic acid Erdtman (1955), Erdtman et al. (1956), Norin et al. (1982)

Chanootin Karlsson et al. (1973), Norin (1964)

Isochamic acid Norin (1964)

Nootkatene Erdtman and Topliss (1957), Kelsey et al. (2005)

Nootkatinb Aulin-Erdman (1950), Campbell and Robertson (1952), Carlsson et al. 

(1952), Duff and Erdtman (1954), Duff et al. (1954), Erdtman and 

Harvey (1952), Johnson and Cserjesi (1975)

Nootkatol Kelsey et al. (2005)

Nootkatone Dastur (1974), Erdtman and Hirose (1962), Ishida et al. (1970), Odom 

and Pinder (1972), Yanami et al. (1980)

Valerianol Odom and Pinder (1972)

Vetivone Dastur (1974)

a

 Biologically active against fungi at 0.01 percent (Rennerfelt and Nacht 1955)

b

 Biologically active against fungi at 0.001 percent (Rennerfelt and Nacht 1955)

the compounds and citations of literature that describes their identification, conformation, synthesis, or assay. Barton diagrams the molecular structure of compounds 

in wood and foliage: carene, carvacrol, chamic acid, chaminic acid, chanootin, 

limonene, methyl carvacrol, nootkatin, nootkatone, and pinene. In particular, nootkatin and carvacrol are associated with reduced growth rates of fungi (Kelsey et al. 

2005, Rennerfelt and Nacht 1955). Nootkatin, carvacrol, valencenes and nootkatone 

extracted from yellow-cedar heartwood reduced spore formation and hyphal growth 

of the oomycete (water-mold) pathogen Phytophthora ramorum, cause of sudden 

oak death, in culture (Manter et al. 2006). Nootkatin is also an effective biocide of 

ticks (Panella et al. 1997) and mosquitoes, even at very low concentrations (Karchesy et al. 2010). Yellow-cedar snags retain strength and decay resistance properties 

long after tree death, which greatly limits snag deterioration. Kelsey et al. (2005) 

measured the concentration of nootkatin, carvacrol, nootkatol, and nootkatene in 

the wood of live cedar trees, and snags that had been dead for various lengths of 

time, and found that chemistry was relatively unaltered until several decades after 

tree death. The salvage potential, wood properties, and heartwood chemistry of 

dead yellow-cedar are covered in section 3. 
33

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Foliage Morphology and Chemistry

Mature yellow-cedar foliage is dull green, scalelike, and pointed at the tips. Juvenile 

foliage of seedlings is needlelike, and mature foliage develops gradually until it is 

the only foliage produced around age 5. Yellow-cedar twigs lack true buds or bud 

scales and are four-angled or somewhat flattened in cross section (Hultén 1968). 

Similar to yellow-cedar heartwood, bioactive compounds in yellow-cedar foliage afford protection from biotic herbivory, such as from insects and deer. These 

compounds include alpha-pinene and limonene, as well as beta-pinene, sabinene, and 

beta-cymene (Clark and Lucas 1926). Cheng and von Rudloff (1970) analyzed volatile 

leaf oils of yellow-cedar foliage, and detected alpha-pinene, 3-carene, and limonene as 

the primary chemical constituents, along with nerolidol, cedrol, bisabolol, and cadinol 

and a whole suite of hydrocarbons, monoterpenes, oxides, aromatic esters, and acids. 

Some of these protective compounds are common to foliage of plants in the Cupressaceae. Others are potentially unique to yellow-cedar or more closely related species. 

Vourc’h et al. (2002) evaluated the relationship between deer browse rates 

and foliar terpene concentrations through yellow-cedar common garden trials at 

two sites on Vancouver Island. The results demonstrated that genetically identical 

individuals (from cloning) with lower terpene levels consistently had higher browse 

pressure, suggesting genetic control over foliar terpene concentration and vulnerability to deer browse. Young, juvenile foliage of seedlings is known to contain 

lower concentrations of defense compounds and is significantly more susceptible 

to herbivory than older, mature foliage. A planting trial near Ketchikan compared 

the growth and survival of yellow-cedars that originated from seedlings and rooted 

cuttings (stecklings), and found that seedlings had higher rates of deer browse than 

did stecklings (Hennon et al. 2009). It is thought that this may be due to the higher 

terpene levels of mature steckling foliage compared to seedlings. On saplings and 

young trees, deer frequently feed on the branch tips, probably consuming only 

recently produced foliage that has relatively lower concentrations of terpenes than 

adjacent older foliage. 

A key feature of yellow-cedar foliage is its greater concentration of foliar 

calcium compared to other conifers (fig. 20). There are several specific ecological 

and physiological causes and consequences of abundant foliar calcium. The calcium 

uptake of yellow-cedar far exceeds its nutritional needs (Krajina 1969, Kranabetter 

et al. 2003). The high foliar calcium concentration is presumed to be the result of 

the nitrogen acquisition strategy of yellow-cedar. Inadequate soil nitrogen limits 

tree growth in low pH (acidic) soils, but yellow-cedar and some related species are 

better able to use the nitrate form of nitrogen present in acidic soils. The role of 

calcium in the strategy is to combine with toxic byproducts (e.g., oxylate) produced 
34

GENERAL TECHNICAL REPORT PNW-GTR-917

during the conversion of nitrate to a usable form (i.e., the elemental reduction of 

nitrate in cells). The compound calcium-oxylate is relatively immobile; production 

of this molecule provides a mechanism for safe storage of the harmful free radical 

oxylate (Marschner 2002). The decomposition of senesced cedar foliage has important feedbacks to the forest floor, as foliar calcium inputs raise pH levels (Alban 

1969, Turner and Franz 1985) and increase calcium availability at the soil surface 

beneath yellow-cedar trees. Within leaves, calcium may also affect the production 

and cycling of organic acids, increasing litter decomposition rates and decreasing 

forage palatability. Changes in pH of the forest floor influence the nitrogen cycle 

in both trees and soils, for example by increasing the concentration of soil nitrogen 

available to plants. 

Distinguishing Yellow-Cedar From Western Redcedar

Yellow-cedar and western redcedar co-occur in the southern half of southeast 

Alaska and coastal British Columbia where they are sometimes confused because 

of their similar morphology (fig. 21) and affinity for wet soils. Molecular genetic 

data (Yang et al. 2012) demonstrated that yellow-cedar and western redcedar are 

only distantly related in the Cupressaceae family, and morphological differences 

make it possible to distinguish these two species (table 5).

Figure 20—Foliar calcium concentration in several conifers common to the coastal temperate 

rainforest. 
35

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 5—Distinctive characteristics of yellow-cedar and western redcedar

Feature Yellow-cedar Western redcedar

Cones Small, spherical with spikes Small, rosebud shaped

Mature foliage Less flattened; dull; darker 

green, little to no white stomatal banding, but if present in 

the shape of “X”

Flattened; bright green; shiny; white 

stomatal banding on underside in 

shape of “W” or butterfly

Shoots Shoots and foliage arrange haphazardly; are droopy, hangingShoots emerge from branches systematically, usually in flat sprays

Branches Branches sometimes with 

sweeping form, lower boles 

tend to be branch-free, 

bayonet-shaped branches near 

top less common

Low sweeping branches often 

maintained on lower bole, bayonetshaped upward branches and forks 

near top common

Bark Gray, whitish or reddish-brown; 

less fibrous; resin ducts present in bark and phloem

Reddish-brown with vertical 

furrows, very fibrous, without

resin ducts

Heartwood Pale to bright yellow, aromatic Variable in color, tan to dark 

reddish-brown, aromatic

Seedlings Develop mature, scale like 

foliage gradually, by the 4th

 or 

5th year

Develop mature, scalelike foliage 

abruptly in spring of 2nd or 3rd year

Figure 21—Foliage and cones of yellow-cedar (top) and western redcedar (bottom). 
36

GENERAL TECHNICAL REPORT PNW-GTR-917

Reproduction and Regeneration

Yellow-cedar reproduces sexually by seed and asexually by layering. Regeneration 

is not uniform and does not occur on all sites. In the western hemlock-yellow-cedar 

series of the Chatham Area, yellow-cedar regeneration was detected in only half 

of the examined stands, and yellow-cedar seedlings were far less common than 

prolific western hemlock (Martin et al. 1995). 

Seed production of yellow-cedar is considered to be low, but some seed is 

produced every year (Owens and Molder 1984). Key factors limiting natural 

regeneration include irregular seed crops, limited cone production, low rates of 

seed viability and germination, reduced seed production in areas of forest decline, 

competition with other species, seedling vulnerability to spring root and foliar 

freezing injury, and preferential deer browsing. Needlelike juvenile foliage is 

particularly vulnerable to browsing pressure, especially where deer populations 

are high. Insects and diseases of seeds and cones may also affect regeneration, but 

these agents are known to be problematic only in yellow-cedar seedling nurseries, 

and information is lacking about their role in natural forests.

Yellow-cedar begins to produce pollen and seed cones at an early age, often 

by the time seedlings reach 7 to 8 yr old. Cone formation can also be induced 

in seedlings as young as 1 yr old in the nursery setting through application of 

gibberellin-A3 (Owens and Molder 1977). Pollen cones are produced early in the 

season (April to May), and pollen viability appears to be diminished by warm 

spring temperatures. Anderson and colleagues (2002) reported that low-elevation 

seed orchards produced lower quantities of viable seed than higher elevation native 

stands, and hypothesized that the low viability could be related to negative impacts 

of higher temperatures on pollen development, as has been reported for other 

conifers (e.g., Luomajoki 1977). Hak and Russell (2004) examined pollen viability 

from diverse climatic sources in British Columbia and found that pollen collected 

from trees at the coldest sites (mean temperature in the coldest month = 18 °F) 

showed average pollen viability up to 70 percent. Pollen collected from trees at 

the warmest sites (mean temperature in the coldest month = 37 °F) showed average pollen viability of 16 percent. The exact mechanism responsible for decreased 

pollen viability is unknown, but it may play a large role in the low germinability of 

yellow-cedar seeds from low-elevation orchards (Hak and Russell 2004, Owens and 

Molder 1977). If higher quality pollen is required for controlled pollination, it could 

be possible to collect pollen from colder sites, but additional investigation is needed 

to identify the climatic conditions that produce high-viability pollen. 

Flowering (cone initiation) takes place from April to May, depending on latitude (Harris 1974, Owens and Molnar 1984). Yellow-cedar produces small, yellow 
37

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 22—Male pollen flowers of yellow-cedar. Figure 23—Inconspicuous female flower of yellow-cedar 

at the time of pollination.

to reddish male flowers (strobili) on branch tips in the lower crown (fig. 22), while 

green, berrylike female flowers are produced on branch tips in the upper crown 

(fig. 23). Cones form on previously vegetative shoots that are 1 to 2 yr old. Pollination takes place during a 2-week period in late spring or early summer about 

1 yr after flower initiation. Pollen is dispersed by the wind. Fertilization occurs 

and embryos develop until winter dormancy is triggered in fall. Seed cones take 

2 full yr to mature, or 28 mo across three growing seasons from the time of cone 

initiation to seed maturity (Owens and Molder 1984). There is evidence that cones 

can develop in 1 yr on sites with longer growing seasons (Colangeli 1991), and 

under controlled greenhouse conditions (personal communication, John H. Russell, British Columbia Forest Service, Cowichan Lake, B.C., 2015). Seed dispersal 

takes place from fall to spring, primarily during periods of dry weather (Harris 

1974). Dispersed seeds overwinter in the snowbank over much of the range of 

yellow-cedar. When collecting seed cones, care must be taken to avoid the soft, 

green 1-yr-old cones. Immature cones occur on branches with mature cones and are 

similar in size (0.5-in diameter), but are found closer to branch tips (Harris 1974). 

Mature cones are hard, yellow- or red-brown to gray, with four to six umbrellashaped scales that are tipped with conical projections. Empty cones persist on trees 

for a year or more after seed dispersal. 

Seed wings are present (fig. 24), but are sometimes reduced (Hultén 1968). On 

average, cones produce seven seeds (Bonner 2008), but seed viability is generally 

low and highly variable (Harris 1974). In British Columbia, Owens and Molder 

(1977) reported that only 29 percent of seeds were viable. Excised yellow-cedar 

embryos show 100-percent germination, suggesting that the mechanisms driving dormancy and low germinability are primarily a consequence of structures 
38

GENERAL TECHNICAL REPORT PNW-GTR-917

enclosing the embryo (e.g., testa, nucellus, and megagametophyte; Raimondi and 

Kermode 2004). Detailed anatomical analysis of the yellow-cedar seed germination 

process points primarily to an inhibitory effect of the megagametophyte (Raimondi 

and Kermode 2004), perhaps via the action of leachable chemical inhibitors such as 

abscisic acid (Raimondi and Kermode 2004, Ren and Kermode 1999, Schmitz et al. 

2002). 

Early attempts to break seed dormancy used a combination of warm and cold 

stratification; for example, Pawuk (1993) found that the highest germination rate 

(69 percent) was achieved with 60 d of warm stratification followed by 90 d of cold 

stratification. Raimondi and Kermode (2004) found that this long stratification 

could be shortened to 65 d by using a regimen of chemical treatment (1-propanol), 

followed by a warmwater soak for 3 d, a 2-d treatment with gibberellin-A3, and a 

60-d moist chilling incubation. In natural settings, the highest germination rates are 

achieved on bare mineral soil; however, alder and spruce tend to have a competitive advantage on bare microsites (Harris 1974). Large seed crops are produced 

every 4 to 7 yr (Bonner 2008, Harris 1974, Hennon 1992b), but seed production is 

never known to be abundant compared to associated conifers (Pawuk 1993). Seed 

dispersal distances have not been assessed for yellow-cedar, but are believed to be 

less than the 400-ft dispersal distance of Port-Orford-cedar due to yellow-cedar’s 

heavier seed weight (Harris 1974) and reduced seed wings (Owens and Molder 

1984). Seeds produce two cotyledons upon germinating (fig. 25). Previous recommendations were to collect and plant yellow-cedar seeds near the planting site and 

within a 500-ft elevation range (Martin et al. 1995), but new quantitative genetic 

research findings show that seed can be moved great distances from source areas 

without expressing maladaptive traits (see “Genetics,” this section).

Figure 24—The winged 

yellow-cedar seeds.
39

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 25—New yellow-cedar germinant 

in organic soil showing the typical two 

cotyledons.

As noted, yellow-cedar also reproduces asexually by layering, as an aerial 

stem (i.e., lower branch) can develop roots while still attached to the parent plant, 

and later detach to form an independent clone (ramet) of the parent (genet) plant. 

For yellow-cedar, layering is most common on open, bog sites, where live lower 

branches are retained and are in direct contact with the ground (Hennon et al. 1990) 

(fig. 26). Ramets derived from layering may be ubiquitous on the landscape. For 

example, surveys of nine small plots in British Columbia showed that clones could 

constitute 8 to 70 percent of all trees in an area as small as 1,600 ft2 each (Thompson et al. 2008). Although most documented clones derived from layering have been 

reported to be small, large ancient ramets have been identified in the Echo Basin 

area of the Oregon Cascades (Rich Cronn, unpublished data).3

 Clonal growth may 

offer advantages by enabling yellow-cedar individuals to capture more resources 

and occupy a larger physical space, and to persist and spread in habitats that may 

be unfavorable for sexual reproduction (Vallejo-Marín et al. 2010). A disadvantage 

of clonal reproduction is that the effective size of local populations may be reduced 

relative to stands produced by sexual reproduction, thereby leading to an increase in 

the self-fertilization rate (Thompson et al. 2008), and the expression of deleterious

3

 Data on file at USDA Forest Service, Pacific Northwest Research Station, Forestry 

Sciences Laboratory, 3200 Jefferson Way, Corvallis, OR 97331.
40

GENERAL TECHNICAL REPORT PNW-GTR-917

mutations (Vallejo-Marín et al. 2010). In long-lived trees like yellow-cedar, clonality 

also increases the per-generation mutation rate, and thus has the potential to contribute to increased inbreeding depression (Muirhead and Lande 1997).

Genetics

An important component of a conservation assessment is an evaluation of the 

magnitude and distribution of genetic variation in native and ex situ (breeding/

germplasm) populations of yellow-cedar. To date, genetic studies of yellow-cedar 

have derived from two sources: quantitative genetic studies and molecular genetic 

studies. These studies are complementary; together they paint a picture of yellowcedar as a generalist species that has responded to historical climate change and 

heterogeneous environments with phenotypic plasticity and frequent migration, as 

opposed to local adaptation. These sources of information are discussed below.

Quantitative genetic variation in yellow-cedar— 

Quantitative genetic information is critical to a working conservation assessment, 

as these data address trait heritability (proportion of the total population variation 

in that trait attributable to genetic effects) and trait variation under specific growing 

Figure 26—Layering, the rooting of lower limbs, is a clonal form of reproduction by 

yellow-cedar. It is common in boggy forested wetlands and may also be common in 

upland productive forests. Rooted cuttings called “stecklings” are used operationally as 

yellow-cedar planting stock for reforestation in British Columbia.
41

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

conditions. Traits modeled in quantitative genetic studies include complex characteristics such as plant growth rhythm, biomass accumulation, reproductive output, 

and biotic/abiotic stress tolerance. Quantitative genetic studies incorporate elements 

common to ecological studies (e.g., spatial variation), but they explicitly account for 

genetic phenomena including the mode of transmission (inheritance), penetrance 

and dominance (trait expression), heritability (ease of trait manipulation, response 

to selection), and fitness consequences that arise from outbreeding, inbreeding,

directional selection, and seed transfer or migration.

Quantitative genetic studies are relevant to conifer landscape restoration and 

conservation because of the known close association between climatic and edaphic 

variation and quantitative genetic variation in many conifers (Aitken et al. 2008). 

The study of this association, called genecology (compare Langlet 1971), forms the 

basis for transfer guidelines for seedlings and other genetic materials in the U.S. 

Forest Service and British Columbia Forest Service (Campbell 1971, Johnson et al. 

2004, Rehfeldt 1991, Russell and Krakowski 2012). Genecology studies are conducted in common gardens so that phenotypic responses of different seed sources 

can be attributed to their genetic history and composition, rather than phenotypic 

plasticity to environmental variability. Typically, linear mixed models are used to 

determine whether differences exist between different populations, and to partition variation among different hierarchies (families, geographic sources, garden 

environments). Multivariate regression approaches are used to specifically test for 

associations between genetic variation and physiographic factors (e.g., latitude, 

longitude, elevation) (Campbell 1971) or climatic variables (temperature, precipitation) (St. Clair et al. 2005) that correspond to the seed source locations. Strong 

correlations between phenotypic responses in common garden studies and the 

source environment are considered evidence that the trait is responsive to selection, 

and that the variation is adaptive.

To date, several studies have examined quantitative genetic variation in traits 

in yellow-cedar. Most have focused on the apportionment of variation within and 

across populations (Cherry and Lester 1992, El-Kassaby 1995, Russell 1993), and 

two studies explicitly evaluated this variation in a genecological framework (Russell 1993, Russell and Krakowski 2012). In addition, a more recent study evaluated 

how additive, dominant, and epistasic modes of inheritance contribute to total variability in yellow-cedar (Russell et al. 2015). All studies were conducted in common 

gardens with hierarchical variation represented by clones, families, populations, 

and geographic provenances. An important issue identified in three studies (Cherry 

and Lester 1992, El-Kassaby 1995, Russell 1993) is that poor germination at the 

seedling stage presents a large selective barrier to the number of genotypes included 
42

GENERAL TECHNICAL REPORT PNW-GTR-917

Table 6—Quantitative traits measured in genetics studies 

Trait

Significant by

provenancea

Significant by family 

within provenancea Significant by familya

Percent filled seed n.s.a n.s. n.s.

Percent seed germination Cherry and Lester (1992) Russell (1993) n.s.

Speed of germination n.s. Russell (1993) n.s.

Height at time intervals Cherry and Lester (1992), 

Russell (1993), Russell 

and Krakowski (2012)

Cherry and Lester 

(1992), Russell 

(1993), Russell and 

Krakowski (2012)

n.s.

Root collar diameter Russell (1993) Cherry and Lester 

1992, Russell (1993)

n.s.

Shoot weight Cherry and Lester (1992) n.s. n.s.

Root weight n.s. n.s. n.s.

Nodes to 1st lateral branch n.s. n.s. n.s.

Nodes to scalelike foliage n.s. n.s. n.s.

Number of lateral branches Cherry and Lester (1992) n.s. n.s.

Needles/node n.s. n.s. n.s.

Branch angle infection n.s. n.s. n.s.

Percent survival to -4 °F Cherry and Lester (1992) n.s. n.s.

January cold injury Russell (1993) Russell (1993) n.s.

Steckling cold hardiness Russell 1993 (altitude) n.s. Russell and Krakowski 

(2012)

Terpene production and 

browse resistance

n.s. n.s. Vourc’h et al. (2002)

Adaptability Russell and Krakowski 

(2012)b

n.s. n.s.

a

 Traits showing nonsignificance by provenance, family within provenance, or family are noted as “n.s.”. Traits showing significant 

differences are identified by the study reporting the result. Cherry and Lester (1992) conducted tests with 1-yr-old seedlings. Russell 

(1993) used first-year seedlings and 1- to 3-yr-old trees. Vourc’h et al. (2002) used rooted stecklings. Russell and Krakowski (2012) 

used 15-yr-old trees.

b

 Trait is significant when outlier populations (Oregon, Siskiyou) are included in the study. Trait is nonsignificant for 

Alaska and British Columbia populations.

in common garden studies. This limitation may prevent genetic diversity associated with seed dormancy from being included in common garden studies, although 

several lines of evidence suggest that this phenomenon has little effect on common 

garden results (e.g., Russell and Krakowski 2012, Russell et al. 2015).

The traits examined for yellow-cedar in quantitative genetic studies include 

life-history and potentially adaptive traits (table 6). Pollen, seed, and seedling traits 

include factors influenced by the maternal tree and embryo, such as pollen viability, 

seed production, seed weight, and seed germination rate. Traits related to juvenile 

growth and differentiation include needle and branch morphology, phenology, 
43

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

interval height, the allocation of above- and below-ground resources (shoot/root 

weights and ratios), and cold injury at -4 °F. Traits related to mature growth include 

survival, height, diameter, tree form, and indices of adaptability (survival × cold 

damage) and a population index (height × population mean adaptability) (Russell 

and Krakowski 2012). Based on the evidence from multiple tests, only a few traits 

show significant differences that are likely to be strongly influenced by genetic 

variation: these traits are seed germination, height, root collar diameter, shoot 

weight, speed of germination, cold injury, and “adaptability.” Traits showing the 

highest likelihood of genetic control and relation to adaption are January cold injury 

and the “adaptability” index of Russell and Krakowski (2012). 

One of the commonly examined adaptive traits measured in conifers—annual 

height growth, or height growth at a defined time interval—is highly variable in 

yellow-cedar. A recent study conducted on 15-yr-old trees (Russell and Krakowski 

2012) showed a significant source difference in heights, with sources from Alaska, 

Oregon, and the Siskiyou region of California and Oregon trending shorter than 

sources from British Columbia. Despite this high variability, traits related to height 

show weak correlations to climatic or environmental factors related to the original 

seed source. This result, reported by Cherry and Lester (1992), Russell (1993), 

and Russell and Krakowski (2012), mirrors findings from other North American 

Cupressaceae (Harry 1987, Zobel 1985). The finding provides evidence that despite 

a genetic component to shoot growth in young yellow-cedar (see “Trait heritabilities” below), the trait primarily exhibits strong phenotypic plasticity. This result 

contrasts with other conifer species, such as Douglas-fir (St Clair et al. 2005), 

where variation in height is correlated with the seed source environment.

Studies of rangewide variation in yellow-cedar (Cherry and Lester 1992, 

Russell 1993, Russell and Krakowski 2012) report significant among-population 

variation, but population variation is correlated with the source climate only when 

the most peripheral yellow-cedar populations (Siskiyou region, interior locations 

from Oregon and British Columbia, and Prince William Sound) are included in the 

analysis. If these outlier populations are removed from studies, genetic variation 

shows no significant correlation with the seed source climate, even though sources 

span a geographic distance of 1,250 mi and 19° latitude. This phenomenon has led 

several authors to conclude that there is limited evidence of climate-related adaptive variation for seed traits, growth traits, and cold-hardiness in yellow-cedar. In 

the words of Russell (1993), “Yellow-cedar seems to have evolved an intermediate 

mode of adaptation with less genetic differentiation associated with geography than 

Douglas-fir, Sitka spruce, and western hemlock, but more genetic differentiation 

than western white pine and western redcedar.”
44

GENERAL TECHNICAL REPORT PNW-GTR-917

Table 7—Narrow-sense (h2) and broad-sense (H2) trait heritabilities in yellow-cedar

Trait Heritability estimate Reference

Height: 32 wk, yr 1, yr 2, yr 3 h2 = 0.69, 0.64, 0.44, 0.31 Cherry and Lester (1992), Russell 

(1993), Russell and Krakowski (2012)

Height: yr 12 h2 = 0.07–0.45 Baltunis et al. (2013), Russell et al. 

(2015)

Shoot growth, first-year growth H2 = 0.58 Russell (1993)

Index of injury to cold H2 = 0.38 Russell (1993)

Reproductive yellow-cedar plasticity H2 = 0.36 El-Kassaby et al. (1993)

Root collar diameter: 32 wk, yr 2 h2 = 0.30, 0.17 Russell (1993)

Diameter at breast height: yr 12 h2 = 0.06–0.27 Russell et al. (2015)

Total growth at growth cessation h2 = 0.16 Russell (1993)

Tree form: yr 12 h2 = 0.02–0.05 Russell et al. (2015)

Trait heritabilities—The heritability of a trait is the proportion of the total population variation in that trait attributable to genetic effects. Heritability is key to understanding how readily a trait responds to natural selection in the environment or 

to selection in tree improvement programs. Quantitative genetic studies commonly 

estimate narrow-sense heritabilities (h2), which consider the portion of total phenotypic variance (Var P) that is due to additive (allelic) genetic effects (Var A):

The response to selection is a function of the product of narrow-sense heritability and the strength of selection. Traits with high heritabilities require comparatively weak selection to change population means; conversely, traits with low 

heritabilities require strong selection to change population means. 

Examples of trait heritabilities estimated for yellow-cedar are shown in table 7. 

Traits showing heritabilities of ≥0.10 are often used in conifer breeding programs, 

as recurrent strong selection on these traits can change population means in a few 

generations. Traits showing heritabilities of this magnitude include seedling and 

young tree height, shoot growth during first-year growth, diameter at age 12, cold 

injury during acclimation, and maximum cold hardiness. Nonadditive inheritance 

due to dominance or epistasis is negligible in traits examined to date (height, diameter; Russell et al. 2015), and the species shows minimal genotype × environment 

interactions (Baltunis et al. 2013, Russell et al. 2015).
45

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Seed transfer guidelines—Seed and clone transfer guidelines have been established for yellow-cedar based on direct quantitative/common garden data (Russell 

1993, Russell and Krakowski 2012) and indirect comparisons with common garden data from other conifer species (Randall and Berrang 2002) and from different 

geographic/topographic provinces (Alden 1991). In the examples based on common 

garden data, the metric used to establish a seed transfer guideline is a “risk factor” 

associated with seed transfer, and it is based on the impact of transfer on individual 

tree productivity, stand-level survival, and changes in the susceptibility to pests and 

diseases. In examples of pest and disease susceptibility (Alden 1991, Randall and 

Berrang 2002), tree seed zones were based on inferred barriers to historical migration (e.g., mountain ranges or channels and straits), and differences in minimum 

annual temperature. The results of these early efforts were geographically oriented 

“seed transfer” maps that divided the range of yellow-cedar into “transfer zones”: 5 

zones for Oregon and Washington (Randall and Berrang 2002), 4 zones for British 

Columbia (Russell 1993), and perhaps as many as 40 zones for southeast Alaska 

(Alden 1991).

Recently, there has been a shift towards defining seed transfer guidelines 

by relating growth to climate models, also known as climate-based seed transfer 

(Aitken et al. 2008, Bower et al. 2014, O’Neill et al. 2008, St Clair et al. 2005). 

This approach is particularly important in the context of climate change, as future 

seed zones can be modeled if projected climate data are available (O’Neill et al. 

2008, St Clair and Howe 2007). With this new perspective, Russell and Krakowski 

(2012) recently summarized 15-yr growth data from 12 provenance trials in British Columbia. The trees in this study spanned the range of yellow-cedar, from the 

Siskiyou Mountains of California (41.8° N) to Mitkof Island, Alaska (55.8° N). 

Climate varies greatly across this range, with a twofold difference in the length of 

growing season and a more than fourfold difference in mean annual precipitation. 

Additionally, these data are derived from five common garden sites that ranged 

from cold and arid (mean annual temperature = 37 °F; mean annual precipitation = 

30 in) to warm and moist (mean annual temperature = 47 °F; mean annual precipitation = 114 in). 

Regional differentiation in adaptability and survival was detected only when 

populations from California and Oregon were included in the analysis. Trees from 

these sources were significantly smaller and showed lower survival at the British 

Columbia garden locations than trees from all other sources. If these locations are 

omitted, tree responses showed no significant relationship to geographic source, 

and population performance could not be predicted with climatic factors. Russell 

and Krakowski (2012) conclude that yellow-cedar is a “climate generalist” that 
46

GENERAL TECHNICAL REPORT PNW-GTR-917

shows phenotypic plasticity to differences in local climate, but no genetic adaptation to climate variation. They also point out that although yellow-cedar shows little 

differentiation across a large geographic expanse, the central “core” of the yellowcedar range is homogeneous with respect to climatic factors, even at scales of ≥600 

mi. Hence, where early transfer recommendations in British Columbia were limited 

to approximately 3° latitude and ±1,600 ft of elevation (Russell 1993), the best available science shows that the species can be transferred over 10° latitude with little 

risk of maladaptation.

The study by Russell and Krakowski (2012) does not explicitly extend to 

Alaskan populations of yellow-cedar, but their findings are important for Alaskan 

populations because they show that: (1) yellow-cedar is a climate generalist, (2) 

historical seed zones for yellow-cedar (e.g., Alden 1991, Randall and Berrang 2002) 

are too restrictive across their entire range, and (3) some northern populations are 

currently maladapted to their local environment because of climate change. This 

last issue is critical for future management of yellow-cedar in Alaska. Evidence 

from Russell and Krakowski (2012) shows that distant southerly and interior 

populations are likely to show much higher fitness and adaptability than the trees 

currently occupying southeast Alaska. For this reason, the use of geographically 

local Alaska sources (e.g., Alden 1991) for reforestation will not address the current 

adaptational lag that exists with climate, and it may exacerbate the adaptational lag 

with future climate change. How far trees can be safely transferred across Alaska 

remains to be formally evaluated, but distances up to hundreds of miles (several 

degrees latitude) should be tested.

Molecular genetic variation in yellow-cedar— 

Molecular genetic information provides important insights into yellow-cedar conservation, as these data address the magnitude of hidden genetic variation that cannot be measured in common garden settings. Molecular genetic studies can incorporate information derived from: (1) the genome of individuals or populations using 

DNA sequences, (2) transcribed messenger RNA copies of genes, and (3) proteins 

or metabolic products derived from gene pathways. Traditionally, molecular markers have sampled only a tiny fraction of a genome. For this reason, they were rarely 

linked to genes responsible for quantitative or adaptive variation, but they could 

provide a proxy for “hidden” variation that could not be quantified in common 

gardens. New advances in genome sequencing can sample a higher proportion of 

the genome, and these methodologies may soon make it possible to identify associations between DNA and traits for simple and complex traits.
47

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Where quantitative traits can be used to show the strength of artificial or 

natural selection, molecular markers reveal the impact of neutral processes such as 

drift and migration. For this reason, they can be used to examine patterns of historical and contemporary migration, historical changes in population size, and random 

sampling due to mating. In restoration or breeding populations, molecular markers 

provide individual identifications, monitor the effectiveness of pollination or seed 

harvesting methods, and identify germplasm sources for conservation. They can 

also be used to develop conservation collections that maximize genetic diversity in 

a small population size.

At present, three classes of molecular markers have been used to assess genetic 

variation in yellow-cedar. These technologies are briefly described, and advantages 

of each are outlined in table 8.

1. Allozymes. Developed in the 1950s, allozyme electrophoresis separates 

enzymes by the protein amino acid sequence. Mutations in amino acid 

sequences produce polymorphisms with a small number of variants (two to 

three per gene). Allozymes have a very low per-sample cost (typically a few 

dollars per sample). Allozymes were used in the rangewide study of yellowcedar by Ritland et al. (2001).

2. Short simple repeat (SSR) markers. Developed in the 1970s, SSR markers 

(or “microsatellites”) are tandemly repeated DNA sequences (2–6 bases) 

that create a multistate polymorphism with a very large number of variants 

Table 8—Attributes of allozyme, short simple repeat (SSR), and single nucleotide polymorphism 

(SNP) genotyping methods (adapted from Guichoux et al. 2011)

Methodological advantages Allozyme

SSR 

markers

SNP 

markers

Low development cost ×

Low ascertainment bias (bias imparted by process of identifying variation) × ×

High power to detect mixed genotypes (e.g., pollen pools) ×

High power, accuracy in pedigree analysis ×

Detecting recent population expansion, migration ×

Identifying private alleles, unique population genetic variation × ×

Power to identify linkage disequilibrium and association with phenotypes × ×

Accurate estimation of allele frequencies from small samples × ×

Low mutation rate, accurate predictor of long-term history × ×

Ultra-high throughput methods available ×

No need to include common controls among studies over time ×

Can be used to assay any tissue (fresh, dried, frozen, degraded/dead) × ×

Can be directly linked to regions of the genome that control traits of interest × ×
48

GENERAL TECHNICAL REPORT PNW-GTR-917

(often 20 per gene). These markers have high mutation rates, high information content, and a low per-sample cost (typically tens of dollars per 

sample). They have been developed for yellow-cedar (Bérubé et al. 2003, 

Jennings et al. 2013) and have been applied to studies of clonality in yellow-cedar (Bérubé et al. 2003, Thompson et al. 2008) and regional genetic 

diversity across Alaska (Cronn et al. 2014).

3. Single nucleotide polymorphism (SNP) markers. These markers originated 

with the advent of DNA sequencing in the 1970s, and they represent the 

most abundant variation in the genome. Because SNP markers show a simple polymorphism (two variants per gene) and exhibit low mutation rates, 

SNP analyses require large numbers of markers to be informative. These 

analyses are comparatively expensive on a per-sample basis (often >$100 

per sample), but the method is amenable to high-throughput analysis and 

genome-scale coverage. To date, SNP markers have not been used to study 

yellow-cedar, but they are likely to be used in the future.

Molecular genetic studies have been conducted on yellow-cedar, although only 

two studies have specifically included Alaskan populations. Studies have considered many different perspectives, with the greatest number focusing on the evolutionary history and phylogenetic resolution of the genus Callitropsis (Mao et al. 

2010, Wang et al. 2003, Yang et al. 2012), spatial genetic variation of yellow-cedar 

populations (Bérubé et al. 2003, Ritland et al. 2001), and the extent of inbreeding in 

natural (Thompson et al. 2008) and managed (Massah et al. 2010) populations. An 

additional study described a single-gene homologue of the hormone abscisic acidinsensitive 3 (Lazarova et al. 2002). One published study included a small number 

of samples from Alaska populations (Ritland et al. 2001), although a newer study 

has been completed that describes the magnitude and pattern of nuclear genetic 

variation in Alaska populations (Cronn et al. 2014).

Across all molecular studies, the consensus emerging for yellow-cedar is that 

the species shows a high level of genetic variation, but little spatial genetic structure 

across an enormous latitudinal range. The spatial genetic structure that is evident 

is driven by locally high rates of self-pollination and clonal reproduction, both 

of which drive populations towards greater homozygosity (similar genes). These 

findings—high variability, but no detectable spatial differentiation across large 

geographic scales—mirror those observed in quantitative genetic studies. This 

information has implications for the management of yellow-cedar, particularly for 

collecting and propagating materials for restoration activities.
49

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Nuclear genomic variation—The nuclear genome of yellow-cedar has much in 

common with other Cupressoid trees, with 11 chromosomes (the common number 

in the family) composed of 12.5 billion base pairs (Bennett and Leitch 2012). The 

high degree of genomic conservation in the Cupressaceae is important because 

two species, Asian Chamaecyparis obtusa (hinoki cypress) and North American 

Thuja plicata (western redcedar), are gaining attention as potential genomic models. Atlases of expressed genes (“transcriptome references”) are already available 

for these species (University of Alberta 2015), and should be directly transferable 

to yellow-cedar. When a Cupressoid genome is sequenced, colinearity and gene 

conservation with yellow-cedar are highly likely, which will enable detailed genetic 

analysis of genes controlling adaptive traits in yellow-cedar.

Allozyme variation—To date, only one published report exists for allozyme variation in yellow-cedar (Ritland et al. 2001). In this study, allozyme variation was 

assayed by using 530 trees from 17 populations across the range of the species, 

from California to Alaska. Genetic information was gathered from eight isoenzyme 

systems. In general, allozyme variation in yellow-cedar was comparable to that of 

other Cupressaceae members for many indices, such as the number of variants, or 

alleles, per locus; percentage of loci that were polymorphic; total observed heterozygosity; and inbreeding coefficient (table 9). 

This study included four yellow-cedar populations from Alaska. The “Anchorage” population (Prince William Sound) showed the lowest allelic diversity and 

heterozygosity in the study; this finding is not surprising, given the degree of geographic isolation of this population. One unexpected finding in this study was the 

large and variable estimated inbreeding coefficient for Alaskan populations. These 

estimates suggest that local inbreeding rates can reach exceptionally high levels

(37 percent and 60 percent in Prince William Sound and Petersburg, respectively), 

Table 9—Allozyme variation in yellow-cedar, as compared to other Pacific Northwest 

Cupressaceae and other gymnosperms

Species La A PPL F

H

exp or

(HT)

FST or 

GST Reference

Yellow-cedar 10 1.7 50 0.184 0.17 0.14 Ritland et al. (2001)

Western redcedar 19 1.2 16 0.057 0.04 0.03 Yeh (1998)

Port-Orford-cedar 32 1.9 65 0.150 0.15 0.05 Millar and Marshall (1991)

Average for 89 gymnosperms 17 2.4 71 0.26 0.07 Hamrick et al. (1992)

a

 Abbreviations: L = number of loci screened; A = average number of alleles per locus; PPL = percent polymorphic loci; F = Wright’s 

inbreeding coefficient; Hexp = expected heterozygosity; HT = total heterozygosity; FST = Wright’s estimator for population-level 

differentiation (or GST, for loci with multiple alleles).
50

GENERAL TECHNICAL REPORT PNW-GTR-917

which are unusual for conifers (compare Ritland et al. 2001: table 2). Phylogeographic inferences resulting from this study were complicated, as populations 

>1,000 mi apart (e.g., Prince William Sound versus Mount Washington, B.C.; or, 

Juneau, Alaska, versus Oakridge, Oregon) appeared to be more closely related to 

each other than they were to neighboring populations.

Although the Ritland et al. (2001) paper is the first report for molecular genetic 

variation in yellow-cedar, the allozyme methodology has limitations that may 

have affected the conclusions reached. A major limitation is that allozyme variability was exceedingly low. In this study (Ritland et al. 2001), four loci showed no 

variation, and the greatest number of alleles observed at any locus was three. As a 

consequence, the study includes an unusually large number of repeated genotypes 

(81 percent of the total), and repeated genotypes were shared among the most 

geographically separated populations (Whiskey Peak, California, to Prince William 

Sound). It is improbable for individuals from distant populations to be genetically 

identical or share recent coancestry; a more reasonable explanation is that allozymes could not discriminate even highly divergent individuals. This low level of 

variation was also paired with a limited genomic sampling, as the study included 10 

marker loci. This number of loci is much lower than the average from 89 published 

allozyme studies of gymnosperms before 1992 (17 loci; Hamrick et al. 1992), and 

the number used in a similarly designed study of Port-Orford-cedar (32 loci; Millar 

and Marshall 1991).

Given the low power of allozymes for discriminating variation in yellow-cedar 

by location, the unusual phylogeographic patterns described in this paper (i.e., 

affinity between populations from Alaska and Oregon) may be inaccurate. Forest 

managers are advised to avoid making interpretations based on this paper until 

the results are confirmed with genetic markers with higher discriminatory power 

between individuals.

Microsatellite variation—Two studies have described 14 microsatellite loci from 

the nuclear genome of yellow-cedar. Bérubé et al. (2003) used a yellow-cedar source 

from British Columbia to produce a library of genomic clones enriched in microsatellite sequences; from this pool, five loci showed expected segregation in known 

pedigrees. The second study used a yellow-cedar source from Alaska (Petersburg 

Ranger District) to produce a library of 489,000 DNA sequences (Jennings et al. 

2011, 2013). Screening of 96 repeat-containing regions revealed 9 loci that conformed to Hardy-Weinberg expectations in Alaskan populations. 

Individual microsatellite markers reveal 20 times more genetic variation than do 

allozymes (table 10). When combined, the available microsatellite markers have the 

potential to resolve >1 billion unique genotypes. The markers identified by Jennings 
51

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 10—Microsatellite variation (standard deviation) in yellow-cedar compared to allozyme variation

Marker sourcea A

H

exp

 o 

(HT) F

Maximum unique 

genotypes possible Reference

6 polymorphic 

allozymes

1.7 0.17 0.18 216 Ritland et al. (2001)

5 SSRs, British 

Columbia source

13.7 0.59 0.16 6.3 × 104 Bérubé et al. (2003)

9 SSRs, Alaskan source 23.8 0.80 (0.045) -0.034 (0.11) >109 Jennings et al. (2013)

a

 Abbreviations: A = average number of alleles per locus; Hexp = expected heterozygosity; Ht = total heterozygosity; F = inbreeding coefficient, 

SSR = short simple repeat marker. In this table, percent polymorphic loci (PPL) for microsatellite markers is 100 percent for all markers, so it is 

not listed.

et al. (2013) show the highest average variability for Alaskan sources of yellow-cedar 

(table 10). High per-locus variability translates into high resolution and accuracy for 

identifying clonal genotypes, discriminating individuals with high coancestry (e.g., 

sibs in breeding programs; Massah et al. 2010), and clarifying patterns of genetic 

relatedness and divergence at fine spatial scales (e.g., Thompson et al. 2008). 

Despite their advantages, microsatellites have limitations, and most notable 

for yellow-cedar is the failure of alleles to amplify with equal efficiency. Alleles 

that are selected against in the polymerase chain reaction process (“null” alleles) 

cannot be detected, and null alleles distort estimates of identity and inbreeding. 

Null alleles were reported in the five microsatellite markers used by Bérubé et al. 

(2003), and these same markers are known to perform poorly in Alaskan sources of 

yellow-cedar (personal communication 2014, Tara N. Jennings, U.S. Forest Service, 

Forestry Sciences Laboratory, Corvallis, OR). Because the microsatellite markers designed by Jennings et al. (2013) were derived from an Alaskan source, they 

should be considered the first choice for future studies of yellow-cedar in Alaska.

Microsatellite-based evidence for natural clonal propagation rates—As noted in 

“Reproduction and regeneration,” yellow-cedar is one of a small number of conifers 

that reproduce clonally and may tolerate self-pollination. The processes can dramatically influence the genetic structure of yellow-cedar on a local scale (Bérubé 

et al. 2003, Thompson et al. 2008). Offspring from ramets of the same genet possess limited capacity for dispersal, and the close proximity of clones increases the 

probability of self-pollination between ramets (Vallejo-Marín et al. 2010). This 

situation contributes to a localized increase in self-pollination, which increases the 

local rate of inbreeding. The multiplicative effects of clonality and self-pollination 

can produce mosaics of genetically uniform trees that form repeatedly across the 

landscape. The long-term fate of self-pollinated individuals is not understood for 

yellow-cedar; young trees may express inbreeding depression and show high 
52

GENERAL TECHNICAL REPORT PNW-GTR-917

mortality at early life stages, or they may show reduced fertility. The local 

clustering of clones has practical considerations for seed collection and restoration 

(Russell and Krakowski 2012, Thompson et al. 2008).

Ritland et al. (2001) provided the first evidence for clonality in yellow-cedar, 

although the allozyme markers used in this study lacked the power to discriminate 

individual trees separated by large distances (e.g., hundreds of miles). The microsatellite-based study of Bérubé et al. (2003) had sufficient power to show that clones 

were abundant at the three sampled populations, and that they ranged in frequency 

from 10 percent at Mount Seymour, B.C., to 25 percent at Black Tusk, B.C. Thompson et al. (2008) conducted more extensive surveys from the same populations and 

showed that clonal reproduction could account for 70 percent of the trees in plots 

approximately 1/8 ac in size. The largest clonal patch discovered by these authors 

was 43 ft long. Cloning in yellow-cedar has been described in Alaska based on 

physical connections of roots and branches in groups of trees (Hennon et al. 1990), 

but the extent and maximum size of a clone are not yet known. An ongoing study 

aims to determine the size and frequency of clones along transects in Alaska. 

A large, rangewide survey of yellow-cedar from 129 populations (Cronn et al. 

2014) found a studywide average of 3.2 percent of repeated genotypes. Three pairs 

of repeated genotypes were shared between populations, separated by remarkable distances of 48 mi, 88 mi, and 227 mi. Sharing of repeated genotypes at this 

scale could be due to chance, back-mutation to the same microsatellite genotype 

in unrelated plants, or long-distance dispersal of cones or vegetative material by 

cataclysmic events such as flooding in coastal forests (e.g., storms or tsunamis). 

Cataclysmic dispersal may seem improbable, but back-mutation is equally improbable. To highlight how unusual repeated genotypes are, a recently completed 

microsatellite survey of nearly 1,100 wild-collected trees of a related conifer 

(Port-Orford-cedar) revealed no repeated genotypes (Cronn et al. 2013).

Microsatellite-based evidence for natural self-pollination and inbreeding rates—

Given the potential for clonal reproduction, inbreeding rates could be elevated in 

yellow-cedar, potentially giving rise to patchy, less random distribution of genetic 

variation on the landscape. The most common measure of inbreeding is Wright’s 

inbreeding coefficient (F), which measures the difference in observed (HO ) and 

expected (HE) heterozygosities, scaled to the expected heterozygosity (HE – HO / 

HE). Restated, F provides an indication of whether populations show a deficiency 

of heterozygotes (inbreeding condition) or an excess of heterozygotes (outbreeding 

condition), relative to equilibrium expectations. If the rate of self-pollination is constant across generations, then the self-pollination rate is approximately proportional 

to F through the relationship 2F / (1 + F).
53

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 11—Comparison of allozyme and microsatellite variation in yellow-cedar 

Study

Populations 

screened

Screening 

method

Inbreeding 

coefficient (F)

Self-pollination 

rate

Percent

Ritland et al. (2001) 17 allozyme 0.180 30.5

Bérubé et al. (2003) 3 SSRa 0.160 27.7

Thompson et al. (2008) 9 SSR 0.146 25.5

Cronn et al. (2014) 109 SSR 0.037 7.2

a SSR = short simple repeat markers.

Published inbreeding rate estimates for British Columbia yellow-cedar are very 

high, with experimentwide averages ranging from 0.146 (Thompson et al. 2008) to 

0.18 (Ritland et al. 2001), and with stand-specific values of 0.40 (Thompson et al. 

2008). Values of this magnitude suggest that self-pollination rates could average 30 

percent, and approach 60 percent at the stand level. 

In the recent large survey of 129 populations of yellow-cedar mostly from 

Alaska (Cronn et al. 2014), F averaged 0.037 (table 11), which is equivalent to an 

overall self-pollination rate of 7.2 percent. This study suggests more moderate levels 

of inbreeding in yellow-cedar, with values that are similar to estimates from other 

conifers (typically <0.1 for wind-pollinated conifers; Ledig et al. 1998). Inbreeding estimates show a geographic trend where the highest levels of inbreeding are 

generally observed in British Columbia and in Alaska at a latitude of about 57.5° 

N (near Sitka), and the lowest inbreeding values are observed in the northernmost 

populations. 

Landscape-level spatial genetic variation in yellow-cedar— 

To date, two studies have examined landscape-level spatial genetic structure in native stands of yellow-cedar. Rangewide spatial genetic variation was first estimated 

with nuclear allozymes (Ritland et al. 2001) and more recently with microsatellites 

(Cronn et al. 2014).4

 The allozyme-based study of Ritland et al. (2001) showed that 

13.9 percent of the total genetic variation was apportioned among populations. This 

finding was noted as “striking” by the authors because it was unusually high relative to other studied conifers (Ritland et al. 2001). Differentiation among Alaskan 

populations was not formally calculated, but this study showed unexpectedly high 

similarity between Alaskan populations and distant sources (e.g., Juneau and 

4

 Also unpublished data on file with R.C. Cronn, USDA Forest Service, Pacific Northwest 

Research Station, Forestry Sciences Laboratory, 3200 Jefferson Way, Corvallis, OR 97331.
54

GENERAL TECHNICAL REPORT PNW-GTR-917

Oakridge, Prince William Sound and Haida Gwaii in British Columbia; compare 

Ritland et al. 2001: fig. 2). 

Recently, evaluation of 129 populations in Alaska and British Columbia by 

Cronn et al. (2014) showed that a much smaller (but significant) share of the genetic 

variation is apportioned among populations, averaging about 3.1 percent when 

based on allelic state. These authors tested whether spatial genetic differentiation 

was associated with climatic factors, isolation-by-distance, and two hypothetical 

migration scenarios, but the results showed that genetic variation—while extensive—was not correlated with climate or geography. Instead, the distribution of 

genetic variation appears patchy and heterogeneous, as if each population were 

founded by a moderate number of unrelated individuals that subsequently increased 

the population size through mostly sexual reproduction. This ”absence of structure” 

pattern for southeast Alaska and northern British Columbia (fig. 27) contrasts with 

the clear pattern of isolation-by-distance exhibited by western redcedar (O’Connell 

et al. 2008), and it provides evidence that yellow-cedar and western redcedar are 

unlikely to have shared similar Pleistocene refugia or similar migration histories. 

Although the absence of genetic signal for recent migration pathways makes it 

difficult to address the location of yellow-cedar Pleistocene refugia, it is consistent 

with hypotheses that Pleistocene refugia were geographically proximal to modern 

populations in coastal Alaska and British Columbia, such as Haida Gwaii or other 

offshore refugia that have become submerged since the Pleistocene (Buma et 

al. 2014, Warner et al. 1982). If recent Pleistocene glaciation history imparted a 

“signature” of migration history on the yellow-cedar genome, the signal is subtle 

Figure 27—Different spatial genetic structure and post-Pleistocene migration scenarios evaluated 

with microsatellite genetic markers (Cronn et al. 2014.). Genetic evidence shows that neither of the 

competing migration hypotheses (“coastal refugium,” “southern refugium”) is supported by current 

patterns of genetic diversity. Instead, modern-day populations best fit a pattern of “unstructured 

populations,” and this pattern is consistent with recent migration from nearby coastal refugia. 
55

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

and cannot be detected from changes in microsatellite allele frequencies. Larger 

chromosome-scale genome sampling methods may show much finer discrimination, as has recently been shown for human populations over a small geographic 

range (Leslie et al. 2015).

Molecular genetic data cannot answer all questions of yellow-cedar population 

history and differentiation; however, studies to date show that the founding source 

or sources for yellow-cedar in Alaska were genetically diverse, that they expanded 

at an exponential rate, and that the variation is still being sorted across coastal 

Alaska and adjacent British Columbia.

Paleoecology

Long-term history of Cupressaceae— 

The Cupressaceae family evolved some 200 million yr ago in the Triassic period 

(Taylor and Taylor 1993). Taxa with affinity to yellow-cedar first appeared in the 

Miocene (Kotyk et al. 2003), although similar macrofossil foliage dates to the 

Eocene (Axelrod 1976) and cones date to the Late Cretaceous. The fossil record 

indicates that close relatives of yellow-cedar were once more broadly distributed 

in the Northern Hemisphere than at present. As of today, they appear to have been 

confined to moist climates, and some species were lost with climate shifts to drier 

environments (Kotyk et al. 2003). 

Pleistocene and Holocene epochs—Paleoecology studies offer some understanding of the species composition of forests in coastal Alaska that emerged and developed as the major ice sheets from the Pleistocene retreated from their maximum 

advancement some 20,000 yr ago. In southeast Alaska, climate during the late 

Pleistocene and the subsequent Holocene epoch can be interpreted from the composition of trees and other plants in pollen profiles taken from lake and peat sediments, including 17 sites investigated by Heusser (1952, 1960). These pollen profiles provide direct evidence of the postglacial abundance of conifers in southeast 

Alaska; however, there is the possibility of some long-distance pollen dispersal 

from trees not growing locally (Elias 2013). Although macrofossils (e.g., foliage, 

cones, and wood) can also be used to detect the history of vegetation, pollen is particularly useful because it integrates plant abundance from surrounding areas. But 

some species’ pollen cannot be readily distinguished in the pollen record, or may 

undergo more rapid breakdown, thus artificially deflating an estimate of the relative 

abundance of a species in the pollen record (Heusser 1960).
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GENERAL TECHNICAL REPORT PNW-GTR-917

Temperatures and precipitation about 4,500 yr ago appear to have reached 

levels somewhat similar to the current maritime climate, both in Alaska (Heusser et 

al. 1985) and in British Columbia (Mathewes and Heusser 1981). This approximate 

date corresponds to the establishment of modern western hemlock-Sitka spruce 

forest composition evident in many pollen cores (Viens 2001) (table 12). 

Unfortunately, yellow-cedar was not included in the early pollen studies 

because, as Heusser (1960: 78) stated, the pollen of Chamaecyparis and some other 

species had “fragility and non-resistance to decay... [Therefore] it was decided 

they be omitted” from analysis. Another problem is that pollen of yellow-cedar 

is difficult to distinguish from that of western redcedar and juniper, and is often 

tallied as “Cupressaceae pollen” or “cedar-type pollen.” The Cupressaceae family 

was included in several more recent pollen studies in British Columbia just south 

of Alaska and reportedly became abundant about 7,000 yr ago (Banner et al. 1983, 

Hebda and Mathewes 1984), which indicated a cooling trend in climate.

A cool, wet climate with its associated development of poorly drained organic 

soils (Ugolini and Mann 1979) favors both cedar species (Banner et al. 1983, Hebda 

1983). The arrival of western redcedar in Alaska was probably via migration up 

the coast from southerly distributions (Hebda and Mathewes 1984, O’Connell et al. 

2008). At several sites, evidence from pollen studies indicates that the first Cupressaceous pollen likely to be from yellow-cedar appeared about 5,000 yr ago, and that 

it became locally abundant in the following millennia. Ager and Rosenbaum (2007) 

showed that cedar pollen on Prince of Wales Island (Pass Lake) dates to about 5,000 

yr before present, and that it became abundant 1,500 yr ago. Hebda (1983) reported 

that Cupressaceae pollen made a relatively recent appearance about 3,000 yr ago in 

pollen profiles at a bog site on northern Vancouver Island. Farther north at Mitkof 

Island near Petersburg, cedar pollen became abundant only about 2,200 yr ago 

(Ager et al. 2010). Studies similar to these could begin to fill in the historical occurrence of yellow-cedar at different locations in Alaska.

Table 12—Interpretation of late Pleistocene and Holocene climate and dominant 

vegetation in southeast Alaska (adapted from a narrative in Viens 2001) 

Geologic epoch Years before present Climate Dominant vegetation

Late Pleistocene 16,000–12,500 

12,500–9,000

Cool, dry 

Warm, dry

Tundra/shrubs 

Pine, alder, willow

Holocene 9,000–6,800 

6,800–4,500 

4,500–present

Warm, wet 

Trending wet, cool 

Cool, wet

Spruce, hemlock 

Hemlock, spruce, cedar 

Modern flora
57

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Debate over Pleistocene refugia and migration pathways in Alaska—The two 

cedars, western redcedar and yellow-cedar, may have different origins and history 

in Alaska. A recent review paper (Elias 2013) dismissed the possibility of latePleistocene refugia as origins for tree species in Alaska and argued that the closest 

possibilities were in Haida Gwaii. A response paper (Buma et al. 2014) provides 

evidence of the Alaska refugia by summarizing information from geology, positions of glacial maximum, small-mammal genetics, and tree species distributions 

and migration rates. 

Yellow-cedar has an incomplete current distribution in coastal Alaska, with 

some large areas of apparently suitable habitat unoccupied (see “Yellow-Cedar 

Distribution,” this section). The variable presence and absence of yellow-cedar in 

suitable areas has been noted in the three plant association guides for the Tongass 

National Forest (DeMeo et al. 1992, Martin et al. 1995, Pawuk and Kissinger 1989). 

This distribution pattern led us to hypothesize that the rarity of yellow-cedar in the 

northeastern portion of the panhandle is explained by the distance from the suspected Alaska glacial refugia (Carrara et al. 2003) and the likelihood of an eastward 

migration from refugia in the western coastal areas. The discontinuous occurrence 

of yellow-cedar along the Gulf of Alaska with presence in Prince William Sound 

also aligns with the respective absence and presence of known refugial areas. 

Yellow-cedar may be able to persist during unfavorable climatic episodes, (e.g., the 

early Holocene epoch) on wet microsites, such as those with abundant soil moisture 

from groundwater discharge, and may possibly be aided by its ability to survive 

in shrubby form (layering) (Hebda 1997). Relative to other tree species, a slow 

postglacial migration from refugia in the western parts of the panhandle and small 

populations in Prince William Sound could reflect the poor regeneration capacity 

of yellow-cedar (Harris 1990, Klinka 1999) and strict germination requirements 

(Pawuk 1983).

As noted under “Genetics,” little of the genetic variation described for yellowcedar (Cronn et al. 2014, Ritland et al. 2001) is currently explained by geography, 

and this result may be a consequence of the recent recolonization history of yellowcedar in Alaska. If palynological evidence is correct in placing yellow-cedar to 

these dates, the average generation time (defined as years required for offspring 

to replace parent in stand) for yellow-cedar is probably measured in hundreds of 

years, and only 15 to 50 generations of trees separate modern-day populations from 

the founding events that gave rise to these stands. The high genetic variability of 

yellow-cedar in Alaska shows no evidence of a genetic bottleneck, and is consistent 

with yellow-cedar occupancy in Alaska throughout the Pleistocene. Our current 

understanding of the broad-scale genetic structure does not reveal patterns of 
58

GENERAL TECHNICAL REPORT PNW-GTR-917

Holocene migration, whether they are from origins in British Columbia or Alaskan 

refugia. Nor does it currently distinguish the isolated populations in Prince William Sound, which may have originated from ice-free refugia near the outer coastal 

Hinchinbrook and Montague Islands.

Little Ice Age—More recently, a cooler shift, known as the Little Ice Age, occurred in the Northern Hemisphere beginning ≥500 yr ago. The onset of the Little 

Ice Age is uncertain, with initial dates of 1200–1500 C.E. given in the literature. 

The influence of the Little Ice Age on the climate of forested regions in southeast 

Alaska is not clearly understood, but advances and retreats of glaciers are consistent with changes in the climate in ice fields at higher elevations than where forests grow (Viens 2001). During the Little Ice Age most of the glaciers in coastal 

Alaska reached their maximum extensions of the last 13,000 yr since the end of the 

Pleistocene epoch (Calkin et al. 2000). It is not known whether these glacial advances were driven by colder temperatures or by increased snowfall. 

The end of the Little Ice Age in the mid-to-late 1800s was associated with 

the onset of yellow-cedar decline, which we have dated as beginning in about 

1880–1900 (see section 2). The ages of mature yellow-cedar trees, whether they are 

dead or still living, indicate that most regenerated and attained upper canopy status 

during the Little Ice Age (Beier et al. 2008, Hennon and Shaw 1994). We hypothesize that this favorable climate allowed yellow-cedar to regenerate prolifically, 

even at low elevations, where it would later be most vulnerable to decline. Therefore, yellow-cedar forests are composed of trees that regenerated and grew during a 

favorable climate, but have since been subjected throughout portions of the range to 

a different climate that exposes them to fine-root freezing injury and decline. 

Dendrochronology

Laroque and Smith (1999) produced the first tree ring chronology for yellow-cedar. 

This study was located in high-elevation forests of Vancouver Island. Later, Colin 

Beier and Scott Sink, then graduate students at University of Alaska Fairbanks, 

conducted a dendrochronology study of yellow-cedar in southeast Alaska, in both 

dying and healthy forests (Beier et al. 2008). Their 400-yr chronology of yellowcedar is the most complete ring chronology for any tree species in southeast Alaska. 

Yellow-cedars currently growing in both declining and healthy forests had similar 

patterns of growth until late in the 1800s, at which point growth patterns departed. 

This publication also reviewed weather station data back through the 1900s and 

related radial tree growth of yellow-cedar to climate data. The authors correlated 

tree ring growth with weather variables that represent particular thaw-freeze cycles 

in the weather record. Their assessment of climate through the 1900s reveals trends 
59

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

consistent with the prevailing hypothesis for yellow-cedar decline: the timing 

of decline injury (resulting in smaller ring widths) was associated with warmer 

winters, less snow, and persistent cold events in late winter through early spring. 

Stan et al. (2011) provide a chronology for yellow-cedar in coastal British Columbia, 

including results showing “marker years” of very poor growth in declining stands. 

They also used cross-dating methods to establish time-since-death estimates for 

yellow-cedar snags. Robertson (2011) produced chronologies for 50 yellow-cedar 

trees in the North Cascade Mountains of Washington. Wiles et al. (2012) produced 

a chronology for yellow-cedar in and near Glacier Bay National Forest at two sites 

north of the distribution of yellow-cedar decline. They report differing tree ring 

responses to temperatures from January through July in episodes during the Little 

Ice Age and periods that followed. They interpreted the observed pattern as the 

initiation of tree stress—but not extensive tree mortality—in response to reduced 

snowpack. Before 1999 there were no published dendrochronology studies for 

yellow-cedar, and now there are five, representing an extensive range of latitudes 

and forest health conditions.

Ecology and Silvics 

General Habitat Characteristics

Yellow-cedar has a defensive ecological strategy, in that it survives on harsh sites 

with limited competition from other species, invests less in reproduction or fast 

growth, and outlives competitors by accumulating defensive compounds in heartwood and foliage. These characteristics make yellow-cedar less competitive on 

productive sites with deep soils. When it does occur on such sites, however, yellowcedar can achieve its fastest growth and greatest stature (fig. 28). More often, 

yellow-cedar composition increases in the middle of the gradient from high to low 

site productivity, as it is able to tolerate poorly drained and shallow, nutrient-poor 

soils (Martin et al. 1995, Neiland 1971). 

Freezing sensitivity has been identified as a key vulnerability of yellow-cedar; 

inadequate snowpack in spring results in freezing injury to fine roots during cold 

weather events, gradually resulting in tree mortality. On sites with poor drainage 

and nutrient availability, yellow-cedar is adapted to root shallowly, exposing roots 

to greater fluctuations in air and soil temperature (D’Amore and Hennon 2006; 

Hennon et al. 2006, 2010). Therefore, throughout much of its range, yellow-cedar is 

most vulnerable to decline on the low-productivity sites on which it previously had 

a competitive advantage. This topic is the focus of section 2. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Table 13—Associated tree species that grow with yellow-cedar in different 

regions of its range (Harris 1990)

Location Associated tree species

Alaska Western hemlock, mountain hemlock, Sitka spruce, western 

redcedar, shore pine

British Columbia Western hemlock, mountain hemlock, western redcedar, shore 

pine, pacific silver fir, western white pine 

Oregon and Washington Western hemlock, mountain hemlock, subalpine fir, whitebark 

pine, Pacific silver fir, noble fir, western white pine 

California California red fir, Brewer spruce, incense-cedar, Pacific yew, 

western white pine

Forest Types and Plant Communities

Yellow-cedar tends to grow singly or in scattered clumps intermixed with other 

tree species (table 13), and rarely grows in pure stands (Harris 1990). Yellow-cedar 

stands typically have multiple canopy layers composed of trees of various ages, 

indicating gap-phase regeneration and a lack of catastrophic disturbance. Associated tree species vary by latitude. Yellow-cedar grows from low elevation to near 

tree line in the northern extent of its range, and is limited to progressively higher 

Figure 28—A yellow-cedar tree, visible with silvery gray bark, in a productive western hemlockdominated forest. Yellow-cedar trees are less abundant in productive forests but often attain their 

largest diameter and height there. 
61

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

elevations in the southern portion of its range. The composition of the plant community associated with yellow-cedar in a given latitude zone is largely controlled 

by soil drainage, climate, elevation, and aspect.

In Alaska, the Tongass National Forest developed three plant association guides 

for administrative areas arranged from north to south: the Chatham Area (Martin 

et al. 1995), the Stikine Area (Pawuk and Kissinger 1989), and the Ketchikan Area 

(DeMeo et al. 1992). These somewhat independent plant association guides were 

created because of the large size and the extensive north-south range of the Tongass 

National Forest. Although there is general consistency in series and associations 

across these areas, as defined by dominant overstory and understory vegetation, 

there are also key differences due to temperature trends and limits on species distributions along the north-south gradient. For example, western redcedar and salal 

are temperature-dependent species common in the southern Ketchikan Area that 

reach their northern range extent in the mid-latitude Stikine Area. Another example 

is that mountain hemlock, which has a competitive advantage over western hemlock 

on colder and more poorly drained sites, is able to persist and dominate at lower 

elevations in the northern Chatham Area than in the Ketchikan Area. Develice et al. 

(1999) produced a guide of plant community types for the Chugach National Forest 

that covers the areas where yellow-cedar grows in Prince William Sound. 

There are different estimates of how yellow-cedar contributes to the total acreage and volume of the forests of southeast Alaska and coastal areas along the Gulf 

of Alaska. Early estimates undervalue yellow-cedar’s importance because they do 

not include unproductive (lower volume, noncommercial) forests (i.e., <8,000 board 

ft/ac). Yellow-cedar and western redcedar received only passing consideration in 

Hutchinson’s (1968) assessment of Alaska’s resource because markets for these species did not exist at the time. Western hemlock and Sitka spruce combined to make 

up 99 percent of the log production in that era. Acreage estimates of 5.8 percent 

presumably combined both cedar species as “cedar” forest type and the growing 

stock estimate was reported for redcedar, but not yellow-cedar. Van Hees (2003: 

17 and fig. 19) estimated that yellow-cedar composed 9 percent of net volume of 

unreserved timberland in southeast Alaska. This amounted to 1.93 billion ft3

. Timberland is forestland that is capable of producing >20 ft3

/ac/yr, so lower productivity 

forests, as well as all reserved lands (e.g., wilderness areas and national parks), were 

excluded. 

Barrett and Christensen (2011) reported estimates of yellow-cedar in forests of 

all ownerships for coastal Alaska extending from the panhandle to Prince William 

Sound and the Kodiak area. Table 42 of that publication gave an estimate of 12.1 

percent for the amount of forest volume that is considered to be the yellow-cedar 
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GENERAL TECHNICAL REPORT PNW-GTR-917

forest type (i.e., all species in these stands). Table 43 reported a volume estimate 

of 5.9 billion ft3 of live yellow-cedar trees, which is 10.5 percent of all tree species 

between 2004 and 2008. An estimated 89.4 percent of this volume of yellow-cedar 

was on lands managed by the Forest Service (table 43). The estimated yellow-cedar 

volume would be a marginally higher percentage if only forests in southeast Alaska 

were considered, as the species is not abundant west of the panhandle. 

The forests of southeast Alaska can be viewed as a fine-scale mosaic of series 

and plant associations, driven by complex landscape patterns of soil drainage 

and soil depth (Martin et al. 1995). It is important to note that yellow-cedar is not 

limited to a single plant association. Yellow-cedar is a common component of the 

western hemlock-yellow-cedar series across the three administrative areas of the 

Tongass National Forest, but can also occur as a component of mixed-conifer, 

mountain hemlock, western hemlock, shore pine, and other series. The plant associations that contain yellow-cedar are arrayed across the drainage gradient. Yellowcedar can grow on productive, well-drained sites, but is usually outcompeted by 

western hemlock (Klinka 1999). The mixed-conifer series generally occurs on less 

productive and poorly drained sites than the western hemlock-yellow-cedar series; 

the mountain hemlock series occurs on cooler (high-elevation) sites. Yellow-cedar 

is also a component of the shore pine series on very poorly drained, low-productivity bog or fen sites that have acidic soils with high organic content. Some series 

and associations that contain yellow-cedar are designated as wetlands and require 

special care when actively managed. 

Drainage is the most important environmental factor affecting series and 

association distributions in southeast Alaska. The open, poorly drained sites on 

which yellow-cedar has a competitive advantage over western hemlock are also the 

sites where it is most vulnerable to root freezing injury due to its shallow rooting 

habit and exposure to dramatic fluctuation in soil temperature (see section 2). 

Furthermore, yellow-cedar is most competitive on nutrient-poor sites with wet soils 

(Gregory 1957, Hennon and Shaw 1997, Krajina 1969, Minore 1983). Biogeographic 

evaluations of yellow-cedar establish it as a hydrophilic species occurring in wet 

habitats of British Columbia where soil moisture is maintained by average precipitation of >88 in, mostly as snow (Krajina 1969). Yellow-cedar is competitive on wet, 

poorly drained soils, as indicated by understory plants in southeast Alaska (Hennon 

et al. 1990b), although large yellow-cedar trees have been documented on better 

drained soils (D’Amore and Hennon 2006). As mentioned previously, yellow-cedar 

is a calcium accumulator and therefore grows best in areas with calcium-bearing 

rocks (Krajina 1969) or soils rich in calcium and magnesium (Krajina 1969, Minore 

1983).
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 14—Biogeoclimate and ecological distribution of yellow-cedar in north coastal British Columbiaa

Subzone or variantb

CWHvh2 CWHvm1 CWHvm2 MHmm1 MHwh1

Elevation range 0–600 m 0–400 m 400–800 m 800–1200 m 600–1100 m

Physiographic 

region

Hecate Lowland Western slope of 

Coast Mountains

Western slope of 

Coast Mountains

Western slope of 

Coast Mountains

Hecate Lowland

Climate Hypermaritime; 

cool, very mild 

with very little 

snow; foggy and 

rainy year round

Wet, humid, mild 

maritime climate 

with relatively little snow and long 

growing season

Cooler with 

shorter growing season and 

much heavier 

snowpack than 

CWHvm1

Maritime, cool 

and very wet 

year round with 

deep, wet snow 

(up to 10 ft); 

soils never freeze

Hypermaritime; 

mild, foggy, 

wet with wet 

intermittent 

snowpack 

(<1.6 ft)

Associated tree 

species (in decreasing order 

of occurrence)

Western redcedar, 

western hemlock, lodgepole 

pine, c mountain 

hemlock

Western hemlock, 

Pacific silver fir, 

western redcedar, 

Sitka spruce

Western hemlock, 

Pacific silver 

fir, mountain 

hemlock

Mountain hemlock, Pacific 

silver fir, western 

hemlock

Mountain hemlock, western 

redcedar, western hemlock, 

Sitka spruce, 

lodgepole pinec

a

 This information may not apply to the small populations of yellow-cedar near Slocan Lake and Evans Lake or those to the south in British Columbia. 

b

 CWHvh2 = Coastal Western Hemlock Zone very wet hypermaritime central variant, CWHvm1 = Coastal Western Hemlock Zone very wet maritime 

submontane variant, CWHvm2 = Coastal Western Hemlock Zone very wet maritime montane variant, MHmm1 = Mountain Hemlock Zone moist 

maritime windward variant, MHwh1 = Mountain Hemlock Zone wet hypermaritime windward variant. Source: Banner et al. (1993).

c

 Lodgepole pine refers to the species level; shore pine is the subspecies most commonly associated with yellow-cedar.

In British Columbia, plant communities are described within the context of 

biogeoclimate zones (table 14). Yellow-cedar is most abundant in the windward 

portion of higher elevation Mountain Hemlock subzones, but is also widely distributed throughout the very wet, low- to moderate-elevation Coastal Western 

Hemlock subzones (Banner et al. 1993, Klinka et al. 2000, Pojar et al. 1987). These 

areas encompass much of the outer coast of British Columbia, including the Queen 

Charlotte Islands, the western side of the Coast Mountains, and the Hecate Strait. 

Consult Antos and Zobel (1986) and Lesher and Henderson (2010) for plant community relationships in yellow-cedar forests in Oregon and Washington. 

Geology and Soils

Yellow-cedar is associated with several specific site attributes. Yellow-cedar may 

gain competitive advantages in nutrient cycling, regeneration, or other processes on 

some sites, but it can grow on an extensive and diverse array of landscapes and soil 

types. Yellow-cedar is most competitive in certain areas due to several adaptations 

and nutrient acquisition strategies.
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GENERAL TECHNICAL REPORT PNW-GTR-917

The reason that cedars persist and are competitive on marginal sites is not 

evident from silvicultural or mineral nutrition studies. The site productivity in most 

yellow-cedar forests is low because of the low turnover and supply of nutrients, 

especially nitrogen (Prescott and Preston 1994). Numerous studies have identified 

the distinctive trait of yellow-cedar and redcedar to accumulate calcium in their 

tissues (Alban 1969, Kranabetter et al. 2003). Calcium accumulation in the foliage 

of trees in the Cupressaceae family is significantly higher compared to trees in the 

Pinaceae family (Kiilsgard et al. 1987, Zobel et al. 1985). Calcium-rich, partially 

decomposed plant litter with elevated pH (higher alkalinity) has been detected on 

the forest floor beneath cedar trees and attributed to higher foliar calcium concentrations compared to other tree species (Alban 1969, Turner and Franz 1985). The 

forest floor chemistry in a cedar forest in British Columbia exhibited higher protein 

content in organic matter compared to western hemlock and Douglas-fir forests 

(Klinka and Lowe 1975). The presence of proteins may be an indicator of favorable 

microbial turnover or mineralized soil organic matter.

Adaptations to Wet Soils and Related Nutrient Cycling

As noted previously, yellow-cedar is competitive on marginal sites with low productivity, nearly saturated soils, and open canopy conditions (Martin et al. 1995). On 

sites with high water tables, yellow-cedar is adapted to root shallowly and concentrate fine root growth near the soil surface; this strategy allows roots to respire and 

avoid hypoxia under saturated conditions. Photosynthetic rates of yellow-cedar 

are highest when water availability is not limited, and decreases with increasing 

moisture stress (Grossnickle and Russell 1991). However, yellow-cedar is plastic 

in its physiological response to environmental conditions, and can stop and start 

growing in response to temperature and, potentially, chemical signaling (Grossnickle and Russell 2006). Grossnickle and Russell (2010) summarize the extensive 

research conducted in British Columbia on the physiology of yellow-cedar. The 

ability of yellow-cedar to persist on marginal sites, where nutrient turnover is low 

and soil rooting depth is limited, may be due to its ability to exploit periodic pulses 

in nutrient availability or other favorable soil conditions (D’Amore et al. 2009). 

Yellow-cedar trees diversify the landscape by occupying soils where other conifers 

cannot grow well. By doing so, yellow-cedar may be tapping sources of nutrients in 

a complementary manner with other tree species to enhance productivity on sites 

(McKane et al. 2002). 

Yellow-cedar absorbs more calcium than it needs, and this is part of a mechanism for obtaining nitrogen. Plants need large amounts of nitrogen to grow but are 

unable to use abundant atmospheric nitrogen, requiring it in the form of ammonia 
65

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

(NH4

+

) or nitrate (NO3

-

). Yellow-cedar commonly grows on acidic soils that have 

inadequate nitrogen for plant growth. Yellow-cedar and some related species are 

able to convert nitrogen gas into a usable form in their leaf cells. This process 

produces the toxic free radical oxalate as a byproduct. Calcium in the leaves binds 

oxalate into a stabile nontoxic compound. An adaptive strategy for nutrient acquisition that may facilitate tree survival on nutrient-poor sites is coupled assimilation 

of calcium and nitrogen (D’Amore et al. 2009). The “cedar-nitrate hypothesis” has 

been proposed as a mechanism that gives yellow-cedar a competitive edge, and 

facilitates its survival, on poor, acidic sites (D’Amore et al. 2009). This scenario 

enables some tree species to assimilate nitrogen as NO3

-

 by accumulating a counterion to nitrate, such as calcium in the form of Ca2+, to control internal cell pH and 

provide electrochemical balance. This process is favored near the soil surface, 

where aerobic soils promote nitrification (microbial oxidation of NH4

+

 to nitrite and 

then nitrate). Anaerobic conditions and low soil pH significantly reduce the activity 

of nitrifying bacteria (Richards 1987). 

Calcium in cedar foliage also has important effects after foliage senesces and 

falls to the forest floor. Upon decomposition, foliar calcium makes soil less acidic, 

thereby increasing both calcium and nitrogen availability in the soil. Within foliage, 

calcium may also affect the production and cycling of organic acids, discouraging 

herbivores and increasing litter decomposition rates. In combination, saturated soil 

conditions and higher nutrient availability in aerobic soils promote prolific fineroot growth of yellow-cedar near the soil surface, where the trees are vulnerable to 

periodic spring freezing injury. 

The foliage of yellow-cedar and other members of the Cupressaceae family 

contains higher concentrations of calcium than that of other species, and can therefore 

lead to increased soil calcium and soil pH below their canopies (see “Geology and 

soils”). Near Ketchikan, yellow-cedar foliage contained about 10.6 g/kg calcium; 

western redcedar contained 75 percent as much, and Sitka spruce and hemlock species contained only about 20 percent as much as yellow-cedar (Schaberg et al. 2011). 

Under more moderate alkaline soil conditions, increased microbial activity and shifts 

in microbial community composition favor the availability of nitrate. These biochemical changes in forests that contain yellow-cedar are thought to have broad impacts on 

nutrient cycling at the landscape or watershed level (D’Amore et al. 2009).

Rooting Habits

As noted previously, yellow-cedar occurs across a gradient of productivity and soil 

drainage, with its fastest and best growth on sites with well-drained, deep soils as 

well as soils rich in base cations (Krajina 1969). Yellow-cedar attains its greatest 
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GENERAL TECHNICAL REPORT PNW-GTR-917

competitive status, however, on poor sites with shallow soils and high water tables. 

These differing soil properties foster deeper or shallower rooting habits. Where 

insulating snow is not present in the winter and early spring, growth of fine roots 

in the surface soil horizons on saturated sites increases yellow-cedar’s vulnerability 

to root freezing injury. Even with limited snowpack, however, yellow-cedar is 

apparently protected from freezing injury where its roots penetrate subsurface soil 

horizons. Soil temperature monitoring in yellow-cedar forests shows that soils 6 in 

or deeper do not frequently freeze (Hennon et al. 2010). 

Characteristics of the rooting habit for mature yellow-cedar trees on welldrained sites are not generally available. It is difficult to predict where roots 

from large trees occur, either vertically or laterally, and this represents a critical 

knowledge gap for yellow-cedar and other tree species. Rooting depth is thought 

to be an important predisposing factor for yellow-cedar decline (D’Amore et al. 

2009, Hennon et al. 2012). Most information on yellow-cedar rooting depth is based 

on knowledge of tree physiology as it relates to soil drainage (i.e., trees root more 

shallowly on sites with high water tables to allow for root respiration and nutrient 

uptake). Both yellow-cedar and redcedar have optimum root growth when the soil 

temperature is about 71 °F, and growth decreases 7 percent per 1.8 °F below the 

optimum (Grossnickle and Russell 2010). This optimum temperature exceeds a typical shallow soil temperature in yellow-cedar forests in Alaska (Hennon et al. 2010). 

In southeast Alaska, surface and subsurface soil horizons show predictable patterns 

of available calcium (concentrated near the surface) and aluminum (concentrated 

deeper); therefore, it is thought that relative concentrations of calcium and aluminum 

can be used as a surrogate for depth of feeder roots (Schaberg et al. 2011). 

Adaptations to Drought

Several studies in British Columbia covered the factors that influence drought tolerance in yellow-cedar regeneration. Yellow-cedar maintains turgor through elastic 

and osmotic control, but primarily through osmotic adjustments when exposed to 

limited soil moisture or low temperature (Grossnickle and Russell 1996). Drought 

tolerance is driven by water availability (late summer drought conditions) and 

by temperature decreases in fall that trigger winter dormancy. Drought tolerance 

of yellow-cedar shifts seasonally, with lower drought tolerance during times of 

active growth and highest tolerance in the winter; it is lowest at air temperatures 

above 59 oF, and increases with decreasing temperature (Grossnickle and Russell 

2010). Yellow-cedar is more sensitive to increased vapor pressure deficits, low 

root temperatures, and reduced soil moisture than some other associated conifers 

(Grossnickle and Russell 1991). Although short day length and water stress reduced 
67

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

shoot growth of yellow-cedar, responses were found to be transitory (Arnott et al. 

1992). Cultural practices in nurseries (Arnott et al. 1992, 1993), planting in spring 

instead of fall (Folk et al. 1996), and the use of seedlings instead of rooted cuttings 

as planting stock (Folk et al. 1995, Grossnickle and Russell 1990) can all be used to 

reduce damage to yellow-cedar regeneration from drought. 

Shade Tolerance

Information on yellow-cedar shade tolerance is mostly anecdotal. In general, 

yellow-cedar is classified as shade-tolerant, but is considered less tolerant in the 

northern parts of its range (Harris 1974). South of Mount Rainier in Washington, 

yellow-cedar seedlings can survive under moderately dense canopies, but may 

have poor form (Harris 1974), and often become established following disturbance 

(Antos and Zobel 1986). In Alaska, yellow-cedar is considered to be less shadetolerant than western hemlock, and is most competitive on less productive sites with 

open canopies and better light availability (Martin et al. 1995). In the understory 

of western hemlock-yellow-cedar stands, yellow-cedar seedlings and saplings 

are patchily distributed and far less abundant than prolific, highly shade-tolerant 

western hemlock (DeMeo et al. 1992, Martin et al. 1995) (see “Reproduction and 

regeneration,” this section). However, slower growing yellow-cedar can be favored 

in productive mixed stands by thinning adjacent trees, and can also be planted on 

cold, wet sites where other tree species are less competitive and abundant spring 

snowpack protects its roots from freezing injury (see section 3). Yellow-cedar was 

found to require a high level of photosynthetically active radiation to reach light 

saturation (Grossnickle and Russell 1991). As light availability increases from 0 to 

25 percent of full sunlight, yellow-cedar shows a sharp increase in photosynthetic 

capacity, which increases more gradually from 25 to 100 percent of full sunlight 

(similar to western redcedar; Grossnickle and Russell 2010). 

Cold Tolerance

Yellow-cedar is more tolerant of cold, wet conditions than many other members of 

the Cupressaceae family. At the southern extent of its range in northern California 

and southern Oregon, yellow-cedar grows at higher elevations (around 5,000 ft). 

These sites have conditions and growing season length comparable to lower elevations at the northern extent of its range in coastal Alaska and British Columbia 

(Harris 1990). 

Research on cold tolerance of yellow-cedar regeneration in British Columbia 

was apparently spurred by freezing injury to outplantings in operational reforestation. Both photoperiod and temperature appear to influence hardening (Hawkins 
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GENERAL TECHNICAL REPORT PNW-GTR-917

1993, Hawkins and McDonald 1993). Maximum frost hardiness cannot be maintained indefinitely with photoperiod (Hawkins and McDonald 1993), and loss of 

frost hardiness was driven primarily by temperature. Loss of hardiness proceeded 

at a faster rate when planting stock was formerly exposed to night frosts, and all 

planting stock in one study began to lose cold tolerance between January and March 

(Hawkins 1993). Puttonen and Arnott (1994) found that short photoperiod-induced 

cold hardiness was reversed by warm temperature. 

Although yellow-cedar occurs in cold environments, research in southeast 

Alaska on the seasonal cold tolerance of root tissue has demonstrated that yellowcedar root tissue is less cold tolerant than redcedar, mountain hemlock, western 

hemlock, and Sitka spruce (ordered from lowest to highest tolerance) (Schaberg 

et al. 2011). Root cold hardiness of associated species generally increases from 

November to January, decreases from January to March, and decreases further 

from March to May. Cold tolerance of yellow-cedar fine roots follows a similar pattern, but exhibits comparatively less seasonal fluctuation, develops minimal winter 

hardiness (tolerant to 21 °F), and becomes fully dehardened by March (Schaberg et 

al. 2011). Premature tissue dehardening, greater vulnerability to freezing injury, and 

a tendency to root shallowly on some sites make fine roots of yellow-cedar susceptible to periodic spring freezing events that lead to gradual tree mortality (Hennon 

et al. 2012).

In southeast Alaska, yellow-cedar is found farther to the north, and at higher 

elevations, than western redcedar. It is unknown whether the distribution of western 

redcedar is limited by migration and regeneration patterns, or the relationship 

between tree physiology and climate factors. Andersen (1953) displayed the northern limit of western redcedar in Alaska and suggested that the species was confined 

by seasonal growing-degree days. It is also possible that the architecture of trees 

plays a role; the broader crown and lower wood strength of western redcedar may 

make it susceptible to breakage under heavy snow loads to the north and at higher 

elevations. Western redcedar has slightly more cold tolerant roots than yellow-cedar 

in mid-winter (Schaberg et al. 2011), and this finding may seem counterintuitive 

given their current distributions. Note that this may not apply to foliage, however. 

The greater cold tolerance of western redcedar may be important because, in the 

absence of insulating snowpack, western redcedar must withstand winter soil 

temperatures that are close to its cold tolerance threshold. 

Yellow-cedar becomes photosynthetically active in response to increasing 

temperature conditions (even when associated tree species remain dormant) and has 

relatively higher photosynthetic capability at cold and near-freezing temperatures 

(Grossnickle and Russell 2010). This may be an adaptation to help yellow-cedar (as 
69

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

a “physiologically opportunistic” species) take advantage of suitable conditions for 

photosynthesis, whenever they occur, and may also allow yellow-cedar to absorb 

nitrogen that becomes available during freeze-thaw events (D’Amore et al. 2009, 

Schaberg et al. 2011). This adaptation could benefit yellow-cedar at high elevations, 

where trees must begin to take advantage of the short growing season as soon as 

snowpack dissipates. Snowmelt varies from year to year and is not highly dependent on photoperiod. This adaptation makes activated tissues vulnerable to freezing 

injury, so there are tradeoffs between early growth and the risk of injury. 

Damage Agents 

Wind

Windthrow of individual trees is common in the forests of southeast Alaska due 

to the combination of wet, often shallow soils and high winds (Martin et al. 1995). 

Less frequently, stand-level replacement windthrow occurs, particularly on exposed 

sites when extreme wind follows heavy rain. Windthrow occurs when “wind loads 

on trees exceed the resistance of tree stems or anchorage” (Zielke et al. 2010: 2-3). 

Shallow rooting depth, soil saturation, and root diseases increase vulnerability to 

windthrow from uprooting by decreasing anchor strength. Stem decays, particularly 

those caused by brown rot fungi, increase vulnerability to windthrow from bole 

breakage by decreasing stem strength. Topographic conditions and stand management activities also influence vulnerability to windthrow. Wind accelerates as it 

moves over and around landscape obstacles, and thinned stands and stands adjacent 

to clearcuts are likely to be more exposed to wind (Zielke et al. 2010). Stand characteristics (height-to-diameter ratios and tree density) and tree metrics (height, 

diameter, crown size, and rooting depth) are important in predicting windthrow 

potential (Zielke et al. 2010). Wind firmness increases with deeper rooting depth 

(greater anchor strength) and tree diameter (greater stem strength), although there is 

higher likelihood of stem decay in larger, older trees. Wind firmness decreases with 

increased height growth and crown size. 

The largest yellow-cedar trees are on well-drained sites with deep soils, but the 

species is often more common on sites with poor drainage and shallow soils due to 

competition with western hemlock and other species. Shallow and poorly drained 

soils limit rooting depth, while soil saturation and high soil organic matter content 

weaken contact between the roots and the soil. However, trees growing in these 

open-canopy forests have been habituated to windy conditions, and stand-replacing 

events are rare. Yellow-cedar is generally less prone to windthrow than western 

hemlock, Sitka spruce, and other associated species because it tends to have a 
70

GENERAL TECHNICAL REPORT PNW-GTR-917

sparser tree crown (“sail area”) (Harris 1999). It also frequently grows in lowproductivity stands of shorter stature and lower density, where wind can maneuver 

around trees (Martin et al. 1995). Large, old trees often contain heart rot (internal 

wood decay) and therefore sometimes succumb to windthrow in the form of bole 

breakage. Yellow-cedar’s heartwood chemical extractives would appear to make it 

less prone to bole breakage from internal decay compared to associated conifers, 

but internal defect is relatively high in old yellow-cedar trees. Yellow-cedar snags 

commonly remain standing 80 yr or more after tree death from yellow-cedar 

decline because of their exceptional retention of strength and decay resistance properties (i.e., postdeath deterioration), and limited “sail area” with the loss of foliage, 

twigs, and branches from the tree crown (Hennon et al. 2000).

The wind regime is a significant influence on the spatial distribution of landslide events within forests containing spruce, hemlock, and yellow-cedar (Buma 

and Johnson 2015, Johnson et al. 2000, Swanston and Howes 1994, Wu et al. 1979). 

This effect is mediated by slope, with little interactive effects at low angles and 

stronger influences on steeper slopes. Mechanistically, the interaction appears to 

be mediated by root strength, which is an important factor in stability of high-angle 

slopes with shallow soils (Buma and Johnson 2015). Further, windthrow was found 

adjacent to at least 75 percent of all hillslope failures for a subset of 45 of 300 

landslides occurring on Prince of Wales Island in 1993 (Johnson et al. 2000). For 

more information on the role of yellow-cedar decline on hillslope stability, refer to 

section 2.

Fire

In the northern portion of its range, yellow-cedar generally grows in coastal rainforest ecosystems with year-round precipitation and very low risk of wildfire (Alaback 

1982). When rare fire occurs in the coastal rainforest, it is generally stand replacing. 

One of the few known older even-aged forests in southeast Alaska dominated by 

yellow-cedar regenerated on a site that experienced wildfire about 1900 at Cannery 

Point near Tenakee. Hennon (1992) found that planted yellow-cedar seedlings had 

good survival and growth on a burned site on Etolin Island. In high-elevation forests of California, Oregon, and Washington, yellow-cedar occurs in discontinuous 

populations, often as a minor stand component. Fire return intervals in these stands 

are probably shorter than in coastal rainforest systems due to the greater incidence 

of lightning strikes and limited summer precipitation. However, fire movement may 

be restricted by fuels in low-density subalpine stands, especially along exposed 

ridges. Yellow-cedar has thin bark and often roots shallowly, and these traits make 
71

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

it unlikely to survive even low-intensity fires. Estimates of mean fire return intervals are 1,500 yr for mountain hemlock stands in the Cascade and Olympic Mountains (Lertzman and Krebs 1991) and 1,150 yr for Sitka spruce forests (Fahnestock 

and Agee 1983).

Insects

Yellow-cedar has fewer problems with insects and pathogens than most other 

conifers. Defensive compounds (secondary metabolites) in the heartwood limit the 

growth and establishment of pathogens and insect organisms, although some agents 

are specialized to overcome these chemical defenses. Several components of the 

essential oils isolated from yellow-cedar are lethal to ticks and mosquitoes and may 

potentially be used to control these pests (Panella et al. 2005). Yellow-cedar foliage 

is also rich in phenolic compounds. Juvenile foliage and new needles have lower 

concentrations of defense compounds than mature, older foliage, and are therefore 

more susceptible to insect and mammal herbivory. 

In Alaska, there are three species of looper known to feed on yellow-cedar 

foliage: the western hemlock looper, the green-striped forest looper, and the saddlebacked looper. All feed on Sitka spruce or western hemlock as their primary host 

and are unlikely to feed on yellow-cedar unless populations reach outbreak level. 

Young cedar foliage is probably more susceptible to feeding due to lower concentrations of phenolic compounds in leaf tissue. On species other than cedars, feeding 

by the green-striped forest looper and saddle-backed looper is most severe in the 

upper crown and sometimes causes topkill. Severe defoliation may predispose trees 

to bark beetle attack, but rarely causes direct tree mortality. Cypress tip moths, and 

cypress leaf tier can also feed on yellow-cedar foliage, but severe damage is uncommon (Hennon 1991).

The yellow-cedar gall midge commonly infests trees planted in residential 

settings and seed orchards (Duncan 1994), and it has also been observed at lower 

levels in forest settings in southeast Alaska. Typically, only a small proportion of 

growing tips are damaged and the health of the tree is not greatly affected. Orangecolored larvae burrow in branch tips and cause tiny galls to form. Adults are small 

dark midges. Damage is usually restricted to lower elevations, possibly because of 

temperature constraints on the insect. 

The yellow-cedar pollen mite causes damage to yellow-cedar pollen and seed 

cones, and has been documented primarily in seed orchards in British Columbia 

(Smith 1977). Callus-like growths form on seed cone scales, and infected cones are 

devoid of mature seeds. Severely damaged seed cones open prematurely and have 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 29—Galleries of the cedar bark 

beetle, Phloeosinus cupressi, on the 

bole of a dead yellow-cedar tree with 

bark removed.

necrotic, discolored cone scales. Mites can be readily observed on damaged portions of 1- and 2-yr-old seed cones (Hunt 1976). The mite also girdles the stalks of 

pollen cones and causes them to abort in fall and winter. It is recognized as a pest of 

yellow-cedar with studies showing 30- to 60-percent loss of seed cones (Anderson 

et al. 2002, Hunt 1976). The known distribution of the yellow-cedar pollen mite in 

the Pacific Northwest extends from coastal British Columbia to Oregon and California (Smith 1984). It has been detected in natural stands on Vancouver Island, but 

its presence in Alaska has yet to be confirmed (Anderson et al. 2002). 

Bark beetles found attacking the inner bark of yellow-cedar almost always 

belong to the genus Phloeosinus (Coleoptera: Curculionidae: Scolytinae). Species 

of this genus are generally considered secondary agents, attacking stressed and 

dying trees (Furniss and Carolin 1977). Three species of Phloeosinus are known to 

infest large branches, boles, and tops of yellow-cedar: P. cupressi, P. sequoia, and 

P. keeni. Frequently detected in stands undergoing yellow-cedar decline, P. cupressi

infests declining yellow-cedar trees before death. Adult beetles of this genus are 

reddish-brown to dark brown and 0.08 to 0.16 in long. Trees are attacked in the 

spring and summer, when adult beetles penetrate the bark to lay their eggs. Larvae 

create distinctive galleries as they excavate the phloem (fig. 29) and there are 1 to 

1.5 generations/yr, depending on location (Furniss and Carolin 1977).
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Ambrosia beetles nearly always infest dead or dying trees, including yellowcedar, and seldom cause tree mortality. However, infestations can cause significant 

loss of wood value in felled trees, and have serious implications for wood exportation due to concerns about introducing nonnative beetles and fungi. Ambrosia 

beetles have a mutualistic relationship with ambrosia fungi (now more commonly 

called ophiastomatoid fungi), which the beetles vector to larval galleries and harvest as a food source (Mitton and Sturgeon 1982). Ambrosia beetles have evolved 

specialized structures known as mycangia, which store fungal spores to be vectored 

in a new host. Ophiastomatoid fungi are diverse, and many are tree pathogens (e.g., 

blue stain fungi) and quarantine pests. Ambrosia beetles are attracted to recently 

downed trees and trees with broken tops, and infest only boles and large branches. 

Damage is confined to the sapwood; therefore, yellow-cedar is as vulnerable as 

other conifer species to ambrosia beetle attack because the sapwood lacks the 

unique defense chemistry of the heartwood. The risk of ambrosia beetle attack can 

be mitigated by appropriately timing timber harvest. Material felled after March is 

unlikely to be attacked that year, but will be susceptible the next year if it remains 

on the ground (Holsten et al. 2009). 

A wood wasp, or horntail (Sirex sp. (Hymenoptera: Siricidae)), infests yellowcedar (Smith and Schiff 2002) and is thought to vector a black stain fungus that has 

been tentatively identified as a Sporidesmium species. Proper identification of the 

horntail and fungus species is needed. Trees usually survive larval feeding, making it difficult to identify attacked trees, and accumulate callus tissue to confine 

the fungus and prevent continued spread. Attacks are apparently cyclic, occurring 

at roughly 60- to 100-yr intervals at one site near Wrangell. It is thought that the 

fungus’ initial infection of the sapwood inhibits the development of decay resistance 

properties in the heartwood where staining has occurred. Staining has significant 

impacts on merchantability. Stained wood has a value about half that of clear wood, 

and is sometimes completely unmarketable (fig. 30). Damage appears to be limited 

to specific sites in southeast Alaska, although no information is available on levels of 

staining at specific geographic locations. Related wood wasps usually attack weakened trees, downed timber, or saw logs, so the situation with Sirex and yellow-cedar 

may be unique. The female penetrates the bark with an ovipositor to deposit a single 

egg. Larval galleries excavated into the sapwood are round in cross section, tightly 

packed with frass, and average 0.1 in wide and 0.27 in long. Larvae require one to 

two seasons to develop, and construct pupal chambers in the outer layers of sapwood 

on the upper sides of logs. The brood adult leaves through a round exit hole. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Diseases

A shoot blight fungus (Kabatina thujae) causes significant disease of yellow-cedar 

seedlings and saplings. It primarily damages shoots of young trees but apparently 

does not affect older shoots and mature trees. Terminal and lateral shoots on seedlings and saplings become infected and die during late winter or early spring, and 

dieback may extend several inches from the tip of the shoot (fig. 31). Entire seedlings up to 1 to 2 ft tall are sometimes killed, but only if they are heavily colonized. 

Surveys suggest that this disease is common on both planted and naturally regenerated seedlings after clearcut harvest. Long-term tree form is not thought to be 

compromised by shoot and leader damage. Symptoms of this disease are sometimes 

confused with spring frost damage.

Shoot blight of yellow-cedar caused by K. thujae has been reported to inflict 

considerable damage in nursery settings in British Columbia. A severe outbreak in 

the Fraser River area in 1969 killed up to half the shoots of affected nursery trees, 

and fungicides were ineffective at treating the outbreak (Funk 1974, Funk and 

Molnar 1972). 

Additional fungi that can attack or kill yellow-cedar seedlings in nursery settings include Botrytis cinerea and damping-off fungi that kill emerging seedlings, 

but these diseases can be effectively controlled with chemical or cultural methods. 

An inconspicuous rust fungus, Gymnosporangium nootkatense, is present wherever 

yellow-cedar grows in Alaska (Hennon 1991, Ziller 1974). It infects individual leaf 

scales as tiny infections and has never been observed causing substantial damage to 

trees. 

Figure 30—Black stain of yellow-cedar heartwood is caused by a fungus but 

probably vectored to trees by a Sirex wood wasp.
75

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 31—Shoot disease of yellow-cedar regeneration caused by a fungal 

pathogen, Kabatina thujae.

Root disease fungi that attack yellow-cedar are generally not aggressive and 

do not cause serious disease. Although an Armillaria species is frequently detected 

on dying or dead yellow-cedar (Hennon et al. 1990), it is not aggressive enough 

to damage healthy trees and therefore tends to occur opportunistically on trees 

stressed by abiotic factors. Inoculation trials have shown that Phytophthora lateralis, which causes severe root disease of Port-Orford-cedar in northern California 

and southern Oregon, has very low virulence on yellow-cedar and does not pose 

a serious risk to yellow-cedar in Alaska (personal communication, 2011. Mike 

McWilliams, Oregon Department of Forestry, Salem, Oregon; currently with the 

USDA Forest Service, Forest Health Protection, La Grande, Oregon).

Wood Decays

Little is known about heart rot, or stem decay, of live yellow-cedar, because 

the species was not evaluated in the two classic studies of cull or stem decay in 

southeast Alaska (Farr et al. 1976, Kimmey 1956). Although yellow-cedar wood in 

service is remarkably decay resistant, some specialized fungi are able to attack the 

heartwood and cause extensive decay in live trees (fig. 32). Cruisers and others with 
76

GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 32—Unidentified white pocket rot stem decay of yellow-cedar.

knowledge from the timber industry indicate that larger, older yellow-cedar trees 

have substantial butt rot and ring shake (concentric patterns of decay in heartwood). 

Observations of snapped yellow-cedar boles suggest that decay fungi can be 

important mortality agents for yellow-cedar (Hennon 1995, Hennon and McClellan 

2003). However, there is limited information on how often such mortality occurs, 

what fungal species are usually responsible, and how it varies by location. Although 

it is assumed that older trees are likely to have higher rates of decay, research has 

not been conducted to establish the relationship between tree age and the volume 

or incidence of decay in yellow-cedar. Many fungal species attack the sapwood of 

yellow-cedar, which does not contain the concentrated chemical defenses found in 

the heartwood, and these fungi are particularly common on dead trees. Only a few 

conk-forming macrofungi such as Polyporus elegans and Auricularia auricularis 

are often observed on dead yellow-cedar in Alaska. These fungi decompose the 

outer sapwood, usually of recently killed trees (Hennon 1990). The cedar form of 

Phellinus weirii may cause significant cull of yellow-cedar as a butt rot, but does 

not cause root disease or direct tree mortality. A study begun in 2013 will attempt 

to identify the “hidden defect” in both western redcedar and yellow-cedar in coastal 

Alaska. Information on the major causal fungi of internal wood decay of live trees 

is expected from this effort.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Potential Invasive Species

Recent findings in Argentina and Scotland indicate the need to learn more about the 

threat of the pathogen Phytophthora austrocedrae to yellow-cedar in Alaska. This 

pathogen was described as a new species in 2007 after it was isolated from dying 

Chilean cypress in Argentina, where it is destructive and presumably invasive 

(Greslebin et al. 2007). In 2011, this pathogen was isolated from dying ornamental 

yellow-cedar in a park in Scotland (Great Britain Forestry Commission 2013). The 

origin of the pathogen, the relative susceptibility of yellow-cedar, and the ability for 

the pathogen to survive in Alaska’s coastal rainforest climate are unknown. This 

pathogen has never been detected in Alaska, even with the use of stream- or soilbaiting, which are common techniques used to monitor Phytophthora species. Other 

diseases and fungal pathogens that could present a threat to yellow-cedar if introduced within its range include Seiridium shoot blight and resinous stem canker.

Animal Damage

Brown bear and Sitka black-tailed deer are the primary animal damage agents of 

yellow-cedar in southeast Alaska. Brown bears typically cause damage to mature 

trees, whereas deer typically browse juvenile foliage of seedlings and saplings. The 

western hemlock-yellow-cedar stand series, especially the skunk cabbage association, is reported to be heavily used by deer and bears in spring, and by deer in the 

fall (Martin et al. 1995). Porcupines damage many tree species in southeast Alaska, 

but tend to avoid feeding on yellow-cedar and western redcedar (Eglitis and Hennon 1997). Therefore, these species may be good options on sites with significant 

damage from porcupine feeding.

In spring, brown bears strip bark from the lower bole of yellow-cedar trees to 

reach the sugary phloem tissue as a food source (fig. 33). In some locations with 

high brown bear populations, such as Chichagof and Baranof Islands, up to half of 

the yellow-cedar boles may be scarred by brown bears, evidenced by teeth marks on 

exposed wood (Hennon et al. 1990a). The highest incidence of basal scarring occurs 

on productive sites with deep soil drainage, where yellow-cedar reaches its greatest 

size. This type of damage is not known to occur on islands inhabited only by black 

bears. Wounding from brown bear feeding creates avenues for infection by decay 

fungi, but yellow-cedar walls off (i.e., compartmentalizes) the fungi to create narrow bands of decay. There is no relationship between the incidence of basal scarring 

and yellow-cedar decline, indicating that bear damage is not a factor in the decline.

Sitka black-tailed deer tend to feed on 1- to 2-yr-old foliage of yellow-cedar, 

which is more palatable to them possibly because it contains lower concentrations 
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GENERAL TECHNICAL REPORT PNW-GTR-917

of defense compounds than older foliage. Seedlings that are browsed over consecutive years assume a bushy form, but usually recover if browsing ceases and they 

are able to attain sufficient height growth to have protected foliage above browseheight. In some locations with high deer populations, deer may have a significant 

impact on yellow-cedar regeneration (Martin et al. 1995), and may make yellowcedar less competitive than fast-growing brush and tree species, such as western 

hemlock (Hennon 1992a). More information on deer browse on yellow-cedar 

regeneration can be found below.

Climate

Climate exerts long-term influence over vegetation patterns, hydrology, and soil 

development, and relatively shorter term influence over seasonal precipitation, 

temperature, and acute weather events. The widespread mortality of yellow-cedar 

in Alaska and British Columbia, or yellow-cedar decline, is associated with freezing injury to fine roots that occurs where snowpack in early spring is insufficient 

to protect roots from late-season cold events. Yellow-cedar trees appear to be 

protected from spring freezing injury where snow is present in spring and able 

to insulate tree roots and prevent premature dehardening and freezing. For more 

information on the role of climate in yellow-cedar decline, refer to section 2.

Figure 33—Bole wounding on yellow-cedar by a brown bear showing marks left by canine teeth.
79

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Commercial Use and Forest Management

Utilization and management of yellow-cedar are usually considered in the context 

of management of western hemlock and Sitka spruce, as those species are more 

abundant, especially on productive forestland. Yellow-cedar is seldom found in pure 

single-species stands in southeast Alaska, and it has fluctuated in commercial value 

from being noncommercial to being the most valuable wood in the region. The 

management history of yellow-cedar in Alaska is also primarily concerned with 

activities on the Tongass National Forest and state and corporate lands. Although 

yellow-cedar’s distribution extends into the Chugach National Forest in the Prince 

William Sound area, records do not indicate that it has been actively managed there. 

Logging History

The coastal forests of Alaska have a long history of providing timber products, 

including yellow-cedar, to local and regional economies and Asian markets. During 

the period of Russian colonization (1799 to 1867), many areas around Sitka were 

harvested for the construction of a fort and magazine, and for supplies of firewood 

and charcoal. Supplying a continuous flow of firewood and charcoal to Sitka 

resulted in some of the earliest clearcut harvests documented in Alaska. At the base 

of Mount Verstovia, just south of present-day Sitka, there is a 189-ac clearcut that 

was harvested in 1861 for fuelwood and charcoal (Russell 1996). This site is now 

an even-aged, single cohort forest composed primarily of western hemlock and 

Sitka spruce, with some yellow-cedar found at higher elevations of the stand. This 

second-growth forest has a stand density of 440 ft2 of basal area/ac and an average 

diameter of 16 in.5 The Russians also did selective partial harvesting for high-quality Sitka spruce and yellow-cedar. Trees were sawn for local construction, as well 

as for export to countries such as Chile and China (Russell 1996). Yellow-cedar was 

favored in hull construction for Sitka’s shipbuilding industry. Selective harvesting 

of yellow-cedar occurred along the shorelines near Sitka and as far as Peril Strait, 

60 mi north of Sitka (Harris and Farr 1974). “Because of the demand for Alaskacedar for ship construction and other uses, the Russians were reported later to have 

exhausted the accessible supply of cedar near Sitka” (Harris and Farr 1974: 3). 

In 1867, Russia ceded the territory of Alaska to the United States. U.S. land 

laws and title of timber lands did not extend to the Alaska territory, so timber 

operators were not permitted to export lumber (Harris and Farr 1974). It was not 

5

 Russell, J. 1996. Mt. Verstovia Russian era harvest young single cohort stand. On file 

with: USDA Forest Service, Alaska Regional Office, 709 West 9th Street, Juneau, AK 

99801.
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GENERAL TECHNICAL REPORT PNW-GTR-917

until 1907, when President Roosevelt created the Chugach and Tongass National 

Forests, that formulized regulations for the cutting and disposal of federal timber 

in Alaska were developed. Alaska’s timber industry was slow to grow because of 

limited national demand for western hemlock, Sitka spruce, western redcedar, or 

yellow-cedar. In 1909 the two national forests in Alaska harvested about 15 million 

board feet (MMBF) (USDA FS 2012). Sitka spruce and yellow-cedar were primarily used in the local fishing, canning, and mining industries, with only a small 

amount of wood exported.

During the early period (1909 to 1950) of forest management in Alaska, the 

total volume of timber harvested from both national forests averaged about 43 

MMBF/yr (USDA FS 2012). Ninety percent of this volume was harvested from the 

Tongass National Forest (fig. 34). Due to the lack of inland road systems, selective 

harvest of high-quality spruce and yellow-cedar predominantly occurred along 

the shorelines near local communities. The U.S. Forest Service believed that an 

extensive timber industry could not expand until a pulp and paper industry was 

developed to improve the economic feasibility of commercial timber harvest.

In the early 1950s the Forest Service’s efforts to contribute to the economic 

development of southeast Alaska were realized with increased demand for residential construction lumber to rebuild Japan after World War II and with the development of long-term (50-yr) timber sale contracts (Brackley et al. 2009). Regional 

timber harvest averaged 356 MMBF/yr for the next 45 yr (1950 to 1995) (fig. 35). 

To ensure the development of pulp mills and large sawmills, the Forest Service 

placed restrictions on the export of unprocessed logs (round logs) (Brackley et al. 

2009, Lane 1998). During this time, export regulations for logs primarily applied to 

western hemlock and Sitka spruce harvested from federal lands. Western redcedar 

and yellow-cedar were only a small portion of the total volume harvested. They 

were determined surplus to local manufacturing needs and therefore were freely 

exported as logs. The policy of unrestricted export of yellow-cedar remains in 

effect today. The export restrictions on western redcedar have been more varied 

over time. Currently, there are restrictions on the export of western redcedar. 

Although the Forest Service oversaw the harvest of most of the timber for local 

pulp mills and sawmills, Native corporation lands also supplied some of the timber. 

The Alaska Native Claim Settlement Act [ANCSA] of 1971 (ANCSA 1971) established 12 local Native corporations and 1 regional corporation in southeast Alaska. 

The Native corporations were entitled to select about 540,000 ac of land from the 

Tongass National Forest; by 1992 about 95 percent of the land had been conveyed 

(Gunnar 1992). The timber harvest from Native corporation lands began in earnest 

in 1980 and by 1983 volume harvested exceeded volume harvested from the Tongass National Forest (fig. 35). 
81

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 34—The average annual timber volume harvested per decade of all species harvested in the 

Alaska Region from 1910 through 2010 (USDA FS 2012).

Figure 35—Annual timber volume of all species harvested in the state of Alaska from 1970 through 

2011. State of Alaska totals also includes volume from State, Bureau of Indian Affairs, Bureau of 

Land Management and Chugach National Forest lands (Brackley 2009, USDA FS 2012, Zhou and 

Warren 2012).
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GENERAL TECHNICAL REPORT PNW-GTR-917

Unlike timber harvested from federal lands, timber harvested from Native lands 

can be freely exported without any primary processing requirements. Most of the 

high-quality western hemlock, Sitka spruce, western redcedar, and yellow-cedar 

from Alaska Native lands is exported to Asian markets. In the 1980s and 1990s, the 

primary markets for Native utility logs (lower grade logs) were the two pulp mills in 

southeast Alaska (Gunnar 1992).

In 1994 the pulp mill located in Sitka closed. The last long-term contract with 

Ketchikan Pulp Company was negotiated in 1997; its pulp mill closed that same 

year. Since 1995, annual volume offered for sale by the Alaska Region has declined 

steadily from 199 MMBF in 1995 to 23 MMBF in 2011 (USDA FS 2012). Timber 

harvested from Native lands has also declined from 454 MMBF in 1995 to 125 

MMBF in 2011 (Brackley et al. 2009, Zhou and Warren 2012). Only one mediumsized sawmill and several small specialty sawmills are in operation today. In 

addition, there are three principal logging companies that sell unprocessed logs to 

the local sawmills or export logs to overseas markets. 

Before the 1990s, most of the harvesting on the Tongass National Forest was 

disproportionally concentrated on higher productivity sites at lower elevations. 

These sites were usually adjacent to the beach and within floodplain riparian areas 

with abundant large Sitka spruce (USDA 2008a). Yellow-cedar simply was not present in any abundance on these high-productivity sites, where it is generally outcompeted by western hemlock and Sitka spruce (D’Amore and Hennon 2006, USDA 

2008b). The yellow-cedar that occurred on high-productivity sites was often felled 

and left in the woods because of the poor export market for yellow-cedar before the 

1980s (Ruth and Harris 1979). 

As more complex and restrictive land use designations and forest management 

practices were crafted under the 1979 and 2008 Tongass Forest Plans (USDA FS 

1979, 2008a) and the Tongass Timber Reform Act (TTRA) of 1990 (TTRA 1990), 

the practice of harvesting a disproportionate amount of old-growth timber on the 

highest volume productivity sites (volume classes 6 and 7) was changed. By the 

late 1990s, harvest activities began to occur across a more diverse range of volume 

classes (volume classes 4 through 7). Correspondingly, more yellow-cedar was 

harvested because yellow-cedar abundance was greater on poorly and moderately 

drained sites. Additionally, the utilization of yellow-cedar increased due to heightened market demand in Asian countries.

On average, yellow-cedar represents about 10 percent of the estimated net 

volume of growing stock on timberland in southeast Alaska (table 15) (USDA 

2008). There is considerable variation in actual cedar volume harvested among sale 

areas, based on site productivity and the local abundance of cedar. Regardless of the 
83

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 15—Percentage of net volume of growing 

stock of commercial softwood species on 

timberlanda

 in southeast Alaska 

Species Net total volume

Percent

Yellow-cedar 10

Sitka spruce 27

Western redcedar 6

Western and mountain hemlock 57

a

 Timberland: forestland that is not withdrawn from timber production 

by statute or administrative regulation and is capable of producing >20 

ft3/ac/yr.

Table 16—Acres and percentages of harvest in three areas of the Tongass National 

Forest by silvicultural system, 1910 through 2010

Locationa

Even-aged 

harvest

Two-aged 

harvest

Uneven-aged 

harvest

Intermediate harvestTotal 

harvest

North Tongass 87,280 372 4,464 3,457 95,573 

(21.1%)

Central Tongass 101,605 1,423 7,956 3,326 114,310 

(25.2%)

South Tongass 238,155 3,912 1,230 601 243,898 

(53.8%)

Tongass National 

Forest grand total

427,040 

(94%)

5,707 

(1.3%)

13,650 

(3.0%)

7,384 

(1.6%)

453,781

(100%)

a

 North Tongass (Yakutat, Hoonah, Juneau, Sitka, and Admiralty Ranger Districts), Central Tongass (Petersburg and 

Wrangell Ranger Districts), South Tongass (Craig, Thorne Bay, and Ketchikan Ranger Districts).

Source: Forest Service Activity Tracking System [FACTS] July 2012.

amount of yellow-cedar harvested, most of it is exported to Asian countries because 

of the premium value it brings in those markets. 

Silvicultural Systems

The primary silvicultural system used to manage Sitka spruce-western hemlock and 

mixed-conifer forest types in southeast Alaska has been, and continues to be, primarily an even-aged regime. Of the 453,781 ac harvested on the Tongass National 

Forest, 94 percent has been harvested under even-aged systems with natural regeneration (table 16). The long-term management objective under an even-aged system 

is to regenerate the stand with a new stand of trees that are essentially the same age, 

which is usually achieved through clearcutting, or felling trees after seed tree and 

shelterwood harvests. In southeast Alaska, clearcutting is primarily used where 
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GENERAL TECHNICAL REPORT PNW-GTR-917

the land use designation is for timber production. Clearcutting is preferred because 

removing essentially all trees produces a fully exposed microclimate that results in 

the following: increased soil temperatures that speed up organic decomposition and, 

thus, improve soil productivity; improved regeneration of less shade-tolerant species, such as Sitka spruce, yellow-cedar, and redcedar, due to increased sunlight and 

exposure of mineral and mixed mineral/organic soil; reduced infections of dwarf 

mistletoe in the regenerating stand; and reduced logging costs. A variant to the 

clearcut regeneration method is clearcut with reserves, in which a minor component 

(<10 percent of full stocking) of the stand may be retained, either in single trees or 

small clumps of trees. Clearcut with reserves is generally used in timber production 

areas where there is a need to meet scenery or wildlife standards and guidelines. 

Figure 36—Yellow-cedar retained in a partially harvested unit. The 

extent to which such trees can serve as a seed source to encourage 

natural regeneration is unknown.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Reserve trees are not necessarily prescribed as “seed trees,” but an auxiliary benefit 

of reserve trees is that they can enhance the natural regeneration and subsequent 

spatial distribution of desired species, such as yellow-cedar, redcedar, and Sitka 

spruce. 

Alternatives to even-aged systems are available and often prescribed when the 

land management objectives emphasize resource values other than timber production, such as wildlife habitat or scenery management. These alternative systems 

are two-aged and uneven-aged. A two-aged system is designed to regenerate and 

maintain a stand with two age classes. The initial harvest entry reserves trees either 

individually or in clumps, with reserve trees representing ≥15 percent of a stand’s 

pretreatment basal area. The resulting stand may be two-aged, or tend toward 

multiaged, as a consequence of an extended rotation period and the retention of 

reserve trees that may represent one or more age classes. Similar to the harvest 

method of clearcut with reserves, a two-aged system can enhance the natural 

regeneration of yellow-cedar, redcedar, and Sitka spruce. The uneven-aged system 

regenerates and maintains a stand that has at least three distinct age classes. The 

initial harvest entry removes 25 to 33 percent of mature trees, in all age classes, 

either individually or in small groups that are <2 ac in size. Individual and group 

tree selection may not provide an adequate exposed microclimate to regenerate and 

establish yellow-cedar. To prevent western hemlock from dominating the new age 

class, prescriptions often call for retaining advanced cedar and spruce regeneration 

(seedlings and small trees present in the understory of the previous stand that may 

grow rapidly after being freed from competition with the dominant harvested trees), 

as well as larger cedar and spruce trees. 

Intermediate harvests, such as salvage and commercial thinning, can also 

be prescribed when managing for yellow-cedar. These harvests are designed 

to improve stand conditions or recover timber losses due to insects, disease, or 

windthrow. Commercial thinning prescriptions can favor the retention of yellowcedar in order to increase its relative abundance. Salvage sales can be designed to 

sell dead yellow-cedar to local sawmills that have developed a niche market for 

yellow-cedar products. 

Reforestation

As stated in the National Forest Management Act (NFMA) of 1976 (NFMA 1976), 

it is the policy of the Congress that all forested lands in the National Forest System 

shall be maintained in appropriate forest cover with species of trees, degree of 

stocking, rate of growth, and conditions of stand designed to secure maximum 
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GENERAL TECHNICAL REPORT PNW-GTR-917

benefits of multiple-use sustained yield management in accordance with land management plans (NFMA 1976). These regulations do not specify that harvested units 

be regenerated with the identical species composition that existed before harvest. 

The current Tongass National Forest Land and Resource Management Plan (USDA 

FS 2008a) also does not specify species compositions to regenerate. Instead, the 

plan defers to site-specific silvicultural prescriptions to determine the appropriate 

species mix based on the potential of the site as indicated by plant associations 

and adjacent stand conditions. The plan does emphasize the need to regenerate 

and maintain particular species such as yellow-cedar and western redcedar where 

appropriate for the site. 

Natural Regeneration

On the Tongass National Forest, natural regeneration accounts for about 94 percent 

of the reforestation program (USDA FS 2008a). To the extent practical, silviculturists prescribe regeneration harvests designed to create microclimates that favor 

the establishment of less shade-tolerant western redcedar, yellow-cedar, and Sitka 

spruce. Yet western hemlock regenerates far more than other species following 

harvest because of differences in soil and light requirements, seed production, 

seed dispersal distance, seed dormancy requirements, and other factors. Western 

hemlock can thrive on organic or mineral soil and in a variety of light conditions. 

Yellow-cedar can grow in a variety of mineral and organic soils, and in fully open 

or partially shaded environments.

Western hemlock is a prolific seed producer. In contrast, yellow-cedar cones 

are small, contain fewer seeds, and irregularly produce large cone crops on a 4- to 

7-yr cycle. Owens and Molder (1977) found that the proportion of filled seeds 

from mature yellow-cedar cones was low and extremely variable. In seven trees 

studied, the number of seeds per cone averaged 7.2, but the proportion of filled seed 

averaged only 29 percent. Western hemlock seeds disperse up to 1 mi (Burns and 

Honkala 1990). Yellow-cedar seed dispersal distances have not been measured, but 

studies of related Port-Orford-cedar suggest that yellow-cedar seed is not dispersed 

>400 ft from its source (Burns and Honkala 1990). 

Western hemlock seed is not deeply dormant and requires only a short stratification to germinate (Burns and Honkala 1990). Germination of yellow-cedar seed 

requires an extensive and complex stratification that consists of warm and cold 

periods (Pawuk 1993). If stratification requirements are not met, then seeds will not 

germinate the first year after seed dispersal. Remaining seed may germinate the 

next year if stratification requirements are met and if the seeds are not consumed by 

birds or rodents or decayed by fungi.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Only limited information is available on yellow-cedar regeneration after timber 

harvests in southeast Alaska. Yellow-cedar is observed regenerating in some 

harvest units but not in others, but a systematic comparison of species composition of the trees before harvest and seedlings after harvest has not been conducted. 

Many harvest units, especially those harvested longer ago or on productive sites, 

did not originally contain yellow-cedar, and the species would not be expected 

to regenerate. Yellow-cedar regeneration success may be associated with certain 

geographic areas or with particular years of harvest that may, in turn, be linked to 

the abundance of deer. 

Observations and plot information in the three main plant association guides 

for the Tongass National Forest developed during the 1980s indicated difficulties 

with the natural regeneration of yellow-cedar. Most of this information came from 

unmanaged forests. “Yellowcedar regeneration is very problematic[,]” DeMeo et 

al. (1992: 168) stated about the southern portion of the Tongass; “regeneration from 

seeding will be sporadic, due to competition from hemlock and irregularity from 

seed crops” (p. 168). In the middle section of the Tongass, Pawuk and Kissinger 

(1989: 26) noted that “‘Alaska cedar’ regeneration is uncommon. Planting will normally be required to establish Alaska cedar as a significant component of second 

growth stands.” In the northern portion, Martin et al. (1995: 8-1) stated, “Cedar 

seedlings are particularly uncommon in areas of high deer use.” These observations 

should be contrasted with areas where yellow-cedar was known to successfully 

regenerate after harvest. 

Silviculturists on the Tongass National Forest shared information on where 

they had observed successful regeneration of yellow-cedar on harvest sites (e.g., fig. 

37). Appendix 3 lists 220 young-growth stands on the Tongass National Forest that 

contain >2 percent yellow-cedar, as determined by postharvest stocking surveys 

(prethinning or post-thinning), FIA plots, stand examinations, roadside composition 

assessments, or qualitative observation. This appendix includes stand identification 

number (FACTSID), location, elevation, harvest year, thinning status, and relative 

yellow-cedar composition. More stands will be added to this list over time, and 

this resource will be used to prioritize young-growth stands with yellow-cedar for 

monitoring, research, or active management. Another goal is to compare yellowcedar composition preharvest data (by using stand examination plot data) and postharvest data (by using regeneration stocking survey data) in the same locations to 

determine if and where significant changes in composition occurred due to harvest 

activities. Natural regeneration is discussed further in section 3 of this report. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Artificial Regeneration

The Tongass National Forest conducts only a modest amount of planting to restock 

harvested stands because establishment of natural regeneration is so successful. 

Interest has increased in planting yellow-cedar to meet management objectives, 

such as increasing species biodiversity, improving future commercial timber values, 

and establishing yellow-cedar in areas where it is not prone to decline. Several studies have been conducted in southeast Alaska to evaluate the feasibility of planting 

yellow-cedar to meet these management objectives.

The first study occurred near Anita Bay on Etolin Island in June 1986 (Hennon 1992b). Eight hundred 2-yr-old containerized seedlings were planted on six 

different sites. Sites were rated for soil drainage (poor, moderate, or good) and light 

exposure. Five years after planting it was evident that drainage and light affected 

seedling survival. Seedling survival was poorest on open sites with poor drainage 

Figure 37—Yellow-cedar natural regeneration near Klu Bay, Alaska, that 

was released by precommercial thinning. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

(23 percent survival) and on closed canopy sites with good drainage (36 percent). 

Sites with moderately drained to well-drained soils and good light exposure had high 

survival rates (88 percent). The planting sites were revisited 20 yr after planting (fig. 

38). The survival rate on well-drained sites was still very high at 85 percent (Hennon and Dowling 2006). The long-term future of these plantings appeared favorable, 

especially in one area where competing vegetation was reduced by burning as a 

site-preparation technique. The results of the Etolin Island planting are similar to 

studies conducted in British Columbia, where outplanting of yellow-cedar resulted in 

an 88-percent survival rate 10 yr after planting (Mitchell and Koppenaal 2006).

A second planting study (Hennon et al. 2009) was initiated in 1988 to evaluate 

the survival and growth of yellow-cedar seedlings relative to “stecklings.” Stecklings are planting stock produced from rooted cuttings, commonly used for reforestation in British Columbia (Karlsson 1974). Stecklings are convenient to produce, 

whereas producing yellow-cedar seedlings from seed can be problematic due to 

difficulty in collecting cones, low seed germination rates, and a complex stratification regime. Regardless of source, all planting stock for the study was grown 

for 1 yr in containers. Survival rates were high (about 87 percent after 6 yr), and 

survival did not differ by the type of planting stock. Although this study found that 

seedlings had small but significantly greater final stem diameters and heights than 

stecklings, a similar study in British Columbia found no difference in growth rates 

between seedlings and stecklings (Karlsson and Russell 1990). During the 1990s, 

the Tongass National Forest had a small, active yellow-cedar planting program on 

the Wrangell and Craig Ranger Districts. Wrangell Ranger District planted 153 ac 

on Etolin Island, 100 ac on Zarembo Island, 4 ac on Wrangell Island, and 190 ac on 

Zarembo Island; Craig Ranger District planted 10 ac near Polk Inlet on Prince of 

Wales Island (Hennon 1992a). These plantings were from local seed sources. Initial 

survival was generally excellent with >80-percent survival. The Tongass National 

Forest is resuming its yellow-cedar planting program by interplanting about 1,100 

ac on Thorne Bay Ranger District.

The Tongass National Forest has continued its partnership with the Pacific Northwest Research Station and has embarked on two planting trials with the objective of 

developing strategies to address yellow-cedar decline and related changes in climate. 

The movement of a species to a new suitable climate, called assisted migration, 

is an approach to expand a species’ range. As a species declines and dies in part of 

its range, there may be new locations, sometimes called the leading edge, where the 

climate becomes suitable. Assisted migration may be necessary for some species 

of trees that cannot migrate rapidly enough to keep pace with a changing climate. 

In 2009, a new planting trial was initiated in Yakutat, Alaska, to determine if 
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GENERAL TECHNICAL REPORT PNW-GTR-917

yellow-cedar could be regenerated and grow in a new, but suitable, environment. This location was selected because it is farther north and accumulates deep 

snowpacks over the winter. It is important to note that Yakutat is not outside of 

yellow-cedar’s range because yellow-cedar extends northwest into Prince William 

Sound. Third-year survival surveys, conducted in 2012, showed 80-percent survival 

(personal communication, Craig Buehler, Tongass National Forest, Sitka, Alaska, 

2012) (fig. 39). 

Another planting trial, a common garden study, was initiated in 2010 to 

compare yellow-cedar growth rates, foliar terpenes, and freezing resistance. Four 

different sites, 3 on Prince of Wales Island at a range of elevations and 1 on the 

Figure 38—Yellow-cedar trees in a harvest unit near Anita Bay, Etolin Island, 

Alaska, 20 years after planting in 1986.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 39—Three year-old yellow-cedar seedling planted near Yakutat, Alaska. 

mainland at Echo Cove north of Juneau, and 16 different seedlots were included in 

the study design. The second-year height growth and survival data are summarized 

in table 17 (Paul Hennon, unpublished data).6 All of the sites on Prince of Wales 

Island had low height growth and poor survival, which were attributed to severe 

deer browsing. The deer browsing resulted in two types of damage: seedlings were 

killed because they were pulled out of the ground or the stem was severed below the 

lowest live branch, or heavy browsing of the terminal and lateral branches resulted 

in severely stunted growth (fig. 40). One of these two types of damage was recorded 

on >95 percent of the seedlings on Prince of Wales Island sites. Survival rates 

are expected to be even poorer on these three sites as browsing by deer continues 

and severely damaged seedlings eventually die or are outcompeted by associated 

vegetation. In contrast, no deer browse damage was recorded on any seedling at 

the Juneau site. Along with low deer concentrations in the area, the seedlings are 

covered by snow during most of the winter, when seedlings are at the highest risk of 

6

 Data from yellow-cedar common garden study: first-and second-year growth and survival 

results, on file with: USDA Forest Service, Forestry Sciences Laboratory, 11175 Auke Lake 

Way, Juneau, AK 99801.
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GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 40—Deer browsing damage on a yellow-cedar seedling from a 

common garden study on Prince of Wales Island.

Table 17—Second-year survival and height of yellowcedar seedlings in a common garden study

Site Survival

Mean seedling 

height

Percent Inches

Harris, Prince of Wales Island 1.4 8.3

Diesel, Prince of Wales Island 42.8 7.8

Sunmore, Prince of Wales Island 61.3 8.8

Echo Cove, Juneau Mainland 98.1 18.3
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

browse. Future common garden trials should be protected from deer (e.g., fencing 

or shelter of individual seedlings) unless evaluating deer browse is an objective of 

the study.

The Alaska Department of Fish and Game’s deer management report (Harper 

2011) shows a significantly higher deer population on Prince of Wales Island 

compared to the Juneau area. Prince of Wales Island is part of Alaska’s game 

management unit (GMU) number 2, which is roughly 3,600 mi2. The deer population goal for GMU 2 is 71,000 deer, or 19 deer/mi2

, with a harvest goal of 2,700 

deer. In 2009, the annual deer harvest in GMU 2 was 3,251. The Juneau area is part 

of GMU 1C, which is 7,600 mi2. The population goal for GMU 1C is 6,200 deer 

(<1 deer/mi2) while maintaining an annual harvest of 456 deer. In 2009, the annual 

deer harvest was 291. These deer management objectives, deer harvest records, 

and the initial results of the yellow-cedar common garden study show that local 

deer populations need to be considered when prescribing artificial regeneration of 

yellow-cedar. The same consideration of deer populations may be useful in predicting successful natural regeneration of yellow-cedar in harvest areas. 

Control of Animal Damage

Herbivory from Sitka black-tailed deer is the most significant animal damage that 

occurs to yellow-cedar regeneration. The yellow-cedar common garden study 

begun in 2010 (table 17 and fig. 40) demonstrates how local deer populations can 

decimate planted yellow-cedar. Studies from British Columbia show that deer can 

also drastically reduce the regeneration of western redcedar (Coates et al. 1985, 

Martin and Baltzinger 2002). When prescribing deer control measures for yellowcedar, a silviculturist often tailors the prescription to site conditions, considering 

local deer population levels, existing habitat, and the timing of deer activity versus 

availability of yellow-cedar and other palatable plants. By considering the traits of 

the animal species to be controlled and traits of the plant species to be protected, it 

may be possible to target costly animal damage control measures such as physical 

barriers and chemical deer repellents to areas where they are most needed. 

Controlling deer browsing could be as simple as delaying spring planting until 

late May or June. Traditionally, reforestation activities in southeast Alaska occur 

shortly after snowmelt but before green-up of herbaceous vegetation and leaves of 

shrubs. Unfortunately, spring planting coincides with deer expanding their movement beyond their winter range in search of new plant growth (Person 2009). If 

preferred browse species such as bunchberry and trailing bramble are not available, 

deer eat woody browse such as blueberry, yellow-cedar and hemlock, and arboreal 

lichens (Alaska Department of Fish and Game 2013). If planting could be delayed 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Table 18—Summary of methods to protect seedlings from browse

Product

Protection 

method Application site

Fencing Physical Small acreage

Vexar® Physical Individual seedling

Solid-walled tubes Physical Individual seedling

Deer Away® Big Game 

Repellent, Plantskydd

Chemical Individual seedling foliage 

and stem

Plug+1 or plug+2 seedlingsa Natural Individual seedling or area

Stecklings Natural Individual seedling or area

Delayed planting Natural Individual seedling or area

a Plug+1 and plug+2 are container stock grown in the green-house and then extracted from 

the container and grown in outside transplant beds for an additional growing year or two, 

respectively. The resulting seedlings generally develop into a larger seedling with more root 

development than if they had been grown in only containers or as bareroot seedlings.

until after “green-up” then deer would browse on species other than planted cedar, 

at least for the first growing season. 

The size and age of the seedling being planted may also influence browsing 

intensity. A 3-yr-old seedling (plug+2) may not be as palatable to deer as a 1-yr-old 

seedling (plug+0) due to higher concentrations of monoterpenes in older foliage 

(Russell 2008). In addition, an older and subsequently larger seedling has more foliage surface area and may be able to survive some browsing while retaining enough 

foliage to continue to grow in height and diameter. In a recent operational 2013 

planting of yellow-cedar in 14 harvest units on Prince of Wales Island, the first-year 

survival was only 56 percent for 1-yr-old seedlings but was 80 percent for 2-yr-old 

seedlings. Nearly all mortality to seedlings was attributed to deer browse.

In cases where local deer populations are high and there is a need to establish 

yellow-cedar, silviculturists may consider physical or chemical controls (table 18). It 

is possible to protect yellow-cedar from deer browse through physical barriers such 

as fencing or individual tree shelters. Fencing large acreages in southeast Alaska 

is not practical due to the steep terrain, uneven surface conditions, and excessive 

costs. A more feasible alternative for protecting yellow-cedar from deer browse is to 

use rigid Vexar® tubing or solid-walled plastic tubes on individual trees. The previously mentioned planting study that compared the survival and growth of seedlings 

to stecklings had a secondary objective to evaluate the use of Vexar tubing for 

enhancing seedling survival, growth, and form (Hennon et al. 2009). Overall the 

survival rates did not differ with the use of Vexar; however, significant problems 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

with tree form resulted. It should be noted that this study occurred in areas of fairly 

low deer population and there was a low incidence of browsing on unprotected 

seedlings. Trees with Vexar were often leaning or prostrate on the ground due to 

snow loading. In addition, leaders and side branches were often found entangled 

in the wall of the tube. Other studies have produced similar results (Brandeis et al. 

2002, Crouch 1980). 

Solid-walled tree shelters are an alternative to Vexar that can withstand high 

snow loads and improve survival and growth of seedlings (Devine and Harrington 

2008, Jacobs and Steinbeck 2001). Even though solid tubes perform better in environments that receive heavy snowfall, it is still recommended that periodic maintenance of the tubes occur. Manufacturers of Vexar and solid-walled tubing claim 

that the material will degrade upon exposure to ultraviolet light within 3 to 5 yr, 

but Jacobs (2011) found little indication of photodegradation 11 yr after installing 

tubes on high-elevation clearcuts in southwestern Colorado. Removing or opening 

shelters is recommended to prevent growth and form deformities rather than relying 

on photodegradation.

Another silvicultural option to limit damage caused by browsing deer is to 

apply chemical deer repellents. Chemical repellents generally rely on fear, conditioned avoidance, pain, or taste (Trent et al. 2001). The most effective products are 

fear-inducing and emit sulfurous odors such as predator urine or degrading animal 

waste products (Nolte 1999, Trent el al. 2001). These repellents include 

Deer Away® Big Game Repellent (powder and liquid), Bye Deer® Sachets,

DeerbustersTM Sachet, and PlantskyddTM (Trent et al. 2001). Deer Away Big 

Game Repellent and Plantskydd are applied directly to the foliage and stem of the 

seedlings and are more effective at reducing deer browsing than the area repellents 

such as Bye Deer Sachets and Deerbuster’s Sachet. Wagner and Nolte (2001) found 

that spring application of these topical repellents resulted in good protection of 

western redcedar for 8 to 12 wk. The challenge in using any topical deer repellent 

is that the repellent needs a sufficient time period, up to 24 h, to dry and adhere to 

the seedling. This drying requirement makes feasibility in the rainforest setting of 

coastal Alaska unlikely. The Tongass National Forest is testing if it is feasible to 

apply deer repellent in the tree cooler before outplanting. 

Recently, the Tongass National Forest, Oregon State University, and Sealaska 

Corporation began a study to evaluate if seedling age, timing of planting, and 

several methods of protection influence the amount of deer browse on yellow-cedar 

and redcedar seedlings. First-year results show a high rate of deer browse on four 

of five sites (47 to 65 percent). Western redcedar had a higher incidence of browse 
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GENERAL TECHNICAL REPORT PNW-GTR-917

than yellow-cedar. The only treatment that reduced browse was the physical protection of tubes. Continuation of this study and similar efforts are needed to develop 

strategies to successfully regenerate western redcedar and yellow-cedar in areas 

with high deer populations.

Precommercial Thinning

The stocking and species composition of young hemlock-spruce stands vary across 

the southeast Alaska landscape primarily due to differences in site productivity 

and seed sources, but understocking of recently disturbed sites is rare. Harvested 

hemlock-spruce stands regenerate rapidly from prolific natural seed fall and 

released advanced regeneration (seedlings and small trees present in the understory 

of the previous stand that may grow rapidly after being freed from competition 

with the dominant harvested trees). In some cases, full site occupancy (full stocking) is achieved within 15 yr after harvest. Thereafter, controlling the density 

of trees influences stand characteristics such as tree species composition, tree 

diameter, height-to-diameter ratios, cover and composition of understory species, 

and horizontal and vertical diversity. Precommercial thinning is the primary means 

to manage tree densities at an early age before trees have a marketable value. In 

southeast Alaska, precommercial thinning is generally prescribed between stand 

ages 15 and 30 to meet land management objectives such as improved wood production and value, wildlife habitat, aesthetics, resistance to insects and diseases, and 

biodiversity. 

By favoring yellow-cedar over other species, precommercial thinning can 

increase the relative abundance of this species within stands and across landscapes. 

Thinning also releases yellow-cedar from overtopping hemlock and spruce, which 

on some sites can outgrow yellow-cedar with their more rapid early height growth. 

Site-specific thinning prescriptions are needed to ensure that yellow-cedar management objectives are compatible with inherent stand variability such as species 

composition, advanced regeneration, residual overstory, and other important 

characteristics of the overstory and understory. It is not appropriate to use a blanket 

prescription that requires all yellow-cedar to be retained during thinning operations. This prescription does not take into consideration factors such as health and 

form of yellow-cedar trees, quantity and distribution of yellow-cedar on a site, competition between trees of the same species, and quality and form of other species. 

In addition, this practice does not consider a changing climate and the potential that 

yellow-cedar may be maladapted to a site.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Section 2: Climate and Yellow-Cedar Decline

The extensive yellow-cedar mortality in southeast Alaska and adjacent coastal 

British Columbia is considered to be a classic forest decline. Forest declines are 

characterized as being widespread and long-term (i.e., not single events), and have 

a cause that is either unknown, or has been determined to be a complex of interrelated biotic and abiotic factors (Manion and Lachance 1992). Although the term 

“decline” suggests reduced growth or changes in populations, forest declines often 

result in extensive tree mortality, as in the case of yellow-cedar decline. There are 

several dozen well-established forest declines around the world, including maple 

and birch declines in the United States and Canada (Manion and Lachance 1992), 

but the causes of few have been elucidated. Gradual tree death and multiple predisposing and inciting factors make it a challenge to unravel the causes of forest 

declines. Persistent forest disturbances are likely to become more numerous and 

important as the pace of climate change accelerates; some forest trees are subject 

to new stresses as climate interacts with other factors, such as insects, pathogens, 

soils, and intrinsic host tree vulnerabilities, to initiate widespread tree death. Forest 

declines triggered by shifting climate regimes may be expected in the southern 

portions of tree species’ ranges. However, yellow-cedar decline diverges from this 

expectation in that it occurs in the northern areas of its range. 

Yellow-Cedar Decline 

Extent and Intensity of Decline

Yellow-cedar mortality is apparent in southeast Alaska and British Columbia, where 

patches of dead and dying trees are a common sight on hillsides (fig. 41). Yellowcedar decline, observable from the air as dying trees with yellow to red crowns, has 

been mapped since about 1990 during annual U.S. Forest Service aerial surveys 

of forest health. Unlike most transient insect and disease outbreaks, the acreage 

of yellow-cedar decline represents a long-term feature on these landscapes, not 

only because tree death occurs gradually, but also because yellow-cedar remains 

standing for 80 to 100 yr after tree death. These mapping efforts have resulted in a 

single distribution map of yellow-cedar decline in Alaska (fig. 42). Merging several 

thousand mapped patches of various sizes creates a cumulative measure of decline 

that covers >500,000 ac. The wide swath of decline extends from the southern part 

of southeast Alaska north towards the western coast of Chichagof Island. This value 

may represent an underestimate of forests affected by yellow-cedar decline because 

it is difficult to detect mortality where it is older or in less productive forest types. 

The potential for underestimation in some of the areas of the southern panhandle 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 41—Intensive yellow-cedar decline on Chichagof Island, Alaska, near 

sea level. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 42—Occurrence of yellow-cedar decline from aerial detection surveys (red) in the context of yellow-cedar populations 

(yellow) in southeast Alaska.
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GENERAL TECHNICAL REPORT PNW-GTR-917

of Alaska that have older mortality on forested wetlands is discussed in appendix 1. 

Yellow-cedar forests in the northeastern portion of the panhandle, north along the 

Gulf of Alaska coast above latitude 57.6° N, and to the northwest in Prince William 

Sound are all apparently free of this intensive mortality. In 2004, yellow-cedar 

decline was discovered along the northern coast of British Columbia during surveys 

with the British Columbia Ministry of Forests (Hennon et al. 2005). Subsequent 

surveys have expanded the acreage and southern extent considerably. To date, 

yellow-cedar decline in British Columbia has been detected on 235,000 ac (Westfall 

and Ebata 2014), extending south to the mainland across from Vancouver Island to 

an area just south of latitude 51° N. Yellow-cedar decline is now known to occur 

along a north-south axis that covers more than 6° of latitude, or about 600 miles. 

This mortality is not known to occur furthur south in British Columbia, Washington, Oregon, or California.

At a broad spatial scale, yellow-cedar decline has elevational limits that vary 

by latitude in a manner that suggests that climate plays a key role in the mortality. 

Decline at southern latitudes in British Columbia occurs at much higher elevations 

(650–2,300 ft) (Hennon et al. 2005, Westfall and Ebata 2014, Wooton and Klinkenberg 2011). Along northern latitudes, decline is found at progressively lower elevations; at the northern extent of decline (57.6° N on Chichagof Island, Alaska), tree 

death is expressed in a narrow, low-elevation band from sea level to only 500 ft. In 

Alaska, elevational patterns of yellow-cedar decline have been documented over the 

3° of latitude where it occurs (Graham and Heutte 2014). This information will be 

merged with accumulating data from British Columbia, providing a seamless view 

of the problem over the full 6° of latitude.

Although much of the mapped yellow-cedar decline occurrence has been 

gathered by using aerial detection survey (ADS) techniques, high-resolution maps 

of yellow-cedar decline have been produced from aerial photographs for parts of 

Alaska’s Kruzof, Chichagof, and Baranof Islands (Hennon and Wittwer 2013) (fig. 

43). As is common on many landscapes where yellow-cedar decline occurs almost 

continuously, discrete pockets are too numerous and small to effectively map in real 

time from a moving aircraft. This finer scale photo-interpreted (PI) dataset showing discrete patches of yellow-cedar decline was developed by using 1:60,000 color 

infrared photographs taken of the Mount Edgecumbe and Peril Strait areas between 

1996 and 1998. The interpreted data were then verified during flights by using 

ADS digital sketch-map techniques. 

The two detection techniques (ADS and PI) showed decline in the same general 

areas, but the fine-scale PI mapping technique yielded only one-fourth the acreage 

suggested by the ADS data, while showing 25 times the number of discrete decline 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 43—A high-resolution map of yellow-cedar decline in Peril Strait, Alaska, one of two areas studied using 

fine-scale photo interpretation. Another such map exists for Mount Edgecumbe on Kruzof Island. These were 

produced by digitizing polygons of yellow-cedar decline that were visible on aerial photographs and then checked 

for accuracy by observation from aircraft. These high-resolution maps differ from the aerial survey-derived map 

of yellow-cedar decline in that mapped patches are more numerous but considerably smaller, resulting in a reduced 

acreage estimate of decline. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

patches. These results should be taken into account when quantifying dead yellowcedar, such as estimating salvage volume. Also, the PI approach may be biased 

toward detection of higher volume dead forests because of the vertical view of this 

photography. When the observer is looking straight down, denser concentrations of 

dead wood are required for detection of affected forest. The more diffuse patches 

of dead cedar are visible in the oblique view used in ADS. This bias toward higher 

density of dead trees could make PI a more selective method for detecting patches 

suitable for commercial salvage recovery.

Mount Edgecumbe, on Kruzof Island near Sitka, Alaska, at a latitude of 57° 

N, is a dormant volcano with radial symmetry and gradual slopes that support 

open-canopy forests with abundant yellow-cedar extending from sea level nearly 

to timberline at approximately 2,000 ft. Subsequent terrain analysis of the Mount 

Edgecumbe PI data suggested that, at that latitude, decline is most abundant at an 

elevation of 400 ft, on southern aspects, and on gentle slopes of 6° to 10°. 

Two studies describe the local intensity of yellow-cedar mortality in stands with 

cedar decline. Both found that, on average, 60 to 70 percent of the yellow-cedar 

basal area was dead in ground plots in decline-affected forests, with mortality >90 

percent in some stands (D’Amore and Hennon 2006, Hennon et al. 1990b). Mortality was more common among larger trees but also occurred in trees with diameters 

as small as 6 in. Tree species other than yellow-cedar typically do not show elevated 

mortality rates in stands affected by yellow-cedar decline. Most of the plots evaluated in these studies were located on Chichagof and Baranof Islands near the 

northern extreme of cedar decline; however, the earlier study (Hennon et al. 1990b) 

also included plots on Wrangell and Prince of Wales Islands. The majority of tree 

death in these plots occurred on wet soils (D’Amore and Hennon 2006, Johnson and 

Wilcock 2002), where, paradoxically, yellow-cedar was previously well-adapted and 

competitive (see “Geology and soils” in section 1) (Hennon et al. 1990a, Neiland 

1971). Affected stands are usually composed of long-dead, recently dead, dying, 

and surviving trees, which suggests that mortality is long-term and continuing. 

Conversely, newer patches of yellow-cedar decline contain mainly recently killed 

and surviving trees, indicating later initiation. 

Yellow-cedar decline was known to occur only in older, unmanaged forests 

until recently, when silviculturist Greg Roberts of the Wrangell Ranger District 

noticed dying yellow-cedar in young-growth forests on Zarembo Island in southeast 

Alaska. He and colleagues assessed this situation initially in the summer of 2013 

(Mulvey et al. 2013). The dying and recently dead yellow-cedars (fig. 44) had been 

previously selected as crop trees in the 38-yr-old precommercially thinned stand. 

Symptoms of dying trees in the young-growth forest mirrored the classic symptoms 
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Figure 44—Dying (left) and nearly dead (right) yellow-cedar crop trees in a thinned 38-year-old stand on 

Zarembo Island, the first example of yellow-cedar decline in a young-growth forest.

of dying mature trees: dead coarse roots, necrotic phloem lesions extending from 

coarse roots vertically up the lower bole, and entire crowns dying as a unit with 

proximal (inner) foliage the first and distal (tip) foliage the last to die. Also, as is 

common on nearly dead or recently dead mature trees, the galleries of the bark beetle Phloeosinus and mycelial fans and rhizomorphs of the fungus Armillaria were 

found on young yellow-cedars in this stand. The dead and dying young-growth 

yellow-cedar trees were found in the wetter portions of the stand, as indicated by 

tree sizes and understory plants, another similarity with yellow-cedar decline in 

unmanaged forests. Dead mature yellow-cedar stands were observed around these 

affected young-growth stands, suggesting that landscape position, including elevation, is conducive to decline development. Monitoring of this site will continue, and 

additional observations in other young-growth yellow-cedar stands will be necessary to determine if this case is an isolated occurrence.

Epidemiology, Timing, and Pulses of Mortality

A unique snag classification system was designed for use in epidemiology studies 

on yellow-cedar (fig. 45) because existing systems developed for tree species that 
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Figure 45—Snag classification for yellow-cedar has a focus on the retention of foliage, twigs, 

and branches. Mean time-since-death estimates are given for five of the six snag classes (Hennon 

et al. 1990c).

have more wood decay and different patterns of deterioration were not adequate for 

cedars. The yellow-cedar snag classification system relies on the retention of foliage, fine twigs, and branches (Hennon et al. 1990c), although other features, such as 

bark retention, sapwood decay, and cracks penetrating into heartwood were evaluated later (Hennon et al. 2000). To establish time since death for five of the six snag 

classes, two methods were used: growth release patterns of hemlock trees in the 

understory of individual dead yellow-cedars, and ring counts back to the cambium 

in partially dead yellow-cedar trees (Hennon et al. 1990c). Stan et al. (2011) verified 

these time-since-death estimates for the first three snag classes by using cross dating techniques with live trees, but could not address the older two classes because 

of decayed and missing sapwood rings. This snag classification system has been the 

basis for all studies on wood properties of dead yellow-cedars and for marking trees 

in operational salvage harvests (see section 3).

The remarkable decay resistance of heartwood in dead yellow-cedar trees 

(Kelsey et al. 2005) allows dead trees to remain standing 80 to 100 yr. Thus, 

patches of yellow-cedar decline provide a standing record of tree death and an 

opportunity to reconstruct patterns of mortality over the past century. Annual 

mortality rates in stands were calculated by combining survey plot data on the 

frequency of each snag class with time-since-death estimates to provide this 

reconstruction. Elevated yellow-cedar mortality began around 1880–1900 and 

continued through the 1900s, with peak values in the 1970s and 1980s (Hennon 

and Shaw 1994). The oldest standing snag class (class 5) encountered in surveys in 

the 1980s represented the original wave of mortality, and many of these trees were 
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still standing on ground plots more than 100 yr after death (Hennon et al. 1990c). 

Class 5 snags eventually weaken and break off low on the bole due to decay at the 

ground line, falling to the forest floor and becoming class 6 downed snags (fig. 46). 

Class 6 downed yellow-cedar snags were infrequently encountered during surveys 

in the 1980s, and were found in equal concentrations in dying and healthy forests 

(Hennon et al. 1990b). This low incidence of downed snags probably represents the 

sustainable rate of yellow-cedar mortality in healthy forests. As more time elapses, 

snags created by the original wave of mortality that occurred around 1900 will 

continue to snap and fall to the ground. 

As noted, the decline is progressive in most dying stands, which typically 

contain a mixture of yellow-cedar trees killed at different times, dying cedars, 

scattered surviving cedars, and other tree species (Hennon and Shaw 1997). In 

some stands, there are clear zones of tree death that occurred at different times, 

suggesting patterns of local (around 300 ft) spread in the last century (Hennon et al. 

Figure 46—Old yellow-cedar snags eventually have sufficient decay 

near the ground line that they break and finally fall to the ground 

some 80–100 years after death. 
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1990b). Plot data reveal that this spread tends to occur along a hydrologic or slope 

gradient, with long-dead trees in central areas with poorly drained soils and more 

recently killed or dying trees around the periphery on sites with better drainage 

(D’Amore and Hennon 2006, Hennon et al. 1990a). A comparative analysis of historical and recent aerial photographs (Hennon et al. 1990b), along with subsequent 

use of remote sensing, vegetation classification, and ground plots with snag class 

data (D’Amore and Hennon 2006), confirms the slow spread of mortality. Stands at 

the northern limits of yellow-cedar decline in southeast Alaska from Slocum Arm 

to Klag Bay on the outer coast of Chichagof Island have a south-to-north sequence 

of older, recently killed, dying, and healthy yellow-cedar stands (Oakes et al. 2014). 

Data from measurements of permanent U.S. Forest Service, Forest Inventory 

and Analysis (FIA) plots in southeast Alaska were used to detect net changes in 

tree species’ populations through gains of in-growth and regeneration and losses 

through harvest and mortality (Barrett and Christensen 2011). Plots were established from 1995 through 1998 and remeasured from 2004 through 2008. Analysis 

of yellow-cedar populations did not reveal significant net biomass loss over this 

period. One explanation is that this evaluation was conducted after the major 

mortality pulse in the late 1970s and 1980s. In general, FIA plots do not cover 

wilderness areas managed by the Forest Service, and several, such as the West 

Chichagof–Yakobi Wilderness Area, are known to have extensive recent mortality 

(Oakes et al. 2014). Also, there is evidence that the roughly 30 percent of surviving 

yellow-cedar trees in decline patches eventually release and have good growth as 

the forest recovers (Beier et al. 2008). The FIA plots throughout coastal Alaska 

were analyzed, not just those in areas of yellow-cedar decline. Regeneration and 

tree growth gains in healthy forests at higher elevations or beyond the distribution 

of yellow-cedar decline may have compensated for mortality losses in declineaffected forests. Every year, the Forest Service’s forest health reports (e.g., Graham 

and Heutte 2014) document new areas of active yellow-cedar decline. These surveys 

show that localized active spots of mortality persist from year to year, but generally 

yellow-cedar decline appears to be episodic on a regional scale. 

Causes of Extensive Tree Death

Early Studies on Symptoms and Biotic Agents

Study of the cause of yellow-cedar decline (fig. 47) was initiated in 1981 with a 

rapid field assessment of the problem (Shaw et al. 1985), including observations on 

crown symptoms, activity of several known insects and disease organisms, and the 

likely duration of the problem. In prior years, the occurrence of a dead and dying 

yellow-cedar component of forests was noted in annual forest insect and disease 
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Figure 47—Dying yellow-cedar expressing symptoms throughout its crown. 

reports with speculation about the cause, but it was not fully investigated other 

than the finding that bark beetles (Phloeosinus species) were present in some of 

the dying trees (Downing 1960). More deliberate studies on symptoms and biotic 

agents began in 1982 in a cooperative agreement between the Pacific Northwest 

Research Station and Oregon State University. Trees in various stages of dying 

were examined for symptoms in their roots (through excavation), boles, and crowns. 

Evaluating trees at various stages of symptom development allowed for a sequential 

description to be formulated on belowground and aboveground symptom progression over the course of tree death (Hennon et al. 1990d). Initially, fine roots die, 

followed by small-diameter root mortality and the formation of necrotic lesions 

on coarse roots. Finally, necrotic lesions spread from dead roots vertically, from 

the root collar up the tree bole (fig. 48). Symptoms of stress in the tree crown lag 

behind the early root symptoms. The entire crown generally dies as a unit, with 
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Figure 48—Lower bole lesions typical of dying yellow-cedar trees in 

the final stages before death. The bole lesion was infected with the 

fungus Armillaria sp., which is present on about one-half of dying 

yellow-cedar trees.

discoloration occurring throughout the crown, sometimes quickly (fig. 47). On 

slower-dying trees, proximal (inner) foliage dies first, followed by the death of 

distal (outer) foliage (fig. 49). This slow death, which is more typical, is expressed 

with crowns thinning progressively over 10 to 15 yr, with an associated stagnation 

in radial growth. In general, the study of symptoms and their progression suggested 

a belowground problem for affected trees. 

Many groups of organisms were evaluated as potential pathogens involved in 

the decline syndrome, but each was ruled out by inoculation trials or by the lack 

of association with symptomatic tissue or dying areas of the forest. Groups of 

organisms investigated were higher fungi (Hennon 1990, Hennon et al. 1990d), 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

oomycetes (Hamm et al. 1988, Hansen et al. 1988), insects (Shaw et al. 1985), 

nematodes (Hennon et al. 1986), viruses and mycoplasmas (Hennon and McWilliams 1999), and bears (Hennon et al. 1990a). The general conclusion from these 

evaluations of symptoms and possible biotic factors was that no single organism 

was the primary cause of the decline problem (Hennon and Shaw 1997, Hennon et 

al. 1990d), with the former being the most detailed summary of these studies. 

Abiotic Factors and the Complex Cause: Freezing Injury

Several assumptions were made based on early studies on symptoms, biotic factors, 

and epidemiology (Hennon and Shaw 1997): the problem appears unique to yellowcedar; mortality starts with fine roots; yellow-cedar decline began about 100 yr ago, 

but increased in the late 1900s; yellow-cedars growing on poorly drained soils are 

predisposed to decline; and the direct cause of decline appears to be some form of 

abiotic injury rather than a pathogen or other organism. A multidisciplinary team 

then broadened the investigation to evaluate several leading hypotheses involving 

Figure 49—Crowns of declining yellow-cedar often thin slowly, sometimes 

over 15 years or more, leaving trees with only distal (outer) foliage before the 

tree finally succumbs and dies. 
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likely abiotic factors to explain tree death: aluminum soil toxicity, calcium deficiency, soil acidity, and freezing injury (D’Amore and Hennon 2006). A risk-factor 

analysis compared the values of these abiotic factors to the health of yellow-cedar 

forests in two watersheds. This study revealed that greater extremes in seasonal 

air and soil temperature were consistently associated with the occurrence of 

yellow-cedar decline, and that other examined factors did not relate to cedar health 

(D’Amore and Hennon 2006). These findings, along with cumulative knowledge of 

the symptoms of dying trees and temporal and spatial patterns of decline, suggested 

a hypothetical cascade of predisposing and inciting factors that led to root-freezing 

injury as the proximate cause of tree death (fig. 50).

Figure 50—The interrelated factors that contribute to the proximal cause of 

yellow-cedar decline—fine root freezing—and the mitigating role of snow. 
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The yellow-cedar injury pathway, with its interrelated factors (fig. 50), was too 

complex to be assessed in a single study; therefore, it became a research program 

framework which guided the design and execution of a series of individual studies 

with the overall goal of resolving the cause of yellow-cedar decline. Interactions 

along the pathway were addressed with one or more studies on hydrology, canopy 

cover, air and soil temperatures, snow accumulation and persistence, yellowcedar phenology, and freezing injury to seedlings and mature trees. These studies 

attempted to answer two basic questions about cedar decline: What is the unique 

physiological vulnerability of yellow-cedar, and what change in the environment 

triggered this mortality? 

Soil drainage is an important contributing factor in yellow-cedar decline. 

Forest species composition and productivity in north coastal temperate rainforests 

are tightly controlled by soil saturation and drainage (Neiland 1971). The optimal 

niche for yellow-cedar is in soils with intermediate drainage, but it can occupy sites 

with a wide range of soil-saturation levels (fig. 51) (Hennon et al. 1990b). Yellowcedar is most productive on well-drained, nutrient-rich sites (D’Amore and Hennon 

2006), where it is frequently outcompeted by western hemlock. The decline of 

Figure 51—Average live basal area of yellow-cedar and associated tree species along the drainage 

gradient as interpreted by understory plants from vegetation plot data (Hennon et al. 1990b). The 

percentage of dead yellow-cedar basal area is also shown (red dashed line), which indicates an apparent threshold of soil drainage that distinguishes yellow-cedar mortality.
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yellow-cedar is associated with the wetter side of the drainage gradient (Hennon 

et al. 1990). There is an apparent threshold that separates live and dead forests (fig. 

51), which means that yellow-cedar’s niche is compromised on sites with poor and 

moderate drainage (Hennon et al. 2012).

Soil saturation and hillslope stability have been compared on steep slopes (>25°) 

of Mitkof, Prince of Wales, Baranof, and Kuiu Islands. Although areas of yellowcedar decline on steep slopes do not have significantly greater soil saturation, soils in 

yellow-cedar decline areas typically have lower hydraulic conductivities and remain 

saturated for longer periods of time than soils of healthy cedar and spruce forests on 

adjacent slopes (Johnson and Wilcock 2002). Yellow-cedar decline was correlated 

with increasing landslide susceptibility in fine-scale studies (Johnson and Wilcock 

1998, 2002) yet the relationship was not significant at larger scales—although a 

stronger relationship may develop with time (Buma and Johnson 2015). 

Nutrient cycling and rooting depth are limited on wet soils, and tree growth 

rates are inhibited, reducing canopy cover and the standing biomass of live trees 

(D’Amore and Hennon 2006). The size and age structure of existing trees (Beier et 

al. 2008, Hennon and Shaw 1994) suggest that wet soil conditions were probably 

present before yellow-cedar decline started around 1900. These soil conditions 

may have been established several thousand years ago, when the climate along the 

Pacific Coast became cool and wet, leading to extensive peatland development 

(Heusser 1960) (see “Paleoecology” in section 1). Estimating forest canopy cover 

with hemispherical ground-based photographs (fig. 52) and light detection and 

ranging (LiDAR) demonstrates that canopy cover varies greatly along drainage 

gradients (from 0 percent in bogs to >89 percent in upland forests), and is highly 

correlated with the basal area of live trees (Hennon et al. 2010).

It was initially assumed that yellow-cedar trees had abundant roots in shallow 

horizons of wet soils as a response to low-oxygen conditions encountered at greater 

depths. However, measurement of yellow-cedar foliar nutrient concentrations 

suggested that yellow-cedar may also root shallowly as part of a nutrient-acquisition 

strategy to maintain growth in a nutrient-limited environment in water-saturated 

soils (Schaberg et al. 2011). This proposed adaptation might allow cedars to link 

uptake of nitrate anions and calcium cations in order to exploit shallow, rich sources 

of nitrogen that are unavailable in deeper soil horizons (D’Amore et al. 2009). 

Nutritional analysis of the foliage indicated that yellow-cedar takes up more calcium (concentrated in upper organic soil horizons) and less aluminum (concentrated 

in deeper mineral horizons) than other associated conifers, which supports the 

hypothesis that yellow-cedar has a greater proportion of shallow fine roots than 

many of its competitors (Schaberg et al. 2011). Along with avoidance of anoxia, this 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 52—Hemispherical photograph in a stand of yellow-cedar decline. Canopy cover varies 

widely along the bog-forest drainage gradient and also is further reduced by tree mortality. Canopy 

cover was estimated from above by modeling LiDAR data and from below by analyzing hemispherical photographs. 

adaptation for enhanced nitrate uptake leads to shallow rooting and predisposes 

yellow-cedar to increased risk of injury from fluctuations in near-surface soil 

temperature.

Yellow-cedar has been observed on steep slopes in both British Columbia and 

Alaska. These observations might appear to conflict with soil drainage and shallow 

rooting as predisposing factors for yellow-cedar decline. Where we have investigated these situations (e.g., Deep Bay in Peril Strait), we found shallow-rooted 

yellow-cedar trees growing in very thin soils overlaying unfractured bedrock with 

seepage coming from above. Thus, even though the sites were extremely steep, tree 

rooting was restricted to a thin mantle of soil and soils appeared wet. 

Canopy cover differs considerably by forest productivity (capacity for a greater 

rate of tree growth) and modifies air and soil temperatures. Dense canopies intercept solar energy and buffer the areas below the canopy from high temperatures 

through shading. This cover also traps heat that emanates from the ground, which 

leads to temperature inversions below the canopy during cold weather. Forests with 

lower canopy cover have warmer daily maximum and colder daily minimum air 

temperatures, and canopy effects on daily temperature ranges are most pronounced 
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in the spring months (D’Amore and Hennon 2006). Soil temperature variability is 

inversely related to soil depth. The shallow-rooting zone (3-in depth) shows pronounced daily temperature variation, with an even greater warming effect and frequent subfreezing temperatures where the canopy is less dense (Hennon et al. 2010). 

In the deeper rooting zone (6-in depth), greater late-winter and spring warming, but 

only infrequent freezing, occurs in areas with lower canopy cover (D’Amore and 

Hennon 2006). The roots in shallow soil horizons, especially in areas of less canopy 

cover, are most vulnerable to repeated cold temperature injury. 

A series of measurements in the field and experiments in collaboration with the 

University of Vermont and the Forest Service’s Northern Research Station established the link between cold tolerance and freezing injury in yellow-cedar trees. 

Past work on the physiology of yellow-cedar (e.g., Hawkins et al. 2001) suggested 

that the species has limited cold hardiness. Seasonal differences in the cold tolerance of mature yellow-cedar and western hemlock were assessed at a site affected 

by decline (Poison Cove on Chichagof Island) to determine whether temperature 

sensitivity was a unique factor predisposing yellow-cedar to decline (Schaberg et 

al. 2005). Measuring foliar cold tolerance as a surrogate for root cold tolerance 

(because the two measurements are seasonally correlated), Sakai and Larcher 

(1987) documented two patterns that were consistent with the proposed decline 

scenario (fig. 50). First, yellow-cedar foliage on trees was more cold hardy in midwinter than western hemlock foliage, but yellow-cedar dehardened more rapidly 

than western hemlock to become more easily injured by early cold temperatures. 

Second, yellow-cedar trees at low and middle elevations, where decline predominates, were more vulnerable to early dehardening and subsequent freezing injury 

(Schaberg et al. 2005).

The decline mechanism was more directly tested by examining the influence 

of simulated snow cover (using perlite) on the cold tolerance and freezing injury 

of potted yellow-cedar seedlings (Schaberg et al. 2008). The roots of all seedlings 

were tolerant only to about 23 °F (-5 °C); when soil temperatures fell below this 

threshold on plots without simulated insulating snow, roots were severely injured 

and seedlings died (fig. 53) (Schaberg et al. 2008). Importantly, the progression of 

injury followed the sequence of symptoms for mature trees documented in the field, 

starting with root mortality in the winter and early spring, then foliar damage, and 

eventually whole-plant mortality when the dead roots were incapable of supplying 

the foliage with water and other resources (Hennon et al. 1990b). The hypothesis 

that yellow-cedar has unique freezing vulnerability was further tested by measuring 

at regular intervals the fine-root cold hardiness of yellow-cedar and four associated 

conifer species growing in a mixed-species stand near Ketchikan, Alaska (Schaberg 
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Figure 53—Experiment with yellow-cedar seedlings leading to root injury and death where unprotected (the group on the right), but uninjured and alive where protected by perlite covering roots to 

buffer soil temperatures and act as a simulated snow cover (Schaberg et al. 2008). 

et al. 2011). Across all measurement dates from fall through spring, yellow-cedar 

roots were less cold tolerant than the roots of western redcedar, the two hemlock 

species, and Sitka spruce, in ascending order of cold tolerance (Schaberg et al. 

2011). Although all of the species reached their maximum hardiness in January, 

yellow-cedar’s maximum winter hardiness was at a much higher temperature than 

other species (with hardened roots showing significant injury at about 21 °F), and 

roots fully dehardened by March. The limited hardiness and high baseline cellular 

membrane leakage of yellow-cedar roots (Schaberg et al. 2011), combined with 

other measures of photosynthesis (Grossnickle and Russell 2006) and root growth 

(Arnott et al. 1993), suggest that yellow-cedar is poised for physiological activity 

when suitable environmental conditions occur (e.g., allowing for nitrate uptake 

when snowpack melts) (D’Amore et al. 2009). Whatever the reasons for its unique 

physiology, yellow-cedar roots are shallower and less cold tolerant than those of 

associated conifers, and, consequently, are more vulnerable to injury from freezing 

of the upper soil horizons.

Changing snow patterns are most likely the environmental change that triggers 

yellow-cedar decline. Snow is an effective insulator for soils, buffering soil temperatures at the threshold between freezing and thawed conditions. Soil temperatures monitored in the shallow-rooting zone frequently drop below the lethal values 

for cedar roots (23 °F) in the winter and early spring, but only when snow is not 

present (Hennon et al. 2010). Shallow soils covered by snow during cold weather 

events usually maintain temperatures just above freezing because of latent heat 
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emanating from deeper soils. The persistence of snow beyond the last hard freeze 

in the spring protects yellow-cedar from root injury, and this relationship explains 

the broad spatial distribution and elevational patterns of yellow-cedar decline on 

the landscape (Hennon et al. 2008). In addition to this extensive geographic pattern 

of decline, mortality-induced changes in microclimate may help spread decline at 

the local-stand scale. Canopy cover was historically controlled by hydrology (i.e., 

open canopies on wetter soils) (D’Amore and Hennon 2006). But when trees die, a 

mortality-caused feedback further opens the canopy, which increases the exposure 

of neighboring trees to extremes in microclimate (Hennon et al. 2010). This type of 

spreading pattern is typical at the leading edge of tree mortality on better drained 

soils, where moving fronts of dying trees have been documented along drainageproductivity gradients (Hennon et al. 1990b).

Relationship of Snow and Yellow-Cedar Decline at 

Different Spatial Scales

Analyzing the occurrence of the dead and dying yellow-cedar component of forests 

at multiple spatial scales has helped to form and evaluate the hypothesis for the 

cause of yellow-cedar decline. Each of three spatial scales offered a unique interpretation of the association between decline and particular climate, landscape, site, 

or microsite features. Evaluation of aerial survey data established that yellow-cedar 

decline is limited to lower elevations, but the actual elevational limits are modified 

by latitude. Snow is the proximal factor that controls this pattern. Maps of yellowcedar decline and a regional snow accumulation model in southeast Alaska show 

a pattern of decline closely aligned with the lowest of four snow zones (Hennon et 

al. 2006) (fig. 54). Beier et al. (2008) quantified this relationship as 79 percent and 

94 percent of yellow-cedar decline occurring in the low- and low-to-moderate snow 

zones, respectively. Yellow-cedar forests appear healthy in Alaska in areas that have 

higher levels of annual snow accumulation, such as the northeastern portion of the 

panhandle, Glacier Bay forelands, and Prince William Sound (Hennon and Trummer 2001).

High-resolution maps of yellow-cedar decline on Mount Edgecumbe, near 

Sitka, were used to evaluate the association between decline and topographic 

features (slope, aspect, and elevation) at a mid-spatial scale. Decline was found to 

have elevational limits that corresponded to aspect, occurring farther upslope on 

southerly aspects than on northerly aspects. Detailed snow-accumulation models, 

which included an elevational downscaling adjustment (Wang et al. 2006) for 

Mount Edgecumbe, revealed the threshold of estimated annual snowfall—about 10 

in (250 mm) of annual precipitation as snow—that distinguishes dying yellow-cedar 
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Figure 54—Regional snow model by Dave Albert (The Nature Conservancy) showing four classes of annual snow 

accumulation (left) and distribution of yellow-cedar decline (right). Note the close alignment of yellow-cedar decline 

with the lowest class of snow accumulation, shown in red. 

forests from healthy ones (fig. 55). This value is incorporated into a snow model 

built from historical weather-station data inputs and future projections from a conservative general circulation model (fig. 55). Output from this model displays how 

snow patterns on Mount Edgecumbe are estimated to have changed over time and 

are projected to change into the future, and how changing patterns are expected to 

affect the distribution of yellow-cedar decline. By the year 2080, the model predicts 

that snow accumulation sufficient to protect superficial roots from freezing injury 

will occur only near the top of the mountain (fig. 55). As noted elsewhere, decline 

is not expected to emerge where yellow-cedar grows on well-drained soils even in 

areas of low snow accumulation. 

Variation of site and forest conditions at a fine landscape scale was studied by 

using a grid of ground-based vegetation plots in two watersheds at Poison Cove 

and Goose Cove north of Sitka, near the northern limit of yellow-cedar decline 

(D’Amore and Hennon 2006). At this local scale yellow-cedar health could be 
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Figure 55—Mount Edgecumbe near Sitka, Alaska. The extent of yellow-cedar decline (red) 

as mapped from 1998 color infrared photographs and the estimated annual precipitation 

as snow between 1961 and 1990 are shown with colors indicating values above (blue) and 

below (tan) the threshold of 10 in (250 mm) of annual precipitation as snow (Hennon et al. 

2012). The historical and future (with input by a general circulation model) occurrence of 

this modeled snow threshold are also shown. Figure produced by Colin Shanley, The Nature 

Conservancy. 

correlated with hydrology, canopy cover, microclimate, and snow in order to test the 

significance of causal factors. Remote cameras were installed to document snow 

presence and depth daily from winter through spring, and thermal data loggers 

monitored how snow altered soil temperatures during cold events. This study found 

that yellow-cedar was dead and dying in low-elevation areas with poor drainage, 

where shallow soil temperatures were frequently below the 23 °F (-5 °C) threshold 

for fine-root mortality. In contrast, yellow-cedar was healthy on wet soils farther 

upslope, where snow insulated the roots, and on adjacent well-drained soils with 

deeper rooting (Hennon et al. 2010) (fig. 56).
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Figure 56—Air (dashed line) and soil temperature (solid lines) through one winter (2004–5) at the 

Poison Cove study site illustrating the difference between soil temperature in the largely snow-free 

lower elevation plots where cedars are dead (red line) and slightly higher elevation plots with a 

persistent snowpack (green line) where cedars are live. 

Climate Interactions With Yellow-Cedar

A chronology of the natural history of yellow-cedar helps put forest decline into 

temporal context, and explains why yellow-cedar is currently maladapted on sites 

where it once thrived. The current distribution of yellow-cedar in Alaska aligns 

with the location of Pleistocene refugia (Carrara et al. 2003), indicating that existing 

yellow-cedar populations may have origins in these refugia; however, an ongoing 

genetics study is providing inconclusive results about yellow-cedar’s origins and 

migration in Alaska (see “Paleoecology” in section 1). Climate reconstruction 

through pollen analysis suggests that only in the last several thousand years, during 

the late Holocene epoch, has coastal Alaska experienced the cool, wet climate that 

led to the extensive peatland habitat (Heusser 1960) favorable for yellow-cedar 
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expansion. During the Little Ice Age (ca. 1200–1900 C.E.) most of the glaciers in 

coastal Alaska reached their maximum extension since the end of the Pleistocene 

epoch (Calkin et al. 2000), but we do not know whether these glacial advances were 

driven by colder temperatures or increased snowfall. As noted previously, snow 

probably favors yellow-cedar regeneration. The ages of mature yellow-cedar trees, 

whether they are dead or still living, indicate that most of them regenerated and 

grew to their canopy status in existing forests during the Little Ice Age (Beier et al. 

2008, Hennon and Shaw 1994). Researchers hypothesize that this favorable climate 

allowed yellow-cedar to regenerate prolifically, at least in part because snow keeps 

populations of Sitka black-tailed deer in check (White et al. 2009), and deer are 

major herbivores of cedar seedlings (see “Animal Damage” in section 1). During the 

Little Ice Age, yellow-cedar may have become more abundant at lower elevations, 

where it would later be most vulnerable to decline.

The onset of yellow-cedar decline coincided with the end of the Little Ice Age 

(Hennon et al. 1990c), which is consistent with reduced snow as the trigger for 

widespread yellow-cedar mortality. A large pulse of yellow-cedar mortality also 

occurred in the 1970s and 1980s (Hennon and Shaw 1994), during a notably warm 

period of the Pacific Decadal Oscillation (Mantua 2011). In an analysis of 20thcentury weather in southeast Alaska, Beier et al. (2008) reported warmer weather 

in the late winter and early spring, reduced snow, and persistent cold events in the 

spring, all of which are conditions consistent with the current understanding of 

yellow-cedar decline. The lag between root injury and crown symptoms, slow death 

of individual trees (which can take 15 yr or more to die; Hennon et al. 1990d), and 

repeated injury events required to kill mature trees all complicate linking the timing of weather events, injury, and mortality.

The forests of coastal Alaska are expected to have the largest increase in frostfree days of anywhere in North America (Meehl et al. 2004) during the 21st century 

as the winter climate crosses the snow-rain threshold. Temperatures averaged near 

freezing during the winter months of the 20th century at weather stations located 

near sea level in southeast Alaska (Beier et al. 2008). With heavy year-round 

precipitation, this near-freezing winter temperature regime suggests that modest 

warming would dramatically reduce snow accumulation. Despite the potential for 

a warming regional climate and less snow accumulation, the close proximity of 

southeast Alaska to the mainland continental climate in adjacent British Columbia 

and Yukon Territory still allows cold air to be pushed over yellow-cedar forests 

during high-pressure weather events in the spring. This juxtaposition of climates 

produces mild maritime weather that maintains the physiological activity of yellowcedar and reduces snow, but also allows for periodic infiltration of cold continental 
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conditions that inflict injury. Overall, yellow-cedar decline is influenced by historical climate that promoted yellow-cedar regeneration and survival at low elevations 

and mid-elevations; climate, nutrient and drainage features that encourage shallow 

root systems which are sensitive to freezing injuries where snowpack is insufficient; and recent climate shifts since the end of the Little Ice Age that promote 

mild winter conditions, favoring limited cold hardening and reducing insulating 

snowpack. Decadal climate oscillations exacerbate these last two effects, leading 

to pulses of mortality, such as that observed in the 1970s and 1980s. The individual 

cold-weather periods in the spring that have the potential to cause proximal injury 

continue to be frequent events in a warming climate due to the interaction between 

coastal and continental weather circulation patterns.

Conclusions

Thirty years of research by a dynamic and collaborative research team determined 

the cause of yellow-cedar decline, which culminates in freezing damage to fine 

roots and eventual tree death. This process is so important to the health and sustainability of yellow-cedar forests in Alaska that it could be the primary consideration 

in developing forest conservation and management plans for the tree species. 

Although the cause of yellow-cedar decline is complex, it can be reduced to just two 

risk factors, levels of snow and soil drainage, for landscape modeling to identify 

favorable and unfavorable yellow-cedar habitat. Section 3 provides considerations 

for lands in either protected or active management status where yellow-cedar may 

be dying and dead or healthy and thriving. Section 4 uses the described risk factors 

in a modeling project to partition landscapes by habitat suitability and the presence 

and health status of yellow-cedar populations.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

In Alaska, yellow-cedar grows in forests that are actively managed or under protection status, and in habitats that are favorable for the species or likely to be vulnerable to decline in the future. The conceptual basis for determining habitat suitability 

for yellow-cedar is described in section 2; models that delineate current and future 

habitat suitability are presented in section 4; and the resulting mix of suitable and 

vulnerable habitats (including future risk of decline), land ownership, and management categories at a local spatial scale are provided in appendix 1. This section (section 3) gives narratives on the impacts of yellow-cedar decline and opportunities for 

monitoring and active management on suitable and vulnerable habitats depending 

on the protection status of landscapes. The section is divided into two parts: the 

vulnerable habitat where yellow-cedar decline has already occurred or where it is 

expected to develop in the future, and the suitable habitat where yellow-cedar is 

expected to remain healthy. 

Impacts and Considerations for Management Within 

the Maladaptation Zone: Species Conversions, Timber 

Salvage, and Conservation on Vulnerable Habitats 

This subsection discusses impacts of the extensive mortality of yellow-cedar 

in coastal Alaskan forests and provides various management considerations for 

adapting to this problem. New information is available about long-term shifts in 

the composition (species mixtures) and shorter term changes in understory plants 

in forests affected by yellow-cedar decline. Yellow-cedar decline can be considered 

a form of slow disturbance that directly targets one species, resulting in overstory 

mortality that then triggers forest succession as stands recover. These changes in 

forest composition (i.e., succession) following mortality have many consequences, 

including reduced availability of yellow-cedar for cultural purposes and timber 

supply, modified soil and stream chemistry, and altered wildlife habitat and plant 

community characteristics. Also, the large acreage of affected forests coupled with 

the slow deterioration of yellow-cedar snags suggests an opportunity to shift some 

of the yellow-cedar timber production from healthy forests to decline-affected 

forests on lands that are actively managed. The extensive climate-induced yellowcedar mortality also demonstrates that forests in protected landscapes with minimal 

management can still be greatly altered by climate change. 

Section 3: Opportunities for Conservation and Management

of Yellow-Cedar On Vulnerable and Suitable Habitats
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Transition in Overstory Trees and Understory Plants

Changes in the composition of tree species, an aspect of plant succession, is taking place in decline-affected yellow-cedar forests (fig. 57). Yellow-cedar nearly 

always grows in mixed-species stands. After extensive mortality from yellow-cedar 

decline, the live overstory is dominated by other tree species, although about 30 

percent of the yellow-cedar basal area tends to survive (D’Amore et al. 2009, 

Hennon et al. 2010, Oakes et al. 2014). The pace and permanency of the overstory 

conversion to other tree species, as well as possible changes in understory plants, 

have been a significant information gap. 

A recent study reported responses in vegetation to yellow-cedar decline (Oakes 

et al. 2014). This research was conducted along the outer coast of Chichagof Island 

in southeast Alaska, which represents the very northern extent of existing yellowcedar decline. Here, Oakes and colleagues documented the slow northerly shift 

of yellow-cedar decline over the last 100 yr. The study area offered a template of 

stands that have been affected by decline for varying lengths of time (i.e., a chronosequence) to determine rates of change and successional pathways. 

Oakes and colleagues’ results indicate that gains by other conifers, especially 

western hemlock, and, to a lesser extent, mountain hemlock, accompany losses of 

yellow-cedar in decline-affected stands. The gains in these tree species result from 

both new regeneration and growth release of surviving understory and overstory 

trees among the yellow-cedar snags. Regeneration of other conifers was profuse in 

recent mortality zones, whereas saplings and small trees were more abundant in 

older yellow-cedar mortality areas. Sitka spruce saplings were common in recent 

mortality zones, but few mature spruce trees were detected in the older mortality 

zones. Understory plant cover increased dramatically after yellow-cedar mortality; 

some plant groups (grasses) responded rapidly (in a few years) and others (shrubs) 

increased more gradually (requiring decades). Blueberry (Vaccinium ovalifolium 

and V. alaskaense) increased ninefold in volume (height × cover area) compared to 

blueberry in healthy, intact yellow-cedar stands (Oakes et al. 2014). These shifts in 

understory vegetation may be somewhat transient, however. In the oldest mortality 

zone, forest canopy cover had returned to levels observed in healthy forests, but 

there was a significant shift in dominant tree species favoring western hemlock. 

Almost a century may be required for canopies to become reestablished after the 

onset of yellow-cedar tree death. Negligible yellow-cedar regeneration combined 

with mature yellow-cedar mortality suggests a long-term (possibly centuries-long) 

reduction of yellow-cedar and gain of other species in these stands. 
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We expect soil drainage and the related forest productivity (capacity for a 

greater rate of tree growth) to play a role in controlling which tree species are 

favored, with western hemlock dominating the more productive dead zones and 

mountain hemlock increasing in prevalence in the wetter, less productive zones. 

Sitka spruce regenerates well following yellow-cedar mortality where seed sources 

are present, but its growth then stagnates on these sites. Growth stagnation may 

occur when trees become too large, and their roots are forced into wetter soils 

beyond the limited raised microsites with aerobic soils. 

The complete tree species life-stage approach that Oakes and others used in 

studying long-term succession in declining yellow-cedar forests could be replicated 

in areas farther south in coastal Alaska to provide a broader geographic perspective 

on succession after yellow-cedar decline and to assess the response of western redcedar. Colleagues from the British Columbia Ministry of Forests and the University 

of British Columbia also view the structural and compositional changes that occur 

in heavily affected forests as a priority research area. U.S. Forest Service, Forest 

Inventory and Analysis (FIA) plot data could be another source of information for 

documenting the species and sizes of trees that accompany dead yellow-cedar in the 

declining stands in southeast Alaska. 

Figure 57—Surviving western and mountain hemlock at Goose Cove, Peril Strait, Alaska appear 

as green trees among the numerous dead yellow-cedar trees, illustrating a successional shift in tree 

species in response to yellow-cedar decline. 
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One species that might substitute for yellow-cedar in the maladapted zone is 

western redcedar (fig. 58). It grows in some of the declining yellow-cedar forests 

at lower elevations in Alaska south of latitude 57° N and in some of the declineaffected forests in British Columbia. Like yellow-cedar, western redcedar is a 

calcium-accumulating, decay-resistant, long-lived tree of commercial value that is 

prized by Alaska Natives and the First Nations people in British Columbia. Its bark 

and wood properties differ from those of yellow-cedar, but the two trees have some 

ecological redundancy, offering similar, but not identical, ecosystem services. The 

northern range extent and elevational limit of western redcedar suggest that future 

warmer climate conditions will favor this tree in Alaska, which also appears to 

be the case in coastal British Columbia (Hamann and Wang 2006). Observations 

suggest that western redcedar is growing well in stands with yellow-cedar mortality, although this growth has not been evaluated. Decline is usually not as recent 

in many of the stands that contain both cedar species, because western redcedar 

occurs farther south and at mid-elevations and low elevations where lower snowfall 

has led to yellow-cedar decline. Western redcedar’s sensitivity to the same freezing 

injury that afflicts yellow-cedar should be tested in greater detail before intensive 

efforts to promote redcedar in decline-affected forests would be justified. However, 

western redcedar tested in Alaska was more tolerant to root freezing than was 

yellow-cedar (Schaberg et al. 2011). 

Figure 58—Western redcedar (left) and western hemlock (right) growing in a forest affected with 

yellow-cedar decline on Prince of Wales Island, Alaska.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

More is known about plant responses to yellow-cedar decline than about 

responses of effects on wildlife species. Sitka black-tailed deer browse on the 

foliage of seedlings and saplings, and brown bears feed on the inner bark of trees 

(Hennon et al. 1990a) (see “Animal Damage” in section 1). Keen’s myotis, a bat 

species with a limited distribution that occurs from western Washington to the 

lower panhandle of Alaska, was reported to have 87 percent of its female day roosts 

and 42 percent of its male day roosts in yellow-cedar or western redcedar snags 

on Prince of Wales Island (Boland et al. 2009). The likelihood of a tree being used 

by a female Keen’s myotis increased with the presence of defects, increasing tree 

diameter, decreasing bark, increasing plot-level quadratic mean diameter, closer 

proximity to the nearest stream, and increasing proportion of old-growth in the 

surrounding landscape. Males were more flexible in roost selection, but selected 

trees with defects and decreasing bark, and those on steeper slopes. However, cedar 

species were not distinguished in this study, and the authors suggest that most study 

trees were probably western redcedar.

Generally, snags of various tree species are considered essential habitat for 

cavity nesting birds and mammals. However, the defensive heartwood chemicals 

present in yellow-cedar make the wood resistant to decay, and snags—even trees 

that have been dead for ≥80 yr—will not offer the same benefits to cavity nesters 

as other tree species. Insectivorous birds may forage on yellow-cedar, but defoliating insect outbreaks are unusual on live yellow-cedar trees. Insects are common in 

dying and recently dead yellow-cedar trees, especially under the bark in the phloem 

and sapwood. This insect resource is short-lived to foraging carnivores as insect 

colonization of yellow-cedar snags diminishes just several years after tree death. 

A likely form of habitat (especially for bats) on yellow-cedar snags is the hanging 

sheets of bark that occur in the first decade after trees die (Hennon et al. 2002) 

although it has not been investigated. 

Potential for Salvaging Dead Yellow-Cedar

The desirable wood characteristics and high contemporary export values for 

yellow-cedar put pressure on this species for timber production. The large acreage 

of yellow-cedar decline creates the possibility for shifting some timber production 

from healthy yellow-cedar forests to decline-affected forests. To determine the 

salvage potential of yellow-cedar snags, we needed to compare the characteristics 

of wood from dead trees to that from live trees. Thus, several years ago, a series 

of studies was initiated to evaluate the value and traits of wood from dead yellowcedar. Each study used the same five-class snag deterioration system (fig. 59) that 

we developed to track population dynamics and time since tree death (Hennon et al. 
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Figure 59—Appearance, characteristics, and mean time-since-death for the five dead tree (snag) classes of yellow-cedar 

(Hennon et al. 1990c) used in the various studies on wood properties of dead yellow-cedar. Not shown are live yellowcedar trees, which were used as a standard for comparison in these studies of wood properties.

1990c). Results could thereby be integrated to understand all important changes in 

wood properties up to 80 yr after tree death. 

Pattern of deterioration— 

The first study on dead yellow-cedar wood properties described yellow-cedar tissue deterioration with time after tree death (Hennon et al. 2000) and focused on 

bark, sapwood, and heartwood retention and condition. Dead yellow-cedars (n = 

138 trees) were observed for bark retention and wood condition, and assigned to 

snag classes in a forest near Point Nemo, south of Wrangell, Alaska. Then 280 log 

cut ends from these trees were measured for sapwood thickness and the penetration 

into wood of stain, decay, and checking cracks. Results from this study showed that 

yellow-cedar trees progressed through a series of recognizable stages of deterioration after they died. Most bark was retained on boles of trees <14 yr (classes 1 and 

2) after death, but thereafter, bark sloughed off and was almost completely missing 

by 51 yr (class 4). These are mean years since death for the snag classes (fig. 59). 

Internal wood decay, or heart rot, is common in the form of ring shake and 

butt rot in older live yellow-cedar trees (Sturrock et al. 2010). In interpreting 

differences in defect between live and dead trees, it is important to separate heart 

rot that occurred before death from postdeath wood decay. This distinction was 
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accomplished by observations on log ends; postdeath deterioration was assumed to 

begin on the outside of trees and progress inward, compared to typical heartwood 

decay of live trees. Stain, decay, and weather checking cracks were limited to the 

narrow sapwood band on 26-yr (class 3) snags (fig. 60). The main form of sapwood 

deterioration is by fungal decay, although insect galleries, especially by longhorned 

borers, were also common in dead sapwood. Many of the fungi responsible for 

sapwood decay were reported in a previous publication (Hennon 1990). In summary, the sapwood is generally intact an average of 26 yr after tree death, but later 

is decayed and begins to slough off (fig. 61). Up to this stage, however, any defect 

factors (stain, decay, checking) are restricted to the sapwood and do not penetrate 

the heartwood. By 51 yr after tree death, however, the sapwood is nearly gone and 

the heartwood is exposed to drying and checking (figs. 60 and 61); this checking is 

the most serious penetrating defect, which continues up to and beyond 81 yr after 

death. A key property of dead yellow-cedar wood is the persistence of sapwood 

through class 3 snags; when sapwood is present, even in a decayed state, the inner 

heartwood is protected from other changes.

Volume and grade of recovery— 

The cubic volume recovery was calculated on >300 logs from dead and live yellowcedar trees that were harvested on Wrangell Island, Alaska, as part of the deterioration study described above (Hennon et al. 2000). Calculations were made possible 

by classifying and marking trees in the forest as living or in one of the snag classes, 

and following their logs to individual boards as they were sawn at a mill. Each 

board was given a domestic and export grade by a certified west coast lumber inspector. An operational approach was used in this study to cut boards to maximize 

value, not volume. As expected, the percentage recovery increased with log diameter, regardless of whether logs were from live trees or snags (fig. 62). Surprisingly, 

there was no difference in domestic recovery among live trees and the first three 

snag classes (figs. 62 and 63). Class 4 and 5 snags yielded less domestic volume than 

the more recent classes of snags or live trees, but the reduction was <15 percent (fig. 

63). Recovery of wood meeting the more restrictive export rules was considerably 

lower and more variable among tree/snag classes but showed the same general pattern as domestic recovery (fig. 63). Generally, these results demonstrate an encouraging rate of volume recovery from dead yellow-cedar trees across snag classes.
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Figure 60—(A) Mean sapwood thickness for logs that came from live trees and for the five classes of 

dead yellow-cedars. Error bars are one standard error. (B) Mean sapwood thickness and mean radial 

penetration of stain, decay, and checking cracks. Note that the sharp reduction in sapwood thickness 

from snag classes 3 and 4 marks an associated deeper penetration of stain, decay, and checking 

(Hennon et al. 2000). 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 61—Left: cross section of a class 3 snag, dead about 26 years. The bark was removed from this log and 

the brown tissue is decayed sapwood. Right: cross section of a snag class 4, which has no sapwood remaining, 

and shows some checking cracks penetrating into the heartwood. 

Figure 62—Volume recovery in cubic feet by log diameter of lumber meeting domestic grades from 

live trees and five snag classes for yellow-cedar (Hennon et al. 2000). 
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Figure 63—Recovery of lumber meeting domestic (A) and export (B) rules from live trees and 

five snag classes for yellow-cedar (Hennon et al. 2000). 

The lumber grade for recovered volume did not differ greatly among live trees 

and the snag classes, but there was a trend for more poor-grade volume from the 

older snag classes (fig. 64). There was little difference in the volume recovered in 

the three most valuable grades (clear, select, and No. 1 structural) from live trees 

and the first four snag classes. Logs of class 5 snags differed from the other classes 

by having no recoverable clear grade and a higher percentage recovery of the lower 

grades. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 64—Percentage of each grade that contributed to domestic recovery volume for live trees and 

five snag classes of yellow-cedar (Hennon et al. 2000). 

Strength properties— 

Yellow-cedar is known for the strength of its wood (Forest Products Laboratory 

1987). Wood strength properties were compared among live yellow-cedar trees and 

snag classes for trees >15-in diameter at breast height (d.b.h.) in the same stand near 

Wrangell, as mentioned earlier. Results were published in McDonald et al. (1997) and 

Green (2002), with the final, combined wood strength values reported in the latter 
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publication. One 4-ft-long bolt was removed from the top of the first 11-ft merchantable log from each tree in the study and shipped to the U.S. Forest Service’s Forest 

Products Laboratory in Madison, Wisconsin, for testing. Mechanical tests were made 

on wood sawn into 1 × 1 × 16 in pieces. 

There were no significant differences in specific gravity, bending strength 

(modulus of rupture), stiffness (modulus of elasticity), or hardiness between wood 

from live trees and any of the four snag classes tested (snag classes 2 through 5) 

(fig. 65). This was an unexpected result as it was assumed that one or more strength 

properties may be diminished in trees dead up to 80 yr. An additional goal of 

the study was to evaluate mechanical properties of wood from live yellow-cedar 

infected with black stain. Black stain is a fungal-caused stain of heartwood (thought 

to originate in the sapwood), common in yellow-cedar growing in Alaska and 

British Columbia (Holsten et al. 2009, Smith 1970). The identity of the fungus is 

Figure 65—Mean values of four strength properties of wood from live trees and four snag classes of 

yellow-cedar from Green et al. (2002). Error bars are not given because these results combine both 

the first and second phases of wood tests. See Green et al. (2002) for details. The earliest (class 1) 

snag class was not evaluated in this study as it was assumed to have wood properties similar to live 

trees. None of the strength properties of wood from snags differed significantly from values from 

live trees, even for the class 5 snags, dead 81 years. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

unresolved. No differences were detected between stained and unstained wood in 

these tests. All results indicate that wood from dead yellow-cedar trees is suitable 

for engineering applications where the mechanical properties of yellow-cedar are 

necessary. 

Durability (decay resistance) and termite resistance— 

Decay resistance of wood from dead trees was tested by two means: in vitro by 

colonizing pieces of wood with decay fungi growing in culture, and in situ by placing pieces of wood in soil for periods of time before remeasuring them for weight 

loss. Standard decay fungi, rather than decay fungi specifically collected from 

yellow-cedar trees or forests, were used to assess wood decomposition rates. In 

the first study (DeGroot et al. 2000), two wood decay fungi (Postia placenta and 

Serpula himantioides) caused relatively rapid decay of small pieces of yellow-cedar 

wood from live trees and snag classes 3 and 5. There were no significant differences 

among wood from any of these tree classes, nor among wood that came from the 

inner or outer heartwood. When challenged against a third fungus (Gloeophyllum 

trabeum), however, wood from live and snag class 3 yellow-cedars had slow decay, 

while the wood from larger class 5 snags had fairly rapid decay. These results revealed that some fungal species can overcome the defensive compounds in yellowcedar heartwood from both live trees and recent snags, at least in culture, and that 

wood from class 5 snags is not as decay resistant when colonized by certain fungi. 

In a companion study, the deterioration rate of heartwood from live and dead 

yellow-cedar trees was evaluated by exposing ministakes (3⁄4 × 3⁄4 × 7 in) in soils 

at field sites in Wrangell and Mississippi for 2 and 4 yr (Hennon et al. 2007). The 

Mississippi site represents severe climate conditions to test the durability of wood 

in service. Regardless of the source of wood, vastly different deterioration was 

found between the two field sites, with considerably more rapid wood decay in 

Mississippi (fig. 66). The Mississippi site had a warmer, longer growing season and 

termites were present. Within each of the locations, wood from live yellow-cedar 

trees and class 3 snags had similar decay rates (fig. 66). Note that wood from snag 

classes 1 and 2 was used as samples in this study. Wood from class 5 snags decayed 

faster, but not as rapidly as heartwood of hard southern yellow pine (slash, longleaf, 

or loblolly pine), which served as the control. Based on the study results, a recommendation was made to use chemically treated wood in applications where yellowcedar is in contact with soil. Wood used aboveground from the early snag classes 

(through class 3, dead about 26 yr) is expected to perform similarly to wood from 

live yellow-cedar trees.
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Figure 66—Median deterioration (dry weight loss) of yellow-cedar wood 

from live trees, class 3 snags, and class 5 snags after 4 years in soil at two 

field sites. Southern yellow pines were used as a control by the Forest 

Products Laboratory in all tests (Hennon et al. 2007). 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

A study on termite feeding on yellow-cedar wood (Morales-Romas et al. 2003) 

is the only project discussed here that did not include wood from yellow-cedar 

snags. Instead, this study evaluated feeding by the Formosan subterranean termite 

on yellow-cedar sapwood and heartwood that was black stained or unstained. Black 

stain, caused by one or more fungi, is commonly observed in the heartwood of live 

yellow-cedar wood in British Columbia (Smith 1970) and Alaska (Holsten et al. 

2009). Stained wood is considered a commercial value defect because of appearance 

but does not affect wood strength. When termites were placed with different types of 

yellow-cedar wood, their survival and feeding was highest in sapwood, followed by 

black-stained heartwood, and then unstained heartwood. This pattern of survival and 

consumption by termites was consistent with moderate concentrations of defensive 

compounds in stained heartwood and high concentrations in unstained heartwood. 

The authors concluded that black stain reduces resistance of yellow-cedar heartwood 

to termites, but not to the extent of sapwood or other susceptible woods. 

Heartwood chemistry— 

The most recent study to date on the properties of wood from yellow-cedar snags 

evaluated changes in heartwood chemistry following tree death (Kelsey et al. 2005). 

Tree cores were extracted from live yellow-cedar trees and the five snag classes at 

four locations throughout southeast Alaska. Gas chromatography was used to measure the concentration of 16 extractable compounds, some of which are known to be 

biologically active against insects, fungi, and other organisms. Heartwood chemistry was similar among live trees and the first two snag classes, but began to be 

altered at class 3. Concentration reductions continued for class 4 and class 5 snags. 

Total extractives and compounds with known biological activity that give decay 

resistance, such as nootkatin, nookatone, carvacrol, nootkatene, and nootkatol, followed this trend. We noticed a qualitative difference in wood from snag classes 4 

and 5 in this and other studies. Internal wood from these older snags lost both the 

pale yellow color (becoming tan in color) and the strong aroma found in live trees 

and earlier snag classes; these changes are consistent with the measured decrease in 

biologically active compounds. 

Mechanisms that may contribute to these chemical changes in aging snags are 

volatilization to the atmosphere, leaching, and structural changes from dehydration or oxidation, and possibly polymerization. The loss of protection from bark in 

class 1 and 2 snags, and then sapwood in class 3 and 4 snags, probably allows these 

mechanisms to proceed. 
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Summary of results on wood properties from dead trees— 

Using the same snag classification system in the various studies on wood properties 

(i.e., mill recovery, strength properties, heartwood chemistry, and decay resistance) 

from dead yellow-cedar trees allowed for all results to be summarized and integrated 

here (table 19). None of the properties tested in these various studies indicates any 

differences in the heartwood from live trees and from snag classes 1 or 2. The first 

detection of any substantial change in wood properties occurred in heartwood chemistry of class 3 snags, about 26 yr after tree death (Kelsey et al. 2005). This change 

corresponded with decaying sapwood beginning to slough off, exposing heartwood to 

external environmental factors that expedite physical and chemical change (Hennon 

et al. 2000). Even with the sapwood decaying in class 3 snags, however, the mill recovery by wood volume and grade was unchanged relative to wood from live trees. 

Additionally, class 3 snags still had high overall levels of defensive compounds (not 

significantly different between live trees and snag classes 1 and 2), but two important 

chemicals thought to confer much of the decay resistance (nootkatin and carvacrol) 

were found at lower concentrations at this stage (Kelsey et al. 2005). 

This gradual reduction in chemical defense continued as snags aged, and it 

subsequently led to a decline in heartwood decay resistance. Nootkatin and carvacrol were reduced even further in class 4 and 5 snags, but some other heartwood 

constituents were still present (Kelsey et al. 2005). The greater wood deterioration 

rates of class 5 snags—but not class 3 snags—when challenged with decay fungi 

both experimentally (DeGroot et al. 2000) and occurring naturally (Hennon et al. 

Table 19—Summary of changes in bark and wood retention, and wood properties in dead yellow-cedar trees 

as compared to live trees 

Live tree Snag 1 Snag 2 Snag 3 Snag 4 Snag 5

Dead (mean years) 0 4 14 26 54 81

Bark Intact Loosening Hanging, sloughing Mainly gone Gone 

Sapwood Intact Staining, intact Stained, intact Decayed, intact Gone

Heartwood Intact Checking 

Volume recovery Intact

Reduced 

about 15%

Reduced 

about 15%

Wood grades Intact

Modestly 

reduced Reduced

Heartwood

compounds Intact

Modestly 

reduced Reduced

Further 

reduced

Decay resistance Intact Reduced Reduced

Strength properties Intact
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

2007) suggest that changes in chemistry precede changes in decay resistance. Full 

exposure of heartwood in class 4 and 5 snags is probably responsible for the slightly 

reduced volume and grade recovery once the protective sapwood is lost (Hennon et 

al. 2000). Strength properties (among which specific gravity, modulus of rupture, 

modulus of elasticity, and hardness were measured) are the wood properties slowest 

to change, with no measurable reduction in any strength property among the snag 

classes, even those dead some 80 yr (Green et al. 2002, McDonald et al. 1997). 

Apparently, the chemical compounds remaining in old snags are adequate to limit 

wood decay aboveground, and strength properties are preserved. Some 100 yr after 

tree death, enough localized wood decay occurs at the root collar of snags near the 

soil line that snags break at the ground level and fall. There, soil-inhabiting fungi 

decompose the wood, or, in extremely wet soils, logs may remain as sequestered 

carbon (Hennon et al. 2002). 

The unique heartwood chemistry of yellow-cedar, and the slow manner in 

which it is altered after tree death, has profound ecological and economic implications. Dead yellow-cedar trees across extensive areas of southeast Alaska remain 

standing as snags for up to a century, and because the heartwood remains strong, 

hard, and undecayed while standing, they probably offer little habitat for cavity 

nesting animals (Hennon et al. 2002). This limited deterioration and surprising persistence of wood properties also offer considerable opportunities to recover valuable 

wood products. Therefore, the forests affected by yellow-cedar decline represent 

an astonishingly valuable wood resource for salvage. Oakes et al. (2015) evaluated 

the social acceptability of salvaging dead yellow-cedar trees. Shifting a portion of 

timber logging to dead yellow-cedar forests could divert some harvest away from 

forests that contain healthy yellow-cedar on suitable habitat, as part of a strategy to 

conserve and manage yellow-cedar.

Sizes of dead yellow-cedar trees— 

Another question about salvage recovery of dead yellow-cedar is whether enough 

dead trees are large enough to make a salvage harvest commercially viable. Dying 

yellow-cedar stands generally occur along the wetter (peatland bog) portions of the 

drainage-productivity gradient (D’Amore and Hennon 2006; Hennon et al. 1990b, 

2010). The volume of dead yellow-cedar and the diameter classes of individual dead 

yellow-cedar trees are expected to vary depending on where they fall along this 

gradient, with greater volume and larger trees on better drained and more productive sites. This variation can be seen in the field or on aerial photographs, or detected with other forms of remote sensing. By using aerial photographs, zones of 

yellow-cedar mortality were classified as bog, scrub, and productive dead in two 

watersheds in Peril Strait north of Sitka (D’Amore and Hennon 2006). As expected, 
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yellow-cedar snags tended to be smallest in the bog zones, of intermediate size in 

the scrub zones, and largest in the productive dead zones (fig. 67). The productive 

dead zone at Poison Cove is a good example of a decline-affected forest with large 

snags of commercial size (i.e., >20 in d.b.h.) (fig. 67). The large snags (fig. 68) most 

often can be found in the better drained, more productive portions of decline-affected forests, which often occur in bands at slope breaks or along the edges of decline 

patches. 

Figure 67—Concentration of dead 

yellow-cedar trees in 5-inch diameter classes from three productivity 

zones at the Poison Cove watershed. 

Note the occurrence and higher 

concentration of larger snags in the 

productive zone. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 68—Large dead yellow-cedar tree of commercial size. 

Economics of salvage— 

The feasibility of salvaging dead yellow-cedar will be based in part on economics. 

Operating in remote, roadless areas may involve the high costs of helicopter yarding and barges to transport logs. The most economically feasible opportunities for 

salvage will include road access through or near dead yellow-cedar forests, high 

concentrations of snags of commercial size and fairly recent mortality in which 

wood values are nearly fully retained (i.e., snag classes 1, 2, and 3), gentle slopes 

for use of ground-based yarding equipment, and access to nearby mills. An ongoing 

study by the University of Alaska Southeast is evaluating the factors that influence 

the economic feasibility of salvaging dead yellow-cedar. 
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Biogeochemical Implications for the Dead and Dying YellowCedar Component of Forests

The death of numerous yellow-cedar trees may alter the concentration of nutrients 

in local soils, streams, and vegetation. As described in section 1, yellow-cedar 

accumulates calcium in its foliage in large concentrations compared to other 

conifers (D’Amore et al. 2009). Litterfall derived from the senescence of older 

foliage from healthy yellow-cedar forests (fig. 69) provides a persistent addition of 

calcium and other nutrients from litter to the forest floor and O horizons of soils. 

However, the impact of large amounts of calcium-rich foliage falling on the forest 

floor under a declining tree is unclear. Both the pulse of normal seasonal litterfall 

and the episodic, large increase in foliar litter to the forest floor when yellow-cedars 

die are expected to affect nutrient cycling in these forested stands. There are two 

main areas of biogeochemical interaction with large-scale yellow-cedar death: the 

successional trajectory of remaining plants in the stand, and the export of nutrients 

from declining yellow-cedar watersheds in groundwater and surface water. 

Preliminary evidence suggests that yellow-cedar stands alter the nutrient 

concentration and availability of both nitrogen and phosphorus in the O horizon 

Figure 69—Yellow-cedar foliar litter on the 

forest floor under a healthy yellow-cedar 

tree in a mixed-species stand at Poison 

Cove, Chichagof Island, Alaska.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

of soils compared to stands dominated by spruce and hemlock.7 Initial results of 

a study evaluating the response of understory plants and trees after the recent loss 

of yellow-cedar show that calcium is redistributed to the remaining plants (Radis 

2014). Nutrients are tightly cycled in Alaskan coastal forests throughout the yellowcedar range. Therefore, the liberation of nutrients and availability of light due to 

reduced canopy cover from dead yellow-cedars could provide a substantial nutrient 

subsidy and basis for shifts in forest productivity, and changes in species composition from yellow-cedar to other trees, shrubs, and forbs. The key tree species that 

would benefit from the addition of both calcium and other nutrients is western 

redcedar (D’Amore et al. 2009). 

Forested watersheds in Alaskan coastal forests are not efficient in the recovery of all mineralized nutrients; inorganic nitrogen and phosphorus are lost from 

the system along with large quantities of organic nitrogen (Fellman et al. 2009). 

Therefore, it seems consistent that the alteration of the nutrient dynamics due to the 

mortality of yellow-cedar will also have a substantial impact on watershed nutrient 

dynamics. Nutrient budgets based on water yields in watersheds with live or declining yellow-cedar forests have not been undertaken, but it is likely that the nitrogen 

liberated from the foliage or available due to reduced uptake by yellow-cedar in 

affected forests will not be completely captured by succession to other species. An 

increase in the mobile nitrate compound would result in an increase in nitrogen to 

freshwater and marine systems in yellow-cedar watersheds. 

Changes in Lands Under Protection Status 

Whatever management regime is undertaken in the maladapted zone where yellowcedar decline occurs, it is important to recognize the impacts to yellow-cedar 

populations and the ineffectiveness of restoring yellow-cedar on sites where it 

is dead, dying, or likely to die. Protected areas are often established to maintain 

biodiversity, sensitive species, and wildlife habitat. Traditionally, protection through 

land designation was done based on the premise that forest ecosystems are somewhat static or that they may be large enough to absorb disturbance events (Millar et 

al. 2007). The U.S. Forest Service developed an integrated old-growth conservation 

strategy of large, medium, and small reserves to protect and maintain old-growth 

habitat in southeast Alaska; the goal is to maintain the mix of habitats at different 

spatial scales capable of supporting the full range of naturally occurring flora, 

fauna, and ecological processes (USDA FS 2008a). Because of the intensive losses 

7

 Manuscript in preparation; data on file with D. D’Amore, USDA Forest Service, Forestry 

Sciences Laboratory, 11175 Auke Lake Way, Juneau, AK 99801. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

of mature yellow-cedar trees in protected landscapes (see appendix 1), yellow-cedar 

decline serves as an example of the need to incorporate shifting climate into conservation planning (Oakes et al. 2015). West Chichagof–Yakobi and South Baranof 

Wilderness Areas are two such large protected areas undergoing dramatic reductions in yellow-cedar from extensive yellow-cedar decline. These areas are north 

of the distribution of western redcedar. Here, plant succession will continue to play 

out, probably without management intervention, and the forests will become more 

dominated by hemlock. On actively managed landscapes with yellow-cedar decline, 

there are probably better uses of resources than for attempted yellow-cedar restoration by planting and thinning the species where it is expected to die prematurely. 

When there is sufficient knowledge of a species’ responses to climate change, 

such as the case of yellow-cedar and its forest decline, climate and landscape 

models can be used to evaluate how well specific conservation areas may meet their 

goals in the future, and where widespread problems might develop to compromise 

those values. Similarly, a species’ response to a projected climate should be evaluated to determine areas of suitable versus unsuitable habitat before restoration 

practices are implemented. The next subsection offers information and management 

considerations on landscapes with suitable climate or soil conditions where yellowcedar is more likely to survive and thrive. 

Considerations for Conservation and Management on 

Suitable Habitat

Section 2 of this report describes how yellow-cedar trees in many areas were once 

well-adapted to local climates, but became maladapted and died due to diminished 

snow and continued frequent cold events in late winter and spring. Reductions of 

yellow-cedar in the maladapted zone heighten the need for the conservation and 

active management of yellow-cedar in habitats that will continue to be favorable. 

Modeling snow accumulation into the future helps predict which areas of existing 

healthy yellow-cedar may be protected by snow (fig. 70), and which are expected to 

suffer elevated mortality. Current and short-term future suitable habitat in highelevation forests and forests in the snowy region of Prince William Sound can help 

meet conservation goals for the species. See section 4 for the model results that 

describe future risk of forest decline to yellow-cedar forests throughout Alaska. 

Climate projections beyond the 100-yr span of those currently used are not available 

but are needed to plan conservation measures for long-lived tree species.

At a more local landscape scale, yellow-cedar is currently healthy on welldrained soils, where it mixes with other tree species, even in areas of little snow 

accumulation. These areas are often located directly adjacent to dead yellow-cedar 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

forests on wet soils (e.g., see Hennon et al. 2012: fig. 6). It is on these productive 

sites with greater tree volume that yellow-cedar roots more deeply and reaches 

its greatest stature, but not its greatest competitive status. Western hemlock and 

Sitka spruce can outcompete yellow-cedar through greater rates of reproduction 

and faster growth to limit yellow-cedar to a smaller component in these forests 

(Harris 1990). However, active forest management through silviculture can alter 

this imbalance of regeneration and competition to favor yellow-cedar. These 

productive sites have received most of the timber harvesting in the region; therefore, 

this is the primary active-management space that is available to achieve conservation goals for yellow-cedar. Favoring yellow-cedar over other tree species through 

planting and thinning will effectively expand yellow-cedar’s realized niche. More 

silvicultural information is needed on the techniques of managing yellow-cedar in 

young-growth forests to ensure the long-term maintenance of the species. These 

topics are expanded upon below.

Figure 70—Healthy yellow-cedar trees (appear as bright 

green) on a peatland and hillside in Dixon Bay, Glacier Bay 

National Park, Alaska. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Monitoring Yellow-Cedar Life Stages in Unmanaged Forests

Monitoring the health and viability of yellow-cedar in the forests of Alaska can take 

different forms. The forest health program of the Forest Service’s State and Private 

Forestry conducts annual forest health detection flights throughout Alaska. Active 

locations of yellow-cedar tree death visible from aircraft are mapped and reported 

each year. These surveys could detect the progressive mortality that occurs in some 

maladapted yellow-cedar forests and expansion of new decline to forests that were 

previously healthy. When mapped carefully, these data might reveal the pattern of 

expansion of yellow-cedar decline to the north, to higher elevations, and to other 

colder regions that are becoming vulnerable because of lower snow accumulation. 

This monitoring could be used to check or calibrate our modeled projections of 

future yellow-cedar decline, particularly in forests that are currently healthy. For 

information on some of the limitations of aerial detection surveys of yellow-cedar 

decline, see “Extent and Intensity of Decline” in section 2.

Vegetation plots on the ground can provide information to monitor changes in 

all life stages of yellow-cedar, including regeneration (fig. 71). Several older as well 

as more contemporary forest inventories are available, but few have repeat measureFigure 71—Yellow-cedar 

seedling from natural 

regeneration. The needlelike immature foliage is a 

clear indication that this is a 

seedling that originated from 

a seed and is not regeneration 

from vegetative layering.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

ments to monitor change. A recent analysis of FIA plots offers an example. Barrett 

and Christensen (2011) report that yellow-cedar populations in coastal Alaska 

were stable regionally from the initial measurement sampling in 1995–2003 to the 

remeasured sampling in 2004–2008. In other words, mortality and harvest were 

offset by tree growth and in-growth, defined as the growth of smaller trees into 

larger size classes. These results suggest that this was a period of reduced mortality 

from yellow-cedar decline, or that gains by tree growth in some areas compensated 

for losses from decline in other areas. The annual forest health aerial surveys detect 

some active yellow-cedar decline each year, but we know that the large pulses of 

tree death are episodic, with mortality in the 1970s and 1980s marking the largest 

losses. Separating vegetation plot data from healthy and decline-affected forests 

would help to identify rates of regeneration, growth, and mortality in each health 

condition within the measurement cycle. 

Vegetation plots can be used to assess natural yellow-cedar regeneration in 

unmanaged forests, a key gap in our understanding. Some older information is 

available from ecologists who worked to produce plant association guides for three 

subregions of the Tongass National Forest during the 1980s. These guides represent 

the southern portion (Ketchikan Area), middle portion (Stikine Area), and northern 

portion (Chatham Area) of the Alaska panhandle. They report plot information and 

observations on trees and regeneration from various plant communities, including 

one series in which yellow-cedar was the most abundant: the western hemlock-yellow-cedar series, which in one case was called the western hemlock-Alaska-cedar 

series. 

In the Ketchikan Area, second-growth sample plots on northern Prince of 

Wales Island showed very little yellow-cedar regeneration (DeMeo et al. 1992: 162). 

The authors state: “Yellowcedar occurred in only half of the sampled understories, 

and averaged 8 percent of the cover” (p. 165). Note that this is in the western 

hemlock-yellow-cedar/blueberry/skunk cabbage series, where yellow-cedar was 

present in all overstory plots. They continue: “Yellowcedar regeneration is very 

problematic. Advanced regeneration will usually be limited, because of the relatively small amount of yellow-cedar in the understory. Regeneration from seeding 

will be sporadic, due to competition from hemlock and irregularity from seed 

crops” (p. 168). 

For the Stikine Area, Pawuk and Kissinger (1989) reported that young secondgrowth stands were mostly western hemlock with lesser amounts of Sitka spruce. 

Yellow-cedar regeneration was uncommon in the western hemlock-Alaska-cedar 

series. They suggest that plantings will normally be required to establish yellowcedar as a significant component of second-growth stands. 
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For the Chatham Area, Martin et al. (1995: 8-15) observed that yellow-cedar 

regeneration was not occurring to the level expected, yet late-seral stands of yellowcedar were abundant. In the western hemlock-yellow-cedar series, they reported 

(p. 8-1) that yellow-cedar regeneration occurred in only about half of the sampled 

stands and was less abundant than western hemlock regeneration. Yellow-cedar 

seedlings were particularly uncommon in areas of high deer use. After clearcutting, regeneration of western hemlock and spruce was abundant, but regeneration 

of yellow-cedar was uncommon. They suggest that hemlock competition, lower 

reproductive rates for yellow-cedar than for hemlock, and browsing by deer are 

major factors affecting yellow-cedar establishment. The authors advise that maintenance of yellow-cedar following clearcutting in areas of high deer densities requires 

planting and protection of seedlings. 

These observations of limited yellow-cedar regeneration should be contrasted 

with information from areas where yellow-cedar regeneration is successful. Growing evidence indicates that yellow-cedar regenerates well in areas of heavy snow as 

long as a seed source is present. Seedlings (fig. 71) and saplings (fig. 72) were common in yellow-cedar forests near the northwestern range limits in Prince William 

Sound (Hennon and Trummer 2001) and in Glacier Bay National Park.8 Farther 

south in Alaska, we have observed numerous yellow-cedar seedlings and saplings 

in higher elevation stands, including Mount Edgecumbe near Sitka. In an analysis 

of FIA plot data throughout coastal Alaska, a severalfold increase in the ratio of 

yellow-cedar saplings to live trees was detected near timberline compared to lower 

elevations (Hennon et al. 2011). Natural regeneration of yellow-cedar remains an 

important information gap in coastal Alaska and should be a priority for research 

and monitoring efforts. Research on all phases of yellow-cedar reproduction (male 

and female flowering, pollination, cone and seed production, seed dispersal, and 

seedling establishment) is needed to determine barriers to successful regeneration. 

Yellow-Cedar Natural Regeneration in Harvested Forests

Quantitative data on the success of natural yellow-cedar regeneration in harvested 

areas are critically needed. A list of 220 young-growth stands with yellow-cedar on 

the Tongass National Forest is provided in appendix 3, with information on stand 

identification and location, harvest year, and the relative composition of yellowcedar compiled from various sources. The location information for these stands will 

be overlaid with yellow-cedar suitability models (described in section 4) to identify 

stands that are projected to be vulnerable to yellow-cedar decline now and into the

8

 Manuscript in preparation; data on file with Lauren E. Oakes, Stanford University.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 72—Yellow-cedar sapling.

Lauren Oakes

future. At this time, yellow-cedar decline symptoms have been documented only in 

two adjacent young-growth stands on Zarembo Island, where the models accurately 

projected moderate-to-high risk of decline due to low snow and wet, shallow soils.

Irrespective of yellow-cedar decline, observations suggest that the return of 

the yellow-cedar component in harvested forests through natural regeneration is 

successful in some areas (fig. 73) and not in others. This topic was discussed in 

a regional meeting of ecologists, silviculturists, and others >20 yr ago (Hennon 

1992a). There are many recent accounts of successful regeneration by yellow-cedar 

following timber harvesting in southeast Alaska (see section 1). The relationship 

between the yellow-cedar component before and after harvest has not yet been 

analyzed, but it could be quantified by contrasting stand examination plot data 

(i.e., preharvest) with stocking survey plot data on seedlings and saplings collected 

after harvest. These paired survey datasets from the same forest stands are not 

widely available, however. The natural regeneration of yellow-cedar in harvested 

areas could be monitored over a geographic and elevational range in southeast 

Alaska in an attempt to determine the factors that allow or limit successful seedling 

and sapling establishment after harvest. It is also possible that there is a temporal 

component to successful yellow-cedar regeneration. Results might reveal periods 
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Figure 73—Yellow-cedar that 

naturally regenerated in a 

harvest unit. 

of heavy yellow-cedar cone crops, favorable environmental factors, or reduced deer 

populations that allowed for greater seed production or seedling establishment. 

Success of Yellow-Cedar Planting in Harvested Forests

Planting trials of yellow-cedar conducted from 1986 (fig. 74) to the present in 

Alaska are described in section 1. The success or failure of yellow-cedar establishment in these trials highlights the importance of deer browse. Methods to reduce 

deer browse of yellow-cedar seedlings are an urgent need. Some form of protection 

is needed in areas where deer populations aggregate in the fall through spring 

although protection may not be needed at high elevations because deer are uncommon during those times or seedlings are protected by snow. 

Applied Genetics

The current knowledge of yellow-cedar genetics was summarized in section 1. 

Here, we turn to applications of this knowledge to the conservation and management of yellow-cedar.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 74—Yellow-cedar trees 

in a harvest unit near Anita 

Bay, Etolin Island, Alaska, 

8 years after planting in 1986. 

Current and future seed inventory in Alaska— 

Seeds collected for artificial reforestation of native tree species in the Alaska 

Region are processed and stored in Petersburg, Alaska. As of 2014, 50 seedlots for 

all species (individual seed collections from one area) were stored at the Petersburg 

seed-processing facility. Fifteen of these seedlots are yellow-cedar collected from 

the Tongass National Forest (table 20). Each is a bulk reforestation lot collected 

from multiple trees. Geneticists recommend routinely testing these for seed viability. There are no seedlots in the regional seed inventory from yellow-cedar populations in Prince William Sound (Chugach National Forest), Icy Bay, Glacier Bay, 

the northeastern portion of the panhandle (i.e., islands and mainland Juneau and 

Admiralty Island), or mainland areas farther south of the panhandle.

In the Alaska Region, the collection and transfer of seed is currently managed 

under “Provisional Tree Seed Zones and Transfer Guidelines for Alaska” (Alden 

1991). Seed collection zones in the absence of genetic data for adaptive traits were 

inferred based on geographic barriers to historical migration (e.g., mountain ranges, 

channels, and straits), and differences in minimum annual temperature across geo-
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GENERAL TECHNICAL REPORT PNW-GTR-917

Table 20—Year of collection and site information for 15 yellow-cedar seedlots maintained at the U.S. Forest 

Service seed-processing facility in Petersburg, AK

Lot. no. Seed zone Year collected Latitude (°N)/Longitude (°W) Seed source Ranger district

156 10 1993 57°37'00"/-136°10'00" Comp 243 Sitka

179 6 1993 56°44'00"/-132°51'00" Twin Creek Petersburg

189 5 1995 56°19'00"/-132°17'00" Wrangell Island Wrangell

201 10 1995 57°59'00"/-135°00'00" Iyoutug Creek Hoonah

204 10 1996 57°58'00"/-135°00'00" Iyoutug Hoonah

208 10 1996 57°57'00"/-135°28'00" Game Creek Hoonah

213 10 1996 57°33'00"/-135°03'00" Sitkoh River Valley Sitka

217 9 1998 57°57'00"/-135°14'00" Appleton Cove Sitka

218 4 1998 55°48'30"/-132°34'00" Little Ratz Thorne Bay

229 4 2000 55°37'29"/-132°53'00" Steelhead Drainage Thorne Bay

237 4 2002 55°48'40"/-132°34'23" Sal Creek Thorne Bay

238 4 2012 55°36'21"/-132°53'02" Steelhead Thorne Bay

239 4 2012 55°25'16"/-132°44'14" Indian Creek Road Craig

240 4 2012 55°25'09"/-132°44'46" Indian Creek Road Craig

241 4 2012 55°52'58"/-132°40'42" Ratz, 3026 Road Thorne Bay

graphic subdivisions. The purpose of zoning is to maintain the genetic integrity of 

indigenous forest species, conserve genetic diversity, minimize maladaptation, and 

ensure long-term survival and vigor of forests artificially regenerated with native 

tree species. Alden (1991) mapped 486 provisional tree seed zones for Alaska and the 

western portion of Canada’s Yukon Territory. In south coastal and southeast Alaska 

(yellow-cedar range), there are 57 mapped seed zones. The Alaska Region’s yellowcedar seed inventory (table 20) originates from only five of these seed zones (fig. 75). 

The preliminary results on the broad-scale genetic structure of yellow-cedar 

given in section 1 suggest remarkably mixed genetics, high gene flow, and little 

genetic differentiation for the species throughout Alaska. These findings have 

implications for both the genetic conservation of yellow-cedar, and the use of seed 

collection zones and seed transfer guidelines. There are no known rare or unique 

genetic populations that need to be preserved by seed collection, tissue preservation, or tree culturing as a form of genetic ex situ conservation, even in the areas 

mentioned above from which seed has not been collected. This broad genetic mixing of yellow-cedar suggests seedlots can be moved to geographic areas that extend 

beyond their collection source and the provisional seed zones shown in figure 

75. In British Columbia, where more information on yellow-cedar genomics and 

provenance trials is available, seed transfer is based on broader geographic areas 

compared to Alaska’s narrowly defined seed collection zones. British Columbia 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

limits the movement of seed in the maritime zone from collection sites by about 

3° latitude and +/-1,600 ft of elevation (Russell 1993).

Recent attention on climate change has stimulated a new consideration of aligning seed transfer with climate zones, rather than having them fixed geographically 

(Aitken et al. 2008, O’Neill et al. 2008, St Clair et al. 2005). Common garden trials 

can be used to test the expression of traits and adaptability of plantings moved from 

Figure 75—Seedlot collection locations from Table 20 (small stars), provisional tree seed zones 

(black outlines), and the distribution of yellow-cedar (yellow shading).
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GENERAL TECHNICAL REPORT PNW-GTR-917

their seed origins, both geographically and climatically. The most comprehensive 

common garden trial for yellow-cedar was conducted at five sites in British Columbia and tested seed from British Columbia, California and Oregon, and one location 

in Alaska on Mitkof Island (Russell and Krakowski 2012). The only regional differences in the adaptability or survival of any seed sources tested were for those from 

California and Oregon, which yielded smaller seedlings with lower survival. With 

these exceptions, tree responses in these trials showed no relationship to geographic 

or climatic zone source. Including more seed sources from Alaska or conducting 

long-term common garden trials in Alaska could expand these findings to the 

northern portions of yellow-cedar’s range. 

New research using chloroplast DNA from the existing yellow-cedar foliar 

collections may distinguish yellow-cedar populations in Alaska. As we learn more 

about the genetic structure of yellow-cedar in Alaska, it may become apparent that 

populations in the north and northwestern portions of its range have some unique 

qualities. If unique genetic structure becomes evident, then seeds or clonal material 

should be collected for genetic conservation and for testing of phenological traits 

through common garden trials. Geneticists recommend taking cuttings from wild 

forms and using them directly in clonal trials. 

Based on current knowledge about yellow-cedar genetic variation, land managers might consider revising current seed transfer guidelines and protocols to assure 

a high probability of adaptation within both the current climatic conditions and 

those predicted for the future. Given that yellow-cedar is showing high adaptability 

to a variety of environmental conditions, broad seed zones based on north/south 

latitudes and high/low elevation bands could be developed. In lieu of creating new 

seed zones, collection areas could be rotated to target new seed collection zones and 

broaden the genetic base. The following best management practices could be considered in seed management to broaden the genetic diversity and limit the number 

of related individuals in a seed lot: (1) Each new seedlot should originate from ≥20 

individual seed trees, (2) individual trees should be separated by 200 ft, (3) collecting seed from isolated individuals that may have less exposure to the pollen cloud 

should be avoided, (4) cones should not be collected from very low in the crown, 

and (5) operational reforestation efforts should consider outplanting more than one 

seedlot into a planting unit. 

Long-term seed procurement plans for yellow-cedar could be developed for 

Alaska. In British Columbia, seed production areas are developed in zones that 

have a high demand for seed, are accessible, and have trees that typically produce 

abundant cones and seeds. Ideally a seed procurement plan would follow a revision 

of seed collection zones, but a plan could be developed with existing seed zones. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Estimating existing and future seed needs requires careful planning to collect sufficient quantities of high-quality seed for future reforestation and restoration needs. 

A seed procurement plan could address the following: (1) the existing reforestation 

needs and anticipated needs from harvest levels; (2) projected restoration/reforestation after large-scale disturbance (wind) or accelerated cedar decline from climate 

change, or a combination thereof; (3) whether there is a need to share seed among 

land management agencies in British Columbia and Alaska; (4) review of the 

existing seed inventory; (5) seed and cone periodicity; (6) seed yield data; (7) seed 

viability data; and (8) nursery sowing factors. The most recent seed stratification 

protocols should be considered.

Cloning and seed collection—

An asexual or cloning form of reproduction called layering (fig. 76) has been observed throughout the natural range of yellow-cedar (Antos and Zobel 1986, Bérubé 

et al. 2003, Hennon et al. 1990b). Layering occurs by adventitious rooting of smaller 

lower limbs; the connecting stem can die, giving rise to adjacent yellow-cedar individuals with identical genotypes. Patches of low-growing, stunted yellow-cedar 

that reproduce by layering are common in bog or peatland settings. Thompson et 

al. (2008) confirmed layering in yellow-cedar stands through molecular analysis. 

Figure 76—Multiple stems of yellow-cedar from layering, or the rooting of lower branches, can 

create a clone of different trees that have identical genotypes. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

They found that a combination of yellow-cedar sexual and asexual reproduction 

was occurring in nine forests in British Columbia. Individual stems (ramets of a 

clone) were often confined to a distance spanning 16 ft, but in one case they were 

separated by 43 ft. Similar sampling has been done in Alaska, but genetic testing 

has not yet been conducted to determine cloning extent or size in bog and upland 

settings. Clones should be considered and avoided when making seedlot collections 

of yellow-cedar. Adjacent trees could be genetically identical and the seeds they 

produce would be considered half-sibs (i.e., pollinated with one parent in common). 

Seed could possibly be full-sibs and selfs between the two ramets of the same clone. 

Collecting from cone trees that are ≥200 ft apart should minimize the possibility 

of two trees representing a clone. In British Columbia, collections are made from 

≥20 trees to create an effective population size because of the possibility that trees 

might be related from pollen dispersal and historically related mothers. 

Adaptation consequences of self-fertilization, cloning, and tree longevity— 

Aitken et al. (2008) suggest that there are three fates for tree species with regard 

to rapid climate change: they can migrate, adapt, or face extirpation. Adaptation is 

achieved through natural selection and differential selection pressures. High genetic 

diversity is maximized by outbreeding and recombination through sexual reproduction. Species with short generation times and high fecundity can adapt quickly. 

Yellow-cedar does not have the capacity to adapt quickly because of its long-lived 

nature and current low reproductive capacity. Compounding this issue is yellowcedar’s tendency to be self-fertile (pollen from a tree can fertilize female flowers in 

the same tree), and the habit of cloning through layers mentioned above. (Note that 

the inbreeding or self-fertilization in yellow-cedar is not found at unusually high 

levels compared to many other conifers.) All of these compounding factors may 

limit yellow-cedar’s ability to adapt to changing climate conditions. The rate of adaptation by yellow-cedar may not keep pace with future environmental change.

Despite yellow-cedar’s common habit of vegetative reproduction and self-fertilization, especially on some poorly drained site types, genetic work has detected a 

high degree of genetic variation within and between populations. Natural selection 

can act upon this potential variation in traits. The long lifespan of trees essentially 

increases the range of conditions they must be adapted to in order to survive and 

reproduce as climate changes.

Natural selection in decline-affected stands and genetic improvement—The 

intensive mortality of yellow-cedar in decline-affected forests may be producing 

a selective pressure that is altering the genetic character of these populations. In 

decline-affected forests, about 30 percent of yellow-cedar trees typically remain 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

alive. Thus, there is differential survival among the trees that grew in these stands 

before the onset of the forest decline. Currently, it is unknown whether the surviving yellow-cedars escape lethal injury by rooting on better, more protected microsites, or whether they might represent a superior genetic form. If the live yellowcedar trees have greater cold hardiness or slower hardening and dehardening than 

their dead cohort, and if these traits could be shown to be heritable, then natural 

selection may shape the genetic structure of these stands. Selecting tissues or seed 

from these surviving trees might offer an opportunity for genetic improvement in 

yellow-cedar that could be used in forest regeneration on suitable habitat or even 

restoration on decline-affected sites. Although we said that restoration planting is 

not recommended in the maladapted zone, the enhancement of these adaptive traits 

could make restoration in these stands feasible. It would be desirable to collect seed 

or foliage material for cloning and begin to test for traits related to cold hardiness. 

Thinning to Favor Yellow-Cedar in Managed Forests

The silvicultural technique of thinning is used operationally to control the density 

and spacing of trees. It is also useful to adjust the mix of species, or composition, of 

tree species in managed forests. Thinning can be used to favor yellow-cedar where 

it successfully regenerates by natural regeneration or planting (fig. 77). Preference 

for yellow-cedar in thinning contracts has been a common practice on the Tongass 

National Forest for more than a decade. More information on thinning is presented 

under “Precommercial thinning” in section 1.

Thinning will be most successful on sites where yellow-cedar is expected to 

thrive (i.e., not wet soils with insufficient snow). Spacing in operational thinning 

treatments varies from about 12 ft between crop trees to as wide as 20 ft or more. 

Recently, yellow-cedar decline was observed in two adjacent 38- to 40-yr-old 

young-growth stands on Zarembo Island. A considerable component of yellow-cedar 

was retained through precommercial thinning. A site visit in 2013 detected signs 

and symptoms of yellow-cedar decline, low productivity (with understory plants and 

stunted trees indicating wet site conditions), and yellow-cedar snags in unmanaged 

forest areas adjacent to the cut unit. Yellow-cedar of similar age growing on deeper 

soils nearby was healthy. Rather than discouraging the practice of favoring yellowcedar through thinning, this exemplifies the need to assess sites for yellow-cedar 

habitat suitability before treatment. It is important to recognize the site variation 

within past harvest units, and to bear in mind that the future health condition of 

yellow-cedar regeneration may differ on poorly drained and well-drained areas.

Evaluating the past or present health of mature yellow-cedar in surrounding stands, along with information about snow and drainage, can help managers 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 77—Yellow-cedar selected as “crop trees” in a thinning implementation on the Ketchikan 

Ranger District. 

determine where it is most appropriate to promote yellow-cedar through thinning. 

It would be desirable to track the survival and growth of yellow-cedar after thinning. Additionally, monitoring is needed to detect any new, unexpected situations of 

young-growth yellow-cedar such as browsing by moose (fig. 78).

Longer Term Young-Growth Management

There is relatively little information or experience with the silvics of yellow-cedar 

in maturing young-growth forests. Tree growth data for southeast Alaska and 

yield plot data typically do not include yellow-cedar. The board foot and cubic 

foot volumes estimated for yellow-cedar by DeMars (1996) were from old-growth 

unmanaged forests. Several known even-aged stands could be used to determine 

tree growth and form. One example is at Cannery Point near the town of Tenakee 

in a 100-yr-old even-aged, unmanaged, mixed yellow-cedar and western hemlock 

stand that regenerated after a fire. Another setting is near Sitka at the approximately 

150-yr-old Verstovia forest, which regenerated after clearcutting by the Russians; 

yellow-cedar mixes with western hemlock in the higher elevation portions of that 

stand. The recent finding of yellow-cedar decline in a young-growth stand on 

Zarembo Island (Mulvey et al. 2013) suggests that young, managed yellow-cedar 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 78—Browse by moose on the lower limbs of a yellow-cedar tree 

on Mitkof Island, Alaska, leaving the tree with a pruned appearance. 

Ben Case

forests should be monitored for decline symptoms. Experts in British Columbia 

could be consulted about yellow-cedar silvics in maturing forests because of their 

longer-term experience with young-growth yellow-cedar in managed stands. 

Special Case of Forest Management: Yellow-Cedar’s Role in the 

Transition to a Young-Growth Utilization Program

The Tongass National Forest has embarked on an effort to rely more on younggrowth than old-growth forests for its future supply of timber. Currently, it is unclear 

how much yellow-cedar is represented in the young-growth forests that have regenerated following clearcut harvests in southeast Alaska. The oldest young-growth 

forests and those on the most productive soils will produce the initial wave of timber 

production on the Tongass National Forest in this transition to young-growth. These 

older young-growth forests have minimal representation of yellow-cedar for perhaps 

three reasons. First, the early harvests on the Tongass National Forest targeted 
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GENERAL TECHNICAL REPORT PNW-GTR-917

higher volume western hemlock-Sitka spruce forests because, from the late 1950s 

through the 1990s, harvests were designed to produce a stream of wood volume 

to the two large pulp mills in Sitka and Ketchikan. Second, yellow-cedar was of 

considerably less value in this industrial era; only after about 1970 did it become 

valued as an export wood. Third, yellow-cedar tends to grow on sites of lower productivity, where the growth rates of all tree species would be expected to be slower. 

Several owners of small mills in southeast Alaska rely on high-value niche wood, 

including yellow-cedar (fig. 79). It is conceivable that the salvage recovery of dead 

yellow-cedar (see “Potential for Salvaging Dead Yellow-Cedar,” this section) may 

satisfy a part of that demand until young-growth yellow-cedar is available. Because 

yellow-cedar is more common in the younger managed forests occurring on lower 

productivity sites, the future supply of young-growth yellow-cedar may be many 

decades away. An evaluation of the amount of yellow-cedar by stand age-class and 

productivity class, coupled with a growth simulation model, is needed to predict the 

timing of the future supply of yellow-cedar in the young-growth forests of southeast 

Alaska. 

Figure 79—Small dimensional pieces of yellow-cedar lumber for carving and other artisan 

purposes available commercially from a small mill in southeast Alaska. Small amounts of yellowcedar lumber can be acquired by order, but are not always readily available to contractors or the 

public for construction projects.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Dispersal of Yellow-Cedar to New Habitat Areas With 

Suitable Climates

When climate favorable for yellow-cedar develops beyond its existing range, the 

species may be particularly slow to migrate because of its low reproductive capacity (Harris 1990). Assisted (or facilitated) migration is the deliberate movement by 

humans of genotypes and species into areas in which the projected climate is associated with high probabilities of persistence over a long time period after establishment. These activities can be controversial because widespread movements of 

species can be interpreted as fostering the introduction of invasive species that could 

bring unanticipated consequences to existing ecosystems. Assisted migration may 

be required for species with narrow resource requirements or poor dispersal ability 

(Warren et al. 2001), such as yellow-cedar. As a test case, the Tongass National Forest conducted a trial planting of yellow-cedar in 2009 near Yakutat, Alaska (an area 

of discontinuous occurrence for yellow-cedar but still within its range limits) (Hennon and Trummer 2001) to test the survival and growth of yellow-cedar where it did 

not previously grow. Survival to date has been >90 percent (fig. 80), which suggests 

that the targeted expansion of yellow-cedar is possible. Although it has not been 

attempted, yellow-cedar could be introduced by planting into new environments 

that would not be subject to future harvest, such as raised microsites in open-canopy 

peatland forests that are expected to have adequate snow into the future.

Figure 80—Yellow-cedar seedling planted 

near Yakutat, far from any known natural 

yellow-cedar populations. 
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GENERAL TECHNICAL REPORT PNW-GTR-917
163

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Introduction and Conceptual Basis

This section integrates the information presented in the first three sections with 

new risk models to create a vulnerability assessment and a conservation and 

management strategy for yellow-cedar in Alaska. The assessment and strategy draw 

on the ecological and silvicultural details of yellow-cedar presented in section 1, 

climate impacts that triggered the extensive tree mortality described in section 2, 

and considerations for the conservation and management of yellow-cedar relative to 

habitat suitability in section 3.

Climate change generates different zones of potential adaptability for tree 

species on the landscape that vary across climate gradients (or by latitude and 

elevation) and through time. “Zones of adaptability” for a tree species are locations 

with specific conditions that are suitable for that species’ growth, survival, and 

reproduction (fig. 81). Therefore, effective adaptive strategies are dynamic because 

the habitat suitability of species becomes a moving target. The vulnerability 

assessment and dynamic climate adaptation strategy presented here can be used 

in making decisions in land management planning. Considerations related to both 

conservation and active management are offered according to risk of decline and 

habitat suitability. For species that are particularly sensitive to climate factors, such 

as yellow-cedar, one must consider past, current, and future climate effects and 

their interactions with ecological traits and life stages. Understanding these interactions, along with knowledge of the other abiotic factors that interact with climate 

to initiate widespread mortality, is the cornerstone of the adaptive strategy for the 

conservation and management of yellow-cedar. 

In the conceptual basis for yellow-cedar habitat suitability (fig. 81), we nested 

the drainage gradient within the broader climate zones. Snow is the overriding 

broad-scale climate factor that controls the health of yellow-cedar in Alaska, but 

soil drainage must also be considered because it creates finer-scale zones of suitable 

habitat in areas of inadequate snow. Yellow-cedar decline emerges in yellow-cedar 

forests with poorly drained soils where roots are shallow and snow levels are insufficient to provide thermal protection during spring cold air events (shown in red in 

figure 81). Conversely, suitable yellow-cedar habitat exists where either soil drainage or snow levels are adequate. 

Section 4: Modeling Future Vulnerability of Yellow-Cedar 

Forests to Climate Change for Conservation and 

Management Planning
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GENERAL TECHNICAL REPORT PNW-GTR-917

Figure 81—Conceptual diagram depicting how climate shifts can create three zones of adaptation 

by a tree species (maladapted, persistent, and migration), and how habitat suitability can be further 

modified with other niche factors including soils. 

The viability of a species depends on its presence, abundance, health condition, 

and successful regeneration. There is a relationship between the localized population status of a species on protected landscapes versus on managed landscapes. For 

example, reductions of yellow-cedar in populations affected by forest decline in 

wilderness areas may influence how the species is harvested or promoted through 

silviculture on actively managed lands. Section 3 of this report provides the details 

on the health status and opportunities for active management on habitats for yellowcedar that are suitable and vulnerable. 

This yellow-cedar vulnerability assessment uses a model designed to predict 

and map the risk of yellow-cedar decline. The model outputs are used to evaluate 

yellow-cedar’s present occurrence and the location of yellow-cedar forests vulnerable to decline, for three time periods in the future. These can be compared to our 

map of preexisting yellow-cedar decline, which represents past mortality events. 

These series of maps cover the entire distribution of yellow-cedar in Alaska, and in 

appendix 1 are summarized and displayed for the 33 separate yellow-cedar management units.

Several terms used in this section are clarified here. Vulnerable refers to habitats where yellow-cedar has some risk of developing yellow-cedar decline. Suitable

indicates habitats at low risk of developing yellow-cedar decline. When modeling 

yellow-cedar occurrence (i.e., not mortality), we also use suitable for areas where 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

the niche factors are met for yellow-cedar, and the species may be present (occupied habitat) or absent. Bioclimatic envelopes model climate variables with species’ current distributions to predict shifts in potential distributions as the climate 

changes. Risk is the probability that yellow-cedar has developed or will develop 

decline, with our models producing three risk classes based on risk factors (snow 

and drainage). Productivity refers to the rate at which a site can produce vegetation 

biomass. Soil drainage is the ability of soil to move water and in coastal Alaska is 

the primary control on productivity. Drainage is both a niche factor that influences 

the presence and abundance of yellow-cedar, and a risk factor that predisposes 

yellow-cedar to decline. Snow is also a risk factor for yellow-cedar decline. Our 

risk models use annual snow accumulation (see next subsection), but future efforts 

could use seasonal snowpack (see appendix 2). Health status of yellow-cedar trees 

is the degree of mortality, and population stability refers to the overall fluctuation 

in abundance of yellow-cedar’s life stages including regeneration. For example, the 

overall population stability of yellow-cedar on protected landscapes (e.g., wilderness areas and national parks) may be steady or increasing due to a low mortality 

rate and vigorous natural regeneration, or may be impaired by either high rates of 

mortality (indicating poor health status) or low natural regeneration. The concept of 

forest decline and the term yellow-cedar decline are explained in section 2. 

Modeling of Suitable and Vulnerable Areas for YellowCedar Based On Risk of Decline 

Habitat suitability models for species in the context of climate often use one of 

two approaches: climate variables are simply correlated with a species’ distribution (e.g., bioclimatic envelope models; Araújo and Peterson 2012), or mechanistic 

methods using specific climate variables known to act on the species’ responses 

of regeneration, growth, and mortality (Pearson and Dawson 2003). Both of these 

approaches rely on accurate information on the distribution of the principal species. 

Yellow-cedar’s incomplete occupancy of large areas of suitable habitat in Alaska, 

presumably because of slow migration, suggests that the first modeling method is 

problematic. The cause of yellow-cedar decline, as described in section 2, involves 

a number of interacting landscape, site, stand structure, and microclimate factors 

that operate on the unique vulnerability of yellow-cedar to root-freezing injury. 

Therefore, our mechanistic knowledge of yellow-cedar’s response to climate allows 

us to use known and specific risk factors to identify current and future suitable and 

vulnerable habitat in areas where yellow-cedar occurs. 

Hydrologic changes, driven by climate change, are affecting terrestrial and 

aquatic ecosystems (Melillo et al. 2014). Many plants are shifting their distribution 
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GENERAL TECHNICAL REPORT PNW-GTR-917

due to altered soil moisture, both as precipitation and snow, caused by changes in 

climate. Land managers in federal and state agencies have placed a high priority on 

creating adaptation strategies to deal with climate change. Our models are intended 

to provide a tool for managers to evaluate the impact of present and future environmental conditions on forest resources consistent with implementation of the U.S. 

Forest Service’s forest planning rule (USDA FS 2015). Our approach can be considered a climate vulnerability assessment (Tillman and Glick 2013) for a species, 

which determines risk factors, provides mitigation and adaptation options, and can 

be the scientific basis for a conservation and management strategy to be developed 

by land managers. 

We use four variables to map and model yellow-cedar habitat vulnerability in 

Alaska: the current distribution of yellow-cedar, the extent of the forest decline to 

date, soil drainage, and snow. The first two factors describe where yellow-cedar 

currently grows (its distribution), and where it has already been affected by climate 

and undergone mortality (mapped forest decline areas). The second two factors, 

described in more detail in section 2, are the forest decline risk factors that help 

predict the location of yellow-cedar forests that are currently healthy but are at 

risk of decline due to predicted future climate change. Of the two leading decline 

risk factors, we assume that soil drainage is relatively stable through time and that 

the soil characteristics of yellow-cedar forests will not be altered enough to affect 

future species distribution within our modeling period to 2100. In contrast, winter 

snow is directly affected by climate and varies on a timescale of years, decades, and 

centuries. The development of each of these component models is described below 

in more detail. 

Note that we have not attempted to predict new habitat that will be available to 

yellow-cedar through range extension as a response to a warming climate. A range 

extension would presumably involve a dispersal of yellow-cedar locally to higher 

elevations, through river and valley passes into adjacent interior British Columbia 

and Alaska, and northwesterly through Prince William Sound and into the Kenai 

Peninsula. Several basic physiological tolerances of yellow-cedar, such as seasonal 

precipitation (to avoid drought stress) and annual minimum temperature (to avoid 

outright freezing regardless of the presence of snow), would need to be contrasted 

with current and future climatic conditions in these areas. Yellow-cedar migration 

to new habitats is expected to be slow because of its low reproductive capacity. 

This topic is also discussed in the “Suitable Habitat” subsection of section 3. The 

approach we took in this section was to assess habitat suitability and vulnerability 

for yellow-cedar where it currently occurs in Alaska. A different modeling framework with a broader geographic area is needed to assess the emergence of new 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

suitable habitat beyond yellow-cedar’s existing range. This would require modeling 

of climatic variables (beyond those considered in this report), edaphic factors, biotic 

interactions, seed dispersal distances, and other factors relevant to yellow-cedar 

dispersal, establishment, growth, and reproduction.

Yellow-Cedar Distribution

The yellow-cedar distribution map that we developed is a major revision of the 

geographic occurrence of yellow-cedar in Alaska and throughout its range since 

publication of the Atlas of United States Trees (Little 1971). The new rangewide 

yellow-cedar map and the components used to build it are described in detail in 

section 1. The Alaska portion is outlined briefly here as it is the basis for the assessment of yellow-cedar habitat suitability and risk of decline presented in this section. 

The rangewide distribution was developed at a resolution of 240 m, which is the 

common denominator for all input data sources. Yellow-cedar areas represented 

in Prince William Sound and Glacier Bay National Park were derived by using 

“sketched polygon” methods from boat and aerial surveys. The 240-m rasterized 

data layer was applied in the respective zones of Glacier Bay, and northwestward 

for the yellow-cedar suitability/vulnerability predictions. There were either few 

or no forest inventory plots in these areas to inform a distribution model such as 

Ellenwood’s for these areas. The Ellenwood model’s 30-m forest parameter data 

are present only in the southeast Alaska subregion. Therefore, this new data layer 

(see following) is represented in an aggregated companion dataset at 240 m in order 

to include the Pacific Coast and south-central Alaska subregions of the Alaskan 

coastal forest. 

The Ellenwood 30-m-extent geographic information systems (GIS) layer for 

yellow-cedar represents the best available predictive source for areas in southeast 

Alaska south of Glacier Bay and the Haines area. This layer was produced for those 

pixels where the calculated probability was ≥50 percent; any single isolated pixels 

were removed and filled in. Those results were then buffered by two pixels and 

applied as representing yellow-cedar presence in the respective zones south of, but 

not including, Glacier Bay and Haines for the yellow-cedar suitability/vulnerability 

predictions.

The yellow-cedar “suitability” data were modeled at a 50-m resolution by using 

methods to nest and combine the 50-m hydrology model with the 200-m snow cover 

models. Here, the term “suitability” is used loosely as additional modeling inputs 

would be required to produce a robust “suitability” model and is beyond the scope 

of this work. The yellow-cedar presence data, existing at either 240-m or 30-m 

resolutions in the northern and southern zones of Alaska, respectively, were applied 
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GENERAL TECHNICAL REPORT PNW-GTR-917

as a yellow-cedar presence mask and used in the vulnerability rating and acreage 

values discussed in the following portions and appendix 1 of this document. The 

240-m-pixel resolution has been used for visual display in the management zone 

maps in appendix 1.

A distinction should be made between all forests where yellow-cedar occurs 

(i.e., its full distribution) and areas where the yellow-cedar forest type (i.e., yellowcedar-dominated cover type or forest type) occurs. The approach we chose for this 

report was closer to a full distribution representation than a yellow-cedar cover 

type. We chose to set a low threshold for including the yellow-cedar component of 

forests (see below) so that our report could help interpret long-term health status of 

yellow-cedar in Alaska, even in places where the species is not predominant. 

A pixel modeled as yellow-cedar by Ellenwood was required to fall within the 

treed areas. A pixel can have a positive response for species presence even as a 

relatively small component of the forest. The presence/absence of total (all species) 

live tree basal area >1 in diameter at breast height (d.b.h.) was independently modeled from the predictor sample files by using See5, version 2.06. The model derived 

from See5 was converted to a raster surface by using the RSAC Cubist/See5 

toolset (Ruefenacht et al. 2008). We consider this layer a geospatial representation 

of treed area, and it was used as a subsequent mask for all other host layers. The 

minimum density that can be measured on a U.S. Forest Service Forest Inventory 

and Analysis (FIA) sub-plot is 1.7 ft2/ac basal area of trees >1 in d.b.h. Therefore, 

a single pixel cannot represent <1.7 ft2/ac basal area (Krist et al. 2014). The yellowcedar distribution derived in this manner encompasses all lands and includes forests 

where yellow-cedar may be abundant or only a minor component. The “all lands” 

category also includes emergent and shrub–scrub wetlands, which are classified as 

nonforested communities in most definitions of cover and forested land, such as the 

National Wetlands Inventory (USFWS 2009) and the National Land Cover Database 

(NLCD) (Multi-Resolution Land Characteristics Consortium 2015). 

The best existing spatially explicit information on yellow-cedar occurrence 

comes from different sources with various resolutions depending on specific area in 

Alaska. In our vulnerability modeling, we use the higher resolution (30 m) yellowcedar cover type layer where it is available, and use the lower resolution (240 m) in 

the remaining area and for graphic display of all maps in appendix 1. However, the 

scaling and compilation of the total areas using a 30-m or 240-m filter to define the 

mapping resolution leads to a disparity in the area estimates (see “Challenges in 

Using Different Scales for Geographic Information Systems Layers,” this section). 

The acreage estimates from both our yellow-cedar cover layers, produced with 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

30-m and 240-m filters, can be compared to various estimates of the area occupied 

by yellow-cedar in Alaska (table 21). The older estimates of yellow-cedar occurrence exclude unproductive forestland where yellow-cedar is likely to occur, so they 

would underestimate total yellow-cedar acreage. The estimates based on species 

distribution models have accompanying mapped output, but they rely on forest 

inventory plot data as input variables. The most reliable estimates of the acreage 

are based on inventory plot data through the use of extrapolation procedures (e.g., 

expansion factors), based on a systemic grid design used in the contemporary FIA 

Table 21—Estimates of the acreage for yellow-cedar in Alaskaa

Estimate sourceb Scopeb Basisb Resolution

Cover type or 

distribution

Estimated 

yellow-cedar 

(acres)

FIA (2000–2003),c

van Hees (2003)

Southeast Alaska 

to Yakutat

Inventory Cover type 403,000

FIA (2004–2008),d

Barrett and Christensen (2011: 

table 31)

Alaska Inventory Cover type 2,355,000

Ellenwood panhandle,e

USDA FS (2014)

Southeast Alaska, 

panhandle only

Model 50 m masked by 30-m 

presence model

Distribution 2,205,791

This reportf Alaska Model + surveys 50 m masked by 240-

m range map model

Distribution 6,486,584

This reportg Alaska Model + surveys 50 m with selections 

from the above two 

datasets for a complete representation 

of yellow-cedar in 

Alaska

Distribution 2,272,164

a

 The resolution or scaling factor and the response surface used for areal estimation are given as a basis for resolving the varying total area 

estimates that result from each method.

b

 The source, areal coverage (scope), and inventory method are noted to provide a clear basis for comparison.

c

 Yellow-cedar cover type: yellow-cedar is >25 percent, sum of yellow-cedar and western hemlock is >60 percent, and lodgepole pine is <10 

percent of tree stocking. Estimate is reduced to 119,000 ac when defined by timberland (capable of producing >20 ft3

 of wood/ac/yr and land 

not removed from timber use).

d

 Includes wilderness areas but not Glacier Bay National Park. Cover type is defined by the tree species that forms the plurality (most 

numerous) of live-tree stocking. 

e

 All zones south and east of Glacier Bay National Park, yellow-cedar management zones 8 through 33 (see appendix 1). Derived from 50-m 

“suitability” index but masked by the Ellenwood 30-m yellow cedar extent layer. The Ellenwood 30-m-extent layer extended into Glacier 

Bay, but that area was not included in this value. 

f

 The 240-m zones were masked by the 240-m range map representation. Custom mapping and observations were used for management 

zones 1 through 7. In management zones 8 through 33, we represented yellow-cedar by using the Ellenwood 240-m yellow-cedar basal area 

layer as a proportion of the Ellenwood 240-m total basal area surface retaining all values >0.01 (1 percent).

g

 The Ellenwood 30-m-extent model for southeast Alaska, management zones 8 through 33, plus aerial and boat surveys in Glacier Bay 

National Park and Prince William Sound, and inclusion of the small reported populations in Icy Bay and Haines, represented in management zones 1 through 7 and rendered at 240 m.
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GENERAL TECHNICAL REPORT PNW-GTR-917

plots. These estimates do not, however, have an accompanying geographic map. 

Several estimates represent either a portion of yellow-cedar’s range in Alaska 

(e.g., limited to the panhandle, or having another geographic gap); others cover the 

entire occurrence as far to the northwest as Prince William Sound. Future efforts 

to develop species distribution maps and GIS layers for yellow-cedar and other tree 

species in Alaska should be reconciled with these estimates of acreage occurrence 

(see appendix 2). 

Yellow-Cedar Decline

The topic of mapping yellow-cedar decline is discussed in more detail in “Extent 

and intensity of decline” in section 2. High-resolution maps of yellow-cedar decline 

currently exist for two study areas (Peril Strait and Mount Edgecumbe), but the 

broader coverage of yellow-cedar decline across the yellow-cedar populations in 

Alaska is available only in the lower resolution aerial survey mapping product. This 

broader layer is not able to capture some large areas of older mortality that occur 

in forested wetland areas or areas where yellow-cedar has died and where it was 

a small component of the forest. In both cases, the scattered snags do not produce 

an adequate signature for detection from the air. At the same time, we recognize 

that the aerial survey mapping overestimates the local occurrence of yellow-cedar 

decline because the large, coarse polygons drawn by observers in aircraft often 

contain imbedded areas without yellow-cedar or even forest trees. 

To reduce overestimation of decline, we modified the yellow-cedar decline layer 

by overlaying a derived vegetation landcover map in an attempt to remove areas 

that would not be expected to have dead yellow-cedar trees. A landscape layer created for carbon modeling was developed through a collaborative project involving 

the U.S. Forest Service’s Pacific Northwest Station, University of Alaska Fairbanks, 

and the U.S. Geological Survey (USGS) (University of Alaska Fairbanks 2015) for 

use in the Alaska LandCarbon assessment (Energy Independence and Security Act 

2007) to model carbon stocks and fluxes. The landcover map was derived primarily 

from the NLCD (Multi-Resolution Land Characteristics Consortium 2015). The 

NLCD cover was modified to more accurately identify nonforested and forested 

landscapes. In particular, the locations of forested wetlands were needed because 

of their key carbon functions on the landscape. Yellow-cedar occurs frequently 

in these areas and the identification of these layers along with subsequent screens 

(described below) for nonforest improved the accuracy of yellow-cedar decline 

zones with substantial basal area. These layers include the USGS 2001 NLCD 

version 1.0, NLCD Percent Tree Canopy Cover version 1.0, Tongass National Forest 

Cover Types, and other layers such as saltwater and second-growth forests. We 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

joined the yellow-cedar decline polygons with the revised NLCD landcover map 

and deleted polygons from the yellow-cedar decline layer that had values of no 

vegetation (rock, snow and ice, saltwater, freshwater, developed areas, sand, and 

clay), fens, other vegetation, and alpine areas. We retained polygons with values of 

upland forest and forested wetlands because these are likely to have yellow-cedar 

decline. The resulting modified yellow-cedar decline layer was used in all further 

comparisons and analysis. 

Future vulnerability assessments and analyses may consider other GIS layers 

to use as overlays to further refine the yellow-cedar decline layer. Also, remote 

sensing combined with image analysis offers a promising opportunity to produce 

spatially explicit, high-resolution coverage of yellow-cedar decline, and may help 

detect locations missed by aerial survey.

Predicting Future Yellow-Cedar Decline With Two Risk Factors: 

Soil Drainage and Snow

The distribution of yellow-cedar decline expressed on the landscape is related to 

two physical factors: snow and soil drainage (Hennon et al. 2012). Our approach 

outlined here was to identify the areas of suitable and vulnerable habitats for 

yellow-cedar where it occurs by incorporating snow cover and drainage as risk 

factors to decline (fig. 81). Yellow-cedar reaches its greatest competitive advantage 

in poorly and moderately drained soils, but a portion of the population has undergone mortality on these sites as reduced snow no longer offers adequate thermal 

protection for yellow-cedar roots. Therefore, we nested soil drainage (considered 

a constant, unchanging factor on the landscape) within areas of changing snow 

levels to predict future emergence of yellow-cedar decline. Sites that receive 

insufficient snow cover will have a reduction in favorable yellow-cedar habitat 

and the species will be limited to better drained soils where its roots can penetrate 

deeper soil horizons to avoid freezing injury (the green zone in the lower ellipse in 

figure 81). Yellow-cedar is expected to be generally less abundant in these vulnerable areas unless active forest management practices favor it over competing tree 

species. Areas of adequate snow cover (the upper two ellipses in figure 81) would 

be expected to continue to provide yellow-cedar’s full edaphic niche, including the 

portions on wet soils. 

Soil drainage modeling— 

Poorly drained sites increase yellow-cedar’s vulnerability to freezing injury, and 

yellow-cedar is generally outcompeted by spruce and hemlock on better drained 

sites. Yellow-cedar forests are abundant on wetter areas of the landscape, where 

water tables are in the rooting zone (approximately 10-in depth) of the soil, as is 
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GENERAL TECHNICAL REPORT PNW-GTR-917

typical in emergent and forested wetlands (D’Amore et al. 2012) (fig. 82). We applied a topographic wetness index (TWI) as the primary tool for modeling soil 

moisture across the landscape. This index was adjusted for local topographic conditions and compared to well-known measurements of soil saturation, and we used 

the index to partition the landscape of coastal Alaska into several wetness classes 

for use in the risk assessment model. This approach is well suited for complex 

forested terrain that is remote and difficult to measure directly (Moore et al. 1991), 

such as the Alaskan coastal forest. The TWI is derived from a digital elevation 

model (DEM) by calculating slope (degrees) and flow accumulation at each 50-m 

pixel (Quinn et al. 2001). Next, TWI is computed by using the form ln(a/tanβ), 

where tanβ is the local slope angle at a particular location on the landscape, and a is 

the upslope contributing area to the location (Beven and Kirkby 1979). The computed values of TWI over a given area represent a continuum of wet-to-dry soil areas. 

High TWI values indicate wet areas and low values indicate dry areas, with mesic 

sites represented in the middle range of the continuum.

The TWI is a compound topographic index (CTI), meaning that it is calculated 

from a combination of primary attributes that are directly computed from the DEM 

(slope and specific catchment area) (Moore et al. 1991). Discrete, continuous soil 

Figure 82—Water table depth in relation to rooting zone (10 in (25 cm)) of typical ecosystems (poor 

fens, forested wetlands, uplands) in the perhumid coastal temperate rainforest. Yellow-cedar is 

commonly found in poor-fen and forested wetland habitats and these areas have water table average 

depths <10 in (D’Amore et al. 2012). 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

wetness was modeled with flow accumulation through a DEM. Mesic areas of water 

accumulation, where yellow-cedar is most likely to occur, were used to compile 

acres of potential yellow-cedar habitat. We subdivided the range of CTI values in 

which yellow-cedar could potentially occur into five classes based on the predicted 

soil drainage. Each class corresponded to the relative potential for yellow-cedar to 

occupy the space on the landscape in the more poorly drained conditions. The soil 

drainage index was combined with the snow model to create a vulnerability scale to 

identify areas where yellow-cedar is likely to decline under the assumption that no 

snow is present. We combined the CTI classes with information on snow accumulation to assign a relative overall risk of yellow-cedar decline, as described below.

Snow modeling— 

Snow protects yellow-cedar from seasonal root freezing (see section 2 and figure 83). There are several different methods for modeling snow on the landscape, 

including the proportion of wet days that precipitation falls as snow, accumulation 

of snow, and persistence or depth of snowpack on the ground. Monthly, annual, 

and decadal estimates of snow are possible with some models. To associate snow 

with yellow-cedar health, we would ideally use variables related to snowpack depth 

or presence in late winter and early spring because this timeframe coincides with 

Figure 83—Yellow-cedar-dominated forest protected by snow on a wet hillside. 
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freezing injury. Such a model is not yet available for coastal Alaska, however. We 

chose to use snow accumulation estimated annually. Note that the unit of “precipitation as snowfall” (PAS) uses water equivalents (i.e., melted snow) and not actual 

snow depth and that PAS may be related to existing snow in late winter if snow is 

not lost through melting, evaporation, or dispersal by wind. These natural losses 

would tend to be built into the comparison of annual snow accumulation and forests 

affected by yellow-cedar decline. The distribution of precipitation as snowfall (PAS) 

was modeled at a 200-m resolution with ClimateWNA v4.71 (Wang et al. 2010). 

This program downscales the climate model Parameter-elevation Relationships on 

Independent Slopes Model (PRISM) (Di Luzio et al. 2008) and calculates climate 

variables such as annual snowfall based on latitude, longitude, and elevation (Wang 

et al. 2006). Precipitation and temperature inputs were used to estimate the amount 

of precipitation as snow that was generated by the ClimateWNA model. We compared the spatial arrangement of annual snowfall in the ClimateWNA model to 

mapped yellow-cedar decline, and determined that about 10.1 in (256 mm) of annual precipitation as snowfall (expressed as water equivalents) distinguishes healthy 

from declining yellow-cedar forests (Hennon et al. 2012). 

To project snow into the future, we chose the same five general circulation 

models (GCMs) that make up the composite used by the Scenarios Network for 

Alaska + Arctic Planning (SNAP) (University of Alaska Fairbanks 2015). Another 

model from the Pacific Climate Impacts Consortium (PCIC) recommendations 

(University of Victoria, PCIC 2013) was added to align with models used for British 

Columbia (University of Victoria, PCIC 2014). Scenario planning uses several different estimates of greenhouse gas emissions to project a range of future potential 

emissions outcomes. The emissions scenarios were applied to each model according 

to the availability of AR4 (Fourth Assessment Report) climate scenarios from the 

Intergovernmental Panel on Climate Change (2007) and temperature and precipitation projections in ClimateWNA v4.71 (Wang et al. 2012). For each GCM we chose 

conservative emissions scenarios (table 22), which entail more limited future greenhouse gases. These modest scenarios predict less potential future warming than do 

higher emissions scenarios. But any rise in temperature, even under conservative 

scenarios, leads to a loss of snow in the models. All models have uncertainty and 

our results should be interpreted as a means to evaluate relative risk of mortality in 

areas where yellow-cedar grows in Alaska. Our estimates are modeled to represent 

a modest change relative to current conditions, yet conditions could potentially have 

substantial impacts on yellow-cedar forests.
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Developing risk classes— 

We developed risk classes through analysis and interpretation of the distribution of 

soil saturation and snow on the landscape as they relate to the current distribution 

of yellow-cedar decline. The distribution of wetness was arrayed into five classes by 

binning the TWI derived from the CTI model into equal categories across the landscape. Each class was assigned a CTI risk score according to an ascending scale of 

relative soil moisture (table 23). These descriptive classes correspond to soil moisture classes that indicate the frequency and duration of soil saturation under local 

conditions of soil formation (Soil Survey Division Staff 1993). The snow risk score 

was based on the annual amount of snow calculated as PAS that accumulated on the 

landscape (table 23). The amount of snow present was divided into five snow risk 

classes from high snow accumulation (low risk) to low snow accumulation (high 

risk) (table 23). 

The overall risk score was calculated for every pixel in the estimated occurrence of yellow-cedar in Alaska by adding the CTI risk score and the snow risk 

score to create an index ranging from 2 to 10. These scores were then translated 

into three classes: low, medium, and high. Higher total risk scores were needed 

to assign a landscape to moderate or high overall risk classes because both risk 

factors—drainage and snow—must be present at certain levels for yellow-cedar 

decline to occur. In other words, risk of yellow-cedar decline is low if either drainage or snow has a low risk score. Accordingly, assignment to the medium or high 

risk class required a high combined overall risk score relative to the low risk score. 

The drainage risk score was held constant, but the snow risk score was modeled 

by using the GCMs described above for three time periods called 2020, 2050, and 

Table 22—General circulation models and emissions scenarios used in snow 

models, which were combined as one input to yellow-cedar decline risk 

classification 

Model name and version Acronym

Emissions 

scenario

General Circulation Model version 3.1-t47a cccma_cgcm31 B1

European Centre Hamburg Model 5 mpi_echam5 B1

Coupled Climate Model 2.1 gfdl_cm21 A1B

Coupled Model 3.0 ukmo_hadcm3 B1

Model for Interdisciplinary Research on Climate 

(medium resolution)

miroc3_2_medres A2

UK Hadleyb Ukmo_ HadGEM1 A1B

a

 University of Victoria, Pacific Climate Impacts Consortium (PCIC) model, but emissions scenario changed 

from A2.

b

 PCIC model.
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GENERAL TECHNICAL REPORT PNW-GTR-917

2080. The reference climate data for the current/normal time period cover a 30-yr 

range. Likewise, the three future dates refer to a 30-yr range: 2020 refers to 2011 

through 2040, 2050 refers to 2041 through 2070, and 2080 refers to 2071 through 

2100. Climate data were obtained from the PCIC (University of Victoria, PCIC 

2014; Wang et al. 2010). Note that the names for these three time periods are not the 

actual midpoints of these ranges; they refer to the middle decade of each interval 

(2020s, 2050s, 2080s). The overall risk scores for these three time series were modeled to produce continuous covers within all the management zones (discussed in the 

next subsection) and across the entire yellow-cedar forested landscape in Alaska. 

Delineating 33 Yellow-Cedar Management Zones in Coastal 

Alaska for Assessment

We consulted with local forest managers and others to divide the range of yellowcedar in Alaska into 33 yellow-cedar management zones for more detailed vulnerability mapping and analysis (fig. 84). The distribution of yellow-cedar extends to 

Table 23—Drainage and snow risk classes and scores, which 

are summed to assign overall risk of yellow-cedar decline in 

the areas where yellow-cedar occurs in Alaska 

Compound topographic 

index (CTI) classes 

CTI value 

rangea CTI risk score

Well drained <5.76 1

Moderately well drained 5.76–6.59 2

Somewhat poorly drained 6.60–7.64 3

Poorly drained 7.65–9.32 4

Very poorly drained >9.32 5

Snow class (annual PASb) Snow risk score

≥350.1 mm (≥13.9 in) 1

300.1–350.0 mm (11.9–13.8 in) 2

250.1–300.0 mm (9.9–11.8 in) 3

200.1–250.0 mm (7.9–9.8 in) 4

≤200 mm (≤7.8 in) 5

Overall risk class Overall risk scorec

Low 2–6

Medium 7–8

High 9–10

a

 Represents a categorization of CTI values into one of five classes (quintiles).

b

 Annual precipitation as snow (PAS) expressed in water equivalents.

c

 Sum of snow risk score and CTI score.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 84—Map of the 33 yellow-cedar management zones used in assessing the current and future health of yellowcedar where it grows in Alaska. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Unakwik Inlet in Prince William Sound, but we added one more management zone 

(Seward, where yellow-cedar is absent) to complete the Chugach National Forest 

and consider an area for future migration. These divisions into management zones 

were made on the basis of land ownership, U.S. Forest Service ranger districts, 

geomorphology, and forest management emphasis. The management zones in 

the northwestern area are large because yellow-cedar is generally uncommon in 

this part of its range. Note that the tools that we used in analysis and mapping are 

available for evaluating smaller project or analysis areas. Total land area provides 

a means to make comparisons among management zones and relate the amount 

of yellow-cedar in the management zone to other factors. The total yellow-cedar 

decline detected in each management zone is the accumulated mortality mapped 

and denotes the past damage to yellow-cedar forests. This damage often represents tree mortality over a range of years, typically at least several decades, and 

sometimes up to a century (see “Epidemiology, Timing, and Pulses of Mortality” 

in section 2). Estimates of both the past and predicted acreage of yellow-cedar at 

risk of decline are important for salvage harvest planning activities on lands where 

this activity is permitted (see “Conversions, Timber Salvage, and Conservation on 

Vulnerable Habitats” subsection in section 3).

Challenges in Using Different Scales for Geographic Information 

Systems Layers

The models and survey GIS layers used in this report were constructed from different data sources and reflect various spatial and temporal scales. One example is the 

different acreage estimates of yellow-cedar occurrence when modeled at two spatial 

resolutions (see description in “Yellow-Cedar Distribution,” this section). Applying 

the 240-m filter in modeling yellow-cedar occurrence produced an estimate with 

nearly three times the acreage as the models based on the application of a 30-m 

filter. This dramatic difference is primarily due to the inflation of the extent of 

yellow-cedar area defined by the pixel size (240 m versus 30 m). The 30-m pixel 

filter provides a finer resolution and identifies the more specific location of the 

cedar forest. The 240-m layer is a coarser filter, which would tend to include both 

yellow-cedar forests and forests not containing yellow-cedar in the mosaic of plant 

communities typical of coastal Alaska. 

Caution should be used when comparing acres of yellow-cedar distribution with 

acres of yellow-cedar decline. Yellow-cedar decline estimates come from aerial 

surveys which detect cumulative mortality over decades and even up to a century 

(see “Yellow-Cedar Decline” subsection in section 2). The most robust yellow-cedar 

distribution acreage estimates (table 21) were derived from data produced in the late 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

1900s or early 2000s, either through direct calculation from inventory estimates 

or as input variables in a species distribution model. Only live yellow-cedar trees 

from inventory plots (i.e., dead trees were excluded) were used in the development 

of these inventory-based or model-based estimates. Many yellow-cedar populations were already declining before any of these estimates were made. Reliance on 

live-tree plot data makes it difficult to reconstruct yellow-cedar occurrence or abundance at the onset of the forest decline in about 1880–1900. No estimate of yellowcedar acreage exists for yellow-cedar forests before the onset of yellow-cedar 

decline. Based on our knowledge of how yellow-cedar decline progresses in stands, 

especially with a minor component of yellow-cedar typically surviving, we suspect 

that yellow-cedar as a percentage of the forest composition has diminished more 

than has the total acreage of forests that contain some yellow-cedar. Total acreage 

values would be more sensitive to estimates of yellow-cedar decline if cover types 

attempted to represent only yellow-cedar-dominated forests. 

The patch of forest shown in figure 85 was previously dominated by live 

yellow-cedar trees, but the progressive mortality that occurred throughout the 1900s 

reduced the amount of live yellow-cedar by about 70 percent (D’Amore and Hennon 2006). The central green section, which represents the area of active mortality 

in the 1900s (Hennon et al. 1990b), is now mainly composed of live trees, most of 

which are mainly hemlock. Models based on plot data limited to live trees would 

predict a different composition of species than occurred before the onset of decline 

throughout this patch. When this situation is repeated across the extent of yellowcedar decline in Alaska, estimates of yellow-cedar from contemporary data sources 

are expected to underestimate the yellow-cedar component in forests, and, perhaps 

to a lesser extent, the acreage of forests that contain yellow-cedar. 

There is interest in estimating the portion of yellow-cedar forests that has been 

affected by yellow-cedar decline in Alaska to gain a broad view of the impacts of 

this forest decline to date. It is problematic, however, to simply compare acres of 

mapped yellow-cedar mortality that developed progressively throughout the 1900s 

with a contemporary (late 1990s to early 2000s) estimate of acres of yellow-cedar 

forest (fig. 85). Because survey polygons can be coarse, we have attempted to constrain the acreage estimate of yellow-cedar decline by overlaying another GIS layer 

to remove areas where yellow-cedar was unlikely to be present. More importantly, 

we cannot detect and account for yellow-cedar mortality where snags are scattered 

in forested wetlands or in forests in which yellow-cedar was not dominant. The 

yellow-cedar decline layer and associated acreage estimates should be viewed as 

representing yellow-cedar-dominated forests with high concentrations of mortality. 

Any future efforts to judge the proportion of yellow-cedar affected by forest decline 
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GENERAL TECHNICAL REPORT PNW-GTR-917

should ensure that the two input acreage estimates (yellow-cedar occurrence and 

yellow-cedar decline) are similar in temporal aspects of inputs, spatial resolution, 

dominance of yellow-cedar, and site productivity classes. Improvements of spatially 

explicit maps and associated areal estimates, for both yellow-cedar occurrence and 

yellow-cedar decline, are high-priority needs (see appendix 2). 

Final Risk Assessment Summary

The detailed risk assessment for each of the proposed 33 yellow-cedar management zones is presented in appendix 1. In this subsection we summarize the broad 

geographic patterns that emerged from those separate analyses by reviewing the 

regional abundance of yellow-cedar, broad areas affected by yellow-cedar decline, 

and general areas at future risk of yellow-cedar decline. We then consider the 

occurrence of land ownership and land use designation to evaluate the major opportunities for the conservation and management of yellow-cedar in Alaska. 

The risk assessment method estimates the acreage of yellow-cedar that is rated 

at low, medium, and high risk of developing yellow-cedar decline at three future 

time intervals: 2020, 2050, and 2080. The predictions are summarized in table 24 to 

evaluate the regional distribution of yellow-cedar, yellow-cedar decline, and future 

risk. The existing yellow-cedar decline acreage is given to indicate forests that have 

been affected to date. The 2020 risk is predicted for a near-term impact, which can 

Figure 85—This patch of dead yellow-cedar decline at Poison Cove on Chichagof Island Alaska 

illustrates the issue of basing species cover types on plot data using live trees only, and the problem of comparing acres of yellow-cedar decline with modeled acres of yellow-cedar occurrence. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 24—Summary of all yellow-cedar management areas in Alaska: acreage of yellow-cedar, acreage of current mapped yellow-cedar decline, and projected percentage of yellow-cedar at risk of decline in 2020 (2011–2040), 2050 (2041–2070), and 2080 (2071–2100)Zonea Forest land Yellow-cedarb

Mapped 

yellow-cedar 

decline, 2013c

Decline risk class, 2020d Decline risk class, 2050d Decline risk class, 2080d

Low Medium High Low Medium High Low Medium High

 - - - - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - - - - - - - -

Seward 262,164 0 0 N/A N/A N/A N/A N/A N/A N/A N/A N/A

Prince William Sound West 766,927 8,512 0 100 0 0 100 0 0 99 1 0

Prince William Sound East 1,020,860 463 0 89 11 0 80 19 1 38 41 22

Icy Bay 474,519 31 0 100 0 0 100 0 0 100 0 0

Yakutat 309,254 0 0 N/A N/A N/A N/A N/A N/A N/A N/A N/A

Glacier Bay 742,116 57,327 0 79 19 3 66 26 8 42 32 27

Haines 323,922 40 0 71 29 0 31 69 0 5 66 29

Chichagof North 451,225 42,928 357 61 27 12 50 32 18 25 45 30

Chichagof South 550,460 116,861 41,061 45 41 14 31 48 21 14 58 28

Kruzof Island 111,770 39,529 26,740 15 37 48 9 41 50 6 43 51

Baranof Island 563,570 154,242 55,668 53 36 12 43 43 14 29 53 18

Juneau 490,097 9,483 62 33 44 23 23 42 35 12 48 41

Tracy Arm 429,496 39,379 1,100 85 11 4 76 18 6 52 35 13

Admiralty 801,620 108,611 4,566 55 32 13 44 38 18 21 52 27

Kuiu Island 438,063 156,263 77,103 38 42 20 24 48 28 9 57 34

Kupreanof Island West 483,563 149,920 68,584 24 38 38 14 38 49 4 39 57

Kupreanof Island East 155,509 24,027 14,637 72 20 8 58 27 15 32 36 33

Thomas Bay 184,384 23,526 11,688 54 31 15 46 31 23 31 39 30

Mitkof Island 134,822 16,458 11,672 75 19 6 64 25 11 35 42 24

Zarembo Island 145,573 25,894 10,555 64 25 10 50 33 17 19 49 32

Etolin Island 201,134 35,317 23,492 67 22 11 56 28 15 34 43 23

Wrangell Island 121,102 24,905 12,505 77 18 5 65 25 9 38 39 23

Stikine 469,111 53,801 21,182 92 7 1 88 10 3 71 21 8

Heceta 216,828 36,923 16,818 50 37 13 38 43 18 20 55 24

Prince of Wales North 725,095 139,491 44,730 39 40 21 27 46 27 11 54 35

Craig Outer Islands 351,514 65,962 7,397 26 48 26 16 52 32 7 57 35

Prince of Wales South 787,246 198,661 37,057 46 38 16 34 45 21 17 55 28

Cleveland Peninsula 269,680 66,541 21,186 55 26 19 45 32 23 26 45 29

Gravina Island 60,418 11,322 3,388 28 39 33 19 45 36 10 53 +37

Revillagigedo Island West 424,668 120,920 22,464 64 19 7 53 25 11 32 39 18

Revillagigedo Island East 176,137 112,815 10,081 68 23 9 57 30 13 35 45 20

Misty Fiords 1,073,635 407,518 22,978 71 20 9 64 25 11 49 36 15

Annette and Duke Islands 111,179 24,494 2,082 24 29 46 19 33 48 13 38 49

 Totals 13,827,661 2,272,164 569,153 - - - - - - - 100 - - - - - - - - - - - - - - 100 - - - - - - - - - - - - - - 100 - - - - - - - 

a See figure 84 for the location of each yellow-cedar management zone. For graphical representation and a breakdown based on land 

ownership and management restrictions, see appendix 1. b Area of current yellow-cedar forests, estimated from species distribution models and surveys (see “Yellow-cedar distribution,” this section).

c See “Yellow-cedar decline,” this section.d Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. N/A = not applicable.
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be compared to existing yellow-cedar decline. The 2050 risk assessment allows for 

a prediction of the likely distribution of yellow-cedar decline in an intermediate 

planning timeline. The pace of this change is uncertain, but the GCM predictions 

are in agreement with the continued reduction of snow through increased temperatures in winter. The 2080 predictions provide a longer term perspective on the 

health of yellow-cedar in the various management zones. 

Yellow-Cedar Forest Distribution and Decline

Yellow-cedar ranges throughout the coastal forests of Alaska with small populations in the northwest around the Gulf of Alaska and larger concentrations in the 

southeast panhandle. The largest population in south-central Alaska is located in 

Prince William Sound West. These yellow-cedar stands are associated with the 

cluster of coastal forests along the fringing area of the mainland and islands. There 

is no known yellow-cedar farther west toward Seward and the coastal mountain 

region of south-central Alaska, but we included this management zone to complete 

the Chugach National Forest. Smaller populations have been identified along the 

edge of Prince William Sound near Cordova and to the east at Icy Bay, and these 

are currently healthy. 

Yellow-cedar has a generally continuous distribution and is abundant in most of 

the panhandle, except for gaps in the northern panhandle. The presence of forests 

currently affected by yellow-cedar decline varies widely from north to south in the 

panhandle. The yellow-cedar forests are free of any known intense mortality in the 

northern and northwestern management zones. The Glacier Bay management zone 

along the coastal fringe of the northwestern part of the panhandle has a sizable 

yellow-cedar forested area that is currently healthy. Yellow-cedar is not particularly 

abundant in some of the areas of the north panhandle (e.g., Juneau, Tracy Arm, and 

Admiralty Island) and there is very little known forest decline in these areas. 

Yellow-cedar is a major component of the landscape in the northwestern portion 

of the panhandle. Chichagof South, Kruzof Island, and Baranof Island have 21, 35, 

and 27 percent of the forested area as yellow-cedar, respectively. There is also a 

high proportion of yellow-cedar southward on Kuiu Island and Kupreanof Island 

West, which have 36 and 31 percent of the forested area as yellow-cedar, respectively. Yellow-cedar accounts for 12 to 29 percent of the forested area in the rest of 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

the central and southwestern areas; exceptions are the inland areas of Revillagigedo 

Island East and Misty Fiords, where yellow-cedar is more abundant. The greatest 

extent of existing yellow-cedar decline acreage is found in management zones in 

the middle portions of the panhandle: together, Kuiu Island, Kupreanof Island West, 

Baranof Island, and Chichagof South account for 43 percent of the mapped decline 

in Alaska. 

These areas occur in a broad band at the northernmost extent of yellow-cedar 

decline (fig. 86). In several cases, they are also north of the distribution of western 

redcedar, which may have allowed for the expanded presence of yellow-cedar in 

these forests. These two features, the abundance of yellow-cedar and the climate 

zone at this latitude, probably contributed to the intensive and relatively recent 

appearance of yellow-cedar decline on the landscape there. Yellow-cedar forests 

appear less extensive to the south of these areas, but there is considerable acreage 

of yellow-cedar decline in Thomas Bay, Mitkof Island, Zarembo Island, Wrangell 

Island, and Etolin Island. 

Yellow-cedar decline has been detected in every management zone farther 

to the south. Sizable acreages of decline occur in the Prince of Wales North and 

Prince of Wales South zones, but mortality often appears scattered and not particularly concentrated on this large island. Yellow-cedar mortality is found in smaller 

acreages in some southern coastal areas (e.g., Gravina Island, Annette and Duke 

Islands). Yellow-cedar is more abundant at higher elevations in this southerly zone. 

Scattered dead yellow-cedar occurs in forested wetland habitats at lower elevations 

in these areas, but its lack of concentration has made the mortality difficult to 

map from the air. Thus, the impacts of yellow-cedar decline are underrepresented. 

The mortality appears older in many of these areas, as if most of the tree death 

occurred decades in the past. To the east, yellow-cedar forests are extensive in the 

Revillagigedo Island East and Misty Fiords management zones. The Revillagigedo 

Island East zone has a sizable percentage (64 percent) of the forested area as yellowcedar. The large southern mainland area of Misty Fiords is notable because of its 

large acreage of yellow-cedar, or 38 percent of its forestland. Yellow-cedar decline 

is present but limited to small coastal low-elevation forests in these management 

zones.
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Figure 86—Yellow-cedar management zones with low (yellow), medium (orange), and high (red) classes of existing yellowcedar decline impacts. The classes reflect the acres of existing yellow-cedar decline as a percentage of yellow-cedar forest. 

Percentage breaks are low ≤10; medium >10 and <40; and high ≥40. Two management zones with no yellow-cedar occurrence 

appear gray.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Projection of Risk of Yellow-Cedar Decline

Strong geographic patterns of near-term and longer term (2020 to 2080) future risk 

of yellow-cedar decline are expected to affect the health of yellow-cedar forests 

in Alaska. These general patterns are: (1) low-snow regions where yellow-cedar 

previously underwent mortality and risk increases only marginally, (2) transitional 

regions that were previously protected by snow but where warming in the next 

century is expected to trigger mortality, and (3) high-snowfall areas where yellowcedar forests remain intact due to sufficient snow cover to protect yellow-cedar by 

the year 2080 even with warming. These three general patterns, described below, 

are arrayed broadly from south to north, coastal to interior mainland, and more 

locally by elevation.

The southern coastal management zones are expected to experience only a 

modest increased risk of yellow-cedar decline in the future. Most of the vulnerable yellow-cedar stands in these areas have already been affected in areas such as 

Gravina Island, Prince of Wales South, Prince of Wales North, and Heceta, where 

only 10 to 20 percent of yellow-cedar is expected to be at low risk by 2080. Thus, 

the high risk continues, but it does not increase dramatically. Although the risk 

remains high based on our modeling techniques, the initial waves of mortality have 

already killed many of the mature yellow-cedar trees in vulnerable microsites and 

some of these forests are recovering with a lower yellow-cedar component. Therefore, there will be fewer yellow-cedar trees that could succumb and die in these 

high-risk areas in the future. Mortality may continue but probably at a lower rate in 

the previously affected forests. Precipitation has been dominated by rain rather than 

snow in winter in these areas, so rising temperatures will not substantially increase 

risk by altering snow patterns. The modest increases in risk of yellow-cedar decline 

are generally at higher elevations, where existing snow cover is predicted to be 

reduced. In addition, the favorable habitat driven by soil drainage does not vary 

through time, maintaining the lower-to-moderate risk acreage at local scales in 

these management zones.

The management zones of Admiralty, Kuiu Island, and Kupreanof Island West 

contain roughly 15 percent of the yellow-cedar acreage in Alaska, and also have a 

relatively high percentage of high risk of yellow-cedar decline. These zones appear 

particularly vulnerable in the future projections. These areas combined with Prince

of Wales North and Prince of Wales South have one-third of the yellow-cedar acreage. About 30 percent of these areas are in the long-term (2080) future high-risk cat-
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egory. The share of high-risk acreage by 2080 is greatest for Kupreanof Island West 

(57 percent), Kruzof Island (51 percent), and Annette and Duke Islands (49 percent).

The most dynamic change to yellow-cedar forests in the next century may be 

in areas of the northern panhandle, just beyond the current distribution of yellowcedar decline (fig. 87). Yellow-cedar forests in Chichagof North, Admiralty, Glacier 

Bay, Juneau, and Haines have only small acreages of existing yellow-cedar decline. 

Although these areas show small amounts of high risk of yellow-cedar decline in 

2020 (e.g., 0 percent and 3 percent in Haines and Glacier Bay, respectively), their 

risk increases to about 30 percent in the high-risk class by 2080. Most other management zones in the northern panhandle are also projected to have 30 percent of their 

yellow-cedar forests in the high-risk class by 2080. The small populations in Prince 

William Sound East that are shown as change in figure 87 are mainly going from 

low to moderate risk between 2020 and 2080. These management zones with anticipated dynamic change represent yellow-cedar forests that were previously protected 

by snow but that will be affected as snow accumulation is reduced through warming.

Finally, there are regions of Alaska with yellow-cedar forests that have little to 

no existing yellow-cedar decline now, and risk is expected to remain relatively low 

by 2080. The most extreme examples are the small populations of yellow-cedar in 

Prince William Sound West and Icy Bay, which are all currently healthy; 99 and 

100 percent of these acreages, respectively, are expected to be at low risk of decline 

by 2080. A larger proportion of the small populations of yellow-cedar in Prince 

William Sound East near Cordova is expected to be at high risk (0 percent in 2020 

but 22 percent in 2080). 

Yellow-cedar forests along the mainland adjacent to the border with British 

Columbia are expected to remain relatively healthy into the future. Yellow-cedar 

is abundant in Tracy Arm, Stikine, and Misty Fiords. Currently these management 

zones contain only small amounts of yellow-cedar decline, all of which is along 

the coastal areas. The Misty Fiords, Revillagigedo Island East, and Revillagigedo 

Island West management zones have almost 30 percent of the yellow-cedar acreage 

in Alaska, but the acreage at high risk does not rise appreciably by 2080 (i.e., not 

>20 percent) and about one-third to one-half of these forests are expected to remain 

at low risk by 2080.

Implications of Risk Models for the Conservation and 

Management of Yellow-Cedar 

Lands Under Conservation or Protection Status

The health status of yellow-cedar in Alaska differs widely with location: the species 

is impaired by concentrated mortality in some areas and unaffected in other areas. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 87—Yellow-cedar management zones with low (yellow), medium (orange), and high (red) percentage increase in high risk rating between 2020 and 2080. Change for each management zone was determined by the difference in the percentage of yellow-cedar 

forests rated at high risk between the two time periods with classes of change of low, <2%; medium, 2 to 10%; and high, >10%. 
188

GENERAL TECHNICAL REPORT PNW-GTR-917

Large portions of two landscapes under protected status, West Chichagof–Yakobi 

and South Baranof Wilderness Areas, exemplify yellow-cedar forests that have 

already undergone intense yellow-cedar decline. These were forested areas with a 

high abundance of yellow-cedar until the decline caused about 70-percent mortality in many stands. A study on succession in the West Chichagof Wilderness Area 

documented the loss of yellow-cedar and the transition to western hemlock and 

other species, and predicted the long-term nature of these changes because of poor 

yellow-cedar regeneration (Oakes et al. 2014). 

Other landscapes that are under protection currently have intact, healthy yellow-cedar populations, but they are at increasing future risk, and the appearance of 

mortality is expected in the next century due to reduced snow. As an example, the 

health status of yellow-cedar in Glacier Bay National Park is expected to change as 

snow accumulation is reduced through warming (Oakes et al. 2015). Yellow-cedar 

may shift from thriving in abundant healthy populations to being compromised 

as yellow-cedar decline emerges in portions of the park. Similarly, yellow-cedar 

decline is now confined to the southern end of Admiralty Island, but mortality is 

expected to appear in yellow-cedar forests over large parts of the island by 2080. 

Without intervention, succession to other species and a long-term reduction in the 

yellow-cedar component in these forests is expected. More information is needed 

on the natural regeneration of yellow-cedar in decline-affected forests to determine 

how permanent these anticipated changes may be.

Meanwhile, other yellow-cedar forests in a land-use classification of protection are expected to persist in a healthy condition even in a warming climate. 

The small populations of yellow-cedar at the northwest range limits in the Prince 

William Sound West zone are expected to be almost entirely at low risk of forest 

decline by 2080. Snow levels are so high in these areas that even with reductions 

through warming there is still adequate snow to buffer trees from root freezing. 

Snow is also expected to favor the abundant natural regeneration that continually 

replenishes yellow-cedar in these forests. Currently, yellow-cedar decline is limited 

to relatively small coastal fringes in some of the mainland areas such as Tracy 

Arm, Stikine, and Misty Fiords. These are primarily lands in protection status, 

and because of their mountainous terrain and colder winter climate, large areas 

are expected to retain enough snow to protect yellow-cedar into the future. The 

large mainland portion of Misty Fiords National Monument contains an estimated 

407,000 ac of yellow-cedar, but only 15 percent of the yellow-cedar resource is 

expected to be at high risk of decline by 2080. The continued population stability 

of yellow-cedar is promising in these important, protected landscapes. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

It is important to note that yellow-cedar will not be extirpated from any major 

areas in Alaska through the process of yellow-cedar decline, even those currently 

affected or where decline is expected to develop in the future. Large mainland 

populations and smaller coastal populations along the Gulf of Alaska are expected 

to remain healthy through the century. At a more local spatial scale, about 30 percent of yellow-cedar survives over the long term in declining stands (D’Amore and 

Hennon 2006, Oakes et al. 2014). Thus, even in intensely affected forests, yellowcedar may be reduced, but it is not extirpated. Furthermore, yellow-cedar remains 

healthy, often as a smaller component of forests in mixed stands, on well-drained 

soils. These healthy yellow-cedar trees are common in stands surrounding patches 

of dead yellow-cedar. Along with evaluating the health of mature yellow-cedar 

trees, natural regeneration could be monitored to assess the long-term sustainability 

of yellow-cedar on these protected landscapes (see appendix 2). 

Lands Under Active Management Status: Intervention Activities

Active forest management offers the most direct opportunity for adapting to climate 

change and responding to yellow-cedar decline. Forest management practices can 

increase the abundance of yellow-cedar in habitats that are expected to be favorable 

into the future, and other approaches can be used to restore some ecosystem functions in decline-affected forests. These management considerations are described in 

more detail in section 3. Direct intervention may be limited to certain land ownerships and land use designations on lands managed by the U.S. Forest Service where 

these activities are permitted. 

Lands owned and managed by the state and by private entities have a great deal 

of flexibility for direct intervention in broad areas of coastal Alaska. Large-scale 

planting of yellow-cedar most likely would require a program of timber harvesting to produce open growing conditions. Good candidates for this approach are 

areas suitable to yellow-cedar because of high snowfall, such as those near Prince 

William Sound, Icy Bay, and Yakutat. In this part of the yellow-cedar range, state 

and private lands are the only lands with an active timber harvesting program. 

Most commercial timber harvests occur on relatively productive sites where higher 

volume forests are selected. Planted yellow-cedar on recently harvested lands would 

have excellent likelihood of survival because they probably would be protected by 

snow, would grow deep roots owing to local site productivity, and may have limited 

browse by deer. An example of this type of success has been the experience thus far 

in the trial planting at Yakutat on lands managed by the Forest Service.

The major areas managed by the Forest Service in land use designations that 

permit active forest management are in the middle and southern portion of the 
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GENERAL TECHNICAL REPORT PNW-GTR-917

panhandle. At first glance, many of these areas appear to be at high risk of yellowcedar decline, and would therefore be unlikely locations to favor yellow-cedar. But 

our maps are displayed at a scale that does not portray the habitat suitable to yellowcedar on well-drained sites. These favorable sites can occur at low elevations that 

receive little winter snow and are sometimes located adjacent to forested wetlands 

with patches of dead and dying yellow-cedar. More importantly, most timber 

harvest activities occur on well-drained soils that support forests of commercial 

volumes. Therefore, these sites represent the management space where techniques 

of planting and thinning to favor yellow-cedar can be applied through traditional 

silviculture. Yellow-cedar can be planted on productive sites that have been recently 

harvested, whether the harvest was a previously unmanaged old-growth stand or a 

young-growth stand. This latter situation of planting yellow-cedar to follow harvest 

of young-growth would be important as the region shifts to more young-growth 

harvest. Yellow-cedar planted on low-elevation productive sites will probably need 

some protection from deer browse to ensure long-term survival. See section 3 for 

more detail on planting and thinning to favor yellow-cedar on productive sites. 

There may be an opportunity to establish new populations of yellow-cedar 

by planting seedlings in forest settings that are not intensively managed. These 

situations are presented here as ideas that have not yet been tested by planting 

trials. Yellow-cedar could be planted in forested wetland environments that receive 

heavy snow and are expected to represent suitable habitat into the future. Ideally, 

the seedlings would be planted on raised areas to avoid anaerobic soil conditions. 

Growth would be expected to be slow on these unproductive sites, yet seedlings 

may eventually grow into trees that produce cones and seed, or they may spread 

by clonal layering. Areas of natural disturbance in the form of windthrow and 

avalanches could be used as planting sites on more productive sites where open 

or semi-open canopy conditions would favor more rapid yellow-cedar growth and 

eventual reproduction. 

Another form of active management is to salvage dead yellow-cedar trees to 

capture high-value wood in the forests that have been affected by yellow-cedar 

decline. Details on the wood properties of dead yellow-cedar and the feasibility of 

salvage are presented in the “Conversions, Timber Salvage, and Conservation on 

Vulnerable Habitats” subsection in section 3. Opportunities for salvage would be 

constrained by the current and future extent of yellow-cedar decline, land ownership and land use policies, and economic feasibility. A considerable proportion 

of yellow-cedar decline—both acreages currently existing and those expected to 

expand in the future—is on lands under protection status. Salvage opportunities are 

mentioned for specific yellow-cedar management zones in appendix 1. The most 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

extensive opportunities for salvage appear to be in the southern and central coastal 

islands on lands administered by the Forest Service where yellow-cedar decline is 

common, road access exists, and land use policies allow this activity. 

Whether dead yellow-cedar is salvaged or not, silvicultural treatments of planting or thinning could be used to favor certain tree species. Western redcedar would 

be a desirable choice because it has ecosystem service values similar (but not identical) to those of yellow-cedar. Western redcedar is often absent in decline-affected 

forests because of the elevational and latitudinal limits of the tree, but the limiting 

climate barriers (growing season growing-degree days and snow duration) are 

expected to be more favorable for redcedar in the future. Although there has been 

no such trial to date, a forest management option for rehabilitating stands affected 

by yellow-cedar decline is to plant and favor western redcedar. 

Another approach could be to combine activities on suitable and vulnerable 

habitat for yellow-cedar in certain local project areas. Salvage of dead yellow-cedar in 

decline-affected forests may produce a stream of revenue that could then be used to 

fund planting, seedling protection, and thinning on nearby suitable habitat (fig. 88). 

Figure 88—A patch of yellow-cedar decline above a series of recent timber harvest 

with a road. This photograph illustrates the opportunity to integrate activities on 

vulnerable and suitable habitat for yellow-cedar: salvage harvest dead yellow-cedar 

in the decline-affected forest to produce revenue to fund planting of yellow-cedar 

seedlings on the productive soils in the new harvest units below.

Allison Bidlack 
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GENERAL TECHNICAL REPORT PNW-GTR-917

Conclusions

This report uses the case of yellow-cedar decline to illustrate how climate can 

interact with other factors to initiate widespread tree mortality, and offers a vulnerability assessment and opportunities for adaptive responses to help in the conservation and management planning for this important species. An understanding of 

the cause of yellow-cedar decline required several decades of study, but research 

eventually revealed that the problem was related to a changing climate. Research 

also exposed the actual mechanism of tree injury, which helped clarify the specific 

role of climate in tree death. Climate is just one of the factors that can lead to injury 

of a forest tree species, but it interacts with soils and a unique vulnerability of 

yellow-cedar to explain stress and death. Knowledge of these interacting factors can 

be the foundation for projecting future change and developing adaptive strategies. 

Conservation and restoration strategies may acknowledge the dynamic nature 

of climate, and managers could take into account predicted changes when deciding 

where to apply these strategies. It is important to recognize that the health status 

of yellow-cedar has been and will continue to be compromised in some protected 

landscapes with minimal human development. Forest management strategies on 

certain land ownerships and land use designations can take several forms, such as 

the movement of tree species from various genetic sources through assisted migration and the favoring of conditions for a species through active management. This 

latter method has promise in coastal Alaska. In this area silvicultural techniques 

of planting or thinning can be used to increase the presence of yellow-cedar on 

productive soils where it would otherwise be less competitive with western hemlock 

and Sitka spruce. 

Our report summarizes current knowledge on the ecology, silvics, and genecology of yellow-cedar. It describes climate impacts on the species and offers 

adaptive strategies to help ensure the long-term abundance and ecosystem services 

of yellow-cedar in Alaska. We hope that this report is a useful reference for educators, forest managers, and scientists, and that it will encourage others to study this 

culturally, economically, and ecologically valuable tree. 

Acknowledgments

We appreciate the many reviews that we received on drafts of this report from Tara 

Barrett, Sarah Bisbing, Andy Bower, Brian Buma, Ben Case, Jackie DeMontigny, 

Rob Develice, Elizabeth Graham, Connie Harrington, Tim Harrington, Pat Heuer, 

Tom Heutte, Adelaide Johnson, John Krapek, Dennis Landwehr, Nick Lisuzzo, 

Kate Mohatt, John Russell, Mike Sheets, and Stefan Zeglen. We thank those who 

helped us interpret distributions of yellow-cedar throughout its natural range: Mike 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Simpson, U.S. Forest Service, Forest Health Protection in Bend, OR, for Oregon 

and Washington; Todd Davis and Stefan Zeglen, British Columbia Ministry of 

Forests, Lands and Natural Resource Operations, Nanaimo, BC, and Pat Martin, 

British Columbia Ministry of Forests, Lands and Natural Resource Operations, 

Victoria, B.C., for British Columbia; Roy Josephson, Alaska Department of Natural 

Resources, for Haines and Icy Bay; and Greg Streveler of Icy Strait Environmental 

Services, Gustavus, Alaska, for Glacier Bay. Joel Nudelman, Alaska Department 

of Natural Resources, Juneau, provided us with the report of yellow-cedar on state 

Mental Health Corporation land near Icy Bay. Special thanks to Marshall Murray, Centralia, Washington, for supplying us with the locations for more than 300 

yellow-cedar populations in Oregon and Washington. We greatly appreciate the 

thorough and helpful copy editing by Cynthia Moser. We thank Inga Petaisto, U.S. 

Forest Service, Alaska Region, for sharing information on the historical economic 

values and export policy of yellow-cedar in Alaska. We are grateful for the financial support from the Forest Management director in the Alaska Region and for the 

Focus Areas grant that we received from the Pacific Northwest Research Station.

Metric Equivalents 

When you know: Multiply by: To find:

Inches (in) 2.54 Centimeters

Feet (ft) 0.305 Meters

Yards (yd) 0.914 Meters

Miles (mi) 1.609 Kilometers

Acres (ac) 0.405 Hectares

Square feet (ft2

) 0.0929 Square meters

Square miles (mi2

) 2.59 Square kilometers

Cubic feet (ft3

) 0.0283 Cubic meters

Cubic inches (in3

) 0.0000164 Cubic meters

Board feet 0.0024 Cubic meter

Cubic feet (ft3

) 28.3 Liters

Pounds (lb) 454 Grams

Pounds (lb) 0.454 Kilograms

Tons (ton) 907 Kilograms

Tons (ton) 0.907 Tonnes or megagrams

Square feet per acre (ft2

/ac), basal 

area

0.229 Square meters per 

hectare

Cubic feet per acre (ft3

/ac) 0.07 Cubic meters per hectare

Trees per acre 2.47 Trees per hectare

Degrees Fahrenheit 0.56(°F – 32) Degrees Celsius

Pounds per square inch (lb/in2

) 6,900 Pascal

Pounds per square foot (lb/ft2

) 47.9 Pascal

Pounds per cubic foot (lb/ft3

) 16.02 Kilograms per cubic meter
194

GENERAL TECHNICAL REPORT PNW-GTR-917

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227

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Overview of Yellow-Cedar Management Zones

We divided the coastal rainforest environment around the range of yellow-cedar 

in Alaska into 33 geographic zones to produce a more fine-scale view of yellowcedar’s current and expected future health status and associated prospects for 

conservation and management (fig. 86). Yellow-cedar’s occurrence in these zones 

ranges from abundant to uncommon, rare, and absent (in one zone, Seward, and 

another, Yakutat, where it exists only due to planting in a small area). The management zones are arranged in a sequence of northwest to southeast from the Seward 

and Prince William Sound area south to Dixon Entrance. For each management 

zone, we briefly describe the geology, climate, acreage of yellow-cedar and mapped 

forest decline, projections of future risk to yellow-cedar forests in three time steps, 

and prospects to adapt with new conservation and management measures given 

changing conditions. We also present a table for each management zone showing the relative change among the three risk categories (low, medium, and high) 

between time steps to describe the amount of change in predicted vulnerability for 

yellow-cedar through 2080. The tabular outputs are arranged by land ownership 

and three broad classes of land use for areas managed by the U.S. Forest Service. 

An accompanying figure summarizes these results in map and chart form for each 

management zone. The results for this evaluation are derived from the models that 

are outlined in section 4 of this report. The interpretation of broad-scale patterns of 

habitat suitability and vulnerability for yellow-cedar, and opportunities for conservation and management are also described in section 4.

The primary source of information for the panhandle geology and geomorphology was the ecological mapping of southeast Alaska (ECOMAP; Nowacki et al. 

2001).1

 South-central Alaska geomorphic information was derived from the Ecological Hierarchy of the Chugach National Forest (DeVelice et al. 1999).2

 Coastal 

information was derived from U.S. Department of the Interior, U.S. Geological 

Survey reports and other geological and geomorphological descriptions. Climate 

information was obtained from the Western Regional Climate Center (2015). Data 

for temperature and precipitation as rain and snow were obtained from weather 

stations in the study area. Some stations had complete records from 1948 through 

1

 References in the appendixes are listed in the “Literature Cited” section of the main text. 

2

 Also from an unpublished administrative report: Davidson, D.F. 1996. Ecological Hierarchy of the Chugach National Forest. On file with the Chugach National Forest, Alaska 

Region 10, Anchorage, AK. 7 p.

Appendix 1: Local Assessments of Yellow-Cedar in Alaska
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GENERAL TECHNICAL REPORT PNW-GTR-917

2005; others had shorter records of observation. The maximum temperature is the 

average of all daily maximum temperatures for each month averaged for the entire 

year for each year of observation at the specific station. The minimum temperature 

is the average of all daily minimum temperatures for each month averaged for each 

year of observation at each station. Therefore, the average high and low temperatures are the annual average of monthly observations of the maximum and minimum temperatures, respectively, recorded at the observation station. Precipitation 

is the average of all daily total precipitation values recorded for each day of the year 

for the period of observation at each station. Precipitation is given as the average 

annual total precipitation as rain. Snowfall is the annual average total measured 

snow at each station. These weather averages do not represent entire management 

areas because they are derived from single weather stations at a specific location, 

often at or near sea level.

For ownership and land use designation on land managed by the Forest Service, 

we used the following input data: 

For ownership designations on Forest Service lands we used “BasicOwnership” data from the Forest Service’s fundamental land survey, the Automated 

Lands Program (ALP); we also used land status information. For lands outside the 

extent of ALP, primarily the Haines and National Park Service zones, ownership 

is informed by the State of Alaska’s “General Land Status,” containing ownership records at the Public Land Survey System section level Clipped to 1:63,360 

Coastline.

For land use designations, we first categorized all lands occurring in the ALP 

“RegulatedUse” layer as restricted. These designations include National Forest 

System land parcels that have management or use limits placed on them by legal 

authority. Examples are National Wilderness Area, National Recreation Area, and 

National Monument. Additionally we included Withdrawal areas in this categorization, areas such as State or Native selections, and power withdrawals.

Additional nonrestricted land use designations were obtained from forest 

management plans and categorized as “development” or “nondevelopment.” For 

the Tongass National Forest we used the layer titled “LandUseDesignation” from 

the “LandUseDesignation” database, which denotes Forest Service land use designations as defined by the 2008 Tongass National Forest Plan. For the Chugach 

National Forest we used the layer titled “LRMP_Category_Dissolve” from the 

“LRMP_2002” geodatabase, used to summarize the 2002 Chugach National Forest 

Plan categories into five categories. For future analyses, we suggest users access the 

most recent ownership and land use geographic information systems (GIS) layers, 

as these boundaries can change frequently. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

1. Seward

Geomorphology and climate— 

The Seward management zone is underlain by the Valdez Formation of the Chugach 

Terrane. This formation consists of Cretaceous marine rocks of metasedimentary 

and metavolcanic origin. Surficial geologic material is dominated by undifferentiated and unconsolidated surficial deposits from glacial till, glacial-fluvial action, and 

alluvium along relic and present water courses. The management zone lies mostly 

within the Western Kenai Mountains and Eastern Kenai Mountains subsections. 

The area consists of both rounded and jagged mountains and alpine valleys shaped 

by glaciers. Many of the valleys in the eastern portion of the Kenai Peninsula contain alpine glaciers in their upper portions. Abundant precipitation as snow is common throughout the management zone, but varies in total accumulation by elevation. The average annual temperature at sea level ranges from a minimum of 34 °F 

to a maximum of 46 °F. The average annual precipitation is 68 in, and the average 

annual snowfall is 83 in (Seward observation station, 508371). 

Extent of yellow-cedar— 

There is no yellow-cedar in this management zone (table 25). The closest natural 

populations are to the east on the east side of Unakwik Inlet. 

Extent of yellow-cedar decline— 

There is no yellow-cedar decline in this management zone.

Extent of yellow-cedar at future risk— 

There are no yellow-cedar populations for which to assess risk (fig. 89). 

Landscapes in protected and active management zones— 

Most of the land ownership is National Forest in restricted, nondevelopment status. 

Therefore, this large area of forest provides a potential conservation area for future 

migration of yellow-cedar populations into this zone. No yellow-cedar has been 

identified yet, but if it does migrate and establish in this zone, it will have protection 

from potential management in most of the area. There are forested areas under State 

of Alaska jurisdiction and private ownership that provide opportunities for planting.

Opportunities for conservation and management— 

The snowy climate makes this a desirable area to test facilitated or assisted migration of yellow-cedar, thereby extending its range westward. However, the present 

habitat is limited to the coastal forest near sea level. The forested habitat is currently drier in much of the area with a mix of black, white, Lutz, and Sitka spruce, 

quaking aspen, and Kenai and paper birch. Deer would presumably not be a threat 

to planted yellow-cedar, but moose and other animals might damage regeneration. 
230

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 25—Seward Yellow-Cedar Management Zone (Seward Ranger District, Chugach National Forest): acreage of yellow-cedar, acreage of current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080 

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 215,223 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, developmentd 67,873 0 0 0 0 0 0 0 0 0 0 0

Nonrestricted, limited developmente 0 0 0 0 0 0 0 0 0 0 0 0

 Restricted, nondevelopment f 147,350 0 0 99 0 0 99 0 0 0 0 0State 42,635 0 0 0 0 0 0 0 0 0 0 0Private 4,306 0 0 0 0 0 0 0 0 0 0 0Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0Unknown 0 0 0 0 0 0 0 0 0 0 0 0 Total 262,164 0 0 0 0 0 0 0 0 0 0 0

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
231

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 89—Seward Yellow-Cedar Management Zone (Seward Ranger District, Chugach National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
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GENERAL TECHNICAL REPORT PNW-GTR-917

2. Prince William Sound West

Geomorphology and climate— 

This management zone is part of the Valdez Formation within the Chugach Terrane. 

These late-Cretaceous sedimentary rocks are prone to weathering due to their 

composition and origin from marine floor deposition and uplift. Surficial geologic 

materials are dominated by glacial drift, colluvial material including redeposited 

glacial materials, and alluvium. The geomorphology is characterized by a diverse 

assemblage of landscape features. Of the several ecological subsections within 

the management zone, the largest are the Chugach Icefields, Turnagain Arm, and 

Eastern Kenai Mountains. The main coniferous forest area is within the Eastern 

Kenai Mountains subsection, which provides the core habitat for yellow-cedar within the management zone. Abundant precipitation as snow is common throughout 

the management zone, but varies in total accumulation by elevation. The foothills of 

this management zone have an average minimum temperature of 30 °F and an average maximum temperature of 44 °F. The average annual precipitation is 68 in, and 

the average annual snowfall is 197 in (Alyeska observation station, 500243). At sea 

level, the average temperature ranges from a minimum of 35 °F to a maximum of 

45 °F. The average annual precipitation is 197 in, and the average annual snowfall is 

248 in (Whittier observation station, 509829). 

Extent of yellow-cedar— 

This management zone marks the northwestern range limit for yellow-cedar. There 

are 8,512 ac of yellow-cedar, which cover 1.1 percent of the total forested area in 

this management zone (table 26). The yellow-cedar populations here contribute to 

just 0.4 percent of the yellow-cedar acreage in Alaska. This management zone includes numerous inland mountain valleys, but yellow-cedar populations are generally restricted to the northernmost coastal forests. Large areas of coastal forests to 

the south represent unoccupied suitable habitat for yellow-cedar. Although yellowcedar has a limited extent in this management zone, separate populations to the east 

near Cordova cover an even smaller area. 

Extent of yellow-cedar decline— 

No yellow-cedar decline has been mapped in this management zone. Observations 

and limited plot data from this area suggest that yellow-cedar populations were 

healthy as of 2000 (Hennon and Trummer 2001). 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Extent of yellow-cedar at future risk— 

All of the existing yellow-cedar is at low risk (100 percent) in both the 2020 and 

2050 projections (fig. 90). By 2080, there is only a 1-percent increase in risk (from 

low to medium), far less than any other management zone with yellow-cedar populations. The presence of snow covering suitable yellow-cedar habitat keeps the area 

at low risk. 

Landscapes in protected and active management zones— 

All of the yellow-cedar on land managed by the U.S. Forest Service is located in 

restricted or nondevelopment land use designations. Yellow-cedar appears to be 

regenerating well, both in forests and avalanche-disturbed areas (Hennon and 

Trummer 2001). Yellow-cedar tree growth here is rapid compared to its growth in 

southeast Alaska. The populations and the range limit may be expanding slowly, 

perhaps aided by the scarcity of deer. A small amount of the yellow-cedar acreage is 

located on private and unknown land holdings. 

Opportunities for conservation and management—

The stable or possibly expanding yellow-cedar populations occur on lands in protection status (Nellie Juan–College Fiord Wilderness Study Area). This management zone is a prime location for conservation of healthy, intact yellow-cedar forests due to low future risk of decline, and potential population and range expansion 

through natural dispersal. The zone is highly variable and any management actions 

must evaluate the specific areas of interest with local knowledge of conditions such 

as snowpack. Some of the areas have a wide range of seasonal temperature and 

snowpack due to local glacial influence. The proposed Research Natural Area at 

Cedar Bay presents an opportunity to focus research and monitoring efforts in these 

intact yellow-cedar forests. This area is also somewhat warmer than other parts of 

the management zone and will be a good location for future monitoring of yellowcedar health in the region. 
234

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 26—Prince William Sound West Yellow-Cedar Management Zone (Glacier Ranger District, Chugach National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080 

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 598,489 8,508 0 100 0 0 100 0 0 99 1 0 Nonrestricted, developmentd 0 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 12,322 0 0 0 0 0 0 0 0 0 0 0 Restricted, nondevelopment f 586,167 8,508 0 99 0 0 99 0 0 97 1 0State 103,903 0 0 0 0 0 0 0 0 0 0 0

Private 64,439 4 0 0 0 0 0 0 0 0 0 0Other governmental entity 92 0 0 0 0 0 0 0 0 0 0 0Unknown 0 0 0 0 0 0 0 0 0 0 0 0 Total 766,927 8,512 0 100 0 0 100 0 0 99 1 0

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
235

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 90—Prince William Sound West Yellow-Cedar Management Zone (Glacier Ranger District, Chugach National Forest): areas and percentages of low, moder- ate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. Arrows indicate ywllow-cedar populations 
236

GENERAL TECHNICAL REPORT PNW-GTR-917

3. Prince William Sound East

Geomorphology and climate— 

This management zone includes the Copper River Delta and Copper River Delta 

ecological subsections as well as portions of the Prince William Sound Islands and 

Prince William Sound Mainland ecological subsections. Extensive icefields are also 

present. The most distinctive feature of this landscape is the distal end and delta of 

the Copper River, with its many islands, sand dunes, and lowlands. This geologically unstable landscape has a great deal of past and present alluvial action and recent 

tectonic activity. The surficial geology is typical of postglacial valleys and deltas 

with flat outwash plains and dunes. The average annual temperature ranges from a 

minimum of 31 °F to a maximum of 46 °F. The average annual precipitation is 91 

in, and the average annual snowfall is 117 in (Cordova observation station, 502177). 

A zone of heavy snow accumulation is located at the interface between the coast 

and the Coast Mountain passes at Valdez. There, the annual temperature ranges 

from an average minimum of 29 °F to an average maximum of 43 °F. The average 

annual precipitation is 62 in, and the average annual snowfall is 220 in (Valdez observation station, 509685). 

Extent of yellow-cedar— 

The presence of yellow-cedar in this zone is limited to small stands on or near 

Hawkins Island. Known yellow-cedar populations occur near Windy and Mud Bays 

on Hawkins Island; Point Gravina, Bomb Point, and Alice Cove on the mainland 

to the north of Hawkins Island; and Yelper Cove on Hinchinbrook Island. The total 

acreage is only about 463 ac, a small fraction of the >1 million ac of forestland in 

this management zone (table 27). These yellow-cedar populations contribute to 0.02 

percent of the yellow-cedar extent in Alaska. 

Extent of yellow-cedar decline— 

Decline has not been documented in any of the small populations in this management 

zone. The stands visited and measured in the year 2000 (Hennon and Trummer 2001) 

indicate that yellow-cedar was healthy and growing well at that time. 

Extent of yellow-cedar at future risk— 

There is no acreage at high risk of yellow-cedar decline in 2020, and 89 percent of 

yellow-cedar acreage is in the low-risk class (fig. 91). High risk rises to 1 percent in 

2050 and 22 percent in 2080 with a reduction in snow. By 2080, the proportion of 

yellow-cedar acreage at low risk is expected to be 38 percent. 
237

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Landscapes in protected and active management zones— 

Most of the yellow-cedar in this management zone is on land managed by the U.S. 

Forest Service, with almost all in nonrestricted, limited development status. Small 

acreages are listed as State, private, and unknown ownership. Yellow-cedar is absent from large, managed forested areas on these non-Forest Service lands. 

Opportunities for conservation and management— 

The small populations of yellow-cedar on land managed by the Forest Service could 

be monitored given their rarity and increasing risk of yellow-cedar decline. The 

populations at Point Gravina, Bomb Point, Alice Cove, and Yelper Cove should be 

mapped comprehensively because their boundaries have never been confirmed. The 

land use classification of the existing yellow-cedar forests may allow some limited 

management activity to enhance the competitiveness of yellow-cedar within the 

small populations or to expand these populations to larger forested areas such as 

Hinchinbrook and Montague Islands. There may be opportunity to plant yellowcedar on more intensively managed State of Alaska and private lands to promote 

or expand yellow-cedar populations in these areas. Deer were introduced into the 

Cordova area in the early 1900s; nonetheless, yellow-cedar is regenerating well on 

Hawkins Island, so planting would be expected to be successful. 
238

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 27—Prince William Sound East Yellow-Cedar Management Zone (Cordova Ranger District, Chugach National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080 

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 770,383 413 0 72 19 1 70 18 1 33 37 22 Nonrestricted, developmentd 12,013 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 682,660 412 0 72 19 1 70 18 1 33 37 22 Restricted, nondevelopment f 75,711 1 0 0 0 0 0 0 0 0 0 0

State 36,086 14 0 3 0 0 3 0 0 0 3 0

Private 213,434 23 0 5 0 0 5 0 0 4 1 0

Other governmental entity 957 0 0 0 0 0 0 0 0 0 0 0

Unknown 0 0 0 0 0 0 2 1 0 0 0 0

 Total 1,020,860 463 0 89 11 0 80 19 1 38 41 22

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
239

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 91—Prince William Sound East Yellow-Cedar Management Zone (Cordova Ranger District, Chugach National Forest): areas and percentages of low, mod- erate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. Arrows indicate yellow-cedar populations. 
240

GENERAL TECHNICAL REPORT PNW-GTR-917

4. Icy Bay

Geomorphology and climate— 

This management zone is dominated by the glaciated St. Elias–Fairweather Icefield 

complex. The area is characterized by a continuous plain along the coast with productive coniferous forest bounded by sheer mountain slopes. This zone of unconsolidated 

glacial, alluvial, and glaciomarine deposits provides substrate that forms a mosaic of 

productive forest and peatland. The area has generally low relief due to the nature of 

the uplifted landforms from isostatic rebound. No local weather station is available for 

this area. However, sea level temperature and precipitation records will be similar to 

those from Yakutat. Snow accumulation will increase with elevation, leading to large 

snow accumulations on the foothills and mountain slopes.

Extent of yellow-cedar— 

There is a very small population of yellow-cedar within the nearly half-million ac 

of forested land in this management zone. The actual size of the single stand of 

live yellow-cedar is not known at this time, but it is estimated at 30 ac (table 28). It 

is located just east of Big Sandy Creek and west of Priest River in a natural stand 

upslope from a harvested area at 60.0050°N, 141.7315°W. A harvested unit on State 

land near Laurence Creek was thought to previously contain yellow-cedar.

Extent of yellow-cedar decline— 

Decline has not been documented in this management zone. 

Extent of yellow-cedar at future risk— 

The area of the small stand of yellow-cedar remains at low risk through 2080 

(fig. 92). 

Landscapes in protected and active management zones— 

The small yellow-cedar stand in this zone is administered as Mental Health Trust 

land and is managed by the State of Alaska. There is no land managed by the U.S. 

Forest Service in this management zone.

Opportunities for conservation and management— 

Extensive areas on State lands have been harvested in this management zone. There 

is a good potential for planting within recent clearcuts to facilitate new yellow-cedar 

forests. The nearest available yellow-cedar seed source was collected near Hoonah. 

The cold weather and abundant snow would create optimal conditions for the survival and persistence of yellow-cedar to maturity over the next century. The small 

live yellow-cedar population near Big Sandy Creek could be genetically unique due 
241

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

to its isolation and small size and should be mapped for extent on the ground, monitored into the future, and protected from harvesting. Collections of foliar tissue 

and seeds are needed from this stand for genetic analyses. The area near Laurence 

Creek, which apparently contained yellow-cedar before it was harvested, should be 

checked for the occurrence of yellow-cedar stumps and regeneration. Further surveys could detect yellow-cedar in more locations within this management zone. 
242

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 28—Icy Bay Yellow-Cedar Management Zone: acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080 

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 0 0 0 0 0 0 0 0 0 0 0 0 Nonrestricted, developmentd 0 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 0 0 0 0 0 0 0 0 0 0 0 0 Restricted, nondevelopment f 0 0 0 0 0 0 0 0 0 0 0 0State 241,304 31 0 100 0 0 100 0 0 100 0 0Private 81,743 0 0 0 0 0 0 0 0 0 0 0Other governmental entity 151,472 0 0 0 0 0 0 0 0 0 0 0Unknown 0 0 0 100 0 0 100 0 0 100 0 0 Total 474,519 31 0 100 0 0 100 0 0 100 0 0

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. 

d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
243

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 92—Icy Bay Yellow-Cedar Management Zone: areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Loca- tion for this zone is given in the inset map. Arrows indicate yellow-cedar populations. 
244

GENERAL TECHNICAL REPORT PNW-GTR-917

5. Yakutat

Geomorphology and climate— 

This area is similar to the Icy Bay management zone. It is dominated by the glaciated St. Elias–Fairweather Icefield complex. The vegetated zone is limited to the 

coastal fringe of the Yakutat Forelands subsection. The Puget Peninsula metasediments also provide areas for coniferous vegetation. This zone of unconsolidated 

glacial, alluvial, and glaciomarine deposits contains substrate that forms a mosaic 

of productive forest and peatland. The forested area has generally low relief due to 

the nature of the uplifted landforms from isostatic rebound. The climate is characterized by abundant precipitation and heavy snowfall in winter. At sea level, the 

annual temperature ranges from an average minimum of 33 °F to an average maximum of 46 °F. The average annual precipitation is 145 in, and the average annual 

snowfall is 186 in (Yakutat observation station, 509941). 

Extent of yellow-cedar— 

There are no known natural yellow-cedar forests in this management zone, which 

contains >300,000 ac of forested land (table 29). As an assisted/facilitated migration 

trial, yellow-cedar was planted in 2009 in several areas near Yakutat that had been 

harvested where some stands had experienced blowdown (see section 1). 

Extent of yellow-cedar decline— 

Given the lack of natural yellow-cedar forests present, there is no yellow-cedar 

decline in this management zone. 

Extent of yellow-cedar at future risk— 

There are no natural yellow-cedar forests to form the basis of risk assessment (fig. 

93). The planted areas near Yakutat should be monitored for health in this management zone. Well-drained sites were selected for plantings and are expected to do 

well. However, the landscape in this area is complex and local areas of near-surface 

saturation may compromise the success of some planted trees. Yakutat and Icy Bay 

are considered to have a similar near-sea-level climate, so we might expect to see a 

low level of risk to yellow-cedar in Yakutat through 2080 similar to that projected 

for Icy Bay. 

Landscapes in protected and active management zones— 

Most of the lands in this management zone are administered by the U.S. Forest 

Service; however, sizable areas are also owned and managed by the State and private entities. The lands managed by the Forest Service are mainly in restricted, 

nondevelopment land use designations, but the planting trial was conducted in nonrestricted, development areas.
245

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management—

This management zone offers no opportunity for conservation because yellowcedar does not naturally occur here, but the snowy climate and diverse ownership suggest good prospects for promoting yellow-cedar forests through planting. 

Yellow-cedar may have occurred here before the late Pleistocene epoch, but that 

is speculative. The artificial planting of yellow-cedar in blowdown forests near 

Yakutat is an example of “assisted” or “facilitated” migration, the dispersal of a 

species to a climate zone that is suitable but where the species does not yet exist. Given the heavy snow regime and well-drained soils where yellow-cedar was 

planted, prospects are high for its survival. Results of this trial will provide some 

information on the suitable microsites for future plantings in this management zone. 
246

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 29—Yakutat Yellow-Cedar Management Zone (Yakutat Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 284,115 0 0 0 0 0 0 0 0 0 0 0 Nonrestricted, developmentd 11,617 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 23,156 0 0 0 0 0 0 0 0 0 0 0

 Restricted, nondevelopment f 249,343 0 0 0 0 0 0 0 0 0 0 0State 6,693 31 0 0 0 0 0 0 0 0 0 0Private 17,981 0 0 0 0 0 0 0 0 0 0 0Other governmental entity 465 0 0 0 0 0 0 0 0 0 0 0Unknown 0 0 0 0 0 0 0 0 0 0 0 0 Total 309,254 31 0 0 0 0 0 0 0 0 0 0

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. 

d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
247

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 93—Yakutat Yellow-Cedar Management Zone (Yakutat Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
248

GENERAL TECHNICAL REPORT PNW-GTR-917

6. Glacier Bay

Geomorphology and climate— 

This zone is a diverse assemblage of both glaciated and recently deglaciated terrain with exposed bedrock. The glaciated area is part of the St. Elias–Fairweather 

Icefields complex. The exposed bedrock consists of several areas of mountainous 

terrain with varying degrees of vegetation. The vegetated areas are composed of a 

thin wedge of the Yakutat Forelands, the Berg Bay complex sedimentary and volcanic subsection, and the Chilkat Peninsula carbonates. A large portion of Glacier 

Bay was covered by glacial ice during the Little Ice Age. The 60-mi glacial retreat 

from the maximum extent in the 1700s has been colonized by vegetation, and evenaged spruce-dominated forests are common. The climate is variable in this management zone but generally has abundant winter snow. At sea level, the average annual 

temperature ranges from a minimum of 35 °F to a maximum of 47 °F. The average 

annual precipitation is 70 in, and the average annual snowfall is 109 in (Glacier Bay 

observation station, 503294).

Extent of yellow-cedar— 

Yellow-cedar forests have been mapped on >50,000 ac (table 30), all on older landscapes that were not glaciated during the Little Ice Age. The landscape is replete 

with yellow-cedar forests along the coastal fringe from the Dundas Bay area west 

of Glacier Bay along Icy Strait and northward on the outer coastal margin. Yellowcedar is also common on hillsides facing the Gulf of Alaska to an area northwest of 

Cape Fairweather. Yellow-cedar is generally lacking on the eastern side of this management zone except for a small population on forested wetlands below Excursion 

Ridge, even though suitable habitat exists in surrounding areas. Yellow-cedar populations in this management zone contribute 2.5 percent of the yellow-cedar extent in 

Alaska. This may represent an overestimate because of the coarse 240-m resolution 

used to convert surveyed acreage to a yellow-cedar map in this management zone. 

Extent of yellow-cedar decline— 

There is no known yellow-cedar decline in this management zone. No mortality 

was seen during the aerial survey flights in 2012 that produced the distribution map 

of yellow-cedar in Glacier Bay National Park (see section 1). 

Extent of yellow-cedar at future risk— 

Just 3 percent of yellow-cedar forests are projected to be at high risk in 2020, but 

this value is expected to rise to 27 percent by 2080 (fig. 94). Low risk prevails in 79 

percent of yellow-cedar forests in 2020, but that share drops to 42 percent by 2080. 
249

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

There is an expected east-to-west progression of high-risk areas developing along 

the outer coast of Glacier Bay. Most of the yellow-cedar forests to the west of Lituya 

Bay and in higher elevation areas to the east are expected to remain in the low-risk 

category through 2080. 

Landscapes in protected and active management zones— 

Most yellow-cedar forests in this management zone occur on lands administered by 

the U.S. Department of the Interior, National Park Service and hence are in protection status. 

Opportunities for conservation and management—The Glacier Bay yellow-cedar forests are currently healthy and appear to be regenerating. Forests that remain 

at low risk are expected to be important for yellow-cedar conservation. The increasing risk in other currently healthy yellow-cedar forests offers the opportunity to 

monitor the emergence of yellow-cedar decline. This monitoring could be accomplished broadly by aerial survey or remote sensing, and on the ground near Graves 

Harbor and Dick’s Arm by remeasuring the permanent plots established by Oakes 

et al. (2015). 
250

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 30—Glacier Bay Yellow-Cedar Management Zone (Glacier Bay National Park and Preserve): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 22 0 0 0 0 0 0 0 0 0 0 0 Nonrestricted, developmentd 0 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 14 0 0 0 0 0 0 0 0 0 0 0 Restricted, nondevelopment f 7 0 0 0 0 0 0 0 0 0 0 0State 4,484 0 0 0 0 0 0 0 0 0 0 0

Private 14,393 118 0 0 0 0 0 0 0 0 0 0

Other governmental entity 723,217 57,209 0 78 19 0 25 8 43 43 30 27Unknown 0 0 0 0 0 0 0 0 0 0 0 0

 Total 742,116 57,327 0 78 19 0 26 8 42 42 32 27

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
251

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 94—Glacier Bay Yellow-Cedar Management Zone (Glacier Bay National Park and Preserve): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
252

GENERAL TECHNICAL REPORT PNW-GTR-917

7. Haines

Geomorphology and climate— 

The vegetated area of this management zone comprises the Chilkat complex of sedimentary and volcanic rock. The zone is considerably drier than many other areas of 

southeast Alaska and has a glacially carved landscape. Coniferous forest is located 

on colluvial toeslopes, and deciduous vegetation covers much of the remaining area. 

There may be little opportunity for yellow-cedar to occupy this zone because of the 

drier conditions and frequency of fire. At sea level, the average annual temperature ranges from a minimum of 35 °F to a maximum of 48 °F. The average annual 

precipitation is 47 in, and the average annual snowfall is 122 in (Haines observation 

station, 503490). 

Extent of yellow-cedar— 

A 40-ac stand (table 31) of yellow-cedar occurs in this management zone just north 

of Haines. Yellow-cedar is also present in a forest inventory plot on the mainland 

across Lynn Canal from Haines, but the extent of this yellow-cedar forest is not 

known. Note that this latter population is in the Juneau management zone. 

Extent of yellow-cedar decline— 

The small yellow-cedar forest near Haines currently appears healthy. 

Extent of yellow-cedar at future risk— 

Most of the small population near Haines is projected to be at low risk in 2020, but 

>60 percent is projected to be at medium risk in 2050 and 2080 (fig. 95). Our snow 

accumulation model may not portray risk as accurately in locations with cold winters but relatively dry conditions because the hydrology model is not as well calibrated for interior climates such as parts of the Haines management zone. 

Landscapes in protected and active management zones— 

The small yellow-cedar population in this zone is managed by the State in the 

Haines State Forest. This area would be available for timber harvest, but logging is 

unlikely because the yellow-cedar stand is in a forested wetland (personal communication, Roy Josephson, Alaska Department of Natural Resources, 2014). 

Opportunities for conservation and management—

Thinning or other silvicultural activities in the small stand are permissible but 

unlikely and probably unnecessary. The genetics of this isolated stand may also 

be of interest because it represents an outlier to the north of most yellow-cedar on 
253

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

the Panhandle. Collections from 10 trees have been made and are available at the 

Juneau Forestry Sciences Laboratory. This currently healthy population could be 

monitored because risk of decline may increase in the future. Other actively managed lands on the Haines State Forest might be available to plant yellow-cedar to 

initiate new stands on well-drained soils. 
254

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 31—Haines Yellow-Cedar Management Zone: acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 94 0 0 0 0 0 0 0 0 0 0 0 Nonrestricted, developmentd 0 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 13 0 0 0 0 0 0 0 0 0 0 0

 Restricted, nondevelopment f 81 0 0 0 0 0 0 0 0 0 0 0

State 228,423 40 0 71 29 0 69 0 5 5 66 29

Private 64,467 0 0 0 0 0 0 0 0 0 0 0

Other governmental entity 30,938 0 0 0 0 0 0 0 0 0 0 0

Unknown 0 0 0 0 0 0 0 0 0 0 0 0 Total 323,922 40 0 71 29 0 69 0 5 5 66 29

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. 

d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
255

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 95—Haines Yellow-Cedar Management Zone: areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Loca- tion for this zone is given in the inset map. Arrows indicate yellow-cedar populations. 
256

GENERAL TECHNICAL REPORT PNW-GTR-917

8. Chichagof North

Geomorphology and climate— 

The Freshwater Bay and Point Adolphus Carbonates ecological subsections 

make up a large part of this management zone on the north and northeast side of 

Chichagof Island. The area has been extensively reworked by glacial action, leaving abundant till, alluvium, and colluvial deposits. The zone has a large component 

of productive forest, but also contains uplifted glaciomarine features with low-elevation wetlands. There are extensive rich fens and areas of emergent peatland. To 

the west lie the North Chichagof Granitics, a rugged subsection with steep, sparsely 

vegetated mountain slopes and coniferous forests limited to valleys and toeslopes. 

Climate is variable in this management zone, ranging from very wet in the west to 

drier in rain shadow areas around the community of Hoonah. In the drier area, the 

average annual temperatures range from a minimum of 37 °F to a maximum of 48 

°F. The average annual precipitation is 62 in, and the average annual snowfall is 87 

in (Hoonah observation station, 503695). To the west, average annual temperatures 

are the same as in the east, but the average annual precipitation is 150 in and the 

average annual snowfall is 109 in. In Elfin Cove, the average annual temperature 

ranges from a minimum of 39 °F to a maximum of 47 °F. The average annual precipitation is 102 in, and the average annual snowfall is 96 in (Elfin Cove observation station, 502785). 

Extent of yellow-cedar— 

An estimated 43,000 ac of yellow-cedar occur in this management zone, which accounts for 1.9 percent of the yellow-cedar acreage in Alaska (table 32). Yellow-cedar 

occurrence is patchy in this management zone. It is very abundant in the western 

region around Yakobi Island, but its distribution to the east around Port Frederick 

is discontinuous despite large areas of unoccupied suitable habitat. We suspect that 

historical migration patterns explain the uneven occurrence of yellow-cedar in this 

management zone. 

Extent of yellow-cedar decline— 

Most of the existing yellow-cedar forests appear healthy; only 357 ac of decline 

have been mapped by aerial survey.

Extent of yellow-cedar at future risk— 

Between 2020 and 2080, the percentage of yellow-cedar forests at high risk is expected to rise from 12 percent to 30 percent (mostly in the eastern portion of this 

zone), and the percentage at low risk is expected to decline from 61 percent to 25 

percent (fig. 96). Sizable areas in the Yakobi Island area are expected to move from 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

low to high risk. The largest concentrations of yellow-cedar forests that persist at 

low risk by 2080 are near Lisianski Inlet and Port Althorp. 

Landscapes in protected and active management zones— 

The bulk of the 43,000 ac of yellow-cedar and surrounding forested land in this 

management zone is managed by the U.S. Forest Service, but there is some yellow-cedar acreage in other ownerships. On land managed by the Forest Service, 

nearly 10,000 ac of yellow-cedar are in development zones. More than 30,000 ac 

of yellow-cedar forest are located in the nondevelopment and restricted land-use 

categories.

Opportunities for conservation and management— 

Many of the yellow-cedar forests in this management zone are expected to go 

through dynamic change, as there is currently little decline but risk is expected to 

increase through time. There will be new opportunities to salvage dead yellowcedar on managed landscapes. Yellow-cedar could be planted or promoted through 

thinning in young forests or harvested areas with productive soils in managed landscapes on various land ownerships. On protected landscapes, the population stability of yellow-cedar is expected to be compromised. Western hemlock and other 

species will take the place of yellow-cedar in declining stands. Yellow-cedar forests 

are expected to be maintained in the lower risk areas at higher elevations, and on 

sites with suitable drainage. 
258

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 32—Chichagof North Yellow-Cedar Management Zone (Hoonah Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 391,672 40,818 342 59 26 10 48 31 16 24 43 28 Nonrestricted, developmentd 106,691 9,309 14 5 11 6 2 10 9 1 9 12

 Nonrestricted, limited developmente 103,964 10,583 33 12 9 4 10 9 5 6 12 7 Restricted, nondevelopment f 181,017 20,926 295 42 6 1 36 11 2 18 22 9State 3,585 870 15 1 0 0 1 0 0 1 1 0Private 51,893 1,202 0 0 1 1 0 1 2 0 1 2Other governmental entity 205 28 0 0 0 0 0 0 0 0 0 0Unknown 3,870 9 0 0 0 0 0 0 0 0 0 0 Total 451,225 42,927 357 61 27 12 50 32 18 25 45 30

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. 

d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
259

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 96—Chichagof North Yellow-Cedar Management Zone (Hoonah Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
260

GENERAL TECHNICAL REPORT PNW-GTR-917

9. Chichagof South

Geomorphology and climate— 

Granitic rock of the Peril Strait Granitics subsection and sedimentary materials of 

the West Chichagof subsection make up most of this management zone. Although 

there are many glacial scour features, nearly half of the West Chichagof complex 

is composed of nonproductive forest and extensive yellow-cedar habitat. The Peril 

Strait Granitics are similar, with about one-third of the area in nonproductive forest. The uplands and forested wetlands provide ample habitat for yellow-cedar on 

wet Spodosols and Histosols. The winter climate and associated snowfall are quite 

variable because of the gradient from western coastal areas to central mountain 

ranges dissected by Hoonah Sound and Tenakee Inlet. The average annual temperature ranges from a minimum of 35 °F to a maximum of 49 °F. The average annual 

precipitation is 68 in, and the average annual snowfall is 97 in (Tenakee Springs 

observation station, 509121). 

Extent of yellow-cedar— 

Yellow-cedar is an important component of the forested land in this management 

zone, especially in the southwestern portion. An estimated 117,000 ac of yellowcedar forest occur in this management zone, which accounts for 5.1 percent of the 

yellow-cedar acreage in Alaska (table 33). 

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on 41,000 ac and is a visible part of the 

landscape in Peril Strait and along the southwest coast of Chichagof Island. This 

acreage accounts for 7.2 percent of the mapped yellow-cedar decline in Alaska. The 

mortality appears intensive in some areas because yellow-cedar was often a significant component of forests before the onset of mortality. 

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forests expected to be at high risk rises from 14 to 

28 percent between 2020 and 2080 (fig. 97). Some of the increased risk occurs to 

the north along the coast, consistent with the documented northerly progression of 

yellow-cedar decline in Slocum Arm of southwest Chichagof Island (Oakes et al. 

2014). By 2080, many low-elevation yellow-cedar forests are at high risk, and low 

risk is reduced to 14 percent of all yellow-cedar forests.
261

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Landscapes in protected and active management zones— 

Nearly all of the yellow-cedar forests and forests with mapped yellow-cedar decline 

are on land managed by the U.S. Forest Service, with sizable acreage in all three 

management categories. The West Chichagof–Yakobi Wilderness Area occupies the 

largest acreage of yellow-cedar and current decline. 

Opportunities for conservation and management— 

The yellow-cedar forests in this zone have already had substantial mortality, especially along Peril Strait and the large West Chichagof–Yakobi Wilderness Area to 

the west. More than 70,000 ac of yellow-cedar forest are in protection status in this 

management zone. The decline-affected forests mark the northernmost extent of 

severe yellow-cedar decline in Alaska, and many of these forests were previously 

dominated by yellow-cedar. The health status and population stability of yellowcedar in protected areas have been, and will continue to be, severely affected as 

decline advances northward and upward in elevation. Oakes et al. (2014) documented succession to western hemlock and other species in decline-affected stands on 

outer Chichagof Island. This change in forest composition appears to be a long-term 

conversion because of the scarcity of yellow-cedar natural regeneration. The permanent plots in this study could be used to monitor further successional changes. 

Opportunities to salvage harvest dead yellow-cedar may be limited because of the 

few road systems in this management zone. Yellow-cedar is expected to remain at 

low risk at the highest elevations of its occurrence and on well-drained soils, where 

it is not a major component. 
262

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 33—Chichagof South Yellow-Cedar Management Zone (Sitka Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 533,054 115,614 40,833 45 40 14 31 47 21 14 57 28 Nonrestricted, developmentd 182,873 27,255 8,104 7 11 5 4 12 7 2 13 8

 Nonrestricted, limited developmente 97,391 18,345 5,445 6 7 3 3 8 4 1 10 5 Restricted, nondevelopment f 252,790 70,014 27,284 32 22 7 23 26 10 11 34 15State 4,000 689 0 0 0 0 0 0 0 0 0 0Private 9,093 536 202 0 0 0 0 0 0 0 0 0Other governmental entity 65 6 0 0 0 0 0 0 0 0 0 0Unknown 4,248 16 26 0 0 0 0 0 0 0 0 0 Total 550,460 116,861 41,061 45 41 14 31 48 21 14 58 28

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. 

d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
263

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 97—Chichagof South Yellow-Cedar Management Zone (Sitka Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
264

GENERAL TECHNICAL REPORT PNW-GTR-917

10. Kruzof Island

Geomorphology and climate— 

This management zone is almost completely covered with volcanic deposits from 

Mount Edgecumbe eruptions. Extensive low-permeability soils and indurated soil 

horizons have led to many wet forested landscape elements in this management 

zone, making yellow-cedar habitat very abundant. The climate is hypermaritime 

with widespread heavy precipitation and snow accumulation related primarily to 

elevation. The average annual temperature ranges from a minimum of 40 °F to a 

maximum of 49 °F. The average annual precipitation is 86 in, and the average annual snowfall is 39 in (Sitka observation station, 508494). 

Extent of yellow-cedar— 

About 40,000 ac of yellow-cedar forest occur throughout this management 

zone, which accounts for about 1.7 percent of the yellow-cedar acreage in Alaska 

(table 34). 

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on 26,740 ac, with the highest concentrations on Mount Edgecumbe and lowland valley and coastal areas of Kruzof and 

adjacent islands. This amounts to 4.7 percent of yellow-cedar decline in Alaska.

Extent of yellow-cedar at future risk— 

Yellow-cedar forests at high risk of decline are expected to rise marginally from 

48 to 51 percent between 2020 and 2080 (fig. 98). This mainly represents an anticipated encroachment of mortality upon higher elevations with snow reductions. 

Conversely, the proportion of yellow-cedar forests considered to be at low risk is 

reduced from 15 to 6 percent by 2080. 

Landscapes in protected and active management zones— 

Most of the yellow-cedar forests are on land managed by the U.S. Forest Service 

with the highest proportion in nonrestricted, limited development status.

Opportunities for conservation and management—

With most of the yellow-cedar forests in protection status, there is only limited opportunity to manage yellow-cedar directly. Succession from yellow-cedar-dominated forests to other species will continue in decline-affected forests. Salvage of dead 

yellow-cedar and planting of live yellow-cedar may be possible in the nonrestricted 

development areas with adequately deep soils. The portion of Kruzof Island with 
265

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

a road system is one area for potential active management. Protection of planted 

seedlings would be necessary because of high deer populations in the area. The 

radial symmetry of Mount Edgecumbe offers an unusual prospect to measure the 

influence of elevation and aspect on environmental factors. Yellow-cedar is regenerating well near timberline, just below the mountain hemlock zone. There is an opportunity to monitor the active upslope advance of yellow-cedar decline on Mount 

Edgecumbe as snow levels are reduced in the future (Hennon et al. 2012). 
266

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 34—Kruzof Island Yellow-Cedar Management Zone (Sitka Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 108,409 39,217 26,461 15 37 48 9 40 50 6 43 51 Nonrestricted, developmentd 33,551 10,424 6,917 5 12 9 4 13 9 2 15 10

 Nonrestricted, limited developmente 74,846 28,790 19,543 9 25 39 6 27 40 4 28 41 Restricted, nondevelopment f 12 3 1 0 0 0 0 0 0 0 0 0State 1,594 233 192 0 0 0 0 0 0 0 0 0

Private 203 76 86 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 1,564 2 1 0 0 0 0 0 0 0 0 0

 Total 111,770 39,528 26,740 15 37 48 9 41 50 6 43 51

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
267

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 98—Kruzof Island Yellow-Cedar Management Zone (Sitka Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
268

GENERAL TECHNICAL REPORT PNW-GTR-917

11. Baranof Island

Geomorphology and climate— 

This management zone is dominated by metasediments with varying levels of 

metamorphic transformation. In general, the zone has very rugged, steep-sided, 

peaked mountains with extensive erosion features. Forested landscapes are limited to footslopes, toeslopes, and alluvial areas. The South Baranof sediments and 

Central Baranof metasediments are nearly all mountain summit and mountain slope 

landforms. The metamorphic North Baranof and volcanic Sitka Sound complexes 

provide more favorable landforms and soils for yellow-cedar, such as low-productivity forested wetland. Forested wetlands are also abundant in the Sitka Sound 

complex. Abundant precipitation occurs as rain in lowland areas and as snow in 

winter at higher elevations and on the eastern side of the island. At sea level, the 

average annual temperature ranges from a minimum of 40 °F to a maximum of 49 

°F. The average annual precipitation is 86 in, and the average annual snowfall is 39 

in (Japonski Island observation station, 508494). In the southeast, there is a very 

wet area on the southern tip of Baranof Island at Little Port Walter. At sea level, the 

average annual temperature ranges from a minimum of 39 °F to a maximum of 48 

°F. The average annual precipitation is 226 in, and the average annual snowfall is 

113 in (Little Port Walter observation station, 505519). Another leeward observation 

station on the southeastern tip of Baranof Island is Port Alexander, where the average annual temperature ranges from a minimum of 39 °F to a maximum of 50 °F. 

The average annual precipitation is 167 in, and the average annual snowfall is 63 in 

(Port Alexander observation station, 507557). 

Extent of yellow-cedar— 

Yellow-cedar forests occupy >154,000 ac, or about 27.4 percent of the forestland on 

Baranof Island (table 35). The yellow-cedar populations here account for 6.8 percent 

of the yellow-cedar acreage in Alaska.

Extent of yellow-cedar decline— 

Almost 56,000 ac of yellow-cedar decline have been mapped in this management 

zone, which constitutes 9.8 percent of the mapped decline in Alaska. Most of this 

acreage occurs at low elevations on the western portion of Baranof Island and 

through Peril Strait to about Duffield Peninsula near Rodman Bay. Only small areas 

of decline have been mapped on the eastern side of the island.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Extent of yellow-cedar at future risk— 

The share of acreage at high risk of yellow-cedar decline is expected to increase 

from 12 to 18 percent between 2020 and 2080, and the share of low risk shows a 

corresponding drop from 53 to 29 percent in the same period (fig. 99). Both sides of 

the southern portion of Baranof Island are expected to have increased risk. Coastal 

areas that are projected to remain generally at low risk through 2080 occur on the 

eastern side of Baranof Island from Kelp Bay south to Patterson Bay.

Landscapes in protected and active management zones— 

Most of Baranof Island is administered by the U.S. Forest Service with large 

amounts of land in nonrestricted, limited development and restricted, nondevelopment status, including the large South Baranof Wilderness Area. Only 16,000 ac of 

land managed by the Forest Service with yellow-cedar are in nonrestricted, development status.

Opportunities for conservation and management—

This management zone contains extensive dead and dying yellow-cedar forests, 

many with a high yellow-cedar component. The large acreage of yellow-cedar forest in protected status suggests only limited management opportunities. Salvage of 

dead yellow-cedar might be possible in some areas, but the lack of roads diminishes 

the economic feasibility of these treatments. Succession to other tree species will 

continue to occur in decline-affected forests. Regeneration of yellow-cedar at low 

elevations is expected to be limited by deer browse and lack of seed source where 

mature trees have died. Conservation of intact yellow-cedar forests will occur 

mainly at high elevations and along eastern portions of Baranof Island. 
270

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 35—Baranof Island Yellow-Cedar Management Zone (Sitka Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 531,421 148,985 52,889 52 34 11 42 40 14 28 51 17 Nonrestricted, developmentd 108,196 16,023 7,025 4 5 2 2 6 2 1 7 3

 Nonrestricted, limited developmente 270,205 65,315 25,714 23 15 5 20 17 6 14 21 7 Restricted, nondevelopment f 153,020 67,647 20,150 25 14 4 20 18 6 13 23 8State 17,878 4,145 2,157 1 2 1 0 2 1 0 2 1

Private 5,101 651 380 0 0 0 0 0 0 0 0 0

Other governmental entity 4,108 409 216 0 0 0 0 0 0 0 0 0

Unknown 5101 53 26 0 0 0 0 0 0 0 0 0 Total 563,570 154,242 55,668 53 36 12 43 43 14 29 53 18

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
271

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 99—Baranof Island Yellow-Cedar Management Zone (Sitka Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
272

GENERAL TECHNICAL REPORT PNW-GTR-917

12. Juneau

Geomorphology and climate— 

This management zone is dominated by the Boundary Ranges Icefields. There are 

areas of forest along the fringe of this subsection, which can be both productive 

and nonproductive. The main forested zones are located in the Stephens Passage–

Glacio-Marine Terrace and Douglas Island Volcanic subsections. The uplifted 

glaciomarine deposits have many emergent and forested wetlands. The Douglas 

Island Volcanics are a diverse assemblage of alpine, productive, and nonproductive 

forest and alluvial areas. These two subsections provide about a third of the area as 

potential yellow-cedar habitat. Climate is variable in this management zone with 

moderate snow levels in the southern coastal section and extremely high snow accumulation in the mountainous inland areas. At sea level, the average annual temperature ranges from a minimum of 35 °F to a maximum of 47 °F. The average annual 

precipitation is 57 in, and the average annual snowfall is 94 in (Juneau Airport observation station, 504100). Near the icefields, the average annual temperature ranges 

from a minimum of 33 °F to a maximum of 45 °F. The average annual precipitation 

is 111 in, and the average annual snowfall is 252 in (Annex Creek observation station, 500363).

Extent of yellow-cedar— 

There are >9,000 ac of yellow-cedar in this management zone, which accounts for 

only about 0.4 percent of the yellow-cedar acreage in Alaska (table 36). We speculate that this management zone is at the fringe of the apparent yellow-cedar migration pathway, with yellow-cedar still actively migrating. Small, isolated populations are common. New populations have been found near the Juneau road system 

and on both sides of Lynn Canal at Berners Bay and St. James Bay. There is one 

reported population in a forest inventory plot farther north on the mainland across 

from Haines. Yellow-cedar is common in some southern areas of this management 

zone, such as at Point Couverden, Point Retreat, and the Shelter Island area. Yellowcedar stands are also known to occur along Taku Inlet and Taku River almost to the 

Canadian border. 

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on only 62 ac in this management zone. 

Extent of yellow-cedar at future risk— 

The risk to the yellow-cedar populations in this management zone is variable, with 

an evenly distributed risk profile for the initial projection in 2020 (fig. 100). This 

diversity in the risk profile is due to the variability in the landscape and landforms 
273

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

that exist in the management zone. The management zone contains low-elevation 

uplifted marine geomorphic surfaces that provide abundant wet forest habitat but 

that are also prone to low snow accumulation currently and into the future. The 

zone also includes the coastal mountain fringe and icefields, which provide extensive cold, snowy areas with low risk. Overall, the risk profile is expected to be moderate to high in 2050 and 2080, with most of the high-risk acreage in the southern 

coastal areas. 

Landscapes in protected and active management zones— 

Most of the yellow-cedar populations occur on land managed by the U.S. Forest 

Service, but about 1,500 ac are on State land. The majority of the yellow-cedar 

acreage on land managed by the Forest Service is located in nonrestricted, limited 

development land use designations.

Opportunities for conservation and management—

There are only limited opportunities for active management of yellow-cedar in most 

of this management zone. The small inland and high-elevation yellow-cedar populations are expected to remain at low risk and offer promise for meeting conservation goals. Cold air drainages that promote persistent snow and favorable soils may 

provide a long-term refuge for yellow-cedar in certain areas in this zone. These 

populations could be monitored to track changes in yellow-cedar health and possible population expansion.
274

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 36—Juneau Yellow-Cedar Management Zone (Juneau Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 417,953 7,228 56 25 31 20 19 30 27 10 35 31

 Nonrestricted, developmentd 70,004 792 0 2 3 3 2 3 4 2 3 4

 Nonrestricted, limited developmente 238,179 6,098 56 21 27 17 15 26 24 8 30 26 Restricted, nondevelopment f 109,770 338 0 2 1 0 2 1 0 1 2 1State 36,369 1,567 6 4 10 2 2 9 5 1 9 7

Private 8,966 390 0 1 2 1 0 2 2 0 2 2

Other governmental entity 12 0 0 0 0 0 0 0 0 0 0 0

Unknown 26,797 298 0 33 44 23 23 42 35 12 48 41

 Total 490,097 9,483 62 33 44 23 23 42 35 12 48 41

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
275

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 100—Juneau Yellow-Cedar Management Zone (Juneau Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
276

GENERAL TECHNICAL REPORT PNW-GTR-917

13. Tracy Arm

Geomorphology and climate— 

This management zone is dominated by the Holkham Bay Complex subsection, 

which is part of the complex sedimentary and volcanic geomorphic class. The 

rounded mountain zone of the inactive glacial terrain is composed of plutonic 

intrusions and sedimentary rock substrate. This area is characterized by glacially 

scoured mountains with little glacial till. Forested wetlands on poorly drained soils 

make up about 12 percent of the landscape. The climate in most of this management 

zone is very snowy with a short growing season, except along the coastal fringe. 

This zone does not have a permanent weather observation system, but is close to 

the Boundary Ranges Icefield and continental influence of snow and ice. Therefore, 

coastal climate effects are common at sea level, but a strong cold, snowy climate 

is present on the continental margin. At sea level, the average annual temperature 

ranges from a minimum of 39 °F to a maximum of 47 °F. The average annual precipitation is 54 in, and the average annual snowfall is 24 in (Five Finger Lighthouse 

observation station, 503072).

Extent of yellow-cedar— 

Yellow-cedar occurs on 39,400 ac, or 9.2 percent of the forestland in this management zone (table 37). These populations account for 1.7 percent of the yellow-cedar 

acreage in Alaska.

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on only 1,100 ac, mostly near the southern 

coastal extent near Cape Fanshaw. 

Extent of yellow-cedar at future risk— 

The proportion of yellow-cedar acreage categorized as high risk is expected to rise 

from 4 to 13 percent by 2080 (fig. 101). Most (85 percent) of the yellow-cedar forests 

are projected to be at low risk in 2020, and 52 percent are expected to remain at low 

risk by 2080. The modest expansion of the high-risk class occurs first in the southwestern part of this zone and then northward along coasts. 

Landscapes in protected and active management zones— 

Most of the yellow-cedar acreage is on land managed by the U.S. Forest Service 

with the highest acreage in nonrestricted, limited development, followed by nonrestricted, development and restricted, nondevelopment status. Yellow-cedar occurs 

in the Tracy Arm–Fords Terror and Chuck River Wilderness Areas. There is a sizable forested area under private ownership, especially at Hobart Bay (about 1,000 ac 

of yellow-cedar). 
277

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

There is an opportunity to plant and manage yellow-cedar on productive soils and 

where ownership and policy allow active management (e.g., Hobart Bay on private 

land). Conservation of yellow-cedar populations is promising in some portions of 

this management zone. Many inland populations appear to be at low risk in 2080, 

and will presumably regenerate well in those locations to maintain populations over 

the long term. 
278

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 37—Tracy Arm Yellow-Cedar Management Zone (Juneau Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 400,219 38,254 1,024 83 11 4 74 17 6 51 34 12

 Nonrestricted, developmentd 130,640 9,709 521 17 4 3 15 6 4 11 8 6

 Nonrestricted, limited developmente 151,064 13,169 427 29 4 1 25 7 1 17 12 4

 Restricted, nondevelopment f 118,515 15,376 76 37 2 0 34 5 0 23 13 3

State 3,647 107 0 0 0 0 0 0 0 0 0 0

Private 24,096 1,017 76 2 1 0 2 1 0 1 1 1

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 1,534 1 0 0 0 0 0 0 0 0 0 0

 Total 429,496 39,379 1,100 85 11 4 76 18 6 52 35 13

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
279

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 101—Tracy Arm Yellow-Cedar Management Zone (Juneau Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
280

GENERAL TECHNICAL REPORT PNW-GTR-917

14. Admiralty

Geomorphology and climate— 

Diverse ecological subsections are represented in this zone, each with different 

origins, compositions, and percentages of forested wetland: the South Admiralty 

Volcanics (17 percent forested wetland), the Thayer Lake Granitics with shallow lithic soils (16 percent forested wetland), the Hood-Gambier Bay Carbonates 

with dense and productive upland forest cover (17 percent forested wetland), the 

Mitchell-Hasselborg Till Lowlands (10 percent forested wetland), and the small 

Glacio-Marine Terrace (19 percent forested wetland). The climate is variable because of some exposure from Chatham Strait to the south, proximity to the mainland to the east, and vertical relief. On the southwest coast, the average annual 

temperature ranges from a minimum of 37 °F to a maximum of 48 °F. The average annual precipitation is 42 in, and the average annual snowfall is 61 in (Angoon 

observation station, 500310). On the northern coast, the average annual temperature 

ranges from a minimum of 38 °F to a maximum of 48 °F. The average annual precipitation is 60 in, and the average annual snowfall is 65 in (Funter Bay observation 

station, 503198).

Extent of yellow-cedar— 

For reasons unknown, yellow-cedar has a patchy distribution on Admiralty Island. 

We estimate >108,000 ac of yellow-cedar forest, constituting about 13.5 percent of 

the forested landscape (table 38). There are large forested areas of the island that 

lack yellow-cedar. The yellow-cedar populations here account for about 4.8 percent 

of yellow-cedar acreage in Alaska.

Extent of yellow-cedar decline— 

A relatively small amount of yellow-cedar decline has been mapped in this management zone, just <4,600 ac in the southern portions.

Extent of yellow-cedar at future risk— 

The yellow-cedar forests are expected to have increased risk of yellow-cedar 

decline. The management areas to the south on Kupreanof Island have extensive 

decline-affected forests. Areas expected to be at high risk of decline more than double from 13 to 27 percent by 2080 (fig. 102). The high relief and cold drainages of 

the landscape initially provide some resilience to loss of snow cover. The high-risk 

areas are expected to be scattered throughout lowland areas of Admiralty Island by 

2080 in stark contrast to the current distribution of decline restricted to southern 

parts of the island. The approximately 73 percent of yellow-cedar forests that are 

expected to be in medium and low risk classes by 2080 occur at higher elevations. 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Landscapes in protected and active management zones— 

Nearly all of the yellow-cedar forests are under U.S. Forest Service jurisdiction and 

restricted, nondevelopment status as Kootznoowoo Wilderness Area (Admiralty 

Island National Monument). 

Opportunities for conservation and management—

The wilderness designation will restrict most, if not all, management activities over 

most of the Admiralty Island management zone. The private land around Cube 

Cove has had extensive forest harvest, and could provide potential areas for planting 

and managing young-growth yellow-cedar on well-drained soils. The health status 

of yellow-cedar is expected to be in flux. Most yellow-cedar forests on Admiralty 

Island are currently intact, but mortality is expected to encroach towards the north 

and upslope. Monitoring the health and regeneration of yellow-cedar here is important, but hampered by the lack of access by forest inventory crews. The upper 

elevations of the southern peninsula represent a low-risk zone with abundant 

yellow-cedar to meet the goal of conservation. 
282

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 38—Admiralty Yellow-Cedar Management Zone (Admiralty National Monument, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 770,765 107,901 4,566 55 32 13 44 38 17 21 52 26

 Nonrestricted, developmentd 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 41 0 0 0 0 0 0 0 0 0 0 Restricted, nondevelopment f 770,724 107,901 4566 55 32 13 44 38 17 21 52 26

State 238 2 0 0 0 0 0 0 0 0 0 0

Private 21,538 707 0 0 0 0 0 0 0 0 0 0

Other governmental entity 13 0 0 0 0 0 0 0 0 0 0 0

Unknown 0 0 0 0 0 0 0 0 0 0 0 0

 Total 801,620 108,611 4,566 55 32 13 44 38 18 21 52 27

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
283

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 102—Admiralty Yellow-Cedar Management Zone (Admiralty National Monument, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
284

GENERAL TECHNICAL REPORT PNW-GTR-917

15. Kuiu Island

Geomorphology and climate— 

This management zone is a very diverse assemblage of several geologic formations 

including granitics, noncarbonate and carbonate sedimentary rocks, and areas of till 

lowlands. The volcanics offer abundant yellow-cedar habitat with gentle slopes and 

low-permeability substrate that form wet forested areas for yellow-cedar. In addition, the till lowlands have abundant wetland areas that expand the yellow-cedar 

habitat in this management zone. Well-drained sites offer opportunities for productive stands of mixed-conifer forest with a yellow-cedar component. This large 

island generally has low snow accumulation in the southern portions and heavier 

snow to the northwest, which may be influenced by the mountainous portion of 

Baranof Island. At sea level, the average annual temperature ranges from a minimum of 36 °F to a maximum of 50 °F. The average annual precipitation is 54 in, 

and the average annual snowfall is 38 in (Kake observation station, 504155).

Extent of yellow-cedar— 

More than 156,000 ac of yellow-cedar forests occur on Kuiu Island (table 39). It is 

locally abundant in the southern portion and less common in the northeast portion 

of this management zone. These populations account for 6.9 percent of the yellowcedar acreage in Alaska.

Extent of yellow-cedar decline— 

Yellow-cedar decline is common. More than 77,000 ac of yellow-cedar decline have 

been mapped, most of it on the southern two-thirds of the island. This acreage accounts for 13.5 percent of the mapped acreage of yellow-cedar decline in Alaska.

Extent of yellow-cedar at future risk— 

High risk of yellow-cedar decline is projected to be initially low (20 percent of 

yellow-cedar acreage) and is expected to increase to 34 percent by 2080 (fig. 103). 

Conversely, low-risk acreage is expected to decrease from 38 percent to just 9 percent between 2020 and 2080. By 2080, low-risk areas mainly occur at high elevations, but are more broadly distributed in the northwestern portion of the island. 

Landscapes in protected and active management zones— 

Most of Kuiu Island and almost all of the yellow-cedar forests are on land managed 

by the U.S. Forest Service, fairly evenly distributed among the three management 

categories. 
285

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

An extensive road system is present, but much of it is on portions of the island 

where yellow-cedar is less common. There may be an opportunity to plant and 

manage yellow-cedar along the roaded areas on well-drained soils. The health status of yellow-cedar has been and will continue to be threatened at low and moderate 

elevations. As succession continues, western redcedar may become a larger component of decline-affected forests in the southern portion of this management zone.
286

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 39—Kuiu Island Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 427,990 153,335 76,490 38 41 20 24 47 28 9 56 33

 Nonrestricted, developmentd 144,716 38,604 17,061 8 11 6 4 12 8 1 14 9

 Nonrestricted, limited developmente 160,963 53,503 32,886 12 14 9 8 15 11 3 18 13

 Restricted, nondevelopment f 122,311 61,228 26,543 19 16 5 12 19 8 4 24 11

State 4,241 2,230 603 0 1 0 0 1 1 0 1 1

Private 2,483 655 0 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 3,349 44 10 0 0 0 0 0 0 0 0 0

 Total 438,063 156,264 77,103 38 42 20 24 48 28 9 57 34

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
287

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 103—Kuiu Island Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
288

GENERAL TECHNICAL REPORT PNW-GTR-917

16. Kupreanof Island West

Geomorphology and climate— 

This management zone has two main areas: (1) The Kake Volcanics with sedimentary and volcanic rocks in the northwest part of the management zone, and (2) the 

Sumner Strait volcanics in the southeast part of the zone. The Kake Volcanics are 

low-relief rounded hills resulting from extensive glacial erosion. These lowlands 

have abundant forested wetlands on both Histosols and Spodosols. The Sumner 

Strait Volcanics are similar, with glacial till lowlands and rolling hills supporting 

forested wetlands and emergent wetlands. The climate is mild without heavy snow, 

especially considering the extensive areas of low elevation. At sea level, the average annual temperature ranges from a minimum of 36 °F to a maximum of 50 °F. 

The average annual precipitation is 54 in, and the average annual snowfall is 38 in 

(Kake observation station, 504155).

Extent of yellow-cedar— 

Nearly 150,000 ac of yellow-cedar forest occur and are well distributed throughout 

this management zone (table 40). These populations account for 6.6 percent of the 

yellow-cedar acreage in Alaska.

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on >68,000 ac, representing about 12.1 percent of yellow-cedar decline in Alaska. 

Extent of yellow-cedar at future risk— 

High risk of decline is expected to rise from 38 to 57 percent of yellow-cedar acreage between 2020 and 2080 (fig. 104). Just 4 percent of the yellow-cedar forest is 

expected to be at low risk by 2080. Large areas with poor drainage and at low elevation contribute to the generally high risk in this management zone.

Landscapes in protected and active management zones— 

Except for about 6,400 ac of yellow-cedar forest on private land, most of the yellowcedar forests are on land managed by the U.S. Forest Service. This management 

zone has a large acreage in nonrestricted, development status. 

Opportunities for conservation and management— 

The large acreage of yellow-cedar decline, nonrestricted development status, and 

access to stands via the Kake Road and a portion of the Portage Bay Road combine 

to provide one of the best opportunities for salvage of dead yellow-cedar in Alaska. 
289

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

There are long stretches of these roads with adjacent concentrations of dead yellowcedar. Because of the low elevation of this management zone, the most favorable 

setting for planting and thinning yellow-cedar would be on productive sites with 

well-drained soils. The relatively small deer population may favor the success of 

natural and artificial yellow-cedar regeneration on suitable sites. The high risk of 

decline by 2080 suggests that the health status and population stability of yellowcedar has been and will continue to be impaired in unmanaged areas. 
290

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 40—Kupreanof Island West Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080 

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 435,814 143,323 65,667 24 36 36 13 35 47 4 37 55

 Nonrestricted, developmentd 257,549 92,062 44,577 19 25 18 11 25 26 3 26 33

 Nonrestricted, limited developmente 167,265 48,959 19,510 5 10 18 3 10 20 1 11 22

 Restricted, nondevelopment f 10,999 2,302 1,580 0 0 1 0 0 1 0 1 1

State 796 110 48 0 0 0 0 0 0 0 0 0

Private 41,216 6,418 2,864 0 2 2 0 2 2 0 2 2

Other governmental entity 1,435 63 0 0 0 0 0 0 0 0 0 0

Unknown 4,302 6 5 0 0 0 0 0 0 0 0 0

 Total 483,563 149,920 68,584 24 38 38 14 38 49 4 39 57

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
291

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 104—Kupreanof Island West Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): areas and percentages of low, moder- ate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
292

GENERAL TECHNICAL REPORT PNW-GTR-917

17. Kupreanof Island East

Geomorphology and climate— 

This management zone is located in a trough between two higher subsections and 

is dominated by low relief underlain with sedimentary and volcanic rocks. The 

thick glacial sediment deposition covering the parent rock has created conditions 

favorable for formation of abundant peatlands and forested wetlands. Histosols are 

the dominant soil type. The climate varies with elevation. At sea level, the average 

annual temperature ranges from a minimum of 35 °F to a maximum of 48 °F. The 

average annual precipitation is 105 in, and the average annual snowfall is 107 in 

(Petersburg observation station, 507233).

Extent of yellow-cedar— 

About 24,000 ac of yellow-cedar occur in this management zone (table 41). These 

populations account for 1.1 percent of the yellow-cedar acreage in Alaska.

Extent of yellow-cedar decline— 

More than 14,000 ac of yellow-cedar decline have been mapped throughout this 

management zone, which accounts for about 2.6 percent of the yellow-cedar decline acreage in Alaska. There are small watersheds in the northeast portion of 

Kupreanof Island with particularly concentrated yellow-cedar decline. 

Extent of yellow-cedar at future risk— 

Risk is expected to increase dramatically in this management zone. The proportion of yellow-cedar forests expected to be at high risk increases from just 8 to 33 

percent between 2020 and 2080 (fig. 105). The high-risk areas initially are around 

Duncan Canal to Portage Bay and other coastal forests, but expand to include many 

interior valleys by 2080. Conversely, low-risk acreage is expected to drop from 72 

to 32 percent in that time and is limited to higher elevations. 

Landscapes in protected and active management zones— 

There are nearly 1,000 ac of yellow-cedar forest under State ownership, but most of 

the yellow-cedar acreage occurs on land managed by the U.S. Forest Service with 

nonrestricted, development status.

Opportunities for conservation and management— 

Land use designation and road access along the Tonka and Portage Bay roads offer 

good prospects for salvaging dead yellow-cedar. There is intensive decline near the 

Bohemian Ridge portion of the Portage Bay road. Expanding mortality is expected 
293

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

to provide new opportunities for yellow-cedar salvage, especially in interior valleys 

with road systems. In unmanaged decline-affected forests, western redcedar may 

increase in abundance, as its northern range limit occurs near this zone. By the end 

of the century, intact yellow-cedar forests meeting conservation goals for the species are expected to be restricted to higher elevations. 
294

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 41—Kupreanof Island East Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 146,402 23,019 13,792 70 19 8 57 25 14 31 34 31

 Nonrestricted, developmentd 81,674 12,185 8,210 39 7 4 33 12 6 18 19 13

 Nonrestricted, limited developmente 28,370 3,869 2,042 11 4 1 9 5 2 5 7 5 Restricted, nondevelopment f 36,358 6,965 3,540 19 7 3 15 9 6 8 9 13State 6,462 804 802 2 1 0 1 1 1 1 1 1

Private 122 4 2 0 0 0 0 0 0 0 0 0

Other governmental entity 1,353 197 39 0 1 0 0 0 0 0 0 1

Unknown 1170 3 2 0 0 0 0 0 0 0 0 0

 Total 155,509 24,027 14,637 72 20 8 58 27 15 32 36 33

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
295

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 105—Kupreanof Island East Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): areas and percentages of low, moder- ate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
296

GENERAL TECHNICAL REPORT PNW-GTR-917

18. Thomas Bay

Geomorphology and climate— 

This zone along the coastal mainland contains the Thomas Bay outwash plains 

subsection, with plains and low rounded hill landforms. The lowlands are composed 

of a mix of poorly sorted surficial deposits from glacial outwash. Productive forest 

has formed on the coarse-textured deposits with some organic soil development. 

Mixed-conifer forests are common, and forested wetlands are also present. The 

climate is generally cold and snowy, especially in the extensive mountainous areas 

and icefields to the west. At sea level, the average annual temperature ranges from 

a minimum of 39 °F to a maximum of 47 °F. The average annual precipitation is 54 

in, and the average annual snowfall is 24 in (Five Finger Lighthouse observation 

station, 503072).

Extent of yellow-cedar— 

An estimated 23,500 ac of yellow-cedar forest occur in this management zone 

(table 42). These populations account for 1.0 percent of the yellow-cedar acreage 

in Alaska. In this zone, yellow-cedar is mainly confined to coastal areas, but also 

extends into forested valleys. 

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on nearly 12,000 ac, or 2.1 percent of 

the yellow-cedar decline acreage in Alaska. Decline is most common near Point 

Agassiz Peninsula and Cape Fanshaw.

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forest at high risk is expected to increase from 15 to 

30 percent by 2080 (fig. 106). Conversely, more than half of yellow-cedar acreage is 

in low risk status in 2020, but that proportion shrinks to 31 percent by 2080. Most 

of the inland valley yellow-cedar forests remain at low risk. 

Landscapes in protected and active management zones— 

Nearly all of yellow-cedar forests in this zone occur on land managed by the U.S. 

Forest Service. Most of the acreage is designated as nonrestricted, development and 

nonrestricted, limited development status, with a higher percentage in the latter 

category.
297

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

Although there is less yellow-cedar in this management zone than in some others, 

there are good prospects for both conservation and active management. Yellowcedar forests in the inland valleys are expected to remain healthy by 2080 to meet 

conservation goals, and high snow levels should allow these populations to sustain 

themselves through natural regeneration. Yellow-cedar could be favored by planting 

and thinning on well-drained soils, although active management may be limited by 

lack of roads. 
298

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 42—Thomas Bay Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 178,482 23,259 11,123 54 30 15 46 31 23 31 38 29

 Nonrestricted, developmentd 77,498 13,595 5,405 25 22 10 20 22 16 12 25 21

 Nonrestricted, limited developmente 97,315 9,369 5,228 28 8 5 25 9 7 18 13 9 Restricted, nondevelopment f 3,670 295 490 1 0 0 1 0 0 1 0 0State 4,386 264 563 0 1 0 0 1 0 0 1 0

Private 804 2 0 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 712 0 2 0 0 0 0 0 0 0 0 0

 Total 184,384 23,526 11,688 54 31 15 46 31 23 31 39 30

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
299

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 106—Thomas Bay Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
300

GENERAL TECHNICAL REPORT PNW-GTR-917

19. Mitkof Island

Geomorphology and climate— 

This management zone is entirely composed of the Wrangell Narrows 

Metasediments subsection. The geomorphology comprises rounded ridge tops and 

U-shaped valleys shaped by heavy Pleistocene glaciation. Alpine areas are uncommon, so conifer forests and extensive emergent wetlands and forested wetlands 

occupy most of the landscape. Productive and nonproductive forest occupy the landscape nearly equally. The landforms are nearly all mountain slopes and lowlands 

with Histosols as the dominant soil type. The climate is variable, with mild conditions to the south in the Woodpecker area to colder, snowier winters to the north 

and east influenced by the mainland. At sea level, the average annual temperature 

ranges from a minimum of 35 °F to a maximum of 48 °F. The average annual precipitation is 105 in, and the average annual snowfall is 107 in (Petersburg observation station, 507233).

Extent of yellow-cedar— 

Yellow-cedar occurs on an estimated 16,000 ac (table 43) on Mitkof Island and 

Woewodski Island to the west. It is well distributed, but more abundant at higher 

elevations and less common in the large valleys. These populations account for 

about 0.7 percent of the yellow-cedar acreage in Alaska.

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on about 11,600 ac, with the highest concentrations at lower elevations of the Sumner Mountains, on Woewodski Island, and 

along eastern coastal portions of Mitkof Island. This accounts for about 2.1 percent 

of the yellow-cedar decline acreage in Alaska. 

Extent of yellow-cedar at future risk— 

High risk of yellow-cedar decline is expected to rise from 6 percent of the yellowcedar forests to 24 percent by 2080 (fig. 107). Risk is initially high on Woewodski 

Island, hillsides around Blind Sough, and the eastern coastal area of Mitkof Island. 

By 2080, high-risk areas are expected to expand to higher elevations in the interior 

valleys. Yellow-cedar at low risk to decline represents 75 percent of yellow-cedar 

forests in 2020, but that share drops to only 35 percent by 2080, generally confined 

to higher elevations. 

Landscapes in protected and active management zones— 

Yellow-cedar forests mainly occur on land managed by the U.S. Forest Service 

(nearly 15,000 ac), but about 1,000 ac occur on State land. A large portion of both 

yellow-cedar occurrence (12,000 ac) and yellow-cedar decline (8,500 ac) is on lands 

in nonrestricted, development status. 
301

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

The large acreage of yellow-cedar and yellow-cedar decline, combined with the 

extensive road system on Mitkof Island and nonrestricted, development status, offers good prospects for active management. Yellow-cedar stands with concentrated 

mortality are available for salvage harvest. The sizable increase in projected risk indicates that more declining yellow-cedar forests may be available for future salvage. 

Road access makes salvage more economically feasible. Yellow-cedar is known 

to have regenerated in some harvest units in this management zone. The relatively 

small deer populations in some areas of Mitkof Island suggest that planting and 

thinning to favor yellow-cedar could be used to increase the yellow-cedar component in managed forests. Protection of seedlings from deer browse may be needed 

in the warmer southwestern areas. Conservation goals for yellow-cedar could be 

met at higher elevations, where unmanaged yellow-cedar forests remain at low risk 

through 2080. 
302

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 43—Mitkof Island Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 110,850 14,973 10,720 70 16 5 60 21 9 33 38 20

 Nonrestricted, developmentd 83,314 12,045 8,555 55 13 4 48 18 8 25 31 17

 Nonrestricted, limited developmente 26,132 2,805 2,161 14 3 1 12 4 1 7 7 3 Restricted, nondevelopment f 1,405 123 4 1 0 0 1 0 0 0 0 0State 14,910 1,096 838 4 2 1 3 3 1 2 3 3

Private 211 4 3 0 0 0 0 0 0 0 0 0

Other governmental entity 7,913 384 105 1 1 0 1 1 1 0 1 1

Unknown 937 1 6 0 0 0 0 0 0 0 0 0

 Total 134,822 16,458 11,672 75 19 6 64 25 11 35 42 24

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
303

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 107—Mitkof Island Yellow-Cedar Management Zone (Petersburg Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
304

GENERAL TECHNICAL REPORT PNW-GTR-917

20. Zarembo Island

Geomorphology and climate— 

This management zone consists of several subsections, including the Sumner Strait 

Volcanics to the west, and the Wrangell Narrows Metasediments to the north, the 

Stikine Strait Complex to the southeast, and the Duncan Canal Till Lowlands in the 

central eastern portion of the island. The North Kuiu–Prince of Wales Carbonates 

dominate the islands to the southwest of Zarembo. This varied geomorphology 

leads to a great amount of diversity in a small area. The Sumner Strait Volcanics 

have glacial till lowlands and rolling hills supporting forested and emergent wetlands. Zarembo Island is very close to Wrangell and has similar weather patterns. 

At sea level, the average annual temperature ranges from a minimum of 37 °F to a 

maximum of 50 °F. The average annual precipitation is 80 in, and the average annual snowfall is 55 in (Wrangell observation station, 509919).

Extent of yellow-cedar— 

Yellow-cedar is estimated to occur on nearly 26,000 ac in this zone, which accounts 

for 1.1 percent of the yellow-cedar acreage in Alaska (table 44). Our GIS layer 

shows yellow-cedar as absent from some of the extensive bog areas on the western 

portion of Zarembo and parts of the other islands, but yellow-cedar probably occurs 

on these unproductive sites as a layering or stunted tree. 

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on about 10,500 ac in this zone, mainly on 

Zarembo Island. Decline-affected forests are well distributed at low elevations, 

except for the northern portion of the island, where forested wetland habitat is 

less common. This management zone contributes about 1.9 percent of the mapped 

yellow-cedar decline in Alaska. 

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forest rated at high risk increases from just 10 to 32 

percent between 2020 and 2080 (fig. 108). High-risk areas are mainly at low elevations along the coast and in the valleys, then progress considerably upslope through 

time. The percentage of yellow-cedar forest at low risk is expected to decrease from 

64 to 19 percent between 2020 and 2080.

Landscapes in protected and active management zones— 

Nearly all of the yellow-cedar acreage is on land managed by the U.S. Forest 

Service. Most yellow-cedar and mapped decline acreages are on lands in nonrestricted, development status, with the remainder mostly in nonrestricted, limited 

development status. 
305

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

There are good prospects for active forest management in this management zone. 

The extensive road system, which extends to higher elevations, may facilitate more 

management. The large amount of yellow-cedar decline and its expected future encroachment upslope suggest an opportunity for salvaging dead trees. Yellow-cedar 

could be planted on newly harvested sites, but care should be taken to favor yellowcedar on well-drained soils. The recently reported decline in two adjacent, relatively 

wet young-growth yellow-cedar stands on Zarembo Island should be monitored. 

Yellow-cedar is present in some existing young-growth forests, so thinning could be 

used to promote yellow-cedar. Succession to other species, including western redcedar at low elevations, will occur in unmanaged decline-affected forests. Yellowcedar is expected to remain healthy at the highest elevations on Zarembo Island, 

thereby helping to meet conservation goals. 
306

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 44—Zarembo Island Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class,

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class,

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 143,301 25,826 10,551 64 25 10 50 33 17 19 49 32

 Nonrestricted, developmentd 97,641 17,160 7,559 45 17 4 34 23 9 11 33 22

 Nonrestricted, limited developmente 42,497 8,291 2,923 19 7 6 16 9 7 7 15 10 Restricted, nondevelopment f 3,163 375 69 0 1 0 0 1 0 0 1 0State 1,599 64 4 0 0 0 0 0 0 0 0 0

Private 3 0 0 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 670 4 0 0 0 0 0 0 0 0 0 0

 Total 145,573 25,894 10,555 64 25 10 50 33 17 19 49 32

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
307

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 108—Zarembo Island Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
308

GENERAL TECHNICAL REPORT PNW-GTR-917

21. Etolin Island

Geomorphology and climate— 

The central portion of this management zone is dominated by the Etolin Island 

Granitics group. Other subsections include the Clarence Strait Volcanics to the 

southwest, the Zimovia Strait Complex to the east, the Stikine Strait Complex to the 

northwest, and the Clarence Strait Volcanics to the south and west. The landforms 

of the volcanics consist of mountain slopes and associated valley floors. These 

landforms support large areas of nonforested vegetation in both alpine and peatland 

areas. The Etolin Island area has a mild climate with winter snow levels being variable and dictated by the island’s considerable elevational variation. At sea level, the 

average annual temperature ranges from a minimum of 40 °F to a maximum of 50 

°F. The average annual precipitation is 64 in, and the average annual snowfall is 12 

in (Lincoln Rock Lighthouse observation station, 505499).

Extent of yellow-cedar— 

There are about 35,000 ac of yellow-cedar forest well distributed across the zone, 

which constitute about 1.6 percent of the yellow-cedar acreage in Alaska (table 45). 

Extent of yellow-cedar decline— 

About 23,500 ac of yellow-cedar decline have been mapped in the area. This 

amounts to about 4.1 percent of the mapped yellow-cedar decline acreage in Alaska. 

Most of the decline is in low-lying areas along the coast or along the deep inlets that 

bisect Etolin Island (e.g., Mosman, Burnett, and Menefee Inlets). 

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forests expected to be at high risk doubles from 11 

to 23 percent between 2020 and 2080 (fig. 109). High-risk areas are initially concentrated on southern, western, and eastern portions of this management zone and then 

encroach upon higher elevations and more northerly latitudes. Several areas known 

to have yellow-cedar decline now do not show high risk until 2080 (e.g., the valley 

between Alice Peak and Helen Peak). Yellow-cedar forests rated at low risk decrease from 67 percent in 2020 to 34 percent in 2080. Low-risk forests in 2080 are 

well distributed, but are mainly found at high elevations and interior areas. 

Landscapes in protected and active management zones— 

Almost all of the yellow-cedar forests in this zone occur on land managed by the 

U.S. Forest Service. The northern portion is mainly in nonrestricted, development 

status, whereas the southern portion is entirely in restricted, nondevelopment status 

as the South Etolin Wilderness Area. 
309

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

Conservation goals for yellow-cedar can be met in the large wilderness area in the 

southern portion of this management zone. There, extensive yellow-cedar decline 

occurs now and is expected to progress upslope, but extensive areas of low to medium risk persist at higher elevations through 2080. However, some areas that are 

currently affected by decline are not projected to be at high risk of decline until 

2080; therefore, relative risk may be underestimated somewhat for other parts of 

this management zone. Succession to other species, including western redcedar, is 

expected in these decline-affected forests. There are good opportunities for active management in the northern areas, given road systems and land-use status. 

Yellow-cedar could be planted on well-drained soils, as was done in 1986 at Anita 

Bay. That small planting trial should be monitored into the future. Yellow-cedar has 

regenerated in some harvest units, and protection of new plantings may be needed if 

deer populations increase. 
310

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 45—Etolin Island Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): acreage of yellow- cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 198,604 35,174 23,474 67 22 11 56 28 15 34 43 23

 Nonrestricted, developmentd 87,689 16,662 9,251 33 11 4 27 14 6 16 21 11

 Nonrestricted, limited developmente 43,233 7,159 6,066 14 4 3 12 5 3 8 9 4 Restricted, nondevelopment f 67,682 11,353 8,157 20 7 5 17 10 6 10 14 8State 1,237 137 14 0 0 0 0 0 0 0 0 0

Private 4 0 0 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 1,289 5 4 0 0 0 0 0 0 0 0 0

 Total 201,134 35,316 23,492 67 22 11 56 28 15 34 43 23

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
311

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 109—Etolin Island Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
312

GENERAL TECHNICAL REPORT PNW-GTR-917

22. Wrangell Island

Geomorphology and Climate— 

Wrangell Island is in the Zimovia Strait Sedimentary and Volcanics Complex subsection. This management zone is underlain by volcanic rock and has extensive 

postglacial surficial deposits. The geomorphology of the area is dominated by rolling hills and lowlands, but has some mountainous terrain. The hills and lowlands 

are poorly to moderately dissected by streams, and the soils are generally moderately well-drained to very poorly drained and moderately deep. There is a large 

area of raised marine sediment that fringes the coastline of the entire management 

zone and that is associated with poorly drained soils. Climate varies by elevation 

but is generally mild; less snow is produced on the south and west sides of Wrangell 

Island. The east side of the island is influenced by mainland mountains. At sea level, the average annual temperature ranges from a minimum of 37 °F to a maximum 

of 50 °F. The average annual precipitation is 80 in, and the average annual snowfall 

is 55 in (Wrangell observation station, 509919).

Extent of yellow-cedar— 

The estimate of live yellow-cedar forest is 25,000 ac, which occupies about 20.6 

percent of the total forested land (table 46). Yellow-cedar is well distributed on 

Wrangell Island. This zone contributes to 1.1 percent of the yellow-cedar acreage 

in Alaska.

Extent of yellow-cedar decline— 

Existing yellow-cedar decline has been mapped on 12,500 ac, or about 2.2 percent 

of the yellow-cedar decline acreage in Alaska. Decline is common on the poorly 

drained areas and low-relief geomorphic zones throughout the island. Yellow-cedar 

decline is also extensive on hillsides on the northeastern portion of Wrangell Island 

facing Blake Inlet.

Extent of yellow-cedar at future risk— 

Moderately high elevation nonalpine areas of Wrangell Island represent a substantial area of yellow-cedar habitat that will be subject to yellow-cedar decline in the 

future. The percentage of yellow-cedar forest area projected to be at high risk of 

yellow-cedar decline rises from 5 to 23 percent between 2020 and 2080 (fig. 110). 

High risk is expected to appear in the interior of the island and to progress upslope. 

Numerous areas where yellow-cedar decline currently occurs are rated at moderate risk in 2020, indicating that models may underestimate risk on Wrangell Island. 

The percentage of yellow-cedar forests expected to be at low risk decreases from 77 

to 38 percent by 2080. These forests primarily occur at higher elevations. 
313

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Landscapes in protected and active management zones— 

Most of the yellow-cedar acreage in this management zone is on land managed by 

the U.S. Forest Service, but >3,000 ac are estimated on State land. All but a few 

hundred acres of mapped yellow-cedar decline are on land managed by the Forest 

Service. Mapped yellow-cedar decline and most of the yellow-cedar acreage in each 

of the risk classes on land managed by the Forest Service occur in nonrestricted, development status. 

Opportunities for conservation and management— 

Road access, land-use status, and the abundance of yellow-cedar and yellowcedar decline all suggest opportunities for active management. Salvage harvest 

was conducted in the late 1990s on Wrangell Island near Nemo Point and these 

activities could continue in already declining yellow-cedar forests or those that 

become affected in the future. Succession to other tree species, including western 

redcedar, will occur in decline-affected forests whether there is salvage harvest or 

not. Yellow-cedar is expected to persist in the highest elevation where it grows on 

Wrangell Island, thereby helping to meet conservation goals. 
314

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 46—Wrangell Island Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 101,394 21,508 12,163 72 12 3 63 18 6 38 32 17

 Nonrestricted, developmentd 72,245 16,118 8,769 57 7 2 50 12 3 30 25 10

 Nonrestricted, limited developmente 26,796 4,876 3,290 14 4 1 12 5 2 8 7 5 Restricted, nondevelopment f 2,353 514 104 1 1 0 1 1 0 0 1 1State 16,017 3,056 230 5 6 2 2 6 3 1 6 6

Private 275 55 0 0 0 0 0 0 0 0 0 0

Other governmental entity 3,196 285 112 0 0 0 0 0 0 0 1 1

Unknown 220 0 0 0 0 0 0 0 0 0 0 0

 Total 121,102 24,904 12,505 77 18 5 65 25 9 38 39 23

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
315

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 110—Wrangell Island Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
316

GENERAL TECHNICAL REPORT PNW-GTR-917

23. Stikine

Geomorphology and climate— 

The Eastern Passage Complex of sedimentary and volcanic material is the dominant 

lithologic formation in this management zone. Mountain slopes and summits dominate the area, with few lowland and hill landforms. There are abundant alpine areas 

on steep mountain slopes; lower elevations support coniferous forest. Small areas 

of wetland are also present, though glacial till is generally rare. Climate and winter 

snow vary along the elevation gradient from the coast to the interior mountains with 

abundant snow associated the steep terrain. There is no permanent weather station located in the mainland area of this management zone. Fringe forests near sea 

level will have a climate similar to the weather station at Petersburg, where average annual temperature ranges from a minimum of 35 °F to a maximum of 48 °F, 

the average annual precipitation is 105 in, and the average annual snowfall is 107 in 

(Petersburg observation station, 507233).

Extent of yellow-cedar— 

There are an estimated 54,000 ac of yellow-cedar in this management zone out of 

a forestland of nearly 500,000 ac (table 47). Yellow-cedar populations here account 

for about 2.4 percent of the yellow-cedar acreage in Alaska. Yellow-cedar forests 

appear well distributed along the coast, including areas around Bradfield Canal, and 

also penetrate some mainland valleys. 

Extent of yellow-cedar decline— 

About 21,000 ac of yellow-cedar decline have been mapped in this management 

zone, representing about 3.8 percent of the yellow-cedar decline acreage in Alaska. 

Decline is common in coastal areas, but also extends far back into the Eagle River 

drainage to the south of Bradfield Canal. 

Extent of yellow-cedar at future risk— 

Projected high risk of yellow-cedar decline is initially low in 2020 (1 percent of 

yellow-cedar acreage), especially in the southern extreme of this management zone 

(fig. 111). By 2080, high risk rises to 8 percent of yellow-cedar acreage, developing 

in some coastal mainland areas adjacent to Wrangell Island. Modeled risk to yellow-cedar may be underestimated in portions of this zone, as yellow-cedar decline 

already occurs in some coastal areas that are rated as low-to-moderate risk in 2020; 

however, some of these areas develop a high risk by 2080. Generally, yellow-cedar 

forests rated at low risk to yellow-cedar decline initially prevail (92 percent) but 
317

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

drop to 71 percent by 2080. Yellow-cedar forests that remain at low risk generally 

occur at high elevation in valleys that extend deeply into the mainland. 

Landscapes in protected and active management zones— 

Nearly all of the yellow-cedar forests in this zone occur on land managed by the 

U.S. Forest Service, with most of the remainder (2,000 ac) on State land; a smaller 

amount is on private land. On land managed by the Forest Service, yellow-cedar is 

well distributed among the land-use categories. Most of the mapped yellow-cedar 

decline is on lands in nonrestricted, limited development status. 

Opportunities for conservation and management— 

There is only limited opportunity for active forest management given the minimal 

road access and negligible recent timber harvests. Planting and thinning to promote 

yellow-cedar is possible, especially considering the large proportion rated at low 

risk into the future. The health status of yellow-cedar is favorable in this management zone, with >90 percent persisting at low-to-medium risk of yellow-cedar 

decline, although this percentage may be an overestimate. Snow protects yellowcedar trees in these areas, and probably facilitates successful natural regeneration to 

sustain yellow-cedar forests. 
318

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 47—Stikine Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 457,226 51,519 20,755 89 5 1 85 8 2 70 19 7

 Nonrestricted, developmentd 129,833 19,673 6,190 32 4 1 30 5 2 21 11 5

 Nonrestricted, limited developmente 179,153 18,139 12,825 33 1 0 32 1 0 29 4 1

 Restricted, nondevelopment f 148,240 13,707 1,740 24 1 0 23 2 0 19 5 1State 9,934 2,247 427 3 1 0 2 2 0 1 2 1

Private 616 26 0 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 1,335 9 0 0 0 0 0 0 0 0 0 0

 Total 469,111 53,801 21,182 92 7 1 88 10 3 71 21 8

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
319

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 111—Stikine Yellow-Cedar Management Zone (Wrangell Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
320

GENERAL TECHNICAL REPORT PNW-GTR-917

24. Heceta

Geomorphology and climate— 

This management zone contains several islands, including Heceta, Kosciusko, 

Tuxecan, Warren, and Coronation Islands. The ecological zones are diverse and 

include volcanic and sedimentary rock complexes and the Kuiu–North Prince of 

Wales Carbonate subsection with abundant karst terrain. Karst-derived soils tend to 

be nutrient-rich and well drained, supporting productive coniferous forests where 

yellow-cedar is generally outcompeted. The North Prince of Wales Sedimentary 

and Volcanics Complex on eastern Kosciusko Island includes low rolling hill landforms, with almost half of this area covered with palustrine and emergent wetland. 

The climate is mild and snowpack is not consistent in winter except at higher elevations. At sea level, the average annual temperature ranges from a minimum of 38 °F 

to a maximum of 47 °F. The average annual precipitation is 72 in, and the average 

annual snowfall is 16 in (Cape Decision Lighthouse observation station, 501269).

Extent of yellow-cedar— 

Yellow-cedar is estimated to occur on 37,000 ac, making up 17.0 percent of the forested land in this zone and about 1.6 percent of the yellow-cedar acreage in Alaska 

(table 48). Yellow-cedar appears concentrated in certain portions of this management zone, probably the result of soils, drainage, and site productivity. The species 

appears less common on some areas of Heceta, Kosciusko, and Tuxecan Islands. 

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on nearly 17,000 ac, or about 3.0 percent of the yellow-cedar decline acreage in Alaska. It exists on the outer islands 

(Coronation and Warren Islands) and the poorly drained portions of the other islands. 

Extent of yellow-cedar at future risk— 

The share of yellow-cedar at high risk of decline is expected to increase from 13 to 

24 percent between 2020 and 2080, while the share at low risk decreases from 50 

to 20 percent in that time (fig. 112). Increased risk is expected to expand to higher 

elevations and on the northeast portion of Kusciusko Island. 

Landscapes in protected and active management zones— 

Nearly all yellow-cedar in this zone occurs on land managed by the U.S. Forest 

Service. Most of the yellow-cedar acreage and the mapped yellow-cedar decline is 

in restricted, nondevelopment status, but sizable areas are also designated as nonrestricted, development status. By 2080, most of the low-risk acreage is projected to 

occur on restricted, nondevelopment status lands.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

A substantial portion of yellow-cedar has already been affected by yellow-cedar 

decline, and modest increases in mortality are expected. The restricted land-use 

classification limits active management, such as salvage harvest and planting of 

yellow-cedar on well-drained soils. As young-growth stands are harvested in the 

nonrestricted, development land, some areas could be planted with yellow-cedar 

where deep rooting would protect them from freezing injury. Any yellow-cedar 

planting will be threatened by abundant deer populations throughout the zone. The 

health status of yellow-cedar in protected landscapes (e.g., Coronation Island and 

Warren Island Wilderness Areas) has been impaired by previous mortality and the 

long-term effects of limited regeneration, and is expected to be further impaired by 

future mortality. 
322

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 48—Heceta Yellow-Cedar Management Zone (Thorne Bay Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 202,852 36,600 16,608 50 37 13 38 43 18 20 55 24

 Nonrestricted, developmentd 86,999 11,170 4,629 11 14 6 7 15 8 2 18 10

 Nonrestricted, limited developmente 38,037 3,618 996 5 4 1 3 5 2 1 6 2

 Restricted, nondevelopment f 77,816 21,812 10,983 34 19 6 27 23 8 17 31 12State 11,189 223 92 0 0 0 0 0 0 0 0 0

Private 1,750 97 113 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 1,037 4 5 0 0 0 0 0 0 0 0 0

 Total 216,828 36,924 16,818 50 37 13 38 43 18 20 55 24

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
323

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 112—Heceta Yellow-Cedar Management Zone (Thorne Bay Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
324

GENERAL TECHNICAL REPORT PNW-GTR-917

25. Prince of Wales North

Geomorphology and climate— 

This management zone is primarily composed of volcanics and till lowlands, with 

volcanic and sedimentary complexes to the north. The Central Prince of Wales 

Volcanics have steep-sided mountains and glacial till interspersed with alluvial valleys. The glacial till along the mountain slopes and hills forms peatlands and forested 

wetlands (20 percent of the area) that provide habitat for yellow-cedar. The Central 

Prince of Wales Till Lowlands are dominated by glacial till with drumlin landforms 

and abundant forested and emergent wetland. The climate is mild at low elevations 

with consistent seasonal snowpack only at higher elevations. In the northern part 

of this zone, on the windward side of Prince of Wales Island, the average annual 

temperature ranges from a minimum of 38 °F to a maximum of 47 °F. The average 

annual precipitation is 72 in, and the average annual snowfall is 16 in (Cape Decision 

Lighthouse observation station, 501269). In the southern part of this zone, on the 

leeward side of Prince of Wales Island, the average annual temperature ranges from 

a minimum of 37 °F to a maximum of 51 °F. The average annual precipitation is 105 

in, and the average annual snowfall is 45 in (Hollis observation station, 503650). 

Extent of yellow-cedar— 

This zone has an estimated 139,500 ac of yellow-cedar forest, or 6.1 percent of 

the yellow-cedar acreage in Alaska (table 49). Yellow-cedar cover makes up 19.2 

percent of the forested land in the management zone. Yellow-cedar appears to be 

widely distributed except in the lowland productive valleys in which much of the 

past timber harvesting has occurred. 

Extent of yellow-cedar decline— 

Decline has been mapped on about 45,000 ac, or just under one-third of the estimated extent of yellow-cedar forest. This acreage accounts for about 7.9 percent 

of yellow-cedar decline in Alaska. Mapped yellow-cedar decline appears scattered 

around this zone, with notable patches along the west coast and northwest portion 

of Prince of Wales Island, often associated with less well-drained sites.

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forests at high risk for decline is projected to rise 

from 21 to 35 percent between 2020 and 2080, while the percentage at low risk is 

expected to fall from 39 to 11 percent (fig. 113). Risk increase (from medium to 

high risk and low to medium risk) through time occurs along an elevation gradient 

as snow is reduced. Most yellow-cedar forests with low projected risk occur at the 

highest elevation range of yellow-cedar.
325

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Landscapes in protected and active management zones— 

The bulk of yellow-cedar and mapped decline are on land managed by the U.S. 

Forest Service, but both also occur on lands under State and private ownership. 

More than half of the yellow-cedar forests and about half of the decline on land 

managed by the Forest Service are in a nonrestricted, development classification. 

Opportunities for conservation and management— 

The occurrence of yellow-cedar and forest decline on different ownerships and the 

nonrestricted, development status on land managed by the Forest Service suggest 

opportunity for active management, including salvage harvest of dead yellow-cedar. 

Forests that are expected to move into higher risk classes may provide increased 

opportunities for salvage. Decline-affected forests in restricted land classes are expected to transition to western hemlock, western redcedar, and other species. Active 

management could facilitate this succession. With the active young-growth program 

on the Thorne Bay Ranger District, there may be opportunity to plant yellow-cedar 

on productive sites after harvest of young-growth. Natural regeneration of yellowcedar in natural stands and in harvest units is expected to be severely limited by 

the large deer population in this management zone; similarly, planted seedlings will 

probably require protection from deer browse. Yellow-cedar is expected to persist 

as a larger forest component in high-elevation forests. 
326

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 49—Prince of Wales North Yellow-Cedar Management Zone (Thorne Bay Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 656,417 129,532 42,757 38 36 19 26 42 25 10 50 32

 Nonrestricted, developmentd 367,282 68,780 21,365 22 18 9 15 22 13 6 26 18

 Nonrestricted, limited developmente 234,570 49,346 17,851 12 16 8 8 18 10 3 20 12 Restricted, nondevelopment f 54,565 11,405 3,541 4 2 2 3 3 2 1 4 3State 40,018 3,993 1,238 0 2 1 0 2 1 0 2 1

Private 25,787 5,951 731 1 2 1 1 2 1 1 2 1

Other governmental entity 43 0 0 0 0 0 0 0 0 0 0 0

Unknown 2,830 15 5 0 0 0 0 0 0 0 0 0

 Total 725,095 139,491 44,730 39 40 21 27 46 27 11 54 35

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
327

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 113—Prince of Wales North Yellow-Cedar Management Zone (Thorne Bay Ranger District, Tongass National Forest): areas and percentages of low, moder- ate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
328

GENERAL TECHNICAL REPORT PNW-GTR-917

26. Craig Outer Islands

Geomorphology and climate— 

This management zone includes Noyes, Lulu, San Fernando, Baker, and Suemez 

Islands to the north, and Dall, Sukkwan, and Long Islands to the south. These 

southwest Prince of Wales islands are dominated by complex sedimentary and volcanic rock and till lowlands. The volcanic rock has led to the development of soils 

conducive to the growth of large and productive coniferous forest. Along with deeper soils on weathered bedrock, there are areas of glacial till and forested wetlands 

that provide habitat for yellow-cedar; palustrine emergent peatlands are not as common. The climate is hypermaritime with mild winters and substantial winter snow 

only at higher elevations. At sea level, the average annual temperature ranges from 

a minimum of 40 °F to a maximum of 51 °F. The average annual precipitation is 97 

in, and the average annual snowfall is 23 in (Craig observation station, 502227).

Extent of yellow-cedar— 

Yellow-cedar occurs on an estimated 66,000 ac, accounting for 18.8 percent of the 

forestland in this management zone, and 2.9 percent of the yellow-cedar acreage in 

Alaska (table 50). There are some large areas of well-drained soil and productive 

forests where yellow-cedar is uncommon or absent. However, there are also observations of where yellow-cedar competes well on extremely exposed sites along the 

outside coast. The exposure appears to be the limiting site factor, rather than soil 

drainage. In this case, yellow-cedar does well, though the trees are not very large.

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on 7,400 ac, a small portion of the yellowcedar forests compared to other management zones. This acreage accounts for 1.3 

percent of the mapped yellow-cedar decline in Alaska. It is scattered throughout the 

islands that make up this management zone.

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forest projected to be at high risk of yellow-cedar 

decline increases from 26 to 35 percent between 2020 and 2080 (fig. 114). The high 

initial risk and relatively minor increase in risk are driven by the low snow levels 

that are already present in this zone. Only 7 percent of yellow-cedar forests are at 

low risk in 2080. 

Landscapes in protected and active management zones— 

Most of the yellow-cedar acreage is on land managed by the U.S. Forest Service. 

Most yellow-cedar occurs on restricted, nondevelopment status lands, but the acreage for existing yellow-cedar decline is mixed among the three land-use categories. 
329

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

About 8,000 ac of yellow-cedar forest and >1,000 ac of yellow-cedar decline are on 

private land. The large private holdings on Dall and Long Islands contain relatively 

little yellow-cedar acreage. 

Opportunities for conservation and management— 

The small amount of yellow-cedar decline, land use designation, and remoteness 

of these areas limit salvage potential of dead yellow-cedar. Succession to other tree 

species (e.g., western redcedar and western hemlock) will occur in the decline-affected forests in the unmanaged wetter forests that are common in this management 

zone. A portion of this zone has well-drained sites and mild climate, which provide an opportunity to produce the largest, fastest growing yellow-cedar in Alaska. 

However, planting, protection of seedlings from deer, and thinning will be required 

to increase the competitive status of yellow-cedar on these sites. In unmanaged areas, the yellow-cedar component is expected to continue to undergo mortality. The 

exposed, windward sides of these islands may prove difficult locations for trees to 

thrive. The small area expected to be at low risk of decline by 2080 suggests that 

conservation goals may be more difficult to meet here than in other management 

zones. 
330

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 50—Craig Outer Islands Yellow-Cedar Management Zone (Craig Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 272,133 57,523 6,118 21 42 24 13 46 28 6 50 31

 Nonrestricted, developmentd 49,721 10,605 1,480 6 8 3 3 8 5 1 9 6

 Nonrestricted, limited developmente 135,942 31,529 1,958 11 23 14 7 25 16 4 27 17

 Restricted, nondevelopment f 86,470 15,389 2,680 5 11 7 3 13 8 1 13 8

State 2,011 150 0 0 0 0 0 0 0 0 0 0

Private 75,864 8,284 1,278 4 5 3 3 6 3 1 7 4

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 1,506 5 1 0 0 0 0 0 0 0 0 0

 Total 351,514 65,962 7,397 26 48 26 16 52 32 7 57 35

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
331

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 114—Craig Outer Islands Yellow-Cedar Management Zone (Craig Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
332

GENERAL TECHNICAL REPORT PNW-GTR-917

27. Prince of Wales South

Geomorphology and climate— 

The ecological subsections in this management zone are the South Prince of Wales 

Granitics to the south, the Moira Sound Complex and Central Prince of Wales 

Volcanics in the central portion, and the Hetta Inlet Metasediments and Skowl Arm 

Till Lowlands to the north. The Moira Sound Complex is lightly metamorphosed 

sedimentary and volcanic bedrock. Most of the area is underlain by colluvium that 

promotes poorly drained soils. The Central Prince of Wales Volcanics subsection 

has igneous intrusive rocks arrayed across mountainous terrain. This area has dissected mountain slopes and many large river drainages with well-developed floodplains. There are also rolling hills at the toeslopes and footslopes of these steep 

mountainsides containing poorly drained soils that serve as the main yellow-cedar 

habitat. Climate is mild, and precipitation is mainly as rain except at higher elevations. At sea level, the average annual temperature ranges from a minimum of 40 °F 

to a maximum of 51 °F. The average annual precipitation is 97 in, and the average 

annual snowfall is 23 in (Craig observation station, 502227).

Extent of yellow-cedar— 

Yellow-cedar occupies nearly 200,000 ac, or 25.2 percent of the forestland in this 

management zone and 8.8 percent of the yellow-cedar acreage in Alaska (table 51). 

Yellow-cedar appears common throughout this zone, but is generally outcompeted 

and less prevalent in productive lowland valley forests. There is a lack of yellowcedar in the oldest young-growth stands, and regeneration of yellow-cedar is more 

likely to occur in more recent harvest areas in less productive sites.

Extent of yellow-cedar decline— 

Just over 37,000 ac of yellow-cedar decline have been mapped in this management zone, accounting for about 6.5 percent of the yellow-cedar decline acreage in 

Alaska. Yellow-cedar decline is currently scattered throughout, but is most common 

on hillsides because yellow-cedar is more abundant at middle and high elevations.

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forest projected to be at high risk to yellow-cedar 

decline is expected to increase from 16 to 28 percent between 2020 and 2080 (fig. 

115). High-risk areas in 2020 are concentrated in the southern portion of the island 

and at several low-elevation areas on to the northwest and western coasts. Some of 
333

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

these areas are low-productivity forested wetland and do not contain large trees. By 

2080, increased risk is predicted for the inland yellow-cedar forests, with decline 

progressing upslope. The percentage of yellow-cedar forest modeled as having low 

risk to decline decreases from 46 to 17 percent by 2080, with relatively lower risk 

projected for upper-elevation yellow-cedar forests. 

Landscapes in protected and active management zones— 

Most of the estimated 200,000 ac of yellow-cedar forest in this zone are on land 

managed by the U.S. Forest Service, but a significant portion (25,500 ac) occurs on 

private land. On land managed by the Forest Service, there are large acreages of 

yellow-cedar forest in all three land use designations, though few are dominated by 

yellow-cedar. 

Opportunities for conservation and management— 

The distribution of yellow-cedar risk classes and land use designations indicate 

good prospects for both yellow-cedar conservation and management. The extensive 

road system may allow for yellow-cedar salvage in decline-affected forests and in 

areas expected to be affected in the future. Succession to other tree species, including western redcedar, will occur in unmanaged forests with yellow-cedar decline, 

such as the extensive southern portion in the South Prince of Wales Wilderness 

Area. Yellow-cedar regeneration is expected to be reduced by deer browse in unmanaged natural stands at low elevations. Yellow-cedar could be promoted through 

planting and thinning in high-elevation forests and on productive sites with welldrained soils. With the active management that is expected in this management 

zone, there may be opportunities to plant yellow-cedar after timber harvest (including young-growth harvest) on all ownerships. Deer are expected to severely 

limit the success of natural yellow-cedar regeneration and planted seedlings unless 

protective measures are taken. 
334

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 51—Prince of Wales South Yellow-Cedar Management Zone (Craig Ranger District, Tongass National Forest): acreage of yellow- cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 583,838 171,738 30,749 40 33 13 29 40 18 15 48 24

 Nonrestricted, developmentd 228,486 66,333 13,934 17 12 4 12 15 6 6 18 9

 Nonrestricted, limited developmente 203,879 62,523 11,392 14 12 5 10 15 7 5 18 8 Restricted, nondevelopment f 151,473 42,882 5,423 9 9 4 7 10 5 3 12 6State 14,025 1,336 828 0 0 0 0 0 0 0 0 0

Private 184,780 25,556 5,468 6 5 3 4 5 3 2 6 4

Other governmental entity 372 11 0 0 0 0 0 0 0 0 0 0

Unknown 4,231 20 13 0 0 0 0 0 0 0 0 0

 Total 787,246 198,661 37,057 46 38 16 34 45 21 17 55 28

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
335

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 115—Prince of Wales South Yellow-Cedar Management Zone (Craig Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
336

GENERAL TECHNICAL REPORT PNW-GTR-917

28. Cleveland Peninsula

Geomorphology and climate— 

The western portion of this management zone is part of the Clarence Strait 

Volcanics subsection. Moving inland, other ecological subsections in this zone are 

the Traitors Cove Metasediments, the Ketchikan Mafics/Ultramafics, the Vixen 

Inlet Till Lowlands, the Zimovia Strait Complex, and the Berg Bay Complex. The 

geology is composed of plutonic rock that has been extensively modified by glacial action. Shallow to bedrock soils on summits and high-elevation alpine areas 

transition to deeper soils formed on colluvial footslopes and till toeslopes. Lowproductivity forested wetlands make up about 35 percent of the western volcanics 

area. Climate varies widely from the mild coastal areas to the mountainous areas of 

the zone’s eastern portion, which has colder winters and consistent winter snowpack. At sea level, the average annual temperature ranges from a minimum of 41 °F 

to a maximum of 51 °F. The average annual precipitation is 66 in, and the average 

annual snowfall is 33 in (Guard Island Lighthouse observation station, 503454).

Extent of yellow-cedar— 

Yellow-cedar occupies an estimated 66,500 ac, constituting 24.7 percent of the forested acreage in this management zone and 2.9 percent of the yellow-cedar forests 

in Alaska (table 52). Yellow-cedar appears well distributed throughout this management zone, but is lacking from some productive forested valleys and the areas above 

timberline to the east.

Extent of yellow-cedar decline— 

About 21,000 ac of yellow-cedar decline have been mapped in this management 

zone. This accounts for about 3.7 percent of yellow-cedar decline acreage in Alaska. 

Yellow-cedar decline is common on hillsides at mid-elevation. 

Extent of yellow-cedar at future risk— 

The pattern of risk to yellow-cedar decline in this zone follows a west-to-east gradient. The percentage of yellow-cedar forest projected to be at high risk to yellowcedar decline is expected to increase from 19 to 29 percent by 2080 (fig. 116). High 

risk is modeled as being concentrated initially at low elevations in the western 

portion of the management zone, advancing to higher elevations and eastward over 

time. The percentage of yellow-cedar projected to be at low risk to yellow-cedar 

decline decreases from 55 to 26 percent by 2080. Despite this significant drop in the 

proportion of acreage at low risk, abundant low-risk forests occur at higher eleva-
337

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

tions in the western portion and extensive inland areas to the east. Our models may 

underestimate risk in some portions of this management zone; for example, yellowcedar decline already occurs on Bell Island and some adjacent mainland coastal 

areas and valleys rated to have medium risk in 2020 and 2050, but these areas progress to high risk by 2080.

Landscapes in protected and active management zones— 

Nearly all of yellow-cedar forests occur on land managed by the U.S. Forest 

Service. Most of this acreage is on nonrestricted, limited development and nonrestricted, development designations. By 2080, most of the yellow-cedar forests at low 

risk are only on nonrestricted, limited development lands.

Opportunities for conservation and management— 

The mixtures of yellow-cedar risk classes and land use designations suggest opportunities for both yellow-cedar conservation and management. Lands with yellowcedar decline and future decline are available for salvage harvest, but the limited 

road access may make this activity less economically feasible. Succession to other 

tree species, including western redcedar at low elevations, will occur in declineaffected forests with no management. Conservation goals for yellow-cedar will be 

met at high elevations and in productive forests where it mixes with other trees species. Planting and thinning of yellow-cedar can occur in high-elevation forests and 

eastern mountainous areas that retain low risk due to heavy snow. The success of 

natural regeneration and planted yellow-cedar are expected to vary by elevation and 

along the gradient from western coastal forests to the mountainous areas to the east. 
338

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 52—Cleveland Peninsula Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): acreage of yellow- cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 258,915 65,003 20,070 55 25 18 45 31 22 26 44 28

 Nonrestricted, developmentd 74,969 22,179 6,120 14 11 9 10 13 11 3 17 13

 Nonrestricted, limited developmente 179,483 41,979 13,823 40 14 8 34 18 11 22 27 14

 Restricted, nondevelopment f 4,463 845 127 1 0 5 1 0 0 1 0 0

State 1,742 453 23 0 0 0 0 0 0 0 0 0

Private 8,121 1,056 1,042 1 1 0 0 1 0 0 1 0

Other governmental entity 259 28 50 0 0 0 0 0 0 0 0 0

Unknown 643 2 1 0 0 0 0 0 0 0 0 0

 Total 269,680 66,542 21,186 55 26 19 45 32 23 26 45 29

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
339

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 116—Cleveland Peninsula Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
340

GENERAL TECHNICAL REPORT PNW-GTR-917

29. Gravina Island

Geomorphology and climate— 

Volcanic rocks of the Gravina Belt make up the Clarence Strait Volcanics subsection in this management zone. Smooth, rounded mountains have been left by 

continental ice floes with the landforms dominated by mountain slopes. Forest is 

abundant with a nearly equal mix of productive and nonproductive forest. Histosols 

and Spodosols are equally common, leading to abundant mixed-conifer forest in 

wetlands and wet forested areas. Climate is mild with low snow levels except at 

higher elevations. The average annual temperature ranges from a minimum of 39 °F 

to a maximum of 52 °F. The average annual precipitation is 152 in, and the average 

annual snowfall is 37 in (Ketchikan observation station, 504590).

Extent of yellow-cedar— 

Yellow-cedar occurs on an estimated 11,300 ac and makes up 18.7 percent of the 

forestland in this small management zone (table 53). Yellow-cedar populations here 

amount to only 0.5 percent of the yellow-cedar acreage in Alaska. 

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on 3,388 ac in this management zone, 

mainly on hillsides at mid-elevations. This accounts for about 0.6 percent of yellowcedar decline acreage in Alaska.

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forest projected to be at high risk of yellow-cedar 

decline increases marginally from 33 to 37 percent between 2020 and 2080 (fig. 

117). Only 10 percent of yellow-cedar forests are expected to be at low risk by 2080, 

mainly at the higher elevations of this management zone.

Landscapes in protected and active management zones— 

Yellow-cedar forests and mapped decline occur on U.S. Forest Service, State, and 

unknown ownerships. On land managed by the Forest Service, most yellow-cedar 

forest and yellow-cedar decline are on lands designated as nonrestricted, limited 

development and nonrestricted, development.

Opportunities for conservation and management— 

Salvage harvest of dead yellow-cedar is an opportunity on State land and land managed by the Forest Service designated as development status. Planting and thinning 

to favor yellow-cedar in harvested areas could be conducted at higher elevations or 
341

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

on well-drained sites. Succession to other tree species, including western redcedar 

at low and middle elevations, will occur in unmanaged, affected forests. Natural 

regeneration will be limited by deer. The health status of yellow-cedar is not favorable on this small management zone given the low acreage projected to be at low 

risk of decline by 2080. 
342

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 53—Gravina Island Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 38,175 7,051 2,012 22 22 19 16 26 21 8 33 21

 Nonrestricted, developmentd 15,972 2,534 925 10 7 5 7 10 6 3 13 6

 Nonrestricted, limited developmente 21,493 4,441 1,087 12 14 13 9 16 14 5 20 15 Restricted, nondevelopment f 710 76 0 0 0 0 0 0 0 0 0 0State 10,901 2,227 818 2 10 8 1 10 8 1 10 8

Private 360 58 6 0 0 0 0 0 0 0 0 0

Other governmental entity 1 0 0 0 0 0 0 0 0 0 0 0

Unknown 10,981 1,986 552 3 8 6 3 8 7 1 9 7

 Total 60,418 11,322 3,388 28 39 33 19 45 36 10 53 37

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
343

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 117—Gravina Island Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
344

GENERAL TECHNICAL REPORT PNW-GTR-917

30. Revillagigedo West

Geomorphology and climate— 

Sedimentary and metasedimentary rocks of the Behm Canal Complex and Traitors 

Cove metasediment subsections dominate this management zone. These rocks, 

along with fissures of weaker rock, were carved by continental ice sheets to form 

resistant mountains and deeply incised valleys. Mountain sideslopes and summits 

are common landforms in this zone. About 15 percent of the area contains forested 

wetlands, but almost half of the area is nonproductive forest. The climate varies 

considerably from the mild west and south coastal sections to interior valleys and 

to the mountains with more consistent winter snowpack. At sea level, the average annual temperature ranges from a minimum of 39 °F to a maximum of 52 °F. 

The average annual precipitation is 152 in, and the average annual snowfall is 37 in 

(Ketchikan Airport observation station, 504590).

Extent of yellow-cedar— 

Yellow-cedar occurs on an estimated 120,900 ac, which accounts for 28.5 percent 

of forestland in this management zone and 5.3 percent of yellow-cedar acreage in 

Alaska (table 54). Yellow-cedar appears well distributed throughout the zone.

Extent of yellow-cedar decline— 

Yellow-cedar decline has been mapped on about 22,500 ac, which constitute about 

4.0 percent of yellow-cedar decline acreage in Alaska. Decline occurs on hillsides 

in coastal sections and in some interior valleys with extensive forested wetlands.

Extent of yellow-cedar at future risk— 

The percentage of yellow-cedar forest projected to be at high risk of decline is expected to rise from 7 to 18 percent between 2020 and 2080, while the percentage at 

low risk is halved from 64 to 32 percent in this period (fig. 118). There is an apparent pattern of higher risk initially developing in southern and coastal areas, and 

then progressing northward and into the interior of the island by 2080. But a significant portion of the landscape remains at low risk by 2080, especially in the higher 

elevation and northern areas. 

Landscapes in protected and active management zones— 

About 10,000 ac of yellow-cedar occur on State and private lands, but >90 percent 

falls under U.S. Forest Service jurisdiction. On land managed by the Forest Service, 

there is substantial acreage of yellow-cedar and yellow-cedar decline on both nonrestricted, development and nonrestricted, limited development land designations. 
345

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

The large acreage in nonrestricted, development status and the presence of several 

road systems suggest opportunities for a range of management activities. Salvage 

of dead yellow-cedar may be feasible in some southern areas that currently have 

decline or in forests that develop decline in the future. Active management, such 

as planting and thinning to favor yellow-cedar in well-drained or high-elevation 

areas, may be warranted. The success of both natural and artificial regeneration is 

expected to be site-specific given the range of elevation and snow patterns in this 

management zone. There are some known harvested areas that had abundant natural yellow-cedar regeneration. High-elevation and northern portions of this management zone offer good prospects for the conservation of yellow-cedar. 
346

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 54—Revillagigedo West Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 371,133 107,852 19,955 64 19 7 53 25 11 32 39 18

 Nonrestricted, developmentd 198,553 56,058 10,418 32 11 4 26 14 6 15 21 10

 Nonrestricted, limited developmente 143,537 41,135 7,832 25 6 3 21 9 4 14 14 6 Restricted, nondevelopment f 29,042 10,659 1,705 7 2 0 5 3 1 3 4 2State 20,300 6,147 919 2 2 1 1 2 2 1 3 2

Private 19,470 4,145 684 2 1 0 1 1 1 1 2 1

Other governmental entity 1 0 0 1 1 0 1 1 1 0 1 1

Unknown 13,765 2,776 905 68 23 9 56 30 14 33 45 22

 Total 424,668 120,920 22,464 64 19 7 53 25 11 32 39 18

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
347

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 118—Revillagigedo West Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
348

GENERAL TECHNICAL REPORT PNW-GTR-917

31. Revillagigedo East

Geomorphology and climate— 

This management zone lies in the Behm Canal Complex subsection, which is part 

of the rounded mountain geomorphic class. The geology of this inactive glacial terrain is dominated by complex sedimentary and volcanic rock. This area was heavily 

worked by glacial action across somewhat less resistant bedrock, leading to linear 

landscape features such as lakes, and low-relief areas. There is an even mix of productive and nonproductive forests within this management zone. About 15 percent 

of the area is forested wetland, and another 10 percent is emergent wetland, both 

of which provide areas of yellow-cedar habitat intermixed with productive upland 

forest. The climate varies by elevation and latitude. The southern portion of Behm 

Canal has mild winters, whereas northern areas and higher elevations have more 

consistent winter snow. At sea level, the average annual temperature ranges from a 

minimum of 39 °F to a maximum of 52 °F. The average annual precipitation is 152 

in, and the average annual snowfall is 37 in (Ketchikan airport observation station, 

504590).

Extent of yellow-cedar— 

Yellow-cedar occupies an estimated 112,800 ac, which represent about 64.1 percent 

of the forestland in this management zone and about 5.0 percent of the yellow-cedar 

acreage in Alaska (table 55). Yellow-cedar appears to be well distributed in all areas 

of the management zone, but is absent from mountainous areas above timberline. 

Extent of yellow-cedar decline— 

Only 10,080 ac of yellow-cedar decline have been mapped in this management 

zone. Most of this decline has been detected in the southern portions of this zone, 

but stands of dead and dying yellow-cedar are mapped to the north along the east 

coast of Behm Canal. 

Extent of yellow-cedar at future risk— 

Risk of yellow-cedar decline varies geographically from south to north. Initially, 

most of the high-risk areas occur in the southern portion of this zone around 

Princess Bay, with smaller areas on the east side of Behm Canal. Between 2020 

and 2080 high risk of yellow-cedar decline is expected to develop in low-elevation 

coastal and valley locations to the north. More of this change is expected to occur 

in the second 30 yrs. Even by 2080, however, the percentage of yellow-cedar forest 

projected to be at high risk of decline is only 20 percent, and 35 percent of yellowcedar forests remain at low risk (fig. 119). 
349

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Landscapes in protected and active management zones— 

Nearly the entire distribution of yellow-cedar in this management zone is on land 

managed by the U.S. Forest Service, and all of it falls under restricted, nondevelopment status as the western portion of the Misty Fiords National Monument.

Opportunities for conservation and management— 

With the restricted, nondevelopment land management classification, there is little 

opportunity for active management of yellow-cedar. This zone provides a good 

opportunity to meet conservation goals, as there is a relatively small amount of 

current yellow-cedar decline and low-to-medium risk accounts for 80 percent of 

yellow-cedar forests by 2080. Succession favoring other tree species has occurred 

and will continue to occur in stands with yellow-cedar decline. High current and 

future snow levels favor yellow-cedar regeneration in healthy forests, which helps 

yellow-cedar populations to be self-sustaining over the long term. 
350

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 55—Revillagigedo East Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): acreage of yellow- cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 175,910 112,810 10,080 68 23 9 57 30 13 35 45 20

 Nonrestricted, developmentd 0 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 0 0 0 0 0 0 0 0 0 0 0 0 Restricted, nondevelopment f 175,910 112,810 0 68 23 9 57 30 13 35 45 20State 0 0 0 0 0 0 0 0 0 0 0 0

Private 0 0 0 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 228 4 1 0 0 0 0 0 0 0 0 0

 Total 176,137 112,815 10,081 68 23 9 57 30 13 35 45 20

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
351

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 119—Revillagigedo East Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
352

GENERAL TECHNICAL REPORT PNW-GTR-917

32. Misty Fiords

Geomorphology and climate— 

This management zone lies in the Misty Fiord Granitics subsection, which is part 

of the granitic subgroup of the rounded mountain geomorphic class. The geology of 

this inactive glacial terrain is dominated by granitic residuum. Due to the resistant 

bedrock, the soils tend to be very shallow with little or no organic matter accumulation. The only deep, heavily forested soils are located on footslopes and along alluvial valleys. Nonforested alpine areas dominate the vegetation classes within this 

management zone. There is very little wetland (about 15 percent), of which about 

half is in forested wetland classes. Given the mountainous and interior geomorphology, winters have heavy and persistent snow in all but the low-elevation southwestern portion. At sea level, the average annual temperature ranges from a minimum 

of 39 °F to a maximum of 52 °F. The average annual precipitation is 152 in, and the 

average annual snowfall is 37 in (Ketchikan Airport observation station, 504590).

Extent of yellow-cedar— 

This large management zone has an estimated 408,000 ac of yellow-cedar, which 

account for 38.0 percent of the forested area of the zone and 17.9 percent of yellowcedar forests in Alaska (table 56). 

Extent of yellow-cedar decline— 

Existing mapped yellow-cedar decline has been detected on nearly 23,000 ac. This 

amounts to about 4.0 percent of yellow-cedar decline acreage in Alaska. It is common on hillsides in some of the valleys of Boca de Quadra, near Smeaton Bay, and 

along the east side of Behm Canal. 

Extent of yellow-cedar at future risk— 

High risk of yellow-cedar decline is expected to be limited to just 9 percent of yellow-cedar forests in 2020 and to rise to 15 percent by 2080 (fig. 120). The proportion of yellow-cedar forests at low or moderate risk of decline in 2020 is expected to 

drop modestly from 91 to 85 percent between 2020 and 2080. 

Landscapes in protected and active management zones— 

Nearly the entire acreage of yellow-cedar is in the Tongass National Forest and in 

the restricted, nondevelopment designation. A very small area of yellow-cedar, just 

86 ac, is in a nonrestricted, development status.
353

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Opportunities for conservation and management— 

The large yellow-cedar acreage, its current health, relatively minor future risk of 

yellow-cedar decline, and protection status indicate that this is a key area for the 

conservation of yellow-cedar. Yellow-cedar decline is projected to be limited to 

southern areas and coastal areas near Behm Canal in the future. Our models may 

marginally underestimate decline in this management zone as existing yellow-cedar 

decline is known to occur along the west side of Behm Canal, and it extends farther 

up Portland Canal than the risk rating in 2020 would suggest. Our models indicate 

high risk of decline does occur in these areas by 2080. Decline-affected forests are 

expected to undergo succession to western hemlock, western redcedar, and other 

species. The persistent snow levels that protect mature yellow-cedar trees from decline also provide protection for yellow-cedar regeneration and facilitate the longterm stability in yellow-cedar populations. 
354

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 56—Misty Fiords Yellow-Cedar Management Zone (Misty Fiords National Monument, Tongass National Forest): acreage of yellow- cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 1,069,508 407,350 22,977 71 20 9 64 25 11 49 36 15

 Nonrestricted, developmentd 5,127 86 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 21,310 569 163 0 0 0 0 0 0 0 0 0 Restricted, nondevelopment f 1,043,071 406,696 22,814 71 20 9 64 25 11 49 36 15

State 529 28 0 0 0 0 0 0 0 0 0 0

Private 1,427 87 0 0 0 0 0 0 0 0 0 0

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 2,172 53 2 0 0 0 0 0 0 0 0 0

 Total 1,073,635 407,518 22,978 71 20 9 64 25 11 49 36 15

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
355

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 120—Misty Fiords Yellow-Cedar Management Zone (Misty Fiords National Monument, Tongass National Forest): areas and percentages of low, moderate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
356

GENERAL TECHNICAL REPORT PNW-GTR-917

33. Annette and Duke Islands

Geomorphology and climate— 

Sedimentary and metasedimentary rocks of the Behm Canal Complex and Traitors 

Cove Metasediment subsections dominate this management zone. These rocks, 

along with fissures of weaker rock, were carved by continental ice sheets to form 

resistant mountains and deeply incised valleys. Mountain sideslopes and summits 

are common landforms except in the generally flat Duke Island. About 15 percent 

of the area contains forested wetlands, but almost half of the area is nonproductive 

forest. The Duke Island Till Lowlands are dominated by glacial till with drumlin 

landforms and abundant forested and emergent wetland. The climate is mild in 

these island environments, with consistent winter snow in only the higher elevations of Annette Island. At sea level, the average annual temperature ranges from a 

minimum of 41 °F to a maximum of 51 °F. The average annual precipitation is 109 

in, and the average annual snowfall is 43 in (Annette Island Observation Station, 

500352).

Extent of yellow-cedar— 

Yellow-cedar occurs on an estimated 24,500 ac in this management zone, which 

makes up about 1.1 percent of the yellow-cedar forests in Alaska (table 57). Nearly 

25 percent of the forested land in this management zone area contains yellow-cedar 

forest, but it probably occurs as a minor component because at this latitude it is generally more abundant at higher elevations. The mountainside slopes provide habitat 

for greater abundance of yellow-cedar. 

Extent of yellow-cedar decline— 

Just over 2,000 ac of yellow-cedar decline are mapped in this management zone, 

or 0.4 percent of the extent in Alaska. Most of the existing yellow-cedar decline is 

on hillsides. Very little yellow-cedar decline has been mapped on Duke Island, but 

there is likely to be scattered dead yellow-cedar present that is difficult to detect 

during aerial surveys. 

Extent of yellow-cedar at future risk— 

Due to the southern latitude and extent of low-elevation forested wetland habitat, 

this area has been at high risk for future decline for some time. The management 

zone already experiences low snow levels, particularly on Duke Island, where low 

elevation prevails. Changing snow patterns will only marginally increase risk in 

this management zone, and most of these changes will be on Annette Island. About 

46 percent of the yellow-cedar resource is expected to be at high risk in 2020 and 

the medium- and high-risk categories will dominate the overall population in this 
357

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

zone by 2080 (fig. 121). Only 13 percent of yellow-cedar forests are expected to be 

at low risk, mainly in the higher elevation areas of Annette Island. Yellow-cedar 

decline has largely played out in this management zone. 

Landscapes in protected and active management zones— 

Most of the yellow-cedar and yellow-cedar decline present in this management zone 

are on private land. The U.S. Forest Service land ownership with yellow-cedar is 

mainly in a nonrestricted, limited development designation. 

Opportunities for conservation and management— 

Yellow-cedar populations probably underwent substantial decline-related mortality 

through the 1900s, but recent and future losses are expected to be minor. Low snow 

levels favor deer, which will reduce natural regeneration in natural forests and the 

long-term abundance of yellow-cedar. Deer will also challenge yellow-cedar natural 

or artificial regeneration in harvested areas. The older and scattered nature of mortality limits salvage opportunities for dead trees. Perhaps the best opportunity for 

salvage of dead yellow-cedar is on private land on Annette Island. Planting yellowcedar should be confined to well-drained soils, and seedlings will probably need 

some protection from deer. Most of the yellow-cedar on Forest Service lands is in a 

restricted status, where the affected populations may have stabilized with a reduced 

yellow-cedar component. 
358

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 57—Annette and Duke Islands Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): acreage of yellow-cedar, current mapped yellow-cedar decline, and projected percentage of yellow-cedar occurrence in three decline risk classes in 2020, 2050, and 2080

Land ownership

Forest 

land

Yellowcedara

Mapped 

yellow-cedar 

decline, 

2013b

Decline risk class, 

projected, 2020c

Decline risk classes, 

projected, 2050c

Decline risk class, 

projected, 2080c

Low Medium High Low Medium High Low Medium High

- - - - - - - - - Acres - - - - - - - - - - - - - - - - - - - - - - - Percentage of yellow-cedar acreage - - - - - - - - - - - - - -

National forest (total) 40,213 8,477 7 0 9 25 0 9 25 0 9 25

 Nonrestricted, developmentd 0 0 0 0 0 0 0 0 0 0 0 0

 Nonrestricted, limited developmente 37,864 8,112 7 0 9 24 0 9 24 0 9 24 Restricted, nondevelopment f 2,350 365 0 0 0 1 0 0 1 0 0 1State 0 0 0 0 0 0 0 0 0 0 0 0

Private 70,089 16,016 2075 24 20 21 19 24 22 13 29 23

Other governmental entity 0 0 0 0 0 0 0 0 0 0 0 0

Unknown 877 1 0 0 0 0 0 0 0 0 0 0

 Total 111,179 24,494 2,082 24 29 46 19 33 48 13 38 49

- - - - - - 100 - - - - - - - - - - - - 100 - - - - - - - - - - - - 100 - - - - - - 

a Area of current yellow-cedar forests estimated from species distribution models and surveys (see “Yellow-cedar distribution” in section 4).b See “Yellow-cedar decline” in section 4 for more information on how acreage of yellow-cedar decline was mapped. c Percentage of the estimated yellow-cedar distribution acreage that is projected to be in low-, medium-, and high-risk classes for yellowcedar decline based on hydrology and snow modeling. Percentages may not sum to 100 because of rounding. d Nonrestricted, development: land use designations that permit commercial timber harvest on a regulated (scheduled) basis.e Nonrestricted, limited development: land use designations that do not permit commercial timber on a regulated basis. On a case-by-case 

basis the following activities may be allowed: salvage, personal use, thinning, pruning, or planting. 

f Restricted land is land permanently reserved from wood products utilization through statute or administrative designation. Examples are 

national forest wilderness areas, national monuments, and withdrawal areas.
359

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska Figure 121—Annette and Duke Islands Yellow-Cedar Management Zone (Ketchikan Ranger District, Tongass National Forest): areas and percentages of low, moder- ate, and high risk of yellow-cedar decline in forests with yellow-cedar based on soil drainage and snow accumulation models. See section 4 for details on models for decline risk classes. Areas without yellow-cedar appear gray. Location for this zone is given in the inset map. 
360

GENERAL TECHNICAL REPORT PNW-GTR-917
361

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

This report provides a comprehensive review of the state of the knowledge for 

yellow-cedar in many facets of its ecology and management. In addition, a review 

of the extent and impacts of yellow-cedar decline, and strategies to cope with it, 

is presented. There remain numerous important information gaps that need to be 

addressed to enhance our understanding and management of this valuable tree. 

The following summary lists high-priority information gaps, research needs, and 

collaboration for yellow-cedar with an emphasis on Alaska.

Yellow-Cedar Values, Ecology, and Silvics 

Document knowledge and uses of yellow-cedar by Alaska Native 

people.

There is a long history of spiritual connection, ecological knowledge, and use of 

yellow-cedar by Alaska Native communities. Recording the oral narratives will 

supplement the current understanding of the yellow-cedar. Traditional ecological 

knowledge of yellow-cedar could be added to and contrasted with information 

from scientific research to create a richer understanding of the tree. Management 

of yellow-cedar should consider Alaska Native communities’ need for access to 

yellow-cedar. Adaptive management of young stands could include silvicultural 

trials to promote particular tree characteristics that meet wood and bark needs for 

Alaska Native uses. 

Determine historical origins of yellow-cedar in Alaska, Holocene 

migration and the influence on current broad genetic structure, 

and extent of local clonal reproduction. 

The origins of yellow-cedar in Prince William Sound and southeast Alaska are still 

unresolved. Thus far, research on the genetic structure of yellow-cedar in Alaska 

has not clearly identified patterns of postglacial migration of the species. A prevailing hypothesis is for the expansion of postglacial populations from outer-coastal 

refugia in Alaska eastward and northward, and potentially from Haida Gwaii to the 

mainland of British Columbia and northerly into Alaska. Future research needs to 

discern both the regional genetic distribution as it relates to historical migration and 

unravel the interaction with the clonal relationships at local scales. 

Appendix 2: Information Gaps, Needed Research,

and Technology Transfer
362

GENERAL TECHNICAL REPORT PNW-GTR-917

Merge knowledge on the ecology, climate interactions, and 

management of yellow-cedar from different parts of the 

species’ range. 

The range of yellow-cedar is about 1,600 mi long and crosses a vast expanse of 

ecosystems and two international boundaries. There is a good opportunity to assess 

the health status of yellow-cedar and management experience with the species in 

a unified manner throughout the entire range. Key steps would be to form official 

working groups and research networks with the goal of refining and implementing 

this strategy. Coordination between U.S. and Canadian colleagues has improved 

recently, but merging geographic information systems (GIS) and adopting common plant community guidelines will enhance the integration and the capacity 

to address the rangewide issues related to ecology, management, and climate 

interactions of yellow-cedar. A rangewide vulnerability assessment of yellow-cedar 

will require a coordinated effort from specialists in the Pacific Northwest, British 

Columbia, and Alaska. Periodic meetings to share information across boundaries on 

the science and management of yellow-cedar are encouraged.

Improve fine-scale mapping of yellow-cedar; develop techniques 

for detecting live yellow-cedar populations.

Certain small populations, such as the one recently discovered near Icy Bay and 

several others around Cordova, should be mapped on the ground for extent. Other 

than aerial observation, remote sensing techniques have thus far been unsuccessful at distinguishing yellow-cedar from some other tree species in mixed-species 

stands. Analysis of higher resolution, multispectral band imagery, possibly 

combined with light detection and ranging (LiDAR), might eventually solve this 

problem. 

Improve Alaska and rangewide species distribution maps and 

GIS layers for yellow-cedar; reconcile the various regional estimates on the areal occurrence of yellow-cedar forests in Alaska. 

A new rangewide distribution map and GIS layer for yellow-cedar is presented in 

section 1. Validation and refinement of the GIS layer are needed. Additional GIS 

layers that describe several abundance levels of yellow-cedar would be desirable 

(i.e., yellow-cedar forest or cover types to any level of occurrence); these will 

undoubtedly have inputs from inventory plot data. Also, this report lists a number 

of acreage estimates on the occurrence of yellow-cedar in Alaska. The acreage 

estimates from our spatially explicit mapping efforts differ from the inventorybased estimates reported in the literature. Future improvement of the yellow-cedar 
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

distribution map and GIS layers should reconcile these differences. A close examination is needed of the plot-based measurements versus models that incorporate 

remote sensing into basal area or volume estimates. A particularly vexing problem 

is the attempt to compare area estimates of yellow-cedar decline with area estimates 

of total yellow-cedar occurrence. This comparison is needed to determine the 

proportion of yellow-cedar populations that have been affected by forest decline. 

The two types of estimates (i.e., declining yellow-cedar forests and total occurrence 

of yellow-cedar) come from different data sources, different resolutions, and different abundance levels of yellow-cedar, and represent different time periods. It will 

be especially difficult to reconstruct estimates on the occurrence and abundance of 

yellow-cedar forests before they began to undergo yellow-cedar decline, in many 

cases more than a century ago. 

Determine factors that influence successful natural regeneration 

in unmanaged forests.

Successful regeneration of yellow-cedar is needed to sustain future populations 

of the species long into the future. There is anecdotal information that seedlings 

and saplings are rare in some yellow-cedar forests, and abundant in others. Forest 

inventory data can be used to address this situation, but caution should be exercised 

if equating seedling and sapling size classes from plot data with actual regeneration 

because of the perpetually stunted layering form of yellow-cedar that is common in 

some plant communities. Monitoring natural regeneration in healthy and declineaffected forests is one of the highest priorities for lands in protected status. A 

comprehensive examination of every aspect of yellow-cedar reproduction is needed 

to identify barriers to successful regeneration, and should include flowering, pollination, cone and seed production, dispersal, germination, seedling establishment, 

and herbivory. 

Climate and Yellow-Cedar Decline 

Improve the modeling of soil hydrology and snowpack characteristics as decline risk factors.

The soil hydrology model in this report is assumed to be static over time due to the 

lack of information on future potential changes in soil moisture. This factor may 

actually be more dynamic, and the variability in soil moisture across the landscape 

must be better understood to refine the risk assessment model. The present snow 

model uses precipitation and temperature to predict snow accumulation. However, 

snow accumulation is not a measure of snowpack, which is the factor that more 

directly protects yellow-cedar roots from freezing injury. A predictive snowpack 
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GENERAL TECHNICAL REPORT PNW-GTR-917

model for February or March would be an improved input for the general risk 

assessment model. The risk models presented in this report used five classes of risk 

for both drainage and snow. Determination of the actual threshold values for soil 

drainage and snow depth and duration that distinguish healthy yellow-cedar forests 

from decline-affected forests would improve the risk assessment model by collapsing five classes into two classes for each of the component input models (drainage 

and snow). 

Refine methods of detecting and mapping yellow-cedar mortality 

to produce higher resolution GIS layers.

The mapping of yellow-cedar decline has been an evolving effort. The coarse 

mapping product that is available regionwide could eventually be replaced by the 

higher resolution maps produced from remote sensing images. Until that regionwide 

layer is available, high-priority areas, such as locations where salvage operations 

may be planned, could be targeted for the high-resolution mapping. We also suggest 

using the specific indicators of individual tree stress (foliage flagging and crown 

thinning) developed by Oakes et al. (2014) as monitoring tools for early detection of 

yellow-cedar decline in managed and protected landscapes. 

Determine successional trajectories of trees and understory vegetation in forests affected by yellow-cedar decline.

Much forested area affected by yellow-cedar decline is in protected landscapes that 

will not be actively managed. It is important to understand whether the reduction 

to yellow-cedar in these forests represents a long-term, semi-permanent conversion 

to other species, and whether forest function and integrity have been impaired. The 

Oakes et al. (2014) study evaluated all life stages of yellow-cedar and co-occurring 

tree species and provided a long-term perspective on the fate of these species. 

Replication of this approach is needed for other affected forests in southeast Alaska 

and British Columbia. A focused goal of future studies could be to determine how 

western redcedar responds to the death of yellow-cedar where the two species cooccur. Such a study could be closely associated with the biogeochemical changes in 

decline-affected forests.
365

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Evaluate the impact of yellow-cedar on biogeochemical cycles in 

terrestrial and aquatic systems including successional trajectories among plant communities affected by dead and dying yellow-cedar trees. 

Yellow-cedar has a distinctive biogeochemical signature in soils, stream water, 

and understory plants of yellow-cedar stands. The implication of the alteration of 

nutrient cycles at broader scales and watersheds is unclear. There is a high likelihood that abundant yellow-cedar concentrated in a watershed will create a signal in 

stream water and possibly even estuaries. Therefore, identifying the range of variability in these systems compared with non-yellow-cedar watersheds will provide 

a new perspective for watershed management in the region. The impacts of yellowcedar mortality on the biogeochemical cycle, ranging from near-term pulses from 

dying trees to long-term effects from the reduction of yellow-cedar, are relatively 

unknown.

Develop a robust bioclimate model and GIS layer for yellowcedar to indicate emergence of new suitable habitat. 

Our report assesses the habitat suitability of yellow-cedar based on risk factors of 

decline within the existing range of yellow-cedar in Alaska. Still unknown is how 

future climate conditions may eliminate the climate barriers for the species for 

potential expansion both locally in elevation and regionally to the north and west in 

Alaska, and east into British Columbia. That investigation will require a separate 

modeling approach and a broader geographic context than used in this report. 

Several basic physiological tolerances of yellow-cedar would need to be contrasted 

with current and future climatic conditions in these areas, such as seasonal precipitation (to avoid drought stress) and annual minimum temperature (to avoid outright 

freezing regardless of the presence of snow). The resulting model outputs should be 

contrasted with expected migration rates for yellow-cedar to differentiate potential 

habitat with actual expected occupancy. Planting trials could field-test these potential suitability areas to address the possibility of assisted migration. 

Strategic Planning for Yellow-Cedar Conservation and 

Management 

Evaluate natural regeneration of yellow-cedar following timber 

harvest.

There is anecdotal information suggesting that natural regeneration by yellow-cedar 

is successful to replace the species after timber harvests in some areas, but may be 

unsuccessful in others. Geographic patterns of successful and unsuccessful natural 
366

GENERAL TECHNICAL REPORT PNW-GTR-917

regeneration could be revealed by compiling and analyzing existing regeneration 

stocking data. There is a need to correlate the yellow-cedar component as a percentage of composition in forests before harvests with the composition percentage in 

regeneration following harvests. Natural regeneration of yellow-cedar in partial harvest treatments could be monitored to determine if any alternative harvest systems 

can promote regeneration of the species.

Develop methods for protecting planted seedlings of yellowcedar from browse.

Deer are a major impediment to the successful establishment and growth of planted 

yellow-cedar seedlings in some areas. Reduced snow levels in the future could 

result in larger deer populations and increased browse pressure at higher elevations 

and regions to the north. The intensity of deer browse on yellow-cedar seedlings 

needs to be related to deer populations and their seasonal movement before decisions are made to leave seedlings unprotected or to use one of the protective 

measures. Although there are many options, the feasibility and cost-effectiveness of 

these methods should be evaluated for successful application in the field.

Quantify the amount of yellow-cedar in young-growth forests 

by stand age and productivity class to indicate future supply of 

yellow-cedar from young-growth forests.

The shift from old-growth to young-growth wood supply on the Tongass National 

Forest is a high priority for the U.S. Forest Service. Yellow-cedar’s contribution to 

the supply from young-growth forests has not been determined. Yellow-cedar is 

not well represented in the oldest and most productive of the young-growth forests 

because the species was not common on these sites when they were originally 

harvested. There is a need to determine where yellow-cedar occurs by stand age 

and site productivity in young-growth forests and project its size and volume by 

growth models. 

Improve understanding of silvicultural options to promote yellowcedar young-growth forests.

Thinning can be used to alter the composition of managed forests and favor one 

tree species over another. Thinning to favor yellow-cedar is a key tool in helping 

yellow-cedar to compete with faster growing associated species on productive sites. 

The response of yellow-cedar that has been released by thinning other trees needs 

to be monitored. The survival and growth in older young-growth forests need to 

be evaluated. Growth and yield models should be developed for yellow-cedar in 

young-growth forests. Communication with foresters in British Columbia would 
367

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

be helpful because of their longer-term experience with yellow-cedar plantations. 

Yellow-cedar in young-growth forests should be monitored for any appearance of 

yellow-cedar decline, as has been observed on Zarembo Island. The emergence of 

this problem would be most likely in wetter portions of young-growth stands that 

occur in areas of low snow accumulation. 

Develop partnerships of different landowners to expand active 

management of yellow-cedar in Alaska. 

Most of the yellow-cedar forests in Alaska occur on land administered by the Tongass and Chugach National Forests. Some forms of active management to promote 

yellow-cedar through planting and thinning may not be permitted on portions of the 

National Forest System lands (e.g., wilderness areas). State and private landowners generally have more discretion for active management but may not have the 

resources for planting or thinning to enhance populations of yellow-cedar. Coordination among various government and private entities is encouraged to expand 

active management of yellow-cedar in Alaska, including planting trials beyond the 

current natural range. 

Determine economic feasibility of salvaging dead yellow-cedar. 

The widespread extent of yellow-cedar decline and results from tests on the wood 

properties of dead yellow-cedar suggest promising prospects for salvage. Economic 

feasibility needs to be considered before salvage harvests will be attempted on 

a larger scale, however. One or more salvage trials are needed to test economic 

feasibility and to identify wood products that might be produced from dead 

yellow-cedar. 

Improve marketing of yellow-cedar wood, including wood from 

dead trees, in domestic outlets.

International export markets for yellow-cedar have been developed and are mature. 

Yellow-cedar is known locally and in certain specialty markets such as carving and 

boatbuilding, but yellow-cedar as a forest product is not well known throughout 

the United States. Marketing wood from dead yellow-cedar as a form of high-value 

wood produced in an environmentally sensitive manner could potentially expand 

domestic demand.
368

GENERAL TECHNICAL REPORT PNW-GTR-917

Evaluate the influence of natural selection on genetic traits for 

surviving yellow-cedar trees in decline-affected forests.

With intense but not complete mortality at the stand level, yellow-cedar decline 

may impose the force of natural selection in affected populations. The surviving 

yellow-cedar trees could be evaluated for genetic traits that differ from the trees 

that died. It is conceivable that the surviving trees have greater cold hardiness or 

deharden more slowly in late winter. If such traits could be found and if they were 

heritable, then a program of genetic improvement could produce planting stock for 

the restoration of yellow-cedar in affected forests.

Develop a plan for genetic conservation of yellow-cedar; expand 

the collections and determine transfer ranges of seedlots.

As genetic tools improve, the ability is gained to discern subtle genetic variability 

among the populations of yellow-cedar in Alaska. Greater understanding of the 

genomics of the species will assist in targeting the conservation of specific genetic 

stock by identifying unique genetic populations. A particular need is to collect 

seeds from the northwestern portion of the species’ range in Prince William Sound, 

both for genetic conservation and for use in future common garden trials. Another 

need is to revise tree seed zone and transfer guidelines for Alaska based on current 

knowledge about yellow-cedar genetic variation. A long-term seed procurement 

plan for yellow-cedar needs to be developed and should address the following: 

(1) the existing reforestation needs and anticipated needs from harvest levels, (2) 

projected restoration/reforestation following large-scale disturbance (wind) or accelerated cedar decline with climate change, (3) the need to share seed with British 

Columbia, the State of Alaska, and Tribal corporations, (4) review of the existing 

seed inventory, (5) seed and cone periodicity, (6) seed yield data, (7) seed viability 

data, and (8) nursery sowing factors. 
369

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Appendix 3: Yellow-Cedar Occurrence in 

Young-Growth Stands in Alaska

This appendix provides a limited but growing list of 220 young-growth stands on 

Tongass National Forest land that contain yellow-cedar, as indicated by roadside 

surveys, qualitative observations, prethinning or post-thinning stocking survey 

plots, stand examinations, or other forest inventories (fig. 122, table 58). This information was compiled from a variety of sources, including reports from Tongass 

National Forest silviculturists and databases designed to store young-growth stand 

management information. These databases are FACTS (Forest Service Activity 

Tracking System), FPS (Forest Planning and Projection System), and FSVeg (Forest 

Sampled Vegetation). We have included location information, elevation, stand size, 

productivity class, harvest date, precommercial thinning date, and quantitative 

information about yellow-cedar composition wherever possible. Stands with <2 

percent yellow-cedar composition were excluded, unless the species was known 

to have been planted. The stands gathered from the FPS database were filtered to 

exclude stands for which species composition had been modeled rather than measured through silvicultural stand examinations.

This working list will help managers and forest health professionals to identify young-growth stands for yellow-cedar monitoring, research, and modeling 

purposes. Projecting the health of these stands into the future, given the known 

hydrologic and snowpack risk factors for decline, may influence thinning prescriptions. For example, on low-snow sites, managers may choose not to retain yellowcedar in particularly wet portions of stands, and retain yellow-cedar within areas 

having deeper or better drained soils. Using and adding to this list will make it 

possible to track how thinning and other forms of stand management influence the 

health of young yellow-cedar. Moving forward, this effort will benefit from more 

detailed information about stand management history (e.g., dates of management 

treatments).

Yellow-cedar regeneration success in both unmanaged stands and managed 

young-growth stands following timber harvest has been identified as a critical 

information need by the three plant association guides for the Tongass National 

Forest (DeMeo et al. 1992, Martin et al. 1995, Pawuk and Kissinger 1989). These 

guides suggest that yellow-cedar regeneration is limited by low reproductive capacity, deer browse, and competition with associated conifers, but regeneration has 
370

GENERAL TECHNICAL REPORT PNW-GTR-917

not been quantified. In particular, it is unknown if yellow-cedar as a percentage of 

forest composition changes preharvest to postharvest, and how various management 

activities in young stands affect the relative composition and competitive status 

of yellow-cedar. If previously unmanaged stands with yellow-cedar snags or live 

trees are harvested, it will be worthwhile to track the relative change in yellowcedar composition in the developing young stand and to add this preharvest versus 

postharvest information to our growing list.

Special thanks to Carol McKenzie, Melissa Cady, Greg Roberts, Craig Buehler, 

Ben Case, Sheila Spores, and other Tongass National Forest silviculturists and 

foresters for their help in gathering this information.
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A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Figure 122—Locations of 220 young-growth stands known to contain yellow-cedar on Tongass National Forest land. More 

young-growth stands with yellow-cedar will be identified and added over time. 
372

GENERAL TECHNICAL REPORT PNW-GTR-917

Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No.

Ranger district Island

Stand 

identification 

number 

(FACTSID)

Latitude 

(°N)

Longitude 

(°W)

Mean 

elevation 

(ft)

Size 

(ac)

Productivity 

classa

Harvest 

year

Year 

thinned

Yellow-cedar 

composition 

(%)b,c,d

Assessment methode

Before/after 

precommercial 

thinning (PCT)?

1 Sitka Chichagof 2330000216 57.73112 -135.30616 226 20 4 1978 2005 3.8 Plots Before

2 Sitka Chichagof 2340000145 57.69935 -135.31526 576 133 4 1979 – 4.8 Plots Before3 Sitka Chichagof 2440000238 57.53943 -135.07798 559 106 3 1971 2012 17.0 Stand exam After4 Sitka Baranof 2920000275 57.45738 -135.44185 380 511 3 1964 – 3.0 Stand exam Before5 Sitka Baranof 2930000207 57.46395 -135.27807 94 16 3 1994 – 5.0 Plots Before6 Sitka Baranof 2930000208 57.45578 -135.30350 335 31 3 1994 – 3.0 (5.0)b Plots Before

7 Sitka Baranof 2930000209 57.45978 -135.28861 214 8 4 1994 – 5.0 (8.0) Plots Before8 Sitka Baranof 2930000210 57.46913 -135.25101 203 31 6 1994 – 7.0c Plots Before9 Sitka Baranof 2930000213 57.44744 -135.29818 829 67 4 1996 – 19.0 Plots Before10 Sitka Baranof 2930000215 57.45924 -135.34681 693 26 4 1995 – 6.0 Plots Before11 Sitka Baranof 2930000217 57.46372 -135.25026 553 15 4 1996 – 3.0c Plots Before12 Sitka Baranof 2930000218 57.47081 -135.21693 327 24 4 1995 – 3.0 (2.0)b plots Before13 Sitka Baranof 2930000219 57.47062 -135.23209 335 51 5 1996 – 3.0 (2.0)b,c plots Before14 Sitka Baranof 2930000221 57.46645 -135.25695 278 22 4 1996 – 9.0 (24.0)b,c Plots Before15 Sitka Baranof 2930000222 57.46120 -135.24557 739 27 4 1996 – 3.0 (13.0)b Plots Before16 Sitka Baranof 2930000226 57.46191 -135.18788 254 6 4 1996 – 0 (8.0)b Plots Before17 Sitka Baranof 2930000230 57.40947 -135.33071 469 18 4 1998 – 16.0 Plots Before18 Sitka Baranof 2930002071 57.46224 -135.28327 143 9 3 1994 – 1.0 (5.0)b Plots Before19 Sitka Baranof 2960000005 57.40481 -135.00030 624 139 3 1978 1993 2.1 Plots Before20 Sitka Baranof 2960000194 57.37618 -134.98176 295 216 3 1974 2009, 2011 “abundant” Stand exam After

21 Sitka Baranof 2960000294 57.40001 -135.00126 210 13 4 1993 – 3.0c Plots Before

22 Sitka Baranof 2960000308 57.39412 -135.04416 1,079 14 4 1998 – 34.0 (44.0)b Plots Before23 Sitka Baranof 2960000309 57.39423 -135.03737 479 32 5 1998 – 1.0 (3.0)b Plots Before24 Sitka Baranof 2960000310 57.39138 -135.04129 806 57 4 1994 – 4.0 Plots Before25 Sitka Baranof 2960000311 57.39060 -135.02637 328 28 4 1994 – 2.0 Plots Before26 Sitka Baranof 2960000315 57.41013 -134.99647 467 16 3 1994 – 1.0c Plots Before27 Sitka Baranof 2960000316 57.40633 -134.99951 624 23 3 1994 – 0c Plots Before28 Sitka Baranof 2960000317 57.40158 -134.99462 789 31 2 1994 – 5.0 Plots Before29 Sitka Baranof 2960000322 57.38706 -135.00489 736 53 3 1997 – 1.0 (9.0)b Plots Before30 Sitka Baranof 2960000354 57.37564 -135.00079 670 27 2 1998 – 1.0 (10.0) Plots Before31 Sitka Baranof 2970000063 57.41108 -134.93775 414 192 3 1977 1992 7.2 Plots and FIA Before

32 Sitka Baranof 2970000087 57.40917 -134.92098 510 65 3 1977 – 12.4 Plots Before
373

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No.

Ranger district Island

Stand 

identification 

number 

(FACTSID)

Latitude 

(°N)

Longitude 

(°W)

Mean 

elevation 

(ft)

Size 

(ac)

Productivity 

classa

Harvest 

year

Year 

thinned

Yellow-cedar 

composition 

(%)b,c,d

Assessment methode

Before/after 

precommercial 

thinning (PCT)?

33 Sitka Baranof 2970000098 57.42156 -134.90927 275 135 3 1976 1995 2.4 Plots Before34 Sitka Baranof 2970000400 57.41078 -134.98395 471 68 4 1994 – 7.0 Plots Before35 Sitka Baranof 2970000402 57.41260 -134.96280 847 48 3 1998 – 7.0 (12.0)b Plots Before

36 Sitka Baranof 2970000403 57.41357 -134.95179 434 50 3 1997 – 11.0 (2.0)b Plots Before37 Sitka Baranof 2970000408 57.40579 -134.94629 499 35 4 1997 – Unmeasuredc Plots Before38 Sitka Baranof 2970000411 57.39789 -134.93538 748 47 3 1997 – 7.0 (27.0)b Plots Before39 Sitka Baranof 2970000413 57.39470 -134.93205 1,215 11 4 1998 – 5.0 (18.0)b Plots Before40 Sitka Baranof 2970000414 57.38885 -134.93674 1,076 41 2 1998 – 5.0 (1.0)b Plots Before41 Sitka Baranof 2970000419 57.41068 -134.90552 1,077 130 3 1994 – 25.0 Plots Before42 Sitka Baranof 2970000449 57.41710 -134.97041 555 30 3 1997 – Unmeasuredc Plots Before43 Petersburg Kuiu 4000000009 56.84807 -134.24618 1,429 70 2 1979 – 14.9c Plots Before44 Petersburg Kupreanof 4250200058 56.91090 -133.73811 469 119 2 1969 1981 15.0 Stand exam After45 Petersburg Mitkof 4470300006 56.70012 -132.83749 531 242 4 1967 1982 3.0 Stand exam After46 Petersburg Mitkof 4500000003 56.73561 -132.78833 785 148 3 1968 1984 2.0 Stand exam After47 Petersburg Mitkof 4500000007 56.67285 -132.78513 952 121 3 1973 2007 41.0 Stand exam After48 Petersburg Mitkof 4500000010 56.66166 -132.78823 781 255 3 1973 1984 3.0 Stand exam After49 Petersburg Mitkof 4520000006 56.61379 -132.70695 444 53 3 1972 1982 7.0 Stand exam After50 Petersburg Mitkof 4520000007 56.59385 -132.71123 702 346 3 1968 1986 9.0 Stand exam After51 Petersburg Mitkof 4520000010 56.55120 -132.70299 671 80 3 1966 1988 23.0 Stand exam After52 Petersburg Mitkof 4520000055 56.60819 -132.72070 423 65 3 1972 1982 8.0 Stand exam After53 Petersburg Mitkof 4530000001 56.64175 -132.70000 1,078 180 3 1972 – 4.0 Stand exam Before54 Petersburg Mitkof 4530000010 56.64375 -132.69125 428 108 4 1972 1984 3.0 Stand exam After55 Petersburg Mitkof 4530000011 56.65321 -132.68572 391 106 3 1972 1984 2.0 Stand exam After56 Petersburg Mitkof 4530000031 56.61888 -132.70211 477 15 3 1972 1982 5.0 Stand exam After57 Petersburg Mitkof 4540000001 56.62054 -132.64199 442 87 3 1981 2014 14.4c? Stand exam After58 Petersburg Mitkof 4540000002 56.61649 -132.65531 631 30 3 1981 2014 3.0 FIA Before59 Petersburg Mitkof 4540000008 56.56708 -132.64269 826 154 3 1966 1987 7.0 Stand exam After60 Wrangell Zarembo 4560000038 56.42053 -132.83076 1,109 97 3 1975 – 15.4 Walk-through Before

61 Wrangell Zarembo 4560000070 56.45345 -132.94087 4 9 – 1973 – 7.8 Plots Before62 Wrangell Zarembo 4560100008 56.44807 -132.75804 438 35 4 1974 2011 4.2 Plots Before
374

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No. Ranger district Island Stand identification number (FACTSID) Latitude (°N) Longitude (°W) Mean elevation (ft) Size (ac) Productivity classa Harvest year Year thinned Yellow-cedar composition (%)b,c,d Assessment methode Before/after precommercial thinning (PCT)? 63 Wrangell Zarembo 4560100011 56.44181 -132.73260 694 73 4 1975 2004 2.8 Plots Before 64 Wrangell Zarembo 4560100014 56.44081 -132.68881 337 100 5 1975 2002 4.9 Plots Before 65 Wrangell Zarembo 4560100017 56.44659 -132.73917 556 28 4 1981 2011 5.1 (7.0)d Plots Before, after 66 Wrangell Zarembo 4560100021 56.43573 -132.73329 912 20 3 1980 2012 3.6 Plots Before 67 Wrangell Zarembo 4560100022 56.44743 -132.72962 616 19 5 1981 2004 8.4 Plots Before 68 Wrangell Zarembo 4560100023 56.44431 -132.74324 654 16 5 1980 2012 9.5 (30.0)d Plots Before, after 69 Wrangell Zarembo 4560100025 56.43701 -132.74603 808 158 4 1980 2012 14.3 (30.0)d Plots Before, after 70 Wrangell Zarembo 4560100026 56.43000 -132.72908 1,174 103 4 1976 2012 2.5 Plots Before

71 Wrangell Zarembo 4560100270 56.43289 -132.67267 168 6 5 1974 – 3.5 Plots Before72 Wrangell Zarembo 4570000004 56.42000 -132.92034 597 297 4 1970 1985 2.1 Plots Before73 Wrangell Zarembo 4570000008 56.41898 -132.87337 1,028 177 3 1972 1987 7.4 Plots Before74 Wrangell Zarembo 4570000012 56.39577 -132.84752 1,483 222 3 1974 2014 3.7 Plots Before75 Wrangell Zarembo 4570000013 56.40036 -132.83294 1,508 52 3 1974 2014 5.7 Plots Before76 Wrangell Zarembo 4570000014 56.35800 -132.86269 865 33 5 1981 2011 3.7 Plots Before

77 Wrangell Zarembo 4570000015 56.36570 -132.86844 704 26 5 1981 2008 7.5 (49.0)d Plots Before, after

78 Wrangell Zarembo 4570000018 56.37947 -132.90496 644 59 3 1975 2011 7.1 (18.0)d Plots Before, after79 Wrangell Zarembo 4570000020 56.37674 -132.92078 759 51 4 1975 2008 38.6 (80.0)d Plots Before, after80 Wrangell Zarembo 4570000022 56.35782 -132.99138 394 43 3 1979 1998 4.8 Plots Before81 Wrangell Zarembo 4570000024 56.38263 -132.97161 115 150 3 1973 1983, 2004 >10 Roadside After82 Wrangell Zarembo 4570000026 56.38687 -132.91910 595 54 3 1975 2002 9.7 Plots Before83 Wrangell Zarembo 4570000039 56.35729 -132.82887 760 22 3 1981 2007 2.4 Plots Before84 Wrangell Zarembo 4570000040 56.36093 -132.84654 725 52 4 1981 2007 2.6 Plots Before85 Wrangell Zarembo 4570000070 56.38784 -132.97752 405 25 3 1975 2004 >10 Roadside After86 Wrangell Zarembo 4580400011 56.24423 -132.87632 100 61 2 1973 1985 2.2 Plots Before87 Wrangell Zarembo 4580400013 56.30039 -132.81657 957 31 4 1981 2012 9.6 (43.0)d Plots Before, after88 Wrangell Zarembo 4580400016 56.31467 -132.83308 559 43 5 1981 2008 3.1 Plots Before89 Wrangell Zarembo 4580400018 – – – – – 1981 – 2.0 Plots Before90 Wrangell Zarembo 4580500001 56.34893 -132.91056 927 114 3 1979 1998 9.5 Plots Before91 Wrangell Zarembo 4580500005 56.34366 -133.00713 405 27 3 1979 2004 2.3 Plots Before

92 Wrangell Zarembo 4580500007 56.32527 -132.99570 674 54 3 1979 2011 7.9 (51.0)d Plots Before, after
375

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No.

Ranger district Island

Stand 

identification 

number 

(FACTSID)

Latitude 

(°N)

Longitude 

(°W)

Mean 

elevation 

(ft)

Size 

(ac)

Productivity 

classa

Harvest 

year

Year 

thinned

Yellow-cedar 

composition 

(%)b,c,d

Assessment methode

Before/after 

precommercial 

thinning (PCT)?

93 Wrangell Zarembo 4590200041 56.35243 -132.81071 682 39 5 1981 2009 4.3 Plots Before94 Wrangell Zarembo 4590200043 56.33514 -132.80981 730 47 4 1981 2013 9.7 (18.0)d Plots Before, after

95 Wrangell Zarembo 4590200044 56.33595 -132.79249 817 123 4 1982 2013 2.9 Plots Before96 Wrangell Zarembo 4590200046 56.33714 -132.77913 939 23 4 1981 2008 3.1 Plots Before97 Wrangell Zarembo 4590200370 56.32579 -132.81394 599 49 4 1981 2012 4.5 Plots Before98 Wrangell Zarembo 4590600002 56.31748 -132.69265 632 29 4 1981 2009 4.1 Plots Before99 Wrangell Zarembo 4590600008 56.25038 -132.79934 106 68 2 1970 1986 2.9 Plots Before100 Wrangell Zarembo 4590600010 56.25454 -132.77274 118 55 2 1970 1985 14.6 Plots Before101 Wrangell Etolin 4650000066 56.19971 -132.59687 618 89 3 1986 2010 11.0 Plots After102 Wrangell Etolin 4670000029 56.19440 -132.59639 606 29 4 1986 2010 11.0 Plots After103 Wrangell Wrangell 4770000123 56.29279 -132.34628 637 35 5 1987 2012 2.0 Plots After104 Wrangell Wrangell 4780000184 56.30855 -132.24684 1,031 58 6 1987 2012 32.0 Plots After105 Wrangell Wrangell 4800100021 56.23177 -132.08894 491 16 5 1991 2014 20.0 Plots After106 Thorne Bay Prince of Wales 5290100504 56.32846 -133.57102 427 72 3 1980 – 7.0 FIA Before107 Thorne Bay Prince of Wales 5320300520 56.28616 -133.34643 220 88 3 1983 2001 2.0 FIA After108 Thorne Bay Prince of Wales 5340400503 56.18344 -133.18011 511 200 3 1969 1984 13.0 Stand exam After109 Thorne Bay Prince of Wales 5380100504 56.17773 -133.20428 1,283 13 3 1969 – 4.0 Stand exam Before110 Thorne Bay Prince of Wales 5380100506 56.17099 -133.19675 834 115 2 1966 2000 2.0 Stand exam After111 Thorne Bay Prince of Wales 5380100507 56.16847 -133.18021 529 350 3 1966 1984 3.0 Stand exam After112 Thorne Bay Prince of Wales 5380200012 56.15242 -133.23322 453 25 3 1969 2012 2.0 Stand exam After113 Thorne Bay Prince of Wales 5380300097 56.14420 -133.17611 789 213 3 1966 1993 5.0 Stand exam After114 Thorne Bay Kosciusko 5450200512 55.98001 -133.71930 275 47 2 1959 1982 7.0 Stand exam After115 Thorne Bay Prince of Wales 5500200511 56.08696 -133.20603 272 76 3 1970 1991 2.0 Stand exam After116 Thorne Bay Prince of Wales 5500300115 56.08663 -133.18694 517 4 3 1966 2002 2.0 Stand exam After117 Thorne Bay Prince of Wales 5500300501 56.07606 -133.18482 674 189 3 1966 1986 2.0 Stand exam After118 Thorne Bay Prince of Wales 5500300506 56.08047 -133.18088 674 155 2 1966 1983 8.0 Stand exam After119 Thorne Bay Prince of Wales 5500300507 56.09436 -133.18164 437 216 2 1966 1983, 1989 2.0 Stand exam After120 Thorne Bay Prince of Wales 5510200511 56.09246 -133.08254 38 10 4 1964 – 37.0 Stand exam Before121 Thorne Bay Prince of Wales 5600100530 55.82121 -133.31236 312 185 2 1947 – 2.0 Stand exam Before122 Thorne Bay Prince of Wales 5710200524 55.91908 -133.06924 406 121 3 1990 2015 3.0 FIA Before
376

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No. Ranger district Island Stand identification number (FACTSID) Latitude (°N) Longitude (°W) Mean elevation (ft) Size (ac) Productivity classa Harvest year Year thinned Yellow-cedar composition (%)b,c,d Assessment methode Before/after precommercial thinning (PCT)? 123 Thorne Bay Prince of Wales 5740100517 55.91209 -132.97329 352 81 3 1988 – 5.0 Roadside Before 124 Thorne Bay Prince of Wales 5740100518 55.89794 -132.94445 288 26 4 1988 2014 Unmeasured Roadside Before 125 Thorne Bay Prince of Wales 5740100599 55.88441 -132.95005 678 24 2 1994 – 5.0 Roadside Before 126 Thorne Bay Prince of Wales 5740109501 55.87023 -132.93003 746 29 4 1994 – 10.0 Roadside Before 127 Thorne Bay Prince of Wales 5740200514 55.91499 -132.89887 1,009 62 4 1991 – 18.0 Roadside Before 128 Thorne Bay Prince of Wales 5740200516 55.92226 -132.91023 1,285 18 4 1990 2014 30.0 Roadside Before 129 Thorne Bay Prince of Wales 5740202516 55.92145 -132.90431 1,336 15 5 1989 2014 30.0 Roadside Before 130 Thorne Bay Prince of Wales 5740300509 55.89916 -132.87369 1,793 27 4 1989 – 30.0 Roadside Before 131 Thorne Bay Prince of Wales 5740300510 55.91313 -132.89462 900 17 3 1991 – 18.0 Roadside Before

132 Thorne Bay Prince of Wales 5740400511 55.86226 -132.83560 1296 78 4 1988 2014 30.0 Roadside Before133 Thorne Bay Prince of Wales 5740400512 55.86565 -132.84510 1115 40 4 1988 2014 15.0 Roadside Before

134 Thorne Bay Prince of Wales 5740400521 55.86324 -132.86044 1,357 88 3 1993 2014 7.0 Roadside Before

135 Thorne Bay Prince of Wales 5740800501 55.77991 -132.85467 457 6 3 1991 – 3.0 Roadside Before

136 Thorne Bay Prince of Wales 5750300508 55.79865 -132.78095 660 45 3 1992 2014 2.0 Roadside Before

137 Thorne Bay Prince of Wales 5750302506 55.80212 -132.77989 614 15 5 1992 2014 5.0 Roadside Before

138 Thorne Bay Prince of Wales 5750302508 55.80008 -132.78737 506 24 5 1992 2014 2.0 Roadside Before

139 Thorne Bay Prince of Wales 5760100502 55.74568 -132.82920 484 65 2 1990 2014 2.0 Roadside Before

140 Thorne Bay Prince of Wales 5760100505 55.77343 -132.85126 525 21 3 1991 – 4.0 Roadside Before

141 Thorne Bay Prince of Wales 5760102504 55.76016 -132.83554 559 41 3 1991 – 2.0 Roadside Before

142 Thorne Bay Prince of Wales 5760102505 55.77399 -132.85248 525 62 4 1991 – 3.0 Roadside Before

143 Thorne Bay Prince of Wales 5770400518 55.83881 -132.97903 533 64 4 1990 2014 Unmeasured – ?

144 Thorne Bay Prince of Wales 5790100506 55.73023 -132.64481 758 165 3 1988 – 6.0 Roadside Before

145 Thorne Bay Prince of Wales 5790100516 55.74032 -132.66110 741 120 3 1990 – 5.0 Roadside Before

146 Thorne Bay Prince of Wales 5790209505 55.72290 -132.56914 894 19 4 1995 – 3.0 Roadside Before

147 Thorne Bay Prince of Wales 5800200516 55.79018 -132.64403 886 102 4 1986 – Unmeasured – –

148 Thorne Bay Prince of Wales 5810100517 55.95861 -132.78950 1,148 71 4 1989 – 9.0 Roadside Before

149 Thorne Bay Prince of Wales 5810200003 55.91768 -132.74019 806 132 3 1969 1994 4.0 Stand exam After

150 Thorne Bay Prince of Wales 5810200007 55.95589 -132.73457 473 76 4 1969 1992 2.0 Stand exam After151 Thorne Bay Prince of Wales 5810200509 55.95300 -132.73185 845 67 5 1996 – 20.0 Roadside Before

152 Thorne Bay Prince of Wales 5810200572 55.94032 -132.74786 1,034 40 4 1993 – 20.0 Roadside Before

153 Thorne Bay Prince of Wales 5810200573 55.92724 -132.73619 1,605 19 5 1993 – 20.0 Roadside Before
377

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No.

Ranger district Island

Stand 

identification 

number 

(FACTSID)

Latitude 

(°N)

Longitude 

(°W)

Mean 

elevation 

(ft)

Size 

(ac)

Productivity 

classa

Harvest 

year

Year 

thinned

Yellow-cedar 

composition 

(%)b,c,d

Assessment methode

Before/after 

precommercial 

thinning (PCT)?

154 Thorne Bay Prince of Wales 5810209501 55.94800 -132.74006 603 11 5 1995 – 2.0 Roadside Before155 Thorne Bay Prince of Wales 5810300501 55.91922 -132.77370 167 9 4 1968 – 4.0 Stand exam Before

156 Thorne Bay Prince of Wales 5810300598 55.89274 -132.79429 227 1 5 1992 – 10.0 Roadside Before

157 Thorne Bay Prince of Wales 5810400518 55.89932 -132.77721 426 62 4 1989 – 5.0 Roadside Before

158 Thorne Bay Prince of Wales 5810400520 55.87726 -132.71887 956 51 3 1989 – 5.0c? Roadside Before

159 Thorne Bay Prince of Wales 5830100513 55.87530 -132.70750 915 23 5 1990 – 5.0 Roadside Before160 Thorne Bay Prince of Wales 5830100516 55.89880 -132.69286 911 97 4 1989 – 10.0 Roadside Before161 Thorne Bay Prince of Wales 5830300503 55.87821 -132.67617 616 19 3 1989 – 7.0 Roadside Before162 Thorne Bay Prince of Wales 5830300504 55.87666 -132.69734 764 149 2 1989 – 5.0 Roadside Before163 Thorne Bay Prince of Wales 5840100026 55.85745 -132.56974 79 21 4 1998 2014 5.0 Roadside Before164 Thorne Bay Prince of Wales 5840200066 55.80977 -132.56889 1,016 51 5 1998 – 5.0 Roadside Before165 Thorne Bay Prince of Wales 5840200075 55.81470 -132.56807 1,162 4 7 1998 – 5.0 Roadside Before166 Thorne Bay Prince of Wales 5840200583 55.80857 -132.58321 857 59 5 1993 – 10.0 Roadside Before167 Thorne Bay Prince of Wales 5840200584 55.81562 -132.58115 1,418 40 4 1993 – 5.0 Roadside Before168 Thorne Bay Prince of Wales 5840200597 55.81701 -132.52456 307 25 4 1992 – 5.0 Roadside Before169 Thorne Bay Prince of Wales 5840201582 55.83608 -132.54943 390 31 5 1994 – 5.0 Roadside Before170 Thorne Bay Prince of Wales 5840300019 55.79706 -132.51592 334 31 3 1997 – 6.0 Roadside Before171 Thorne Bay Prince of Wales 5840300594 55.80899 -132.52060 154 86 5 1992 – 5.0 Roadside Before172 Thorne Bay Prince of Wales 5850100538 55.77786 -132.56979 1,014 48 5 1992 – 10.0 Roadside Before173 Thorne Bay Prince of Wales 5850100539 55.76797 -132.57740 875 61 5 1993 – 48.0 Roadside Before174 Thorne Bay Prince of Wales 5850100540 55.78666 -132.58566 1,233 34 5 1993 – 25.0 Roadside Before175 Thorne Bay Prince of Wales 5850100542 55.78632 -132.59508 1,463 169 4 1993 – 28.0 Roadside Before176 Thorne Bay Prince of Wales 5850100544 55.77907 -132.59531 1,243 60 4 1993 – 40.0 Roadside Before177 Thorne Bay Prince of Wales 5850109501 55.76431 -132.53486 702 32 5 1995 – 5.0 Roadside Before178 Thorne Bay Prince of Wales 5850109505 55.77186 -132.54712 731 14 6 1995 – 5.0 Roadside Before179 Thorne Bay Prince of Wales 5850109601 55.76039 -132.57183 1,071 29 5 1996 – 2.0 Roadside Before180 Thorne Bay Prince of Wales 5850109603 55.76734 -132.51200 458 25 7 1995 – 2.0 Roadside Before181 Thorne Bay Prince of Wales 5850109604 55.76303 -132.51736 570 4 7 1995 – 2.0 Roadside Before182 Thorne Bay Prince of Wales 5860100501 55.70572 -132.57549 591 653 3 1963 – 4.0 Stand exam Before183 Thorne Bay Prince of Wales 5860109507 55.72036 -132.56758 945 9 5 1995 – 3.0 Roadside Before
378

GENERAL TECHNICAL REPORT PNW-GTR-917 Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No. Ranger district Island Stand identification number (FACTSID) Latitude (°N) Longitude (°W) Mean elevation (ft) Size (ac) Productivity classa Harvest year Year thinned Yellow-cedar composition (%)b,c,d Assessment methode Before/after precommercial thinning (PCT)? 184 Thorne Bay Prince of Wales 5860300504 55.68363 -132.57294 241 412 3 1962 – 4.0 Stand exam Before 185 Thorne Bay Prince of Wales 5900300514 55.73303 -132.95260 1,121 338 3 1967 1984 5.0 Stand exam After 186 Thorne Bay Prince of Wales 5950300074 55.65059 -132.86157 1,317 6 7 1999 – 2.0 Roadside – 187 Thorne Bay Prince of Wales 5950300521 55.66448 -132.89306 497 61 3 1987 – 3.0 Roadside Before 188 Thorne Bay Prince of Wales 5950400514 55.63436 -132.85973 1,030 54 3 1990 – 8.0 Roadside Before 189 Craig Prince of Wales 5950400516 55.64389 -132.90677 619 59 3 1991 – 5.0 Roadside Before 190 Thorne Bay Prince of Wales 5950402519 55.62118 -132.83990 1,543 17 4 1991 2014 3.0 Roadside Before 191 Thorne Bay Prince of Wales 5960500502 55.69308 -132.81523 882 54 4 1989 – 10.0 Roadside Before 192 Thorne Bay Prince of Wales 5960500505 55.69062 -132.80210 827 35 4 1990 – 10.0 Roadside Before

193 Thorne Bay Prince of Wales 5971100505 55.70592 -132.66229 217 76 3 1988 – 5.0c? Roadside Before

194 Thorne Bay Prince of Wales 5972100046 55.64925 -132.74817 1,013 80 3 1966 1985 2.0 Stand exam After195 Thorne Bay Prince of Wales 5972200506 55.66677 -132.72135 744 98 2 1988 – 3.0 Roadside Before196 Thorne Bay Prince of Wales 5972200523 55.65388 -132.71990 1,228 43 2 1993 – 2.0 Roadside Before197 Thorne Bay Prince of Wales 5972300518 55.64722 -132.65290 645 94 2 1992 – 5.0 Roadside Before198 Thorne Bay Prince of Wales 5972300519 55.64262 -132.64433 500 25 3 1992 – 5.0 Roadside Before199 Thorne Bay Prince of Wales 5972300520 55.63611 -132.64012 505 47 4 1992 – Unmeasured – –

200 Thorne Bay Prince of Wales 5972400513 55.64210 -132.70298 1,427 77 3 1989 – 3.0 Roadside Before201 Thorne Bay Prince of Wales 5972400514 55.62701 -132.63495 574 40 5 1992 – 10.0 Roadside Before202 Thorne Bay Prince of Wales 5972400515 55.61768 -132.63835 717 70 4 1992 – 2.0 Roadside Before203 Thorne Bay Prince of Wales 5972400516 55.61227 -132.64806 1,012 28 3 1992 – 5.0 Roadside Before204 Thorne Bay Prince of Wales 5980200522 55.59305 -132.56055 64 102 3 1945 – 22.0 Stand exam Before205 Craig Prince of Wales 6130100509 55.39232 -132.65459 1,959 14 7? 2000 – 34.0 Research plot Before206 Craig Prince of Wales 6200500504 55.33714 -132.49037 390 44 2 1954 1991 6.0 Stand exam After207 Craig Prince of Wales 6200500512 55.33502 -132.48522 286 123 2 1954 – 10.0 Stand exam Before208 Craig Prince of Wales 6200500517 55.34269 -132.49560 161 133 2 1954 – 19.0 Stand exam Before209 Craig Prince of Wales 6210500522 55.35612 -132.73058 115 177 2 1960 2012 3.0 Stand exam Before

210 Craig Prince of Wales 6210500534 55.32158 -132.66451 1,032 25 2 1997 – Unmeasured – –211 Craig Prince of Wales 6210600513 55.33029 -132.73669 966 129 2 1961 – 3.0 Stand exam Stand exam

212 Craig Prince of Wales 6220100506 55.50089 -132.84617 779 48 3 1961 – 3.0 Stand exam Stand exam

213 Ketchikan Revillagigedo 7370100128 55.76925 -131.49739 1,375 66 2 1996 2014 14.0 Plots After214 Ketchikan Revillagigedo 7380400009 55.66518 -131.56539 1,206 46 2 1990 2005 Unmeasured – –
379

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Table 58—Young-growth forest stands on Tongass National Forest land that are known to contain a regenerated yellow-cedar component (continued) No.

Ranger district Island

Stand 

identification 

number 

(FACTSID)

Latitude 

(°N)

Longitude 

(°W)

Mean 

elevation 

(ft)

Size 

(ac)

Productivity 

classa

Harvest 

year

Year 

thinned

Yellow-cedar 

composition 

(%)b,c,d

Assessment methode

Before/after 

precommercial 

thinning (PCT)?

215 Ketchikan Revillagigedo 7460800115 55.53074 -131.36483 394 49 3 1994 2011 18.0 Plots After

216 Ketchikan Revillagigedo 7470600084 55.48943 -131.44776 435 31 4 1995 2011 53.0c Plots After

217 Ketchikan Revillagigedo 7480400084 55.43930 -131.61103 851 16 2 1989 2006 Unmeasured – –218 Ketchikan Revillagigedo 7480400094 55.44762 -131.62072 610 17 3 1997 – Unmeasuredc? – –219 Ketchikan Revillagigedo 7480400095 55.44388 -131.61781 687 3 2 1997 – Unmeasured – –220 Ketchikan Revillagigedo 7530200066 55.50137 -131.26201 1,294 79 1 1993 2011 16.0 Plots After

a Productivity classes range from 1 to 7, from highest to lowest site productivity on the basis of preharvest timber volume (USDA FS 2008b, listed in “Literature Cited” for main text of this report).b The first composition estimate applies to seedlings ≥4 in tall; the second applies to seedlings <4 in tall.c Stand planted with yellow-cedar. A question mark after this symbol signifies that a site was planted, but possibly with species other than yellow-cedar.d The first composition estimate applies to surveys before thinning, and the second estimate applies to surveys after thinning.e Yellow-cedar composition assessments were made through plot-based stocking surveys, visually estimated roadside stocking surveys, stand examinations or other inventories, or research plot 

measurements. “Roadside” is listed as the survey method when the specific survey method is not known, as this is the most informal type of composition assessment listed here. FIA = U.S. Forest Service, Forest Inventory and Analysis.
380

GENERAL TECHNICAL REPORT PNW-GTR-917

Appendix 4: Common and Scientific Names

of Plants, Mammals, Insects, and Fungi 

Mentioned in This Report

Common name Scientific name

Plants

Alaska blueberry Vaccinium alaskaense Howell

Alder Alnus Mill.

American skunk cabbage Lysichiton americanus Hultén & H. St. John

Baker cypress, Modoc cypress, Siskiyou 

cypress

Cupressus bakeri Jeps.

Birch Betula L.

Black spruce Picea mariana (Mill.) Britton, Sterns & 

Poggenb

Blueberry Vaccinium L.

Brewer spruce, Brewer’s weeping spruce Picea breweriana S. Watson

Bunchberry dogwood, dwarf dogwood Cornus canadensis L.

California red fir Abies magnifica A. Murray

Chilean cypress, Chilean cedar Austrocedrus chilensis (D. Don) Pic. Serm. & 

Bizzarri

Coast redwood Sequoia sempervirens (D. Don) Endl.

Common juniper Juniperus communis L.

Creeping juniper Juniperus horizontalis Moench

Douglas-fir Pseudotsuga menziesi (Mirb.) Franco

Golden Vietnamese cypress Xanthocyparis vietnamensis Farjon & Hiep

Hard southern yellow pines (slash, 

longleaf, or loblolly pine)

Pinus elliotii Engelm., P. palustris Mill., or P. 

taeda L.

Hinoki cedar/cypress, Japanese cedar/

cypress

Chamaecyparis obtusa (Siebold & Zucc.) 

Endl.

Incense-cedar Calocedrus decurrens (Torr.) Florin

Kenai birch Betula kenaic W.H. Evans

Lutz spruce (Sitka × white) Picea lutzi Little

Maple Acer L.

Monterey cypress Cupressus macrocarpa Hartw.

Mountain hemlock Tsuga mertensiana (Bong.) Carr.

Noble fir Abies procera Rehder

Oval-leaved blueberry Vaccinium ovalifolium Sm.

Pacific silver fir Abies amabilis Dougl. ex J. Forbes

Pacific yew Taxus brevifolia Nutt.

Paper birch Betula papyrifera Marshall 

Port-Orford-cedar Chamaecyparis lawsonia (Murray) Parl.

Quaking aspen Populus tremuloides Michx.
381

A Climate Adaptation Strategy for Conservation and Management of Yellow-Cedar in Alaska

Common name Scientific name

Redwood Sequoia Endl.

Salal Gaultheria shallon Pursh

Shore pine (ssp. Lodgepole pine) Pinus contorta Dougl. ex Loud. var. contorta

Sitka spruce Picea sitchensis (Bong.) Carr.

Skunkcabbage Lysichiton Schott.

Trailing bramble Rubus pedatus Sm.

Western redcedar Thuja plicata Donn ex D. Don

Western white pine Pinus monticola Dougl. ex D. Don

White spruce Picea glauca (Moench) Voss

Whitebark pine Pinus albicaulis Engelm.

Yellow-cedar Callitropsis nootkatensis (D. Don) Little

Yew Taxus L.

Mammals

Black bear Ursus americanus

Brown bear Ursus arctos

Keen’s myotis Myotis keeni

Moose Alces alces

North American beaver Castor canadensis

Porcupine Erethizon dorsatum

Sitka black-tailed deer Odocoileus hemionus sitkensis

Insects

Ambrosia beetles Trypodendron spp. (Coleoptera: 

Curculionidae)

Cedar bark beetle Phloeosinus cupressi, P. sequoia, and P. keeni 

(Coleoptera: Curculionidae: Scolytinae)

Cypress tip moths Argyresthia spp. (Lepidoptera: 

Yponomeutidae)

Formosan subterranean termite Coptotermes formosanus (Blattodea: 

Rhinotermitidae)

Green-striped forest looper Melanolophia imitata (Lepidoptera: 

Geometridae)

Longhorned borers Coleoptera: Cerambycidae

Saddle-backed looper Ectropis crepuscularia (Lepidoptera: 

Geometridae)

Western hemlock looper Lambdina fiscellaria lugubrosa (Lepidoptera: 

Geometridae)

Wood wasp, horntail Sirex sp. (Hymenoptera: Siricidae)

Yellow-cedar gall midge Chamaediplosis nootkatensis (Diptera: 

Cecidomyiidae) 

Yellow-cedar pollen mite Trisetacus chamaecyparis (Prostigmata: 

Phytopidae) 
382

GENERAL TECHNICAL REPORT PNW-GTR-917

Common name Scientific name

Fungi

Ambrosia fungi, ophiastomatoid fungi Ambrosiella spp., Rafaellea spp., 

Dryadomyces spp. (Ophiostomatales)

Armillaria root disease Armillaria sp.

Brown cubical and pocket rot Postia placenta (Fr.) M.J. Larsen & Lombard

Cedar-apple rust Gymnosporangium nootkatense Arthur

Dry rot fungus Serpula himantioides (Fr.) P. Karst.

Ear fungus Auricularia auricularis (Gray) G.W. Martin 

Elegant polypore Polyporus elegans (Bull.) Trog, Flora

(Regensburg)

Gloeophyllum conk Gloeophyllum trabeum (Pers.: Fr.) Murrill 

Gray mold Botrytis cinerera Pers.: Fr.

Laminated root/butt rot Phellinus weirii (Murrill) Gilb.

Mal del ciprés Phytophthora austrocedrae Gresl. & EM 

Hansen

Port-Orford-cedar root rot Phytopththora lateralis Tucker & Milbrath

Resinous stem canker Cistella japonica Suto & Kobayashi 

Seiridium shoot blight Seiridium cardinal (W. Wagener) B. Sutton 

& I. Gibson

Yellow-cedar black stain Sporidesmium spp. [tentative identification]

Yellow-cedar shoot blight Kabatina thujae Schneider & Arx
Pacific Northwest Research Station

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