5

What Types of

Vegetation

Are Present?

T HE TOTAL LAND AND FRESHWATER area of the south-central Alaska inventory 

area is 18.5 million acres. Almost two-thirds of it 

has some kind of vegetation on it (fig. 2). Of this 

vegetated portion, 33 percent has forest as the major 

cover, 51 percent has shrubs and dwarf trees, and 

16 percent has herbs and grass (fig. 3).

Land Cover Categories

South-Central Alaska

PNW-FIA

Forest

Nonforest

Water, ice, and snow

I

0 25 50 100

Miles

Figure 2—Land cover categories, south-central Alaska. Source: Statewide land cover/vegetation 

map of Alaska (Fleming 1998).

Walter Foss

Blueberry (Vaccinium spp.)
6

Needleleaf forest (25%)

Broadleaf and mixed forest (8%)

Dwarf tree forest (1%)

Tall shrub (16%)

Low shrub (5%)

Dwarf shrub (4%)

Shrub, unidentified (25%)

Herbaceous (8%)

Forb herbaceous (3%)

Graminoid (5%)

2,850

945

79

1,781 601 458

2,800

935

348 571

Figure 3—Area (thousand acres) of vegetated land by vegetation type, south-central Alaska, 2003.

Location and Abundance of 

Nonforest Vegetation Types 

Nonforest areas of south-central Alaska differ 

from the southeast archipelago; these areas are 

even more heavily influenced by recent glaciation 

on both lowland and high alpine sites. The largest 

North American subpolar ice field, the Bagley 

Ice Field, dominates the Chugach Mountains and 

feeds many tidewater glaciers there. The Harding 

Ice Field on the Kenai Peninusla feeds 35 glaciers. 

Vegetation near these areas occurs on soils that are 

typically thin and rocky. Nonforest communities 

may dominate these glacier-influenced areas 

for long periods. Alpine tundra and snowbed 

tundra types are common. On lower elevation 

sites, pioneer nitrogen-fixing plants such as 

alder1

 are common and serve to prepare soils 

for colonization and further succession into 

forest community types. Marshes and wetland 

bogs are also common throughout the region. 

1

 See “Common and Scientific Names” on page 25. 

Jerry Bednarczik

Woodland horsetail (Equisetum sylvaticum), 

dwarf birch (Betula nana),and nagoon berry 

(Rubus articus).

Devil’s club (Oplopanax horridum).

Karen Waddell
7

• Dwarf-tree shrub types cover an estimated 

79,000 acres, occurring either on alpine sites 

near treeline as krummholz or as stunted 

trees on wet or bog soil conditions at lower 

elevations. Woodland mountain hemlock 

dwarf-tree type is the most common 

(25,000 acres).

• Tall shrub types are the most common 

nonforest condition sampled found on 

1,781,000 acres, representing 15.7 percent of 

the vegetated area of south-central Alaska. 

• Low shrub types predominate on 601,000 

acres with willow types on 132,000 acres, 

and three sweetgale types on 85,000 acres. 

• Dwarf shrub types are found on 458,000 

acres. Alaska moss heather occurred on 

157,000 acres and mountain heather on 

another 82,000 acres. Crowberry ericaceous 

dwarf shrub tundra occurs on 109,000 acres. 

• Herbaceous and grass types cover 1,854,500 

acres, with bluejoint, bluejoint-herb and 

bluejoint-shrub types predominating on 

232,000 acres. Fresh sedge-marsh was 

found on 44,000 acres, and the mesic 

mixed herb type covered 201,000 acres. 

• Numerous other community types were 

documented on only a small number of 

plots, so detailed community descriptions 

and complete species lists cannot be written 

from the inventory data. 

Of the 556 unique vascular plant species or 

groups tallied by inventory crews, only 5 species 

were identified as nonnative species; these included rough bluegrass, field clover, wild chives, 

common dandelion, and Asian forget-me-not.

Walter Foss Karen Waddell

Arrowleaf groundsel (Senecio triangularis), 

Wingham Island.

Alder leaves and catkins (Alnus spp.).

Karen Waddell

White spruce branch.

Andy Tasler

Lily pond.
8

Diversity of Vegetation 

Among closed forest plots, Sitka spruce forest had the highest diversity (a measure of 

heterogeneity within a community) across all locations, followed by the mountain hemlock 

type. In open forests, the highest diversity was also found in open Sitka spruce stands, 

followed by black spruce and white spruce, respectively. Lowest diversity values were found 

in mixed-spruce-birch-poplar type and mixed-conifer types, although smaller numbers of 

plots in these types may have highly influenced the lower diversity values. Woodland forests, 

the most open category, showed similar trends, with Sitka spruce, black spruce, and white 

spruce stands having highest diversity and mixed spruce-birch forests having the lowest 

diversity values.

Among tall shrub types, highest diversity was found in closed tall alder type, and 

lowest in the open scrub birch-willow type. Among low shrub types, the willow type had 

the highest diversity, and among dwarf shrub types, crowberry tundra type was highest. 

On herbaceous plots, mixed-herb types had highest diversity and wet sedge-herb meadow 

tundra had the lowest diversity.
9

How Much of

South-Central Alaska Is Forest

and Who Owns It?

14.4

2.2

1.9

Nonforest (78%)

Timberland (10%)

Other forest (12%)

Figure 4—Area (million acres) 

of forest and nonforest, southcentral Alaska, 2003.

Land Ownership

South-Central Alaska

PNW-FIA

I

0 25 50 100

Miles

Forest Service

Other federal

State and local

Private

Figure 5—Land ownership, south-central Alaska, 2003. Source: Alaska Department of Natural Resources, 2005.

L ESS THAN ONE-QUARTERof south-central Alaska—4.0 

million acres or 22 percent—is defined 

as forest land (figs. 2 and 4). 

Forest land ownership in southcentral Alaska is fairly evenly divided 

among the Chugach National Forest 

(27 percent), other federal agencies (28 

percent), private owners (26 percent), 

and state and local governments (20 

percent) (table 1, fig. 5). 

Owner group

TimberlandOther 

forest land

Total 

forest land

 - - - - - - Thousand acres - - - - - -

National forest 324 755 1,079

Other federal:

Bureau of Land Management 43 37 80

Kenai National Wildlife Refuge 90 850 940

National parks — 60 60

Department of Defense 31 7 38

Other 6 — 6

Total other federal 170 954 1,124

State and local 646 156 801

Private 736 305 1,040

Table 1—Estimated area by forest land class and owner group, 

south-central Alaska, 2003
10

What Forest Land

Is Protected

From Harvest?

T HIRTY-TWO PERCENT OF the forest land in south-central 

Alaska (1.3 million acres) is reserved 

(withdrawn from timber use through 

statute or administrative regulation) 

and includes national parks, national 

forest wilderness study areas, and 

national wildlife refuges (fig. 6). State, 

local, and private lands do not currently have any forest land that is 

designated as reserved. In addition to 

lands officially designated as reserved, most of the forest land on the Chugach National 

Forest (75 percent) is not considered suitable for timber harvest under the revised Chugach 

Land Management Plan (USDA Forest Service 1999) because it is currently managed for 

other uses such as research natural areas, recreation areas, beach fringe, riparian areas, scenic 

viewsheds, and wild and scenic recreational rivers. Revisions of the plan in the future could 

result in changes in timber production locations and acres. Glenn Christensen Joe Donnegan

Kenai Fjords National Park.

Exit Glacier, Kenai Fjords National Park.
11

Reserved Land Status

South-Central Alaska

PNW-FIA

Reserved national forest

Reserved national parks

Reserved national wildlife refuges

Unreserved lands

I

0 25 50 100

Miles

Figure 6—Protected areas in south-central Alaska. Source: Alaska Department of Natural 

Resources, 2005. Joe Donnegan

Portage Bay, south-central Alaska.
12

How Much

Timber Is Available

for Harvest?

Timberland Area and Owners 

A total of 1.9 million acres is classified as timberland, the productive component of forest land 

not withdrawn from timber harvest by law or statute (fig. 7). Over two-thirds of this is privately 

owned (736,000 acres) or managed by state and local governments (646,000 acres). The Chugach 

National Forest and other federal agencies manage the remaining third (324,000 and 170,000 

acres, respectively). 

800

600

400

200

0

Acres (thousand)

National

forest

Owner group

Other

federal

State and

local

Private

324

170

646

736

Figure 7—Area of timberland by owner group, south-central Alaska, 

2003.

Shawn Osborn

Duke Island.
13

Timberland Volume and Owners

Timber availability also can be measured 

by the amount of wood volume available for 

harvest (fig. 8). The total volume of growing 

stock on timberland in south-central Alaska 

is 5.1 billion cubic feet. The state of Alaska 

and local governments manage the largest 

proportion of this volume—44 percent. 

Private companies, Native corporations, and 

individual landowners own and manage 

another 28 percent. The Chugach National 

Forest and other federal agencies manage 

the remaining 27 percent.

1,185

201

2,253

1,449

National forest

Other federal

State and local

Private

Figure 8—Growing-stock volume (million 

cubic feet) of timberland by owner group, 

south-central Alaska, 2003.

Karen Waddell

Black cottonwood, Portage area.
14

How Much of the

Forest Is Sawtimber

and Where Is It ?

Area in Sawtimber

About 57 percent of timberland stands in south-central Alaska are sawtimber sized (fig. 9). 

There is a fairly even distribution of age classes across the sawtimber-sized stands but a slight 

majority of these stands—61 percent—are 150 years old or younger (fig. 10). Eighty-one percent 

of timberland on the Chugach National Forest has sawtimber stands, and 59 percent of them are 

more than 150 years old; in comparison, 53 percent of state and private timberland has sawtimber 

stands of which 35 percent are more than 150 years old. Sitka spruce is the primary species in 

most of the sawtimber-sized stands (fig. 11). Other common forest types include white spruce, 

mixed conifer, paper birch, and poplar. Stacy Allen

FIA crew member, Misha Yatskov, measuring a tree diameter. 
15

188

324

638

298

426

700

600

500

400

300

200

100

0

Seedlings

 and saplings

Poletimber Nonstocked

Stand size class

Acres (thousand)

Young

sawtimber

Old

sawtimber

Figure 9—Distribution of timberland area by stand size classes, all owners, southcentral Alaska, 2003.

16

297

332

138

282

<50 50–100 110–150 160–200 200+

Stand age class

Acres (thousand)

350

300

250

200

150

100

50

0

Figure 10—Distribution of sawtimber on timberland by stand age classes, southcentral Alaska, 2003. 

Black

spruce

Mixed

conifer

Mountain

hemlock

Sitka

spruce

Western

hemlock

White

spruce

Aspen Paper

birch

Poplar

Forest type

Acres (thousand)

350

300

250

200

150

100

50

0

Young sawtimber

Old sawtimber

Figure 11—Sawtimber area on timberland by forest type, south-central Alaska, 2003. 
16

Sawtimber Volume 

Growing-stock volume on timberland is evenly divided between young and old sawtimbersized stands (2.4 and 2.3 billion cubic feet, respectively) with only minor volume in poletimber 

stands (0.3 billion cubic feet). Almost half of the timberland volume is in sawtimber-sized stands 

of Sitka spruce (fig. 12). Stands of western hemlock, mixed conifer, and mountain hemlock also 

contribute significant volume. Seventy percent of old sawtimber-sized stands are either Sitka 

spruce or western hemlock. Hardwoods are a minor contributor to volume on timberland. Volume (million cubic feet)

1,600

1,200

800

400

0

Forest type

Young sawtimber

Old sawtimber

Mixed

conifer

Mountain

hemlock

Sitka

spruce

Western

hemlock

White

spruce

Aspen Paper

birch

Poplar

Figure 12—Volume of sawtimber growing stock on timberland by forest type, south-central Alaska, 2003. Jerry Bednarczyk

FIA crew member, Walter Grabowiecki, counting tree rings.
17

What Is the

Productivity

of South-Central Alaska Timberland?

PRODUCTIVITY IN THIS SECTION refers to timber productivity rather than 

other measures of forest productivity. Most timberland in south-central Alaska is 

only slightly more productive than the minimum needed to qualify as timberland. Only 

about 10 percent of all south-central Alaska timberland produces 85 cubic feet or more 

per acre per year. In comparison, 23 percent of the timberland in southeast Alaska and 86 

percent of timberland in western Washington produces more than 85 cubic feet per acre 

per year (MacLean et al. 1992, van Hees 2003). Timber productivity in Alaska tends to 

be low, a characteristic of more northern latitudes. It is likely that, as in southeast Alaska, 

stands with the greatest tree volume are generally near tidewater, with stand heights and 

wood quality diminishing with increasing elevation (Harris and Farr 1974). Bert Mead

White spruce, Kenai Peninsula. 
18

Timber Productivity by Owner

Highly productive timberland (≥120 cubic feet per acre per year) is a minor component of 

south-central Alaska’s forests; only 51,000 acres of timberland are in this category, and most of 

this is owned by the state of Alaska and local municipalities. Sixty-three percent of timberland 

area across all owners is in the lowest productivity class (20 to 49 cubic feet per year) with an 

additional 27 percent in the next class (50 to 84 cubic feet per year) (fig. 13). 

20–49 50–84 85–119 120–164

Site productivity class (cubic feet)

Acres (thousand)

National forest

Other federal

State and local

Private

600

500

400

300

200

100

0

Figure 13—Percentage distribution of timberland acres by selected owner groups and 

cubic-foot site productivity classes, south-central Alaska, 2003. Karen Waddell

Black cottonwood. 
19

What Is the Rate of Forest

Growth, Mortality, and Harvest?

AVERAGE NET ANNUAL GROWTH of growing stock on timberland is estimated at -8.8 million cubic feet. Mortality exceeded growth for growing stock on 

timberland for state, local, and private owners (fig. 14), resulting in overall negative net 

growth. Only on national forests and other federal lands did growth exceed mortality, 

resulting in positive net growth on those lands.

National

forest

Other 

federal

State and 

local

Private

Owner group

45

40

35

30

25

20

15

10

5

0

-5

-10

-15

Volume (million cubic feet)

Gross growth

Mortality

Net growth

Figure 14—Average gross annual growth, average annual mortality, and 

average net annual growth (gross growth minus mortality) of growing 

stock on timberland by owner group, south-central Alaska, 2003. 
20

Positive net growth (gross 

growth minus mortality) occurred in only about two-thirds 

of the forest types. Mountain 

hemlock, white spruce, and 

paper birch types all experienced 

negative net growth owing to 

large amounts of mortality (fig. 

15). Mortality was also high in 

the Sitka spruce type but was 

exceeded by gross growth resulting in positive net growth. The 

primary causes of mortality were 

insects (84 percent), unknown 

factors (16 percent), physical 

defect (<1 percent), and rot and 

decay (<1 percent).

Karen Waddell

Walter Foss

Clearcut in Seldovia area, Kenai Peninsula.

White birch snag with spruce-beetle-killed white spruce.
21

Harvest levels in south-central 

Alaska have decreased in recent 

years, from over 60 million cubic 

feet in 1997 to about 18 million in 

2001. The majority (97 percent) of 

harvesting between 1988 and 2001 

took place on private lands so that 

private land harvesting drove overall trends. Although the Chugach 

National Forest shows net annual 

growth (gross growth minus mortality) exceeding annual harvest 

amounts, net annual growth on 

both state and private lands was 

negative and thus lower than any 

level of annual harvest (fig. 16). 

Figure 15—Average gross annual growth, average annual mortality, and average net annual growth of 

growing stock on timberland by softwood forest type, south-central Alaska, 2003. 

40

30

20

10

0

-10

-20

Volume (million cubic feet)

Gross growth

Mortality

Net growth

Black

spruce

Mixed

conifer

Mountain

hemlock

Sitka

spruce

Western

hemlock

White

spruce

Aspen Paper

birch

Poplar

Forest type

National 

forest

State Private

Owner group

Growth, average 

net annual

Harvest, average 

annual, 1998–2001

30

20

10

0

-10

-20

Volume (million cubic feet)

1.6

.16

-18.9

-4.3

.85

26.76

Figure 16—Net growth and harvest for sawtimber trees on 

timberland by owner group, south-central Alaska. Source: 

USDA Forest Service, Alaska Region, 2003.
22

DURING THE PAST 30 YEARS, 

spruce forests of Alaska’s Kenai 

Peninsula have undergone dramatic changes 

resulting from widespread spruce bark beetle 

infestation. In 1987 and again in 2000, the 

Pacific Northwest Forest Inventory and 

Analysis Program conducted initial and 

remeasurement inventories to assess broadscale impacts of this infestation. Ground 

data were collected on 130 plots. Detailed 

results are provided in Schulz (2003), 

van Hees (2004), and van Hees (2005a). 

Spruce Volume Change, 

Growth, and Mortality

The total volume of Sitka and white 

spruce growing stock on timberland on the 

Kenai Peninsula decreased from 872 million 

cubic feet in 1987 to 400 million in 2000, a 

54 percent decrease (fig. 17). Volume on lands considered nonstocked (land not 

meeting the minimum occupancy by trees to be considered stocked) showed about 

a fiftyfold increase. In the same period, mortality exceeded growth for all stand 

sizes resulting in negative net annual growth overall (fig. 18).

What Is the Impact of the

Spruce Bark Beetle

on the Kenai Peninsula? Tina Boucher

Mortality from spruce beetle, Tustumena Lake, 

Kenai Peninsula. 
23

Seedling/sapling Poletimber Sawtimber

Stand size

1987

2000

Nonstocked

900

750

600

450

300

150

Volume (million cubic feet)

0

Figure 17—Net volume change for Sitka spruce and white spruce growing stock on timberland, 

Kenai Peninsula, 1987 to 2000. 

Growth (gross average annual)

Mortality (average annual)

Seedling/sapling Poletimber Sawtimber

Stand size

Nonstocked

15

12

9

6

3

Volume (million cubic feet)

0

Figure 18—Growth (gross average annual) and mortality (average annual) of Sitka spruce and 

white spruce growing stock on timberland, Kenai Peninsula, 1987 to 2000.
24

Spruce Regeneration

Spruce reproduction on timberland on the 

Kenai Peninsula in 2000 was not dramatically 

different from that found in 1987. Seedling 

stocking remained at 1987 levels, or improved, 

on 51 percent of the inventoried plots. Seventytwo percent of the area was less than fully 

stocked (≥5 seedlings per plot) on both 

occasions. Regeneration differed by forest type 

and ecological region. In the northwest where 

mixed types dominate and spruce mortality 

decreased, spruce reproduction was relatively 

unchanged. In the southwest where there is 

more spruce and spruce types dominate, spruce mortality was high and spruce regeneration 

was more dynamic. Stocking declined to zero on 33 percent of plots, but 26 percent of plots 

became stocked. Overall, this inventory showed that spruce regeneration is taking place, 

sometimes at relatively high levels, such as along the southern edge of the lowlands region.

Fuels 

Fuel heights, fine fuels, and sound large 

fuels increased between 1987 and 2000 on the 

Kenai Peninsula (Schulz 2003). Moss depths 

and rotten large fuels decreased. Areas where 

white spruce was salvage logged (as a result 

of bark beetle mortality) showed the greatest 

increase of fine fuel classes—10- and 100-hour 

fuels (<0.25-inch and 0.25- to 1-inch diameter 

fuels, respectively). Sound 1,000-hour fuels 

(>3-inch diameter) increased on both harvested 

and nonharvested stands, but this increase was only significant in the nonharvested stands. 

All forest types showed a decrease in moss depth and rotten 1,000-hour fuels (rotten 

fuels, >3-inch diameter) indicating greater rates of site dehydration as stands become more 

open after spruce mortality. The white spruce forest type showed the largest number of 

significantly changed measures, including all fuel classes, but no significant difference in 

rotten 1,000-hour fuels. 

Bertr Mead Bert Mead

White spruce regeneration, Kenai Peninsula. 

Down wood. 
Common and Scientific Names

Common name Scientific name

Softwoods:

 Black spruce Picea mariana (Mill.) B.S.P.

 Mountain hemlock Tsuga mertensiana (Bong.) Carr. 

 Sitka spruce Picea sitchensis (Bong.) Carr.

 Western hemlock Tsuga heterophylla (Raf.) Sarg.

 White spruce Picea glauca (Moench) Voss

Hardwoods:

 Poplar Populus spp. 

 Paper birch Betula papyrifera Marsh.

 Red alder Alnus rubra (Bong.)

 Quaking aspen Populus tremuloides Michx.

 Willow Salix spp.

Other vegetation: 

 Alaska moss heather Cassiope mertensiana (Bong.) D. Don.

 Asian forget-me-not Myosotis asiatica (Vesterg.) Schischkin & Sergievskaja

 Common dandelion Taraxacum officinale G.H. Weber ex Wiggers

 Crowberry Empetrum nigrum L.

 Field clover Trifolium campestre Schreb.

 Mountain heather Phyllodoce spp. Salisb.

 Rough bluegrass Poa trivialis L. 

 Sweetgale Myrica gale L.

 Wild chives Allium schoenoprasum L. 

Metric Equivalents

1 inch = 2.54 centimeters

1 foot = 0.3048 meter

1 mile = 1.609 kilometers

1 acre = 0.4047 hectare

1 cubic foot = 0.0283 cubic meter

20 cubic feet per acre = 1.3994 cubic meters per hectare
26

Literature Cited

Alaska Department of Natural Resources. 2005. Administrative large parcel boundaries. 

Land status. [CD-ROM]. Anchorage, AK. Land records information section. 

Fleming, M. 1998. Statewide vegetation/land cover. [Vegetation map of Alaska, 23 classes, 

19 vegetated, raster format.] http://agdc.usgs.gov/data/projects/fhm/#G. (May 2003).

Harris, A.S.; Farr, W.A. 1974. The forest ecosystem of south-central Alaska. Gen. Tech. Rep. 

PNW-GTR-25. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Forest and Range Experiment Station. 109 p.

MacLean, C.D.; Bassett, P.M.; Yeary, G. 1992. Timber resource statistics for western 

Washington. Resour. Bull. PNW-RB-191. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 135 p.

Schulz, B. 2003. Changes in downed and dead woody material following a spruce beetle 

outbreak on the Kenai Peninsula, Alaska. Res. Pap. PNW-RP-559. Portland, OR: U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Research Station. 9 p.

Scott, C.T.; Bechtold, W.A. 1995. Techniques and computations for mapping plot clusters 

that straddle stand boundaries. Forest Science Monograph. 31: 46–61. 

U.S. Department of Agriculture, Forest Service. 1999. Chugach National Forest Revised Land 

and Resource Management Plan. http://www.fs.fed.us/r10/chugach/revision/pdfs/suitable_

timberlands.pdf (last accessed May 5, 2005).

U.S. Department of Agriculture, Forest Service. 2003. Timber harvest data. On file with: 

Ecosystems Planning, USDA Forest Service, Alaska Region, P.O. Box 21628, Juneau, AK 

99802-1628.

U.S. Department of Agriculture, Forest Service. 2000–2003. Field procedures for the southcentral Alaska inventory. Anchorage, AK: Pacific Northwest Research Station and Region 

10 [Alaska Region]. Annual.

van Hees, W.W.S. 2003. Forest resources of southeast Alaska, 2000: results of a single-phase 

systematic sample. Res. Pap. PNW-RP-557. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 96 p.

van Hees, W.W.S. 2004. Broad-scale spruce forest change, Kenai Peninsula, 1987–2000. 

Presentation at: A changing Alaskan forest ecosystem–effects of spruce beetle outbreaks and 

associated management practices on forest ecosystems in south-central Alaska. Homer, AK. 

Feb. 24–26, 2004.

van Hees, W.W.S. 2005a. Spruce reproduction dynamics on Alaska’s Kenai Peninsula, 

1987–2000. Res. Pap. PNW-RP-563. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 18 p. 
27

van Hees, W.W.S. 2005b. Timber resource statistics of south-central Alaska, 2003. Resour. 

Bull. PNW-RB-248. Portland, OR: U.S. Department of Agriculture, Forest Service, 

Pacific Northwest Research Station. 24 p. 

Glossary 

average gross annual growth—The increase in net volume of wood (the gross volume less 

deductions for defect) for growing-stock trees during the year.

average net annual growth—Average gross annual growth minus the volume of trees that 

died during the year (average annual mortality). 

cull trees—Live trees of sawtimber or poletimber size that are not merchantable for saw logs 

and are unlikely to become merchantable because of defect, rot, or species. 

d.b.h.—Diameter at breast height. 

forest land—Land that is at least 16.7 percent stocked by live trees of any size or that formerly 

had such tree cover and is at least an acre in size and 120 feet wide. 

forest type—A classification of forest land based on the species forming a plurality of stocking 

on the area currently occupied by tree cover. Identification of the appropriate forest type for this 

inventory required a decision process described in van Hees 2003. 

growing-stock trees—All live trees except cull trees.

growing-stock volume—Net volume in cubic feet of live sawtimber and poletimber growingstock trees from stump to a minimum 4.0-inch top (of central stem) outside the bark. Net 

volume equals gross volume less deductions for rot and missing stem sections.

land class—A classification of land by major use, such as timberland, other forest, or nonforest. 

The minimum size (area) for classification is 1 acre.

mortality—The volume of wood from trees that died from natural causes during a specified 

period. 

nonforest land—Land that does not qualify as forest land. Includes land that has never supported 

forests and lands formerly forested where forest use is precluded by development for nonforest 

uses. 

other forest land—Forest land not capable of producing 20 cubic feet per acre per year or more 

of wood and not withdrawn from timber use by statute or administrative regulation.
28

poletimber stands—Stands at least 16.7-percent stocked with live growing-stock trees, with half 

or more of this stocking in poletimber (growing stock trees greater than 5.0 inches and less than 

11.0 in d.b.h.) and sawtimber trees and with poletimber stocking exceeding that of sawtimber. 

reserved forest land—Forest land withdrawn from timber use through statute or administrative 

regulation.

sawtimber stands—Stands at least 16.7-percent stocked with live growing-stock trees, with half 

or more of this stocking in sawtimber trees (growing-stock trees at least 11.0 inches in d.b.h. for 

hardwoods and 9.0 inches for softwoods) and with sawtimber stocking at least equal to that of 

poletimber.

sawtimber volume—Net volume of sawtimber trees measured in board feet. Net volume equals 

gross volume less deduction for rot, sweep, crook, and other defects that affect use for lumber. 

Board feet are often converted to cubic feet.

seedling and sapling stands—Stands at least 16.7 percent stocked with live growing-stock trees 

and with live saplings (1.0 to 4.9 in d.b.h.) or seedlings (<1.0 in d.b.h.) composing more than 

half this stocking.

stand size class—A classification of forest land based on the predominant size of trees present: 

sawtimber, poletimber, or seedlings and saplings.

stand age class—The 10-year age class that best characterizes the stand. 

stocking—The degree of occupancy of land by trees, measured by basal area or number of trees 

by size and spacing, or both, compared to a stocking standard: that is, the basal area or number 

of trees, or both, required to fully utilize the growth potential of the land.

timberland—Forest land that is capable of producing 20 cubic feet of wood per acre per year, 

and is not reserved from timber harvest. 
The Forest Service of the U.S. Department of Agriculture is dedicated to the 

principle of multiple use management of the Nation’s forest resources for sustained yields of wood, water, forage, wildlife, and recreation. Through forestry 

research, cooperation with the States and private forest owners, and management of the National Forests and National Grasslands, it strives—as directed 

by Congress—to provide increasingly greater service to a growing Nation.

The U.S. Department of Agriculture (USDA) prohibits discrimination in 

all its programs and activities on the basis of race, color, national origin, age, 

disability, and where applicable, sex, marital status, familial status, parental 

status, religion, sexual orientation, genetic information, political beliefs, 

reprisal, or because all or part of an individual’s income is derived from any 

public assistance program. (Not all prohibited bases apply to all programs.) 

Persons with disabilities who require alternative means for communication 

of program information (Braille, large print, audiotape, etc.) should contact 

USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a 

complaint of discrimination, write USDA, Director, Office of Civil Rights, 

Room 1400 Independence Avenue, SW, Washington, DC 20250-9410 or 

call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal 

opportunity provider and employer.

Pacific Northwest Research Station

Web site http://www.fs.fed.us/pnw

Telephone (503) 808-2592

Publication requests (503) 808-2138

FAX (503) 808-2130

E-mail pnw_pnwpubs@fs.fed.us

Mailing address Publications Distribution

 Pacific Northwest Research Station

 P.O. Box 3890

 Portland, OR 97208-3890
U.S. Department of Agriculture

Pacific Northwest Research Station

333 SW First Avenue

P.O. Box 3890

Portland, OR 97208-3890

Official Business

Penalty for Private Use, $300