United States

Department of 

Agriculture

Forest Service

Northern 

Research Station

Research Paper NRS-15

Differences Between ifferences Between 

Standing and Downed tanding and Downed 

Dead Tree Wood Density ead Tree Wood Density 

Reduction Factors: eduction Factors: 

A Comparison Across Decay Comparison Across Decay 

Classes and Tree Species lasses and Tree Species 

Mark E. Harmon ark E. Harmon

Christopher W. Woodall hristopher W. Woodall

Becky Fasth ecky Fasth

Jay Sexton ay Sexton

Misha Yatkov isha Yatkov
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Cover Photo

Standing dead tree on the shores of Octopus Lake, Boundary Waters Canoe Area Wilderness, 

Superior National Forest, Minnesota, USA. Christopher W. Woodall, U.S. Forest Service.

Abstract

Woody detritus or dead wood is an important part of forest ecosystems and has now become 

a routine facet of forest monitoring and inventory. Biomass and carbon estimates of dead 

wood depend on knowledge of species- and decay class- specifi c density or density reduction 

factors. While some progress has been made in determining these parameters for dead and 

downed trees (DD), there are very few estimates of these key parameters for standing dead 

trees (SD). In this study we evaluated indicators of decay to relate subjective SD and DD decay 

classifi cations then compared SD and DD density and density reduction factors by decay class 

for a total of 19 tree species at nine sites in the United States and Russia. A set of preliminary 

decay reduction factors for SD trees by species and decay class was developed for tree 

species inventoried by the U.S. Department of Agriculture’s Forest Inventory and Analysis (FIA) 

program. Results indicate that SD density declined with decay class for all examined species. 

For six of the examined species, SD tree density could be assumed equal to that of DD tree 

density. The most common situation (13 species) was for SD density to be higher than for DD 

density. The likely cause of these differences was the drier microenvironment of SD which 

slows decomposition relative to that of DD. By applying these results, a new set of SD density 

reduction factors was developed for 260 species inventoried by FIA in forests of the United 

States. Comparison of biomass estimates using this study’s proposed SD density reduction 

factors with existing SD volume estimates based solely on undecayed wood density indicated 

a possible biomass overestimate of 16.5 percent for Minnesota. Given the size of the potential 

biases involved and the uncertainty associated with decay reduction factors developed in this 

study, additional work to develop a multispecies SD decay class system and further empirical 

sampling of SD tree density is recommended.

Manuscript received for publication 19 April 2011
1

INTRODUCTION

Woody detritus or dead wood is an important part of forest ecosystems, 

providing habitats and food sources, a store of carbon, nutrients, and 

water, as well as infl uencing geomorphic processes (Franklin et al. 

1987, Harmon et al. 1986, Triska and Cromack 1980). In particular, 

standing dead trees provide structural complexity and enhance 

biodiversity in many forest ecosystems (Jonsell et al. 1998, Kruys et 

al. 1999, Nilsson et al. 2001). Th erefore, dead wood is increasingly 

being included in ecological studies and environmental assessments 

(Woodall et al. 2009), with the number of publications on this subject 

rapidly growing. Both downed (DD) and standing dead (SD) wood 

store carbon and are important components of forest carbon dynamics, 

but also release carbon via decomposition and combustion in fi res. 

However, given the contrasting microenvironments that SD and DD 

trees inhabit, their decay dynamics and attributes may vary (Aakala 

et al. 2008, Aakala 2010, Lee 1998, Vanderwel et al. 2006). Accurate 

estimates of standing dead tree carbon stocks are important for 

monitoring carbon fl ux, for characterizing processes such as respiration 

and combustion losses, and for validating simulation models that are 

used to project how carbon dynamics will change in the future.

It is diffi cult to develop accurate estimates of dead wood biomass for 

several reasons. First, until recently there have been few systematic, 

regional-scale dead wood inventories, resulting in highly uncertain 

dead wood population estimates (Harmon et al. 2001). However, 

regional-scale inventories of dead wood are becoming more common 

(Woodall et al. 2009). For example, the Forest Inventory and Analysis 

(FIA) program of the U.S. Forest Service now conducts a national 

inventory of woody material including fi ne woody detritus (FWD)

and DD (for more details see Woodall and Monleon 2008). Second, 

given the size and actively decomposing nature of dead trees, direct 

measurements of biomass during forest inventories are not possible. 

Instead, the volume of individual DD pieces is estimated from fi xedarea plot or line-intersect transect estimators (Woodall and Monleon 

2008). Biomass of DD is then often estimated by multiplying volume 

by an estimate of density specifi c to a dead wood piece’s individual 

attributes (e.g., species and stage of decay). Density reduction 

factors may be defi ned as the ratio of the decayed density (current 

mass/volume) of a piece of dead wood compared to its undecayed 

density (initial live tree mass/volume; Miles and Smith 2009). Th e 

development of DD species- and decay class-specifi c density and 

decay reduction values for the FIA program has off ered the promise of 

substantially reducing the uncertainty associated with DD mass/carbon 

population estimates resulting from large-scale inventories (Harmon 

et al. 2008). Unfortunately, there are very few decay class- or speciesTh e Authors

MARK E. HARMON is a Richardson 

Chair and professor in forest science with the 

Department of Forest Science, Oregon State 

University, Corvallis, OR.

CHRISTOPHER W. WOODALL is research 

forester with the U.S. Forest Service, Northern 

Research Station’s Forest Inventory and 

Analysis unit, St, Paul MN.

BECKY FASTH is a senior research assistant 

with the Department of Forest Science, Oregon 

State University, Corvallis, OR.

JAY SEXTON is a senior research assistant 

with the Department of Forest Science, Oregon 

State University, Corvallis, OR.

MISHA YATKOV is a Ph.D. candidate with 

the Department of Forest Science, Oregon 

State University, Corvallis, OR.
2

specifi c estimates of density or decay reduction factors for 

SD trees. Th e lack of these estimates is likely due to the 

danger in felling snags during sampling and the historical 

lack of emphasis on SD biomass/carbon estimates during 

traditional forest inventories focused on estimating live 

tree growing stock volume on timberlands.

Several assumptions regarding wood density infl uence 

biomass estimates of SD trees. In the case of the FIA 

program, it is currently assumed that the density of 

SD trees is the same as that of live trees. While this 

seems unlikely, in some situations (e.g., extremely slow 

decomposition in arid environments) this assumption may 

be accurate. Alternately, (e.g., Smithwick et al. 2002) the 

density of SD trees for a given decay class may be assumed 

to be similar to that of DD wood. While this would seem 

to be a more realistic assumption, it has yet to be tested 

across a wide range of tree species and environments. 

Th e uncertainty associated with SD tree density is likely 

to have major impacts on biomass, carbon, and fuel 

estimates, but without knowledge of how SD tree wood 

density changes through its decay process, the eff ect of 

this uncertainty cannot be quantifi ed.

OBJECTIVES

Given that deadwood inventories are rapidly becoming 

a common component of forest resource inventories 

around the world, there is a need to refi ne the constants 

used in biomass estimation procedures for both SD and 

DD. Our objective was to determine SD species- and 

decay-class specifi c density and density reduction factors 

for forest tree species in the United States by linking 

empirical SD data from a subset of study species with 

that of DD of those same species to develop constants 

that can then be applied to other SD species. Th e broad 

concept was to use SD:DD density relationships to utilize 

currently available DD density information to provide an 

initial approximation of SD density attributes for forest 

tree species in the United States.

Harmon et al. (2008) developed a set of density 

reduction factors, including estimates of uncertainty, 

for DD and FWD based on a thorough literature 

review and unpublished data. Our approach for this 

study was to sample SD and DD for 19 tree species in 

temperate forests of the northern hemisphere. As the 

decay classifi cation system for both SD and DD trees are 

qualitative (i.e., visual assessments of wood condition 

and structure) and separate, the two classifi cation systems 

need to be linked in order to propose SD to DD wood 

density relationships by decay class. First, indicators 

of decay were evaluated for SD and DD decay classes 

to ensure decay classifi cation system compatibility. 

Second, the density of SD and DD was compared for 

the same decay classes and species. Th ese ratios were 

then used to estimate SD density and density reduction 

factors for species that have not been sampled across the 

United States. Finally, to initially assess the impact of 

wood density decay reduction factors on SD population 

estimates, a SD tree inventory in Minnesota was used 

to calculate state SD biomass using no decay reduction 

factor and using factors developed in previous objectives.

MATERIALS AND METHODS

Study Areas

To ensure our study acquired a robust estimate of SD 

to DD, we sampled fi ve study sites in the United States 

and four in Russia representing a range of species and 

climates in North America and Russia (Table 1). Given 

the similarity between the temperate and boreal forests of 

North America and Russia, it was felt that the additional 

statistical rigor resulting from the combination of data 

outweighed the loss of some regional specifi city. As study 

objectives focus on tree species in the United States along 

with greater diversity among the study sites (e.g., species 

composition), study site locations in the United States 

were kept separate and identifi ed by unique abbreviations 

in subsequent tables, while Russian study sites were 

pooled with the abbreviation “RUS.” Site descriptions for 

Russian locations are based on information from Yatskov 

(2000).

Cascade Head Experimental Forest (CHE), Oregon

Cascade Head is located on the north-central coast of 

Oregon, 8 km north of Lincoln City. It lies entirely 

within the Hebo Ranger District of the Siuslaw National 

Forest. Th e site is in the Oregon Coast Range ecoregion 

and the forests are representative of the sitka sprucewestern hemlock (Picea sitchensis (Bong.) Carrière -Tsuga 

heterophylla (Raf.) Sarg.) and Douglas-fi r (Pseudotsuga 
3

menziesii (Mirb.) Franco) zones of the region. Soils, 

derived primarily from tuff aceous siltstones, are fi ne 

textured, moderately well drained, and deep (up to 

100+ cm). Because of the Pacifi c Ocean infl uence, CHE 

has a moderate and very wet climate. Mean annual 

temperature is 10 °C with minimal seasonal variation. 

Average yearly rainfall is 2489 mm, although fog drip 

through the forest canopy can add 500 mm or more 

precipitation a year (Greene and Acker 1999).

Fraser Experimental Forest (FEF), Colorado

Fraser Experimental Forest is located in the heart of the 

central Rocky Mountains, about 80 km from Denver. 

FEF includes subalpine forests typical of the area, with 

Engelmann spruce (Picea engelmannii Parry x Engelm.) 

and subalpine fi r (Abies lasiocarpa (Hook.) Nutt.) 

predominating at higher elevations, and lodgepole pine 

(Pinus contorta var. latifolia (Douglas ex Louden var. 

latifolia Engelm. ex S. Watson)) predominating at lower 

elevations and on drier upper slopes. Soils are generally 

derived from gneiss and schist and typically contain 

angular gravel and stone with very little silt or clay. 

Th ese soils are very permeable and can store considerable 

water during snowmelt. Climate varies strongly with 

elevation. Overall, the climate is cool and dry with long, 

cold winters and short, cool summers. Mean annual 

temperature at the Fraser Forest headquarters is 0.5 °C 

and mean annual precipitation over the entire FEF is 737 

mm. (Adams et al. 2004).

Chapel Hill (NCB), North Carolina

Th e study was conducted at the North Carolina Botanical 

Garden, a 242-ha tract of oak-hickory-pine forest in 

Chapel Hill, North Carolina. Th e area sampled in this 

project was dominated by mixed hardwoods including 

Liriodendron tulipifera L. on the moist lower slopes and 

mixed hardwoods with pine (Pinus taeda L. and Pinus 

echinata Mill.) on the dryer mid and upper slopes. It is an 

area defi ned by undulating topography, soils of poor to 

good quality, and a temperate climate. Soils of the study 

area include Wedowee sandy loam and Goldston slaty 

silt loam (Dunn 1977). Th e average annual temperature 

is 14.6 °C and the average annual precipitation is 1220 

mm. Precipitation is uniformly distributed throughout 

the year. Th e elevation ranges from 103 to 150 m (Fasth 

et al., in press).

Marcell Experimental Forest (MEF), Minnesota

Th e Marcell Experimental Forest is an 890-ha tract of 

land in the Chippewa National Forest, located 40 km 

north of Grand Rapids, Minnesota. Vegetation in the 

upland topography includes jack pine (Pinus banksiana

Lamb.) and trembling aspen (Populus tremuloides Michx.) 

among other species. Mineral soils of the area are derived 

from glacial processes that occurred during and after the 

Wisconsinan glaciation. Soils are mainly loamy sands 

covered with fi ne sandy loam derived from eolean loess 

after glacial melt. Th e climate is subhumid continental, 

with wide and rapid diurnal and seasonal temperature 

fl uctuations. Th e average annual temperature is 3 °C 

and the average annual precipitation is 785 mm with 75 

percent occurring in the snow-free period (mid-April to 

early November) (Adams et al. 2004).

Kenai Peninsula (AK), Alaska

Th e study was conducted on the Kenai Peninsula of 

Alaska on Federal lands including the Chugach National 

Forest as well as on State owned lands. Th e maritime 

Table 1.—Site name, location, and climate description for areas sampled

Site Name Climate Temperature

Cascade Head EF, Oregon (CHE) Very wet Moderate

Fraser EF, Colorado (FEF) Dry Cool

Chapel Hill, North Carolina (NCB) Moderate Moderate

Marcell EF, Minnesota (MEF) Moderate Cold

Kenai Peninsula, Alaska (AK) Dry Cold

St. Petersburg, Russia (RUS) Moderate Cool

Krasnoyarsk, Russia (RUS) Dry Cold

Irkutsk, Russia (RUS) Dry Cold

Khabarovsk, Russia (RUS) Moderate Cold
4

climate of this study site supports temperate, coniferous 

rainforest. Th e drier and colder climate inland from 

the coastal mountains supports forests dominated by 

white spruce (Picea glauca (Moench) Voss), black spruce 

(Picea mariana (Miller) Britt), and paper birch (Betula 

papyrifera Marsh). A fertile hybrid between white spruce 

and Sitka spruce (Lutz spruce, Picea x lutzii Little) is a 

common tree in maritime and mountainous areas of the 

Kenai Peninsula. Th e topography of the study area varies 

from lowlands to foothills. Th e lowlands of the Kenai 

Peninsula are a glaciated surface with gentle relief and 

a mean elevation of approximately 300 m. Th roughout 

most of this lowland glacial till of Wisconsin age is 

overlain by deep glacial lake and fl uvial sediments and is 

mantled with loess. Th e Alaska Climate Research Center 

(ACRC) climatic summaries indicate the study area has 

a mean annual temperature of approximately 1.1 °C and 

annual precipitation of 630 mm (Harmon et al. 2005).

St. Petersburg, Russia (RUS)

Th e region of northwestern Russia has a cool maritime 

climate with cool wet summers and long cold winters. 

Major forest tree species include silver birch (Betula 

pendula Roth.), Norway spruce (Picea abies (L.) Karst.), 

and Eurasian aspen (Populus tremula L.). Th e mean 

annual temperature of July is 16.5 °C, while the mean 

temperature of January is 8.5 °C with an annual mean of 

3.4 °C. Th e mean annual precipitation is 708 mm.

Krasnoyarsk, Russia (RUS)

Th is region of central Siberia has a moderately cold and 

continental climate. It belongs to the Angara province of 

the southern taiga and is dominated by Russian larchScots pine (Larix siberica Ledeb. and Pinus sylvestris L.) 

forests. Th e vegetation period lasts 126 days with a frostfree period of 110 days. Th e mean temperature of July is 

16 °C, while the mean temperature of January is -25 °C, 

and the overall mean annual temperature is -3.2 °C. Th e 

mean annual precipitation is 361 mm.

Irkutsk, Russia (RUS)

Th is region of Eastern Siberia has sites located in the 

area of strictly continental climate with permafrost. 

Forests were primarily comprised of Scots pine (Pinus 

sylvestris). In mountainous areas Siberian larch (Larix 

siberica), Siberian white pine (Pinus siberica Ledeb.), and 

Siberian spruce (Picea obovata Ledeb.) were common, 

and were associated with small amounts of Siberian fi r 

(Abies siberica Ledeb.). Th e mean temperature of July is 

17 °C and mean temperature of January is -20 °C with an 

overall mean annual temperature of -0.6 °C and a mean 

annual precipitation of 216 mm.

Khabarovsk, Russia (RUS)

Th is region is part of the Far East and has a continental 

climate that promotes the growth of a wide range of plant 

species, including Korean white pine (Pinus koraiensis 

Sieb. et Zucc.), Dahurian larch (Larix dahurica Turcz.) 

spruce (Picea obovata and Picea ajanensis Fisch.), true fi r 

(Abies siberica), and yellow birch (Betula costata Trautv.). 

Th e vegetation period lasts 174 days in lowlands and 158 

days in mountainous areas. Th e mean temperature of July 

is 17 °C, while mean temperature of January is -24 °C, 

with an overall annual mean of -1.9 °C. Th e mean annual 

precipitation is 909 mm.

Linking SD and DD Decay 

Classifi cations through Indicators 

of Decay

To accurately estimate DD and SD population attributes 

such as biomass or carbon, the FIA program assigns each 

sampled DD and SD individual to a decay class. To 

facilitate linkage of DD and SD decay classes, indicators 

of decay were developed in this study that were assessed 

for each study dead wood piece. For both DD and SD, 

there were fi ve decay classes that span a spectrum of 

decay from fresh mortality to nearly complete decay. 

Decay classes are largely qualitative based on the physical 

appearance and structural integrity of individual dead 

wood pieces (USDA 2007, Woundenberg et al. 2010). 

For SD trees the fi ve decay classes were defi ned as:

Class 1: All limbs and branches are present; the top of the 

crown is still present; all bark remains; sapwood is intact, 

with minimal decay; heartwood is sound and hard.

Class 2: Th ere are few limbs and no fi ne branches; the 

top may be broken; a variable amount of bark remains; 

sapwood is sloughing with advanced decay; heartwood is 

sound at base but beginning to decay in the outer part of 

the upper bole.
5

Class 3: Only limb stubs exist; the top is broken; a 

variable amount of bark remains; sapwood is sloughing; 

heartwood has advanced decay in upper bole and is 

beginning at the base.

Class 4: Few or no limb stubs remain; the top is broken; 

a variable amount of bark remains; sapwood is sloughing; 

heartwood has advanced decay at the base and is 

sloughing in the upper bole.

Class 5: No evidence of branches remains; the top is 

broken; <20 percent of the bark remains; sapwood is 

gone; heartwood is sloughing throughout.

For DD trees the fi ve decay classes were defi ned as:

Class 1: Sound, freshly fallen, intact logs with no rot, no 

conks present indicating a lack of decay, original color of 

wood, no invading roots, fi ne twigs attached with tight 

bark.

Class 2: Sound log sapwood partly soft but can’t be 

pulled apart by hand, original color of wood, no invading 

roots, many fi ne twigs are gone and remaining fi ne twigs 

have peeling bark.

Class 3: Heartwood is still sound with piece supporting 

its own weight, sapwood can be pulled apart by hand or 

is missing, wood color is reddish-brown or original color, 

roots may be invading sapwood, only branch stubs are 

remaining which cannot be pulled out of log.

Class 4: Heartwood is rotten with piece unable to 

support own weight, rotten portions of piece are soft 

and/or blocky in appearance, a metal pin can be pushed 

into heartwood, wood color is reddish or light brown, 

invading roots may be found throughout the log, branch 

stubs can be pulled out.

Class 5: Th ere is no remaining structural integrity to 

the piece with a lack of circular shape as rot spreads out 

across ground, rotten texture is soft and can become 

powder when dry, wood color is red-brown to dark 

brown, invading roots are present throughout, branch 

stubs and pitch pockets have usually rotten down.

Based on decades of research into the ecological role 

of detritus in forest ecosystems, we hypothesized that 

the diff erences between SD and DD would be greatest 

for intermediate decay classes (i.e., 2 and 3). Given 

the lack of time in decay class 1, decay reductions are 

likely minimal for both SD and DD. For decay classes 

4 and 5, which are based on structural strength, it is 

likely that SD and DD are similar given that structural 

strength of wood is highly dependent on density. We 

also hypothesized that the wood density of SD and DD 

would diverge more in dry climates than in humid ones 

due to moisture limitations in dry climates that inhibit 

SD decomposition. Since SD falls and becomes DD, 

the input of decayed SD-related wood might infl uence 

the overall density of DD. Since decay classes are largely 

based on exterior appearances, it is likely that SD in 

dry climates will be denser than DD for a given decay 

class because the exterior of SD will continue to degrade 

(e.g., bark loss, fragmentation of twigs, etc) whereas 

the interior will remain relatively sound. Conversely, 

in very wet environments, fragmentation of bark and 

cover of mosses and other bryophytes are likely to make 

the exterior of DD look decayed despite the slow rate of 

decomposition of DD in very wet environments. Based 

on these hypotheses, a variety of indicators of decay 

were visually assessed for both SD and DD in this study 

(Table 2). Similarities in indicators of decay among 

SD and DD pieces sampled in this study will suggest 

appropriate linkage between the SD and DD decay 

classifi cation systems and subsequent development of SD 

decay reduction factors based on extensive DD woody 

decay information.

FIELD AND LABORATORY

Decay Classes and Indicators of Decay

At each study site we sampled SD and DD covering the 

full range of decomposition stages, which necessitated 

the felling of SD trees. To sample indicators of decay, 

selected SD or DD pieces were categorized into one of 

fi ve decay classes based on visual characteristics linked 

to the degree of decomposition that was noted in the 

previous section: the presence of leaves, twigs, branches, 

percent bark cover on branches and bole, sloughing of 

wood, collapsing and spreading of DD or SD (indicating 

the transition from intact elliptical forms to degraded 
6

shapes), friability or crushability of wood, color of wood, 

and mobility of branch stubs (Triska and Cromack 

1980, Graham and Cromack 1982, Sollins 1982, 

Harmon and Sexton 1996). In addition to visual and 

structural indicators of decay used by the FIA program, 

biological indicators (Table 2) of decomposition, such as 

moss cover, presence of fungal fruiting bodies, and the 

presence of insect galleries, were also noted. In addition, 

at most sites we sampled live trees to determine densities 

of undecayed wood and bark. Dimensions recorded 

for each tree sampled included length, base and top 

diameters, and current d.b.h. Th e decay classes of both 

SD and DD used in this study align with the same decay 

classes used by the FIA program. Please refer to USDA 

(2010), Woodall et al. (2010), and Woudenberg et 

al. (2010) for details regarding the SD and DD decay 

classifi cation systems used by FIA.

Wood Density and Density Reduction 

Factors

To measure wood density of SD and DD, samples were 

divided into four sections of similar length. Short pieces 

(e.g., in more advanced decay classes) were divided into 

two or three sections. For each section, end diameters 

and length were recorded. From the end of each section, 

a disk (a cross section 5 to 10 cm thick) was cut with 

a chainsaw to determine wood and bark density. To 

determine disk volume, for each cross-section disk we 

recorded the outermost diameter, outer wood diameter, 

mean longitudinal thickness, circumference covered by 

bark, radial thickness of bark, and mean radial depth of 

decay. Bark was separated from wood and the total wet 

weight of each tissue was determined. Lengths of bark 

and wedge-shaped wood subsamples of ~100 g taken 

from each disk using a hammer and chisel were weighed. 

Dry weights were recorded after oven drying at 55 °C 

to a constant weight (within 0.01 g). For disks that had 

not been dried and weighed, dry weights of wood and 

bark were calculated from total wet weights of these 

tissues and the ratio of dry-to-wet weight determined 

from subsamples. Th e density of the bark and wood for 

each disk was calculated as the ratio of its dry weight 

to undecayed volume (g/cm3). Mean bark density and 

mean wood density for each tree were calculated by 

averaging the density of all the cross-section values of 

each tissue for each tree. Recorded values of percent bark 

cover for the whole tree and bark circumferential length 

for each disk were used to determine the proportion of 

total tree volume that was bark. Total density per tree 

was calculated as the summation of each tissue density 

multiplied by the proportion of total tree volume 

applicable to that tissue. An average density for each 

tree species, decay class, and position (i.e., SD or DD) 

was calculated using total tree density. Trees were also 

categorized as either hardwood (i.e., angiosperm) or 

softwood (i.e., gymnosperm) and total density per tree 

was averaged across each category for each decay class 

and position. Finally, an average of total density was 

calculated for all trees by decay class and position.

Table 2.—Decay indicators used to determine decay 

classes for standing and downed dead trees

Code Indicator question

Foliage Is foliage present?

Twigs Are twigs present?

Branches Are branches present?

Bark_br Is there bark present on the branches?

Bark_bole Is there bark present on the bole?

Moss Is there moss present?

Lichens Are there lichens present?

Beetles Is there evidence of beetle presence?

Woodborer Is there evidence of woodborer presence?

Conks Are there conks present?

Whiterot Is there white rot present?

Brownrot Is there brown rot present?

Casehard Does the bole exhibit case hardening?

SW_friable Is the sapwood crushable by hand?

HW_friable Is the heartwood crushable by hand?

Ants Is there evidence of ants present?

SW slough Is the sapwood sloughing?

Collapse Has the bole shape collapsed?

Scatter Is the bole scattered in the ground?

Stub_move Do the branch stubs move in the bole?
7

Th e density reduction factor was calculated as the ratio 

of the average current density to average undecayed 

density for each species, category, or combination and 

by each decay class and position (i.e., SD versus DD) to 

indicate the relative rate that tree density declined for 

each scenario. 

Statistical Analysis

We used analysis of variance (ANOVA) to test how the 

dependent variable density reduction factor varied by the 

independent variables taxa (i.e., species or hardwood/

softwood), decay class, and position. Th e following 

model was fi t:

Ykhij = m + k +h+ di

 + aj+ daij + khij

where:

 m is the overall mean value of Ykhij, the average 

density reduction factor of the j

th decay class in the 

i

th position in region k and stand h

k is the random eff ect of the region k that was 

sampled, that adds variability to the value of Y, 

k=region name, k h ~ N(0, 2

b), k and k’ are 

independent

h is the random eff ect of stand h that was sampled, 

that adds variability to the value of Y, h=stand 

name, h ~ N(0, 2

b), h and h’ are independent

 di is the eff ect of the i

th level of the independent 

variable position, i=SD or DD

 aj

 is the eff ect of the j

th level of the independent 

variable decay, j= 1, 2, 3, 4

 daij is the interaction of position and decay

khij is the random error term that adds variability 

to the value of Y, khij ~ N(0, 2) and khij and 

khi’j’ are independent.

When comparing softwoods and hardwoods, species was 

added as an additional random variable in the model. In 

the case of all species combined, the variables species and 

type (softwood or hardwood) were added as additional 

random variables. Residuals from the models were fairly 

symmetric and there was no indication of increasing 

variance with decreasing mean. Th erefore, assumptions 

of normality and constant variance of residuals appeared 

to be adequately met. Th rough ANOVA testing, three 

results were postulated: 1) No signifi cant diff erence 

between DD and SD density reduction factors by 

decay classes. Th is would indicate that decay occurred 

with similar patterns for dead wood in standing or 

lying positions; 2) Th e main eff ects of position and 

decay class would both be signifi cant when the density 

reduction diverged early in the decomposition process 

(i.e., between class 0 and 1). Th is might suggest that 

one position started with a lower density than the other; 

3) A signifi cant interaction of position and decay class. 

Th is would indicate that one position was decaying to a 

lesser extent than the other and that density reduction 

factors were diverging. We tested these hypotheses at 

three separate levels: individual species, softwoods versus 

hardwoods, and for all species combined.

To examine why DD and SD might have diff erent 

densities and density reduction factors, we compared 

indicators of decay (Table 2) between the two positions. 

We computed the relative frequency that indicators were 

present for two positions and the three taxonomic levels 

described above to examine which characteristics might 

be associated with diff erences in dependent variables.

All statistical tests based on the model outlined above 

were performed by the MIXED procedure of SAS 

(SAS Institute Inc.) using the LSMEANS statement 

which computes least squares means of fi xed eff ects 

and corresponding t and F tests. Statistical tests were 

signifi cant if 0.05 > P > 0.01 and highly signifi cant if P

< or = 0.01. We emphasize that a minimal amount of 

replication was conducted within species, study sites, and 

decay classes. Replication was limited by the diffi culty in 

fi nding study sites with a full representation of DD and 

SD decay classes. Furthermore, the felling of SD trees is 

extremely hazardous to the sawyer. We have expressed 

the high levels of uncertainty in Appendix C. Th e results 

presented in this study should be considered preliminary 

to guide future research and promote refi ned SD 

population estimation (i.e., use of decay reduction factors 

in biomass/carbon estimates).
8

Development of Standing Dead (SD) Databases

We used the fi ndings of the current study to estimate 

decayed density and the density reduction factors of SD 

for tree species inventoried by the FIA program. For the 

species that we sampled, we used the observed densities 

and density reduction factors. For the species that we did 

not sample, we calculated decayed density and density 

reduction factors using ratios of the species we sampled 

and the estimated values for DD from Harmon et al. 

(2008). Specifi cally, for decay classes 1 to 3 we multiplied 

the SD to DD ratio for either hardwoods or softwoods 

(depending on the species) by the DD density or density 

reduction factor. For decay class 4, there were few species 

sampled. We therefore used the average SD to DD ratio 

of all species sampled. For decay class 5, as no species 

were sampled given the scarcity of these trees, this study 

suggests future research or assuming decay class 4 wood 

density results can be extrapolated to decay class 5.

To provide an estimate of uncertainty, we used one of 

the following methods:

A. Species that had been sampled for SD density. 

We used standard error of the observed values of 

decayed density or the density reduction factor.

B. Species lacking sampling to determine decayed SD 

density. Th e uncertainty (U) in the decayed SD 

density for this set of species was estimated by: 

 ୈୣୡୟ୷ୣୢୗୈ ൌ ටሺୈୈ

ଶ ሻሺୈୈଶ ሻ ൅ ሺଶሻሺୖଶሻ

where UDD is the uncertainty in DD (Harmon et al. 

2008), DenDD is the mean DD density, and UR is the 

uncertainty in R, the mean SD to DD density ratio. 

Th is formula accounts for the fact that uncertainty for 

decayed SD density is a function of two uncertainties. 

Our formula assumed no correlation between the 

uncertainties. Uncertainty was estimated for each decay 

class of SD. For decay classes 1 to 3 we used R values 

associated with either hardwoods or softwoods and 

applied them to appropriate taxa. For decay class 4 there 

were few observations, so we used values for all the taxa 

sampled.

A similar uncertainty estimate was made for density 

reduction factors using the average density reduction 

factor and associated uncertainty for DD.

RESULTS

Decay Indicators

All Species

Th e relative frequency of decay indicators (Table 2) as DD 

and SD decomposed was surprisingly similar (Figure 1). 

In terms of physical indicators (presence of parts, shape, 

friability) prior to reaching decay class 4, DD and SD were 

quite comparable and go through a similar progression 

from one decay class to the next. Decay class 4 DD and 

SD diff ered in terms of structural integrity indicators. Th is 

is a logical result as SD that lacks physical integrity tends 

to fall and form DD. Th e nearly entire lack of bark in 

decay class 4 SD, as compared to DD, is related to vertical 

orientation, as even loose bark can remain on the surface 

of DD. Across all species and study sites, the means of SD 

bark cover (percent of piece covered by bark) were 91.62, 

65.55, 38.91, and 21.11 for decay classes 1 through 4, 

respectively.

In terms of biological indicators (presence of moss, 

lichens, insects, and fungi), the major diff erence between 

SD and DD appeared to be the abundance of moss. 

DD tended to have higher presence of moss than SD, 

which would be consistent with the wetter microclimate 

associated with DD versus SD. Conversely, lichens 

were slightly more abundant on SD than DD, which is 

consistent with a drier microclimate associated more with 

SD than DD. DD also had a greater tendency to support 

fungal fruiting bodies, whereas SD had a greater tendency 

to support wood borers. Th e former may indicate a 

more favorable decomposition environment; the latter 

may be an artifact related to greater moss cover and 

decay state in DD hiding evidence of wood borers. For 

further evaluation of these moss/lichen results we suggest 

consulting the abundance of literature regarding lichen 

substrate preferences.

We observed little bark cover in both class 2 and 3 SD 

for some species, making the characteristic less useful as 

an indicator than for DD. Two characteristics proved 
9

useful in distinguishing these two decay classes when 

SD had little bark cover. First, decay class 3 SD tended 

to have more lichens than decay class 2 SD. Th is is 

likely related to the older surface having more time to 

accumulate lichens. Second, the wood of decay class 

3 SD tended to take on what might be described as a 

“ropey” texture. Th is is caused by a weakening of the 

outer wood layers causing cracks that look similar to the 

strands in a rope often associated with white-rot fungus. 

Findings by Aakala et al. (2008) indicate that the surface 

appearance of standing dead trees can remain static for 

long periods of time, thus the presence/absence of surface 

biological indicators may not fully indicate internal decay 

dynamics. Barring destructive sampling, standard forest 

inventory fi eld crew must continue to rely on qualitative 

SD appearance to determine decay classifi cation.

Hardwoods versus Softwoods

While the overall relationship between external 

characteristics and decay classes were similar for 

hardwoods and softwoods, there were some notable 

diff erences (Figure 2). In terms of physical indicators, 

Figure 1.—Percent frequency of abundance for physical indicators of decay class for standing dead and downed 

dead trees 
10

hardwoods appeared to lose twigs and branches to a 

higher degree than softwoods as decay class increased. 

Conversely, softwoods lost bark on the bole to a higher 

degree than hardwoods, although this was likely related 

to the presence of birch (Betula sp.), a genus well 

known for bark retention. For the biological indicators, 

hardwoods were more likely to have white-rot fungus, 

whereas softwoods were more likely to have brown-rot 

fungus, at least in decay classes 2 and 3. In decay class 

1, hardwood SD were more likely to have lichens and 

mosses present than softwoods, but this likely stems from 

the diff erence of these tree taxa to support epiphytes in 

general.

Overall, indicators of decay were not evaluated in 

this study as an in-depth discourse on SD and DD 

decay dynamics and ecology, rather as a qualitative 

means to assure diff erentiation between decay classes 

and alignment with FIA sampling protocols. Results 

indicated adequate decay class diff erentiation, linkage 

between SD and DD decay classifi cation systems, and 

FIA sampling protocol alignment allowing subsequent 

development of wood density estimates for SD tree 

species in U.S. forests based on relatively extensive DD 

wood density information.

Wood Density

As expected, SD wood density declined with decay class 

(Appendix A). Th e initial, undecayed tree densities for 

the 19 species studied ranged from 0.31 to 0.54 g/cm3

(Table 3). Th e overall mean initial density was 0.39 

g/cm3. Decay class 3, the most advanced decay class 

common to SD and DD, had densities that ranged from 

0.16 to 0.34 g/cm3 for DD and 0.21 to 0.46 g/cm3 for 

SD. Decay class 3 density for all species of DD averaged 

0.26 g/cm3 and averaged 0.35 g/cm3 for SD indicating 

that SD contain less decay than logs (Table 4). Th is is 

Figure 2.—Percent frequency of abundance for physical indicators of decay class for hardwood and softwood standing 

and downed dead trees
11

undecayed density for hardwoods and softwoods was 

0.40 and 0.38 g/cm3, respectively. However, decay class 

3 hardwood DD and SD had mean densities of 0.23 and 

0.24 g/cm3, whereas softwood DD and SD had mean 

densities of 0.27 and 0.38 g/cm3, respectively.

Density Reduction Factors

Individual species

Density reduction factors for decay class 3 ranged from 

0.34 to 0.80 and from 0.44 to 1.11 for DD and SD, 

respectively (Appendix B). Statistical analysis showed fi ve 

species with highly signifi cant interactions and two with 

signifi cant interactions between position and decay class 

(P-values: Larix sibirica 0.00; Pinus contorta 0.00; Picea 

lutzii 0.00; Pinus species 0.01; Pinus sibirica 0.01; Pinus 

banksiana 0.05; Pinus koraiensis 0.05). Of these seven 

species, four were in the genus Pinus. Th is interaction 

indicated that SD for these species retained a higher 

density than DD and that these diff erences increased 

as decay proceeded. Aakala (2010) found similar 

results in Picea abies forests of northern Europe, with 

the wood density of SD signifi cantly higher than DD. 

Furthermore, in our study three species (two hardwood 

and one softwood) had highly signifi cant decay class 

and position main eff ects, but no signifi cant interaction 

between the two factors. Th is result may indicate that 

early in the decay process, DD and SD diverge, with 

DD undergoing an initial rapid period of decomposition 

and SD subject to a lag. Four species (three hardwoods 

and one softwood) showed only decay class as a highly 

signifi cant factor in density reduction (P-values: Betula 

pendula 0.00; Tsuga heterophylla 0.00; Populus tremula

0.00; Populus tremuloides 0.00). Th is would indicate 

that decay progresses similarly in SD and DD for these 

species. Two species showed only position as a highly 

signifi cant factor in density reduction, but this was likely 

an artifact related to the few decay classes sampled for 

these species.

Hardwoods versus softwoods

Compared to hardwoods, softwoods, on average, are 

more likely to have a greater divergence in SD and DD 

decay reduction factors as decay progresses (Table 6). 

For example, the mean density reduction factors for 

decay class 3 hardwood DD and SD were 0.51 and 0.54, 

Table 3.—Undecayed wood density by tree species code, 

scientifi c name, and location of sample collection (U.S. 

study site or general Russian location)

Code Scientifi c name Location

Undecayed 

Density 

(g/cm3)

PILU Picea x lutzii AK 0.36

PICO Pinus contorta FEF 0.40

PIBA2 Pinus banksiana MEF 0.42

POTR Populus tremuloides MEF 0.39

LITU Liriodendron tulipifera NCB 0.41

PINE Pinus species NCB 0.49

TSHE Tsuga heterophylla CHE 0.44

ABSI Abies siberica RUS 0.31

BECO Betula costata RUS 0.54

BEPE Betula pendula RUS 0.48

LADA Larix daurica RUS 0.46

LASI Larix sibirica RUS 0.49

PIAB Picea abies RUS 0.37

PIAJ Picea ajanensis RUS 0.36

PIOB Picea obovata RUS 0.38

PIKO Pinus koraiensis RUS 0.35

PISI2 Pinus sibirica RUS 0.34

PISY Pinus sylvestris RUS 0.38

POTR2 Populus tremula RUS 0.35

Table 4.—Average density (g/cm3) for standing dead (SD) 

to downed dead (DD) trees and associated ratio (SD/DD 

average density) for all species and sites combined by 

decay class

Decay 

class

SD 

(g/cm3) n

DD 

(g/cm3) n

SD/DD 

Ratio

1 0.40 (0.00) 175 0.40 (0.00) 185 1.00

2 0.38 (0.00) 189 0.33 (0.00) 292 1.15

3 0.35 (0.01) 78 0.26 (0.00) 391 1.35

4 0.25 (0.03) 14 0.15 (0.00) 246 1.67

5 0.11 (0.00) 174

Note: Values are means with standard errors in parentheses. “n” is 

the number of SD or DD.

consistent with the notion that SD must retain some 

sound wood to remain upright. Aakala’s (2010) study in 

Picea abies forests in northern Europe found a range of 

SD decayed density ranging from 0.14 to 0.47 g/cm3.

Hardwoods tended to have slightly higher initial 

density than softwoods, but the opposite was true after 

extensive decay (Table 5). For example, the mean initial, 
12

respectively. In contrast, the mean density reduction 

factors for decay class 3 softwood DD and SD were 0.70 

and 0.92, respectively. For softwood species collectively, 

there was a highly signifi cant interaction between 

position and decay class eff ects. For hardwood species, 

decay class was a highly signifi cant factor in density 

reduction. Th is indicates that DD density factors could 

be substituted for SD ones in hardwoods, but not for 

softwoods.

All species combined

Th e density reduction factors for all decay class 3 DD 

and SD was 0.67 and 0.86, respectively (Table 7). Th ere 

was a highly signifi cant interaction between position and 

decay class in the reduction factor, which may be due to 

softwood species being over represented in the data set.

Standing Dead Databases

Of 260 species considered by the FIA inventory, eight 

(3 percent) have had some SD decay classes sampled. 

For sampled species, the uncertainty of SD density was 

approximately 3 to 14 percent of the mean estimate. 

In contrast for species in which SD density had to be 

estimated from the DD database produced by Harmon 

et al. (2008), the uncertainty is approximately 20 to 100 

Table 5.—Average density (g/cm3) for standing dead (SD) and downed dead (DD) 

trees and associated ratio (SD/DD average density) by hardwood/softwood and 

decay class

Type Decay 

class

SD

(g/cm3) n

DD

(g/cm3) n

Ratio SD/

DD

Hardwood 1 0.46 (0.01) 37 0.43 (0.01) 51 1.07

2 0.36 (0.01) 31 0.33 (0.01) 58 1.09

3 0.24 (0.02) 14 0.23 (0.01) 60 1.04

4 0.20 (0.03) 2 0.13 (0.01) 55 1.54

5 0.11 (0.01) 31

Softwood 1 0.38 (0.00) 138 0.38 (0.00) 134 1.00

2 0.39 (0.00) 158 0.34 (0.00) 234 1.15

3 0.38 (0.01) 64 0.27 (0.00) 331 1.41

4 0.26 (0.03) 12 0.15 (0.00) 191 1.73

5 0.11 (0.00) 143

Note: Values are means with standard errors in parentheses. “n” is the number of SD or DD.

Table 6.—Average density reduction factor (decayed density/undecayed density) 

for standing dead (SD) and downed dead (DD) trees and associated ratio (SD/DD 

density reduction factor) by hardwood/softwood and decay class

Type Decay 

class

SD n DD n Ratio SD/

DD

Hardwood 1 0.99 (0.01) 37 0.95 (0.01) 51 1.04

2 0.80 (0.02) 31 0.74 (0.02) 58 1.08

3 0.54 (0.04) 14 0.51 (0.03) 60 1.06

4 0.43 (0.05) 2 0.29 (0.02) 55 1.48

5 0.22 (0.02) 31

Softwood 1 0.97 (0.01) 138 0.93 (0.01) 134 1.04

2 1.00 (0.01) 158 0.87 (0.01) 234 1.15

3 0.92 (0.03) 64 0.70 (0.01) 331 1.33

4 0.55 (0.06) 12 0.40 (0.01) 191 1.38

5 0.29 (0.01) 143

Note: Values are means with standard errors in parentheses. “n” is the number of SD or DD.
13

percent of the mean estimate, the latter for decay class 

4 SD. Th is indicates that actual sampling of SD density 

could reduce the uncertainties with this material at least 

an order of magnitude.

Implications of Density Reduction on 

Population Estimates

Th e implications of assumptions of SD density can be 

potentially profound in terms of biomass estimates. 

Using FIA’s forest inventory of the state of Minnesota 

(2005-2009), we explored the impact of three plausible 

scenarios for estimating total SD biomass (i.e., SD wood 

density assumptions): 1) SD wood density equals live 

tree wood density; 2) SD and DD wood density are 

equal; and 3) SD wood density based on this study’s 

newly created SD density reduction factors. To convert 

that volumetric estimate to one of biomass, the three SD 

wood density assumptions were evaluated. Assuming 

that SD wood density was equal to live trees gives a total 

SD biomass estimate of 32.98 million Mg. By assuming 

that SD and DD wood density are equal, the estimated 

biomass was 24.38 million Mg, or 26 percent less. Using 

the new estimates of SD wood density provided an 

estimated biomass of 27.52 million Mg or 16.5 percent 

less than the assumption of undecayed density.

DISCUSSION

SD inhabit a very diff erent environment than DD, with 

the former usually being drier. Given that the response 

of decomposition to moisture shows an optimum 

range (i.e., woody tissues can be too dry or too wet to 

decompose readily), the position supporting the fastest 

decomposition can change with macroclimate (Harmon 

2009). Th is might lead to consistent diff erences in the 

density of SD versus DD. In very humid environments, 

DD and SD both may retain moisture and hence the 

density of SD and DD might remain similar. Th is may 

explain our results from Cascade Head, the wettest site 

examined. In very dry environments SD decay may be 

limited relative to that of DD and that could lead to an 

increasing diff erence as decay class increases. Specifi c to 

sites in this study, but possibly not pertinent to all forest 

conditions across the United States, softwoods tended to 

grow in drier climates and microsites than hardwoods, 

which may explain why many softwoods exhibited an 

increasing diff erence in density as decay classes increased. 

In environments with intermediate moisture, SD may 

be slightly drier than DD. Th is could lead to a relatively 

short lag in decomposition that would result in a 

constant diff erence between decay classes in terms of 

density. While our observations are consistent with these 

hypotheses, other factors could be causing the patterns 

observed and more SD:DD comparisons in a wider 

range of environments would be helpful in determining 

the mechanisms explaining these phenomena. 

Diff erences in the density of SD versus DD may also be 

related to the physical limits of strength of woody tissues. 

Th at is, SD have to be fully self supporting, and once 

their strength decreases past a threshold they will collapse 

to form DD. In contrast, DD with minimal structural 

strength can collapse, but remain as DD. Th is may lead 

to an apparent abundance of higher wood density SD 

trees as less sound SD fall to become DD. However, 

SD do not necessarily have to decompose throughout 

to fall. For example, SD in dry environments fall after 

root systems decompose, adding relatively sound wood 

to the DD pool. When this occurs the density of DD 

might increase due to this input of relatively sound SD 

wood. Th erefore, the diff erence in wood density between 

SD and DD are likely to be controlled by a number of 

interacting factors. Care should be taken not to infer 

rates of decay with assigned decay classes. Diff erences in 

wood density were quantitively determined between SD 

and DD qualitative decay classes in this study. Rates of 

decay are only inferred as initial hypotheses for future 

research.

Th ere is an emerging abundance of research discussing 

the dynamics of SD and DD decay and subsequent 

Table 7.—Average density reduction factor for standing 

dead (SD) and downed dead (DD) trees and associated 

ratio (SD/DD density reduction factor) for all sites/

species combined by decay class

Decay 

class SD n DD n

Ratio SD/

DD

1 0.97 (0.01) 175 0.94 (0.01) 185 1.03

2 0.97 (0.01) 189 0.84 (0.01) 292 1.15

3 0.86 (0.03) 78 0.67 (0.01) 391 1.28

4 0.53 (0.06) 14 0.38 (0.01) 246 1.39

5 0.28 (0.01) 174

Note: Values are means with standard errors in parentheses. “n” is 

the number of SD or DD.
14

eff ects on biomass/residence times (Aakala et al. 2008, 

Aakala 2010, Kruys et al. 2002, Vanderwel et al. 2006, 

Zielonka 2006,). Moving beyond initial characterizations 

of SD and DD decay dynamics on intensively monitored 

study sites towards estimates of SD wood density by 

decay class for all forest tree species in the United States 

is a tremendous change in study scope. However, the 

immediate need to develop and document SD decay 

reduction factors for most forest tree species in the 

United States to meet mandated carbon stock reports 

requires a timely assimilation of the best available science. 

Given the lack of information on SD decayed wood 

density for hundreds of tree species in the United States, 

several approaches were considered. First, SD tree density 

can be assumed to be similar to undecayed tree density. 

For some environments in which decomposition is very 

slow, this might be acceptable. However, in our analysis 

we did not fi nd a single species in which density did not 

decline with decay class. Second, SD tree density could 

be assumed equal to that of DD tree density. Th is would 

be appropriate for 6 of the 19 species we examined. 

Th e most common situation in our study (13 of 19 

species) was for either position or a position X decay class 

interaction to be signifi cant.

To create the needed SD decay reduction factors for all 

tree species in the United States, decay classes in this 

study were aligned with those used by FIA using this 

study’s indicators of decay. FIA’s SD decay classes 1 

and 2 were quite similar to the classes 1 and 2 assessed 

in this study. Given the more highly decayed nature of 

SD decay classes 3 and 4, FIA’s SD decay classes 3 and 

4 seem to span the characteristics of decay class 3 SD 

trees with some overlap into decay class 4. Th e FIA SD 

decay class 5 would seem to be similar to this study’s SD 

decay class 4. Based on this fi nding, it is suggested that 

the decay reductions for SD decay class 4 be used as an 

approximation for SD decay class 5 until such time that 

empirical information refi nes SD decay class 5 attributes 

or a model is suggested to extrapolate decay class 4 

attributes to decay class 5 pieces. Furthermore, given the 

potential safety hazard of felling decay class 5 SD trees, 

this assumption may be the most practical. In general, 

these are gross approximations and, given the fact that 

the FIA system is based on Douglas-fi r with unspecifi ed 

modifi cations for other species, it would be logical to 

develop a SD decay class system based on a wider range 

of species better aligned with the DD system.

While it is important to eventually determine density and 

density reduction factors for SD and DD of the major 

species encountered in inventories, in the short-term one 

is forced to make assumptions when species or positions 

have not been sampled. Whether considering individual 

species, hardwoods and softwoods, or all samples 

combined, the ranges of density reduction factors for SD 

were consistently higher compared to DD. Th is indicates 

generally less reduction in density as decay progresses in 

SD than DD. Softwood species tended to exhibit this 

pattern more strongly than hardwood species, sometimes 

even increasing in density. Th ere were exceptions to this 

pattern in the statistical analysis (insignifi cant eff ect of 

position), but inspection of the charted data indicated 

that these cases had samples for only decay classes 1 and 

2, were hardwood species, or were located in a warm and 

wet climate. Th e assumption with the strongest support 

at this time is that softwoods tend to have a greater 

divergence in SD and DD density reduction factors than 

hardwoods. However, additional sampling of species, 

hardwoods in particular, is required to confi rm if this is 

actually the case.

Irrespective of the fi ndings of this study, SD wood 

density at some point in its decay process will become 

substantially less than that of living trees. Th e selection 

of density reduction factors can have a profound eff ect 

on resulting population estimates (e.g., SD carbon in 

a state). Th is study found substantial variation in SD 

biomass population estimates for Minnesota when using 

undecayed density versus reduced wood density values. 

Th e diff erences in estimates depend strongly on the 

dominance of hardwoods versus softwoods. When only 

softwood species were considered, the diff erence between 

the assumption of live tree wood density and the SD 

densities that we estimated was 2.5 percent. In contrast, 

when only hardwood species were considered the diff erence 

between these two methods was 22 percent. Th erefore, the 

potential biases contained in current SD estimates are likely 

to vary substantially. Th is analysis is considered preliminary 

for illustrative purposes as structural reductions for decay 

were not incorporated into the estimation procedures.
15

CONCLUSIONS

To provide accurate, unbiased estimates of the biomass 

and carbon stocks of SD trees, it is necessary to have 

species- and decay class-specifi c estimates of either 

density or density reduction factors. Empirically 

sampling the wood density of SD by species and decay 

class across the forests of the United States is currently 

restricted by the inherent costs and felling hazards 

involved. As an approach to estimate preliminary SD 

wood density reduction factors, this study established 

relationships between SD and DD such that extensive 

DD woody density studies could be used to suggest 

SD wood density attributes. Th is study suggests a new 

set of SD decay specifi c density and density reduction 

factors for many tree species in the United States that 

may be used to refi ne FIA’s SD population estimation 

procedures. Given the size of the uncertainty involved 

with the SD wood decay attributes proposed in this 

study, additional work to develop a multispecies SD 

decay class system and to better characterize diff erences 

between SD and DD trees is recommended.

ACKNOWLEDGMENTS

Th is work was funded by a joint venture agreement 

between the U.S. Forest Service Forest Inventory and 

Analysis and Oregon State University (09-JV-11242305-

025).

Special thanks are extended to Shawn Fraver, Ph.D., 

and Brad Oberle, Ph.D., who provided abundant 

constructive criticism that improved the quality of this 

documentation.

Th e cooperation of numerous experimental forest staff at 

locations in the United States and Russia were critical to 

this study’s success. In particular, Randy Kolka, Ph.D. 

and his staff at the Marcell Experimental Forest were 

especially helpful with facilitating the fi eld work. We 

would also like to thank Peter White, Ph.D. of the North 

Carolina Botanical Garden for the use of facilities and his 

many students whose eff orts made this project possible.

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18

Appendix A

Average density (g/cm3) for standing dead (SD) and downed dead (DD) trees 

and their associated ratio (SD/DD average density) for all study species

Species 

code

Decay 

class

SD 

(g/cm3) n

DD 

(g/cm3) n

Ratio 

SD/DD

ABSI 1 0.30 (0.02) 7

ABSI 2 0.33 (0.02) 4 0.30 (0.02) 4 1.10

ABSI 3 0.32 () 1 0.25 (0.03) 7 1.28

ABSI 4 0.20 (0.02) 10

ABSI 5 0.17 (0.02) 7

BECO 1 0.54 (0.01) 5 0.50 (0.01) 8 1.08

BECO 2 0.33 (0.04) 3

BECO 3 0.24 (0.00) 2 0.18 (0.01) 8 1.33

BECO 4 0.12 (0.00) 2

BECO 5 0.08 (0.00) 2

BEPE 1 0.48 (0.01) 21 0.47 (0.01) 25 1.02

BEPE 2 0.39 (0.01) 19 0.37 (0.01) 28 1.05

BEPE 3 0.27 (0.03) 6 0.25 (0.02) 29 1.08

BEPE 4 0.20 (0.03) 2 0.15 (0.01) 41 1.33

BEPE 5 0.11 (0.01) 29

LADA 1 0.44 (0.01) 2 0.46 (0.01) 13 0.96

LADA 2 0.46 (0.03) 8 0.39 (0.02) 13 1.18

LADA 3 0.33 (0.02) 14

LADA 4 0.19 (0.01) 9

LADA 5 0.11 (0.02) 4

LASI 1 0.45 (0.01) 12 0.46 (0.01) 16 0.98

LASI 2 0.46 (0.02) 11 0.40 (0.01) 13 1.15

LASI 3 0.46 (0.01) 12 0.34 (0.02) 16 1.35

LASI 4 0.15 (0.01) 16

LASI 5 0.11 (0.01) 16

LITU 0 0.40 (0.00) 2

LITU 1 0.37 (0.01) 6 0.31 (0.05) 3 1.19

LITU 2 0.35 (0.01) 5 0.28 (0.02) 9 1.25

LITU 3 0.20 (0.03) 5

LITU 4 0.11 (0.02) 3

PIAB 1 0.37 (0.03) 4 0.33 (0.01) 5 1.12

PIAB 2 0.37 (0.02) 5 0.27 (0.01) 6 1.37

PIAB 3 0.21 (0.02) 7

PIAB 4 0.13 (0.05) 3

PIAJ 1 0.38 (0.01) 8 0.34 (0.01) 11 1.12

PIAJ 2 0.39 (0.01) 3 0.32 (0.02) 11 1.22

PIAJ 3 0.36 () 1 0.24 (0.02) 15 1.50

PIAJ 4 0.15 (0.02) 10

PIAJ 5 0.12 (0.01) 6

PIBA2 1 0.39 (0.02) 7 0.39 (0.01) 5 1.00

PIBA2 2 0.38 (0.01) 5 0.36 (0.01) 7 1.06

PIBA2 3 0.32 (0.04) 6 0.22 (0.02) 6 1.45

PIBA2 4 0.12 (0.01) 7

PICO 1 0.39 (0.00) 27 0.37 (0.01) 18 1.05

PICO 2 0.41 (0.01) 8 0.36 (0.01) 15 1.14

continued
19

PICO 3 0.40 (0.00) 7 0.32 (0.02) 15 1.25

PICO 4 0.17 (0.01) 7

PICO 5 0.16 (0.01) 9

PIKO 1 0.36 (0.00) 4 0.35 (0.01) 8 1.03

PIKO 2 0.34 (0.02) 5 0.32 (0.01) 10 1.06

PIKO 3 0.33 (0.02) 3 0.24 (0.01) 12 1.38

PIKO 4 0.16 (0.01) 4

PIKO 5 0.13 (0.03) 2

PILU 0 0.38 (0.01) 11

PILU 1 0.38 (0.01) 21 0.36 (0.01) 7 1.06

PILU 2 0.38 (0.01) 69 0.34 (0.01) 92 1.12

PILU 3 0.40 (0.02) 17 0.26 (0.01) 153 1.54

PILU 4 0.13 (0.01) 58

PILU 5 0.08 (0.00) 52

PINE 1 0.37 (0.02) 5 0.37 (0.03) 5 1.00

PINE 2 0.36 (0.02) 4 0.27 (0.02) 9 1.33

PINE 3 0.35 (0.05) 5 0.19 (0.02) 8 1.84

PINE 4 0.35 (0.03) 6 0.19 (0.03) 7 1.84

PINE 5 0.22 () 1

PIOB 1 0.36 (0.02) 4 0.37 (0.01) 10 0.97

PIOB 2 0.39 (0.01) 4 0.33 (0.02) 10 1.18

PIOB 3 0.25 (0.01) 14

PIOB 4 0.13 (0.01) 13

PIOB 5 0.10 (0.01) 8

PISI2 1 0.33 (0.01) 8 0.33 (0.01) 8 1.00

PISI2 2 0.34 (0.00) 7 0.30 (0.01) 8 1.13

PISI2 3 0.30 (0.00) 2 0.23 (0.02) 8 1.30

PISI2 4 0.14 (0.01) 8

PISI2 5 0.10 (0.01) 8

PISY 1 0.37 (0.01) 23 0.36 (0.01) 20 1.03

PISY 2 0.36 (0.01) 19 0.32 (0.01) 31 1.13

PISY 3 0.31 (0.03) 4 0.27 (0.01) 47 1.15

PISY 4 0.18 (0.01) 32

PISY 5 0.12 (0.01) 29

POTR 1 0.37 (0.02) 5 0.36 (0.01) 7 1.03

POTR 2 0.29 (0.02) 6 0.28 (0.02) 6 1.04

POTR 3 0.21 (0.03) 5 0.16 (0.01) 7 1.31

POTR 4 0.07 (0.01) 6

POTR2 1 0.35 (0.01) 8

POTR2 2 0.25 () 1 0.29 (0.02) 12 0.86

POTR2 3 0.24 () 1 0.25 (0.02) 11 0.96

POTR2 4 0.14 (0.01) 3

TSHE 1 0.39 (0.01) 6 0.42 (0.01) 8 0.93

TSHE 2 0.36 (0.02) 6 0.35 (0.03) 5 1.03

TSHE 3 0.29 (0.02) 6 0.28 (0.02) 9 1.04

TSHE 4 0.17 (0.02) 6 0.17 (0.03) 7 1.00

TSHE 5 0.12 () 1

Note: Values are means with standard errors in parentheses. “n” is the number of SD or DD.

Appendix A.—continued

Species 

code

Decay 

class

SD 

(g/cm3) n

DD 

(g/cm3) n

Ratio 

SD/DD
20

Appendix B

Average density reduction factor for standing dead (SD) and downed dead (DD) 

trees and their associated ratio (SD/DD decay reduction factor) for all study species

Species 

code Decay class SD n DD n

Ratio 

SD/DD

ABSI 1 0.95 (0.06) 7

ABSI 2 1.06 (0.06) 4 0.97 (0.05) 4 1.09

ABSI 3 1.03 () 1 0.79 (0.08) 7 1.30

ABSI 4 0.66 (0.07) 10

ABSI 5 0.55 (0.08) 7

BECO 1 1.00 (0.01) 5 0.93 (0.01) 8 1.08

BECO 2 0.62 (0.07) 3

BECO 3 0.44 (0.01) 2 0.34 (0.02) 8 1.29

BECO 4 0.22 (0.01) 2

BECO 5 0.16 (0.00) 2

BEPE 1 1.01 (0.01) 21 0.98 (0.02) 25 1.03

BEPE 2 0.81 (0.03) 19 0.77 (0.02) 28 1.05

BEPE 3 0.56 (0.07) 6 0.53 (0.04) 29 1.06

BEPE 4 0.43 (0.05) 2 0.30 (0.03) 41 1.43

BEPE 5 0.23 (0.02) 29

LADA 1 0.88 (0.01) 2 0.90 (0.02) 13 0.98

LADA 2 0.92 (0.05) 8 0.77 (0.03) 13 1.19

LADA 3 0.66 (0.04) 14

LADA 4 0.37 (0.03) 9

LADA 5 0.22 (0.05) 4

LASI 1 0.92 (0.02) 12 0.94 (0.03) 16 0.98

LASI 2 0.95 (0.03) 11 0.82 (0.02) 13 1.16

LASI 3 0.95 (0.02) 12 0.70 (0.04) 16 1.36

LASI 4 0.30 (0.02) 16

LASI 5 0.22 (0.02) 16

LITU 0 0.97 (0.00) 2

LITU 1 0.91 (0.03) 6 0.76 (0.12) 3 1.20

LITU 2 0.85 (0.02) 5 0.68 (0.04) 9 1.25

LITU 3 0.48 (0.07) 5

LITU 4 0.28 (0.05) 3

PIAB 1 1.01 (0.09) 4 0.88 (0.03) 5 1.15

PIAB 2 1.01 (0.04) 5 0.73 (0.03) 6 1.38

PIAB 3 0.57 (0.05) 7

PIAB 4 0.36 (0.12) 3

PIAJ 1 1.07 (0.02) 8 0.97 (0.03) 11 1.10

PIAJ 2 1.11 (0.02) 3 0.92 (0.05) 11 1.21

PIAJ 3 1.03 () 1 0.68 (0.06) 15 1.51

PIAJ 4 0.43 (0.05) 10

PIAJ 5 0.34 (0.02) 6

PIBA2 1 0.95 (0.04) 7 0.95 (0.03) 5 1.00

PIBA2 2 0.92 (0.03) 5 0.87 (0.03) 7 1.06

PIBA2 3 0.78 (0.09) 6 0.53 (0.04) 6 1.47

PIBA2 4 0.29 (0.03) 7

PICO 1 0.98 (0.01) 27 0.95 (0.02) 18 1.03

PICO 2 1.04 (0.03) 8 0.92 (0.02) 15 1.13

continued
21

PICO 3 1.02 (0.01) 7 0.80 (0.05) 15 1.28

PICO 4 0.43 (0.03) 7

PICO 5 0.42 (0.02) 9

PIKO 1 0.92 (0.01) 4 0.90 (0.02) 8 1.02

PIKO 2 0.88 (0.05) 5 0.81 (0.03) 10 1.09

PIKO 3 0.86 (0.05) 3 0.62 (0.03) 12 1.39

PIKO 4 0.41 (0.03) 4

PIKO 5 0.34 (0.07) 2

PILU 0 1.06 (0.03) 11

PILU 1 1.06 (0.02) 21 1.01 (0.04) 7 1.05

PILU 2 1.06 (0.02) 69 0.93 (0.01) 92 1.14

PILU 3 1.11 (0.04) 17 0.73 (0.02) 153 1.52

PILU 4 0.37 (0.01) 58

PILU 5 0.23 (0.01) 52

PINE 1 0.76 (0.05) 5 0.75 (0.06) 5 1.01

PINE 2 0.74 (0.03) 4 0.55 (0.04) 9 1.35

PINE 3 0.72 (0.09) 5 0.40 (0.03) 8 1.80

PINE 4 0.72 (0.07) 6 0.39 (0.06) 7 1.85

PINE 5 0.46 () 1

PIOB 1 0.97 (0.04) 4 0.98 (0.03) 10 0.99

PIOB 2 1.03 (0.03) 4 0.87 (0.05) 10 1.18

PIOB 3 0.66 (0.03) 14

PIOB 4 0.35 (0.03) 13

PIOB 5 0.26 (0.02) 8

PISI2 1 0.86 (0.02) 8 0.85 (0.02) 8 1.01

PISI2 2 0.89 (0.01) 7 0.77 (0.03) 8 1.16

PISI2 3 0.78 (0.01) 2 0.58 (0.04) 8 1.34

PISI2 4 0.36 (0.03) 8

PISI2 5 0.27 (0.02) 8

PISY 1 0.99 (0.02) 23 0.96 (0.02) 20 1.03

PISY 2 0.98 (0.02) 19 0.87 (0.02) 31 1.13

PISY 3 0.83 (0.08) 4 0.71 (0.02) 47 1.17

PISY 4 0.48 (0.04) 32

PISY 5 0.33 (0.02) 29

POTR 1 0.97 (0.04) 5 0.93 (0.03) 7 1.04

POTR 2 0.75 (0.05) 6 0.72 (0.04) 6 1.04

POTR 3 0.54 (0.07) 5 0.41 (0.03) 7 1.32

POTR 4 0.18 (0.01) 6

POTR2 1 0.95 (0.02) 8

POTR2 2 0.66 () 1 0.78 (0.05) 12 0.85

POTR2 3 0.63 () 1 0.66 (0.07) 11 0.95

POTR2 4 0.36 (0.03) 3

TSHE 1 0.90 (0.03) 6 0.96 (0.02) 8 0.94

TSHE 2 0.83 (0.04) 6 0.80 (0.06) 5 1.04

TSHE 3 0.66 (0.05) 6 0.64 (0.05) 9 1.03

TSHE 4 0.38 (0.05) 6 0.40 (0.06) 7 0.95

TSHE 5 0.27 () 1

Note: Values are means with standard errors in parentheses. “n” is the number of SD or DD.

Appendix B.—continued

Species 

code Decay class SD n DD n

Ratio 

SD/DD
22 Appendix C

Standing dead tree absolute density and its uncertainty for each decay class by species present in the U.S. FIA inventoryGenus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4Abies amabilis ABAM 0.400 0.356 0.020 B 0.382 0.014 B 0.301 0.060 B 0.239 0.336 CAbies balsamea ABBA 0.340 0.356 0.024 B 0.414 0.014 B 0.412 0.058 B 0.286 0.336 CAbies bracteata ABBR 0.360 0.367 0.024 B 0.354 0.029 B 0.301 0.060 B 0.239 0.336 CAbies concolor ABCO 0.370 0.337 0.012 B 0.319 0.013 B 0.172 0.057 B 0.232 0.336 CAbies fraseri ABFR 0.340 0.367 0.024 B 0.354 0.029 B 0.301 0.060 B 0.239 0.336 CAbies grandis ABGR 0.350 0.338 0.010 B 0.338 0.013 B 0.320 0.057 B 0.239 0.336 CAbies lasiocarpa ABLA 0.310 0.367 0.014 B 0.331 0.025 B 0.331 0.057 B 0.255 0.336 CAbies magnifi ca ABMA 0.360 0.473 0.012 B 0.435 0.023 B 0.213 0.057 B 0.240 0.336 CAbies magnifi ca var. 

shastensis

ABMA2 0.360 0.367 0.024 B 0.354 0.029 B 0.301 0.060 B 0.239 0.336 C

Abies procera ABPR 0.370 0.364 0.010 B 0.309 0.012 B 0.334 0.057 B 0.252 0.336 CAbies species ABIE 0.340 0.367 0.024 B 0.354 0.029 B 0.301 0.060 B 0.239 0.336 CAcacia species ACSP2 0.600 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAcer barbatum ACBA 0.540 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer glabrum ACGL 0.440 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer grandidentatum ACGR 0.440 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer macrophyllum ACMA 0.440 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer negundo ACNE 0.440 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer nigrum ACNI 0.520 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer pensylvanicum ACPE 0.440 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer rubrum ACRU 0.490 0.462 0.030 B 0.286 0.047 B 0.208 0.085 B 0.297 0.336 CAcer saccharinum ACSA2 0.440 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer saccharum ACSA 0.560 0.720 0.028 B 0.497 0.052 B 0.340 0.085 B 0.306 0.336 CAcer species ACER 0.490 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAcer spicatum ACSP 0.440 0.568 0.048 B 0.415 0.053 B 0.295 0.087 B 0.297 0.336 CAesculus californica AECA 0.380 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAesculus species AESP 0.330 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAilanthus altissima AIAL 0.370 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAleurites fordii ALFO 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAlnus rubra ALRU 0.370 0.409 0.021 B 0.359 0.047 B 0.207 0.084 B 0.181 0.336 CAlnus species ALSP 0.370 0.409 0.092 B 0.359 0.096 B 0.207 0.098 B 0.181 0.337 CAmelanchier species AMSP 0.660 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 C

continued
23

Arbutus menziesii ARME 0.580 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAsimina triloba ASTR 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CBetula alleghaniensis BEAL 0.550 0.615 0.049 B 0.443 0.115 B 0.200 0.084 B 0.286 0.336 CBetula lenta BELE 0.600 0.673 0.049 B 0.462 0.061 B 0.297 0.087 B 0.286 0.337 CBetula lutea BELU 0.600 0.674 0.035 B 0.424 0.049 B 0.246 0.085 B 0.286 0.337 CBetula nigra BENI 0.560 0.615 0.049 B 0.443 0.115 B 0.278 0.088 B 0.286 0.337 CBetula occidentalis BEOC 0.530 0.615 0.049 B 0.443 0.115 B 0.278 0.088 B 0.286 0.337 CBetula papyrifera BEPA 0.480 0.497 0.032 B 0.443 0.115 B 0.370 0.095 B 0.286 0.337 CBetula papyrifera var. 

commutata

BEPA2 0.480 0.615 0.049 B 0.443 0.115 B 0.278 0.088 B 0.286 0.337 C

Betula populifolia BEPO 0.450 0.615 0.049 B 0.443 0.115 B 0.278 0.088 B 0.286 0.337 CBetula species BESP 0.480 0.615 0.049 B 0.443 0.115 B 0.278 0.088 B 0.286 0.337 CBumelia lanuginosa BULA 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCalocedrus decurrens CADE3 0.370 0.421 0.046 B 0.309 0.019 B 0.328 0.058 B 0.262 0.336 CCarpinus caroliniana CACA 0.580 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCarya aquatica CAAQ 0.610 0.635 0.041 B 0.450 0.053 B 0.250 0.085 B 0.291 0.337 CCarya cordiformis CACO 0.600 0.647 0.050 B 0.404 0.052 B 0.261 0.085 B 0.291 0.337 CCarya glabra CAGL 0.660 0.635 0.041 B 0.450 0.053 B 0.250 0.085 B 0.291 0.337 CCarya illinoensis CAIL 0.600 0.635 0.041 B 0.450 0.053 B 0.250 0.085 B 0.291 0.337 CCarya laciniosa CALA 0.620 0.635 0.041 B 0.450 0.053 B 0.250 0.085 B 0.291 0.337 CCarya myristicaeformis CAMY 0.560 0.635 0.041 B 0.450 0.053 B 0.250 0.085 B 0.291 0.337 CCarya ovata CAOV 0.640 0.584 0.044 B 0.527 0.061 B 0.323 0.086 B 0.291 0.337 CCarya species CASP 0.620 0.671 0.029 B 0.459 0.045 B 0.205 0.084 B 0.291 0.336 CCarya texana CATE 0.540 0.635 0.041 B 0.450 0.053 B 0.250 0.085 B 0.291 0.337 CCarya tomentosa CATO 0.640 0.637 0.041 B 0.409 0.046 B 0.250 0.085 B 0.291 0.337 CCastanea dentata CADE 0.400 0.382 0.027 B 0.383 0.046 B 0.268 0.085 B 0.356 0.338 CCastanea ozarkensis CAOZ 0.400 0.382 0.087 B 0.383 0.102 B 0.268 0.107 B 0.356 0.338 CCastanea pumila CAPU 0.400 0.382 0.087 B 0.383 0.102 B 0.268 0.107 B 0.356 0.338 CCastanopsis species CAST 0.420 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCatalpa species CATA 0.380 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCeltis laevigata CELA 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCeltis occidentalis CEOC 0.490 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCeltis species CESP 0.490 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAppendix C.—continued

continued

Genus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4
24

Cercis canadensis CECA 0.580 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCercocarpus intricatus CEIN 1.000 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCercocarpus ledifolius CELE 1.000 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCercocarpus montanus CEMO 1.000 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CChamaecyparis lawsoniana CHLA 0.390 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CChamaecyparis nootkatensis CHNO 0.420 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CChamaecyparis thyoides CHTH 0.310 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CCladrastis lutea CLLU 0.520 0.528 0.125 B 0.485 0.112 B 0.462 0.102 B 0.356 0.338 CCornus fl orida COFL 0.640 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 C

Cornus nuttallii CONU 0.580 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCornus species COSP 0.640 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCotinus obovaus COOB 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCrataegus species CRSP 0.620 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CCupressus species CUSP 0.440 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CDiospyros virginiana DIVI 0.640 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CEucalyptus species EUSP 0.670 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CFagus grandifolia FAGR 0.560 0.604 0.038 B 0.330 0.046 B 0.175 0.084 B 0.403 0.336 CFraxinus americana FRAM 0.550 0.504 0.039 B 0.315 0.048 B 0.333 0.085 B 0.356 0.338 CFraxinus latifolia FRLA 0.500 0.504 0.113 B 0.349 0.094 B 0.313 0.114 B 0.356 0.338 CFraxinus nigra FRNI 0.450 0.504 0.113 B 0.349 0.094 B 0.313 0.114 B 0.356 0.338 CFraxinus pennsylvanica FRPE 0.530 0.504 0.113 B 0.349 0.094 B 0.313 0.114 B 0.356 0.338 CFraxinus profunda FRPR 0.540 0.504 0.113 B 0.349 0.094 B 0.313 0.114 B 0.356 0.338 CFraxinus quadrangulata FRQU 0.530 0.504 0.113 B 0.349 0.094 B 0.313 0.114 B 0.356 0.338 CFraxinus species FRSP 0.540 0.504 0.113 B 0.349 0.094 B 0.313 0.114 B 0.356 0.338 CGleditsia aquatica GLAQ 0.600 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CGleditsia triacanthos GLTR 0.600 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CGordonia lasianthus GOLA 0.370 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CGymnocladus dioicus GYDI 0.500 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CHalesia species HASP 0.320 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CIlex opaca ILOP 0.500 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CJuglans cinerea JUCI 0.360 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CJuglans species JUSP 0.510 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CJulglans nigra JUNI 0.510 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAppendix C.—continued

continued

Genus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4
25

Juniperus monosperma JUMO 0.450 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CJuniperus occidentalis JUOC 0.440 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CJuniperus species JUSP2 0.440 0.528 0.125 B 0.485 0.112 B 0.462 0.102 B 0.356 0.338 CLarix laricina LALA 0.490 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CLarix lyallii LALY 0.480 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CLarix occidentalis LAOC 0.480 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CLarix species LASP 0.440 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CLiquidambar styracifl ua LIST 0.460 0.477 0.022 B 0.364 0.045 B 0.239 0.084 B 0.356 0.338 CLiriodendron tulipifera LITU 0.410 0.370 0.010 A 0.350 0.010 A 0.213 0.084 B 0.237 0.336 CLithocarpus densifl orus LIDE 0.580 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 C

Maclura pomifera MAPO 0.760 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CMagnolia acuminata MAAC 0.450 0.451 0.024 B 0.439 0.055 B 0.263 0.085 B 0.356 0.338 CMagnolia species MASP 0.450 0.451 0.101 B 0.439 0.114 B 0.263 0.106 B 0.356 0.338 CMalus species MASP2 0.610 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CMelia azedarach MEAZ 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CMorus alba MOAL 0.590 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CMorus rubra MORU 0.590 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CMorus species MOSP 0.590 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CNyssa aquatica NYAQ 0.460 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CNyssa ogeche NYOG 0.460 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CNyssa sylvatica NYSY 0.460 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 COlneya tesota OLTE 1.000 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 COstrya virginiana OSVI 0.630 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 COxydendrum arboreum OXAR 0.500 0.555 0.058 B 0.447 0.046 B 0.354 0.086 B 0.356 0.338 CPaulownia tomentosa PATO 0.380 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CPersea borbonia PEBO 0.510 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CPicea abies PIAB 0.370 0.370 0.030 A 0.370 0.020 A 0.398 0.065 B 0.260 0.336 CPicea breweriana PIBR 0.330 0.389 0.024 B 0.359 0.017 B 0.398 0.065 B 0.260 0.336 CPicea engelmannii PIEN 0.330 0.389 0.024 B 0.297 0.013 B 0.398 0.065 B 0.197 0.336 CPicea glauca PIGL2 0.370 0.389 0.024 B 0.359 0.017 B 0.398 0.065 B 0.260 0.336 CPicea lutzii PILU 0.360 0.380 0.010 A 0.380 0.010 A 0.400 0.020 A 0.254 0.336 CPicea mariana PIMA 0.380 0.389 0.024 B 0.359 0.017 B 0.398 0.065 B 0.260 0.336 CPicea pungens PIPU 0.380 0.389 0.024 B 0.359 0.017 B 0.398 0.065 B 0.260 0.336 CAppendix C.—continued

continued

Genus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4
26

Picea rubens PIRU 0.380 0.402 0.025 B 0.359 0.017 B 0.449 0.067 B 0.260 0.336 CPicea sitchensis PISI 0.370 0.406 0.010 B 0.392 0.014 B 0.373 0.057 B 0.323 0.336 CPicea species PICE 0.380 0.389 0.024 B 0.359 0.017 B 0.398 0.065 B 0.260 0.336 CPinus albicaulis PIAL 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus aristata PIAR 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus arizonica PIAR2 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus attenuata PIAT 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus balfouriana PIBA 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus banksiana PIBA2 0.420 0.390 0.020 A 0.380 0.010 A 0.320 0.040 A 0.284 0.336 CPinus clausa PICL 0.460 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus contorta PICO 0.400 0.390 0.001 A 0.415 0.015 A 0.400 0.001 A 0.284 0.336 CPinus coulteri PICO2 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus discolor PIDI 0.500 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus echinata PIEC 0.470 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus edulis PIED 0.500 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus elliotti PIEL 0.540 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus engelmannii PIEN2 0.370 0.364 0.015 B 0.373 0.017 B 0.398 0.060 B 0.284 0.336 CPinus fl exilis PIFL 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 C

Pinus glabra PIGL 0.410 0.389 0.021 B 0.359 0.017 B 0.398 0.060 B 0.260 0.336 CPinus jeffreyi PIJE 0.370 0.361 0.014 B 0.412 0.019 B 0.308 0.058 B 0.344 0.336 CPinus lambertiana PILA 0.340 0.365 0.017 B 0.307 0.012 B 0.220 0.057 B 0.205 0.336 CPinus leiophylla PILE 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus monophylla PIMO 0.500 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus monticola PIMO3 0.350 0.341 0.010 B 0.348 0.012 B 0.437 0.057 B 0.284 0.336 CPinus muricata PIMU 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus nigra PINI 0.410 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus palustris PIPA 0.540 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus ponderosa PIPO 0.380 0.335 0.010 B 0.383 0.013 B 0.469 0.058 B 0.217 0.336 CPinus pungens PIPU2 0.490 0.389 0.021 B 0.359 0.017 B 0.398 0.060 B 0.260 0.336 CPinus radiata PIRA 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus resinosa PIRE 0.410 0.337 0.019 B 0.373 0.017 B 0.383 0.060 B 0.252 0.336 CPinus rigida PIRI 0.470 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus sabiniana PISA 0.370 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CAppendix C.—continued

continued

Genus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4
27

Pinus serotina PISE 0.510 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus strobiformis PIST2 0.350 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus strobus PIST 0.340 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPinus sylvestris PISY 0.380 0.370 0.010 A 0.360 0.010 A 0.310 0.030 A 0.284 0.336 CPinus taeda PITA 0.470 0.382 0.011 B 0.352 0.012 B 0.325 0.057 B 0.324 0.336 CPinus virginiana PIVI 0.450 0.364 0.015 B 0.373 0.017 B 0.388 0.060 B 0.284 0.336 CPlanera aquatica PLAQ 0.530 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CPlatanus occidentalis PLOC 0.460 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CPopulus alba POAL 0.370 0.374 0.085 B 0.464 0.119 B 0.314 0.115 B 0.269 0.337 CPopulus angustifolia POAN 0.340 0.374 0.085 B 0.464 0.119 B 0.314 0.115 B 0.269 0.337 CPopulus balsamifera POBA 0.310 0.374 0.085 B 0.464 0.119 B 0.314 0.115 B 0.269 0.337 CPopulus deltoides PODE 0.370 0.374 0.085 B 0.464 0.119 B 0.314 0.115 B 0.269 0.337 CPopulus fremontii POFR 0.340 0.374 0.085 B 0.464 0.119 B 0.314 0.115 B 0.269 0.337 CPopulus grandidentata POGR 0.360 0.356 0.031 B 0.464 0.119 B 0.313 0.086 B 0.269 0.337 CPopulus heterophylla POHE 0.370 0.374 0.085 B 0.464 0.119 B 0.314 0.115 B 0.269 0.337 CPopulus sargentii POSA 0.370 0.374 0.085 B 0.464 0.119 B 0.314 0.115 B 0.269 0.337 CPopulus species POSP 0.370 0.392 0.033 B 0.464 0.119 B 0.315 0.086 B 0.269 0.336 CPopulus tremuloides POTR 0.390 0.370 0.020 A 0.290 0.020 A 0.210 0.030 A 0.269 0.337 CProsopis species PRSP 0.580 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CPrunus americana PRAM 0.470 0.518 0.044 B 0.460 0.052 B 0.295 0.112 B 0.356 0.338 CPrunus nigra PRNI 0.470 0.518 0.044 B 0.460 0.052 B 0.295 0.112 B 0.356 0.338 CPrunus pensylvanica PRPE 0.360 0.425 0.024 B 0.371 0.045 B 0.227 0.084 B 0.356 0.338 CPrunus serotina PRSE 0.470 0.612 0.047 B 0.549 0.050 B 0.363 0.090 B 0.356 0.338 CPrunus species PRSP2 0.470 0.518 0.044 B 0.460 0.052 B 0.295 0.112 B 0.356 0.338 CPrunus virginiana PRVI 0.360 0.518 0.044 B 0.460 0.052 B 0.295 0.112 B 0.356 0.338 CPseudotsuga menziesii PSME 0.450 0.382 0.011 B 0.354 0.013 B 0.216 0.057 B 0.207 0.336 CQuercus agrifolia QUAG 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus alba QUAL 0.600 0.601 0.028 B 0.426 0.045 B 0.352 0.085 B 0.282 0.336 CQuercus arizonica, grisea QUAR 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus bicolor QUBI 0.640 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus chrysolepis QUCH 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus coccinea QUCO 0.600 0.605 0.037 B 0.552 0.049 B 0.464 0.085 B 0.405 0.336 CQuercus douglasii QUDO 0.510 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CAppendix C.—continued

continued

Genus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4
28

Quercus durandii QUDU 0.600 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus ellipsoidalis QUEL 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus emoryi QUEM 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus engelmannii QUEN 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus falcata var. falcata QUFA 0.520 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus falcata var. 

pagodaefolia

QUFA2 0.610 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 C

Quercus gambelii QUGA 0.640 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus garryana QUGA2 0.640 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus hypoleucoides QUHY 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus ilicifolia QUIL 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus imbricaria QUIM 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus incana QUIN 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus kelloggii QUKE 0.510 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus laevis QULA 0.520 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus laurifolia QULA2 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus lobata QULO 0.640 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus lyrata QULY 0.570 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus macrocarpa QUMA 0.580 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus marilandica QUMA2 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus michauxii QUMI 0.600 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus muehlenbergii QUMU 0.600 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus nigra QUNI 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus nuttalli QUNU 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus oblongifolia QUOB 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus palustris QUPA 0.580 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus phellos QUPH 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus prinus QUPR 0.570 0.773 0.061 B 0.538 0.063 B 0.309 0.085 B 0.405 0.336 CQuercus rubra QURU 0.560 0.578 0.032 B 0.333 0.051 B 0.406 0.090 B 0.393 0.336 CQuercus shumardii QUSH 0.560 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus species QUSP 0.580 0.599 0.024 B 0.508 0.048 B 0.334 0.085 B 0.329 0.336 CQuercus stellata QUST 0.600 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus velutina QUVE 0.560 0.648 0.056 B 0.399 0.056 B 0.476 0.095 B 0.405 0.336 CAppendix C.—continued

continued

Genus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4
29

Quercus virginiana QUVI 0.800 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CQuercus wislizeni QUWI 0.700 0.648 0.056 B 0.495 0.062 B 0.401 0.092 B 0.405 0.336 CRobinia neomexicana RONE 0.660 0.769 0.170 B 0.616 0.154 B 0.341 0.119 B 0.356 0.338 CRobinia pseudoacacia ROPS 0.660 0.769 0.031 B 0.616 0.053 B 0.341 0.119 B 0.356 0.338 CSalix species SASP 0.360 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CSapium sebiferum SASE 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CSassafras albidum SAAL 0.420 0.458 0.024 B 0.427 0.047 B 0.355 0.084 B 0.356 0.338 CSequoia sempervirens SESE 0.340 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CSequoiadendron giganteum SEGI 0.340 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CSorbus americana SOAM 0.420 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CTamarix species TASP 0.400 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CTaxodium distichum var. 

nutans

TADI 0.420 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 C

Taxus brevifolia TABR 0.600 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CThuja occidentalis THOC 0.290 0.326 0.016 B 0.298 0.102 B 0.447 0.059 B 0.240 0.336 CThuja plicata THPL 0.310 0.315 0.016 B 0.298 0.102 B 0.352 0.057 B 0.222 0.336 CTilia americana TIAM 0.320 0.430 0.023 B 0.366 0.045 B 0.269 0.084 B 0.356 0.338 CTilia heterophylla TIHE 0.320 0.430 0.097 B 0.366 0.098 B 0.269 0.107 B 0.356 0.338 CTilia species TISP 0.320 0.430 0.097 B 0.366 0.098 B 0.269 0.107 B 0.356 0.338 CTorreya californica TOCA 0.340 0.377 0.041 B 0.366 0.079 B 0.365 0.065 B 0.272 0.336 CTsuga canadensis TSCA 0.400 0.394 0.025 B 0.370 0.080 B 0.462 0.063 B 0.299 0.336 CTsuga heterophylla TSHE 0.440 0.390 0.010 A 0.360 0.020 A 0.290 0.020 A 0.170 0.024 ATsuga mertensiana TSME 0.420 0.376 0.025 B 0.370 0.080 B 0.400 0.066 B 0.299 0.336 CTsuga species TSSP 0.380 0.376 0.025 B 0.370 0.080 B 0.400 0.066 B 0.299 0.336 CUlmus alata ULAL 0.570 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUlmus americana ULAM 0.460 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUlmus crassifolia ULCR 0.570 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUlmus pumila ULPU 0.460 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUlmus rubra ULRU 0.480 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUlmus serotina ULSE 0.570 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUlmus species ULSP 0.500 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUlmus thomasii ULTH 0.570 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CUmbellularia californica UMCA 0.510 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CVaccinium arboreum VAAR 0.470 0.565 0.126 B 0.464 0.119 B 0.341 0.119 B 0.356 0.338 CAppendix C.—continuedGenus Species Code den0 den1 unc1 cod1 den2 unc2 cod2 den3 unc3 cod3 den4 unc4 cod4

continued
30

Standing Dead Absolute Density Predictions Metadata (Appendix C)Fieldname Defi nition Code/Units Methodgenus Sample genusspecies Sample speciescode Genus-species codeden0 Green density (decay class “0”) g/cm3den1 Density of decay class 1 snag g/cm3unc1 Uncertainty of den1cod1 Uncertainty code for den1 (A, B, C) A Species sampledcod1 Uncertainty code for den1 (A, B, C) B Genera sampledcod1 Uncertainty code for den1 (A, B, C) C Species and genus not sampledden2 Density of decay class 2 snag g/cm3unc2 Uncertainty of den2cod2 Uncertainty code for den2 (A, B, C) A Species sampledcod2 Uncertainty code for den2 (A, B, C) B Genera sampledcod2 Uncertainty code for den2 (A, B, C) C Species and genus not sampledden3 Density of decay class 3 snag g/cm3unc3 Uncertainty of den3cod3 Uncertainty code for den3 (A, B, C) A Species sampledcod3 Uncertainty code for den3 (A, B, C) B Genera sampledcod3 Uncertainty code for den3 (A, B, C) C Species and genus not sampledden4 Density of decay class 4 snag g/cm3Appendix C.—continuedunc4 Uncertainty of den4cod4 Uncertainty code for den4 (A, B, C) A Species sampledcod4 Uncertainty code for den4 (A, B, C) B Genera sampledcod4 Uncertainty code for den4 (A, B, C) C Species and genus not sampled
31

Appendix DStanding dead tree relative density and its uncertainty for each decay class by species present in the U.S. FIA inventoryGenus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4Abies amabilis ABAM 0.400 0.936 0.044 B 0.955 0.022 B 0.803 0.107 B 0.574 0.216 CAbies balsamea ABBA 0.340 1.040 0.062 B 1.150 0.023 B 1.101 0.064 B 0.710 0.219 CAbies bracteata ABBR 0.360 1.018 0.056 B 0.975 0.091 B 0.803 0.107 B 0.574 0.216 CAbies concolor ABCO 0.370 0.996 0.021 B 0.873 0.018 B 0.625 0.054 B 0.541 0.213 CAbies fraseri ABFR 0.340 1.018 0.056 B 0.975 0.091 B 0.803 0.107 B 0.574 0.216 CAbies grandis ABGR 0.350 1.013 0.011 B 0.966 0.021 B 0.855 0.054 B 0.574 0.216 CAbies lasiocarpa ABLA 0.310 1.040 0.030 B 1.068 0.073 B 1.000 0.056 B 0.696 0.214 CAbies magnifi ca ABMA 0.360 1.040 0.017 B 1.080 0.051 B 0.626 0.054 B 0.467 0.213 CAbies magnifi ca var. 

shastensis ABMA2 0.360 1.018 0.056 B 0.975 0.091 B 0.803 0.107 B 0.574 0.216 C

Abies procera ABPR 0.370 1.035 0.013 B 0.836 0.013 B 0.845 0.054 B 0.575 0.213 CAbies species ABIE 0.340 1.018 0.056 B 0.975 0.091 B 0.803 0.107 B 0.622 0.217 CAcacia species ACSP2 0.600 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CAcer barbatum ACBA 0.540 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer glabrum ACGL 0.440 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer grandidentatum ACGR 0.440 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer macrophyllum ACMA 0.440 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer negundo ACNE 0.440 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer nigrum ACNI 0.520 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer pensylvanicum ACPE 0.440 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer rubrum ACRU 0.490 1.002 0.049 B 0.773 0.056 B 0.618 0.086 B 0.450 0.221 CAcer saccharinum ACSA2 0.440 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer saccharum ACSA 0.560 0.956 0.028 B 0.761 0.055 B 0.526 0.077 B 0.450 0.213 CAcer species ACER 0.490 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAcer spicatum ACSP 0.440 0.979 0.035 B 0.766 0.194 B 0.565 0.160 B 0.450 0.221 CAesculus californica AECA 0.380 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CAesculus species AESP 0.330 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CAilanthus altissima AIAL 0.370 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CAleurites fordii ALFO 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 C

continued
32

Alnus rubra ALRU 0.370 1.030 0.013 B 0.903 0.051 B 0.535 0.074 B 0.393 0.213 CAlnus species ALSP 0.370 1.030 0.135 B 0.903 0.228 B 0.535 0.153 B 0.393 0.219 CAmelanchier species AMSP 0.660 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CArbutus menziesii ARME 0.580 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CAsimina triloba ASTR 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CBetula alleghaniensis BEAL 0.550 1.032 0.135 B 0.713 0.181 B 0.336 0.075 B 0.402 0.213 CBetula lenta BELE 0.600 1.040 0.070 B 0.756 0.077 B 0.500 0.084 B 0.439 0.220 CBetula lutea BELU 0.600 1.040 0.044 B 0.671 0.048 B 0.400 0.076 B 0.439 0.220 CBetula nigra BENI 0.560 1.032 0.135 B 0.713 0.181 B 0.511 0.148 B 0.439 0.220 CBetula occidentalis BEOC 0.530 1.032 0.135 B 0.713 0.181 B 0.511 0.148 B 0.439 0.220 CBetula papyrifera BEPA 0.480 1.016 0.052 B 0.713 0.181 B 0.777 0.120 B 0.439 0.220 CBetula papyrifera var. 

commutata BEPA2 0.480 1.032 0.135 B 0.713 0.181 B 0.511 0.148 B 0.439 0.220 C

Betula populifolia BEPO 0.450 1.032 0.135 B 0.713 0.181 B 0.511 0.148 B 0.439 0.220 CBetula species BESP 0.480 1.032 0.135 B 0.713 0.181 B 0.511 0.148 B 0.439 0.220 CBumelia lanuginosa BULA 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCalocedrus decurrens CADE3 0.370 1.040 0.074 B 0.972 0.035 B 1.011 0.059 B 0.596 0.218 CCarpinus caroliniana CACA 0.580 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCarya aquatica CAAQ 0.610 0.988 0.069 B 0.705 0.064 B 0.404 0.080 B 0.396 0.219 CCarya cordiformis CACO 0.600 1.040 0.075 B 0.661 0.056 B 0.440 0.077 B 0.396 0.219 CCarya glabra CAGL 0.660 0.988 0.069 B 0.705 0.064 B 0.404 0.080 B 0.396 0.219 CCarya illinoensis CAIL 0.600 0.988 0.069 B 0.705 0.064 B 0.404 0.080 B 0.396 0.219 CCarya laciniosa CALA 0.620 0.988 0.069 B 0.705 0.064 B 0.404 0.080 B 0.396 0.219 CCarya myristicaeformis CAMY 0.560 0.988 0.069 B 0.705 0.064 B 0.404 0.080 B 0.396 0.219 CCarya ovata CAOV 0.640 0.895 0.062 B 0.808 0.073 B 0.510 0.081 B 0.396 0.219 CCarya species CASP 0.620 1.040 0.033 B 0.727 0.035 B 0.334 0.074 B 0.396 0.213 CCarya texana CATE 0.540 0.988 0.069 B 0.705 0.064 B 0.404 0.080 B 0.396 0.219 CCarya tomentosa CATO 0.640 0.977 0.056 B 0.627 0.038 B 0.332 0.078 B 0.396 0.219 CCastanea dentata CADE 0.400 0.936 0.043 B 0.940 0.046 B 0.668 0.082 B 0.525 0.223 CCastanea ozarkensis CAOZ 0.400 0.936 0.123 B 0.940 0.237 B 0.676 0.185 B 0.525 0.223 CAppendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
33

Castanea pumila CAPU 0.400 0.936 0.123 B 0.940 0.237 B 0.676 0.185 B 0.525 0.223 CCastanopsis species CAST 0.420 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCatalpa species CATA 0.380 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCeltis laevigata CELA 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCeltis occidentalis CEOC 0.490 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCeltis species CESP 0.490 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCercis canadensis CECA 0.580 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCercocarpus intricatus CEIN 1.000 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCercocarpus ledifolius CELE 1.000 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCercocarpus montanus CEMO 1.000 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CChamaecyparis lawsoniana CHLA 0.390 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CChamaecyparis nootkatensis CHNO 0.420 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CChamaecyparis thyoides CHTH 0.310 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CCladrastis lutea CLLU 0.520 0.982 0.129 B 0.844 0.199 B 0.775 0.163 B 0.525 0.223 CCornus fl orida COFL 0.640 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 C

Cornus nuttallii CONU 0.580 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCornus species COSP 0.640 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCotinus obovaus COOB 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCrataegus species CRSP 0.620 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CCupressus species CUSP 0.440 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CDiospyros virginiana DIVI 0.640 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CEucalyptus species EUSP 0.670 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CFagus grandifolia FAGR 0.560 1.015 0.056 B 0.663 0.041 B 0.508 0.076 B 0.533 0.213 CFraxinus americana FRAM 0.550 0.899 0.061 B 0.562 0.049 B 0.604 0.079 B 0.525 0.223 CFraxinus latifolia FRLA 0.500 0.899 0.118 B 0.622 0.159 B 0.575 0.162 B 0.525 0.223 CFraxinus nigra FRNI 0.450 0.899 0.118 B 0.622 0.159 B 0.575 0.162 B 0.525 0.223 CFraxinus pennsylvanica FRPE 0.530 0.899 0.118 B 0.622 0.159 B 0.575 0.162 B 0.525 0.223 CFraxinus profunda FRPR 0.540 0.899 0.118 B 0.622 0.159 B 0.575 0.162 B 0.525 0.223 CFraxinus quadrangulata FRQU 0.530 0.899 0.118 B 0.622 0.159 B 0.575 0.162 B 0.525 0.223 CFraxinus species FRSP 0.540 0.899 0.118 B 0.622 0.159 B 0.575 0.162 B 0.525 0.223 CAppendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
34

Gleditsia aquatica GLAQ 0.600 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CGleditsia triacanthos GLTR 0.600 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CGordonia lasianthus GOLA 0.370 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CGymnocladus dioicus GYDI 0.500 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CHalesia species HASP 0.320 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CIlex opaca ILOP 0.500 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CJuglans cinerea JUCI 0.360 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CJuglans species JUSP 0.510 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CJulglans nigra JUNI 0.510 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CJuniperus monosperma JUMO 0.450 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CJuniperus occidentalis JUOC 0.440 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CJuniperus species JUSP2 0.440 0.982 0.129 B 0.844 0.199 B 0.775 0.163 B 0.525 0.223 CLarix laricina LALA 0.490 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CLarix lyallii LALY 0.480 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CLarix occidentalis LAOC 0.480 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CLarix species LASP 0.440 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CLiquidambar styracifl ua LIST 0.460 1.017 0.013 B 0.778 0.039 B 0.526 0.075 B 0.525 0.223 C

Liriodendron tulipifera LITU 0.410 0.910 0.030 A 0.850 0.020 A 0.554 0.075 B 0.501 0.214 CLithocarpus densifl orus LIDE 0.580 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 C

Maclura pomifera MAPO 0.760 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CMagnolia acuminata MAAC 0.450 0.884 0.026 B 0.862 0.074 B 0.530 0.080 B 0.525 0.223 CMagnolia species MASP 0.450 0.884 0.116 B 0.862 0.218 B 0.530 0.152 B 0.525 0.223 CMalus species MASP2 0.610 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CMelia azedarach MEAZ 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CMorus alba MOAL 0.590 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CMorus rubra MORU 0.590 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CMorus species MOSP 0.590 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CNyssa aquatica NYAQ 0.460 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CNyssa ogeche NYOG 0.460 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CNyssa sylvatica NYSY 0.460 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CAppendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
35

Olneya tesota OLTE 1.000 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 COstrya virginiana OSVI 0.630 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 COxydendrum arboreum OXAR 0.500 1.040 0.104 B 0.877 0.043 B 0.714 0.084 B 0.525 0.223 CPaulownia tomentosa PATO 0.380 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CPersea borbonia PEBO 0.510 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CPicea abies PIAB 0.370 1.010 0.083 A 1.010 0.040 A 0.991 0.159 B 0.605 0.218 CPicea breweriana PIBR 0.330 1.038 0.074 B 0.987 0.270 B 0.991 0.159 B 0.605 0.218 CPicea engelmannii PIEN 0.330 0.953 0.068 B 0.899 0.021 B 0.991 0.159 B 0.504 0.213 CPicea glauca PIGL2 0.370 1.038 0.074 B 0.987 0.270 B 0.991 0.159 B 0.605 0.218 CPicea lutzii PILU 0.360 1.060 0.020 A 1.060 0.020 A 1.110 0.040 A 0.564 0.213 CPicea mariana PIMA 0.380 1.038 0.074 B 0.987 0.270 B 0.991 0.159 B 0.605 0.218 CPicea pungens PIPU 0.380 1.038 0.074 B 0.987 0.270 B 0.991 0.159 B 0.605 0.218 CPicea rubens PIRU 0.380 1.040 0.058 B 0.987 0.270 B 1.107 0.107 B 0.605 0.218 CPicea sitchensis PISI 0.370 1.040 0.013 B 0.998 0.022 B 0.984 0.055 B 0.676 0.213 CPicea species PICE 0.380 1.038 0.074 B 0.987 0.270 B 0.991 0.159 B 0.605 0.218 CPinus albicaulis PIAL 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus aristata PIAR 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus arizonica PIAR2 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus attenuata PIAT 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus balfouriana PIBA 0.370 0.916 0.061 A 0.876 0.095 A 1.018 0.155 A 0.598 0.215 CPinus banksiana PIBA2 0.420 0.953 0.040 A 0.920 0.030 A 0.780 0.091 A 0.598 0.215 CPinus clausa PICL 0.460 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus contorta PICO 0.400 0.980 0.010 A 1.040 0.030 A 1.020 0.010 A 0.727 0.213 CPinus coulteri PICO2 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus discolor PIDI 0.500 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus echinata PIEC 0.470 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus edulis PIED 0.500 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus elliotti PIEL 0.540 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus engelmannii PIEN2 0.370 0.953 0.057 B 0.950 0.075 B 0.991 0.089 B 0.598 0.215 CPinus fl exilis PIFL 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 C

Appendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
36

Pinus glabra PIGL 0.410 1.038 0.062 B 0.987 0.078 B 0.991 0.095 B 0.605 0.215 CPinus jeffreyi PIJE 0.370 0.904 0.025 B 0.960 0.037 B 0.883 0.062 B 0.645 0.214 CPinus lambertiana PILA 0.340 1.040 0.038 B 0.906 0.014 B 0.735 0.054 B 0.517 0.213 CPinus leiophylla PILE 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus monophylla PIMO 0.500 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus monticola PIMO3 0.350 1.022 0.012 B 0.996 0.015 B 1.170 0.055 B 0.598 0.215 CPinus muricata PIMU 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus nigra PINI 0.410 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus palustris PIPA 0.540 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus ponderosa PIPO 0.380 0.925 0.011 B 1.007 0.020 B 1.154 0.061 B 0.481 0.213 CPinus pungens PIPU2 0.490 1.038 0.062 B 0.987 0.078 B 0.991 0.095 B 0.605 0.215 CPinus radiata PIRA 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus resinosa PIRE 0.410 0.862 0.052 B 0.950 0.075 B 0.876 0.088 B 0.520 0.214 CPinus rigida PIRI 0.470 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus sabiniana PISA 0.370 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus serotina PISE 0.510 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus strobiformis PIST2 0.350 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus strobus PIST 0.340 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPinus sylvestris PISY 0.380 0.990 0.020 A 0.980 0.020 A 0.830 0.080 A 0.598 0.215 CPinus taeda PITA 0.470 0.862 0.014 B 0.784 0.012 B 0.732 0.053 B 0.601 0.213 CPinus virginiana PIVI 0.450 0.953 0.057 B 0.950 0.075 B 0.927 0.091 B 0.598 0.215 CPlanera aquatica PLAQ 0.530 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CPlatanus occidentalis PLOC 0.460 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CPopulus alba POAL 0.370 1.006 0.132 B 0.793 0.201 B 0.868 0.229 B 0.613 0.227 CPopulus angustifolia POAN 0.340 1.006 0.132 B 0.793 0.201 B 0.868 0.229 B 0.613 0.227 CPopulus balsamifera POBA 0.310 1.006 0.132 B 0.793 0.201 B 0.868 0.229 B 0.613 0.227 CPopulus deltoides PODE 0.370 1.006 0.132 B 0.793 0.201 B 0.868 0.229 B 0.613 0.227 CPopulus fremontii POFR 0.340 1.006 0.132 B 0.793 0.201 B 0.868 0.229 B 0.613 0.227 CPopulus grandidentata POGR 0.360 0.970 0.063 B 0.793 0.201 B 0.878 0.092 B 0.613 0.227 CPopulus heterophylla POHE 0.370 1.006 0.132 B 0.793 0.201 B 0.868 0.229 B 0.613 0.227 CAppendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
37

Populus sargentii POSA 0.370 1.006 0.132 B 0.793 0.201 B 0.868 0.229 B 0.613 0.227 CPopulus species POSP 0.370 1.040 0.136 B 0.793 0.201 B 0.860 0.227 B 0.613 0.227 CPopulus tremuloides POTR 0.390 0.970 0.040 A 0.750 0.050 A 0.540 0.070 A 0.613 0.227 CProsopis species PRSP 0.580 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CPrunus americana PRAM 0.470 1.040 0.136 B 1.045 0.263 B 0.708 0.192 B 0.525 0.223 CPrunus nigra PRNI 0.470 1.040 0.136 B 1.045 0.263 B 0.708 0.192 B 0.525 0.223 CPrunus pensylvanica PRPE 0.360 1.040 0.031 B 1.011 0.041 B 0.636 0.076 B 0.525 0.223 CPrunus serotina PRSE 0.470 1.040 0.073 B 1.080 0.059 B 0.780 0.103 B 0.525 0.223 CPrunus species PRSP2 0.470 1.040 0.136 B 1.045 0.263 B 0.708 0.192 B 0.525 0.223 CPrunus virginiana PRVI 0.360 1.040 0.136 B 1.045 0.263 B 0.708 0.192 B 0.525 0.223 CPseudotsuga menziesii PSME 0.450 0.892 0.015 B 0.831 0.017 B 0.591 0.054 B 0.433 0.213 CQuercus agrifolia QUAG 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus alba QUAL 0.600 1.012 0.032 B 0.806 0.035 B 0.591 0.078 B 0.398 0.214 CQuercus arizonica, grisea QUAR 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus bicolor QUBI 0.640 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus chrysolepis QUCH 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus coccinea QUCO 0.600 0.990 0.052 B 0.904 0.047 B 0.781 0.078 B 0.591 0.216 CQuercus douglasii QUDO 0.510 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus durandii QUDU 0.600 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus ellipsoidalis QUEL 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus emoryi QUEM 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus engelmannii QUEN 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus falcata var. falcata QUFA 0.520 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus falcata var. 

pagodaefolia QUFA2 0.610 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 C

Quercus gambelii QUGA 0.640 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus garryana QUGA2 0.640 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus hypoleucoides QUHY 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus ilicifolia QUIL 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus imbricaria QUIM 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CAppendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
38

Quercus incana QUIN 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus kelloggii QUKE 0.510 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus laevis QULA 0.520 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus laurifolia QULA2 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus lobata QULO 0.640 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus lyrata QULY 0.570 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus macrocarpa QUMA 0.580 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus marilandica QUMA2 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus michauxii QUMI 0.600 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus muehlenbergii QUMU 0.600 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus nigra QUNI 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus nuttalli QUNU 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus oblongifolia QUOB 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus palustris QUPA 0.580 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus phellos QUPH 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus prinus QUPR 0.570 1.040 0.079 B 0.927 0.086 B 0.547 0.077 B 0.591 0.216 CQuercus rubra QURU 0.560 1.031 0.044 B 0.859 0.074 B 0.731 0.093 B 0.591 0.216 CQuercus shumardii QUSH 0.560 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus species QUSP 0.580 1.013 0.021 B 0.861 0.045 B 0.688 0.079 B 0.686 0.213 CQuercus stellata QUST 0.600 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus velutina QUVE 0.560 1.020 0.051 B 0.700 0.072 B 0.858 0.118 B 0.591 0.216 CQuercus virginiana QUVI 0.800 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CQuercus wislizeni QUWI 0.700 1.020 0.051 B 0.841 0.084 B 0.705 0.106 B 0.591 0.216 CRobinia neomexicana RONE 0.660 1.040 0.136 B 0.916 0.231 B 0.618 0.171 B 0.525 0.223 CRobinia pseudoacacia ROPS 0.660 1.040 0.033 B 0.916 0.055 B 0.618 0.171 B 0.525 0.223 CSalix species SASP 0.360 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CSapium sebiferum SASE 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CSassafras albidum SAAL 0.420 1.040 0.030 B 0.998 0.051 B 0.853 0.077 B 0.525 0.223 CSequoia sempervirens SESE 0.340 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CSequoiadendron giganteum SEGI 0.340 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CAppendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
39

Sorbus americana SOAM 0.420 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CTamarix species TASP 0.400 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CTaxodium distichum var. 

nutans TADI 0.420 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 C

Taxus brevifolia TABR 0.600 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CThuja occidentalis THOC 0.290 1.040 0.039 B 0.960 0.163 B 1.330 0.075 B 0.655 0.213 CThuja plicata THPL 0.310 1.040 0.074 B 0.960 0.326 B 1.064 0.058 B 0.656 0.213 CTilia americana TIAM 0.320 1.040 0.026 B 1.080 0.046 B 0.848 0.076 B 0.525 0.223 CTilia heterophylla TIHE 0.320 1.040 0.136 B 1.080 0.272 B 0.848 0.225 B 0.525 0.223 CTilia species TISP 0.320 1.040 0.136 B 1.080 0.272 B 0.848 0.225 B 0.525 0.223 CTorreya californica TOCA 0.340 0.994 0.071 B 0.951 0.260 B 0.902 0.146 B 0.605 0.218 CTsuga canadensis TSCA 0.400 1.035 0.060 B 0.882 0.241 B 1.081 0.087 B 0.604 0.218 CTsuga heterophylla TSHE 0.440 0.900 0.030 A 0.830 0.040 A 0.661 0.050 A 0.380 0.050 ATsuga mertensiana TSME 0.420 0.953 0.052 B 0.882 0.241 B 0.906 0.079 B 0.604 0.218 CTsuga species TSSP 0.380 0.953 0.052 B 0.882 0.241 B 0.906 0.079 B 0.604 0.218 CUlmus alata ULAL 0.570 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUlmus americana ULAM 0.460 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUlmus crassifolia ULCR 0.570 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUlmus pumila ULPU 0.460 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUlmus rubra ULRU 0.480 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUlmus serotina ULSE 0.570 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUlmus species ULSP 0.500 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUlmus thomasii ULTH 0.570 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CUmbellularia californica UMCA 0.510 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CVaccinium arboreum VAAR 0.470 0.982 0.129 B 0.793 0.201 B 0.618 0.171 B 0.525 0.223 CAppendix D.—continued

continued

Genus Species Code den0 rel1 unc1 cod1 rel2 unc2 cod2 rel3 unc3 cod3 rel4 unc4 cod4
40

Standing Dead Tree Relative Density Predictions Metadata (Appendix D)Fieldname Defi nition Code/Units Method

genus genusspecies speciescode genus-species codeden0 green density g/cm3

rel1 relative density decay class 1 dimensionlessunc1 uncertainty of rel1 dimensionlesscod1 uncertaintly code for rel1 A Species sampled

B Genera sampledC Species and genus not sampled

rel2 relative density decay class 2 dimensionlessunc2 uncertainty of rel2 dimensionlesscod2 uncertaintly code for rel2 A Species sampled

B Genera sampledC Species and genus not sampled

rel3 relative density decay class 3 dimensionlessunc3 uncertainty of rel3 dimensionlesscod3 uncertaintly code for rel3 A Species sampled

B Genera sampledC Species and genus not sampled

rel4 relative density decay class 4 dimensionlessunc4 uncertainty of rel4 dimensionlesscod4 uncertaintly code for rel4 A Species sampled

B Genera sampledC Species and genus not sampled

Appendix D.—continued
Printed on Recycled Paper

Harmon, Mark E.; Woodall, Christopher W.; Fasth, Becky; Sexton, Jay; Yatkov, Misha. 

2011. Differences between standing and downed dead tree wood density 

reduction factors: A comparison across decay classes and tree species. Res. 

Pap. NRS-15. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, 

Northern Research Station. 40 p.

Woody detritus or dead wood is an important part of forest ecosystems and has become 

a routine facet of forest monitoring and inventory. Biomass and carbon estimates of 

dead wood depend on knowledge of species- and decay class-specifi c density or density 

reduction factors. While some progress has been made in determining these parameters 

for dead and downed trees (DD), there are very few estimates of these key parameters 

for standing dead trees (SD). We evaluated indicators of decay to relate subjective SD 

and DD decay classifi cations then compared SD and DD density and density reduction 

factors by decay class for a total of 19 tree species at nine sites in the United States 

and Russia. Results indicate that SD density declined with decay class for all examined 

species. By applying these results, a new set of SD density reduction factors was 

developed for 260 species inventoried by the U.S. Forest Service’s Forest Inventory and 

Analysis program in forests of the United States.

KEY WORDS: standing dead trees, downed dead trees, carbon, biomass, decay 

reduction factor

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