A Brief Overview of the Forest Resources of the United States, 1997

by
	W. Brad Smith	Raymond M. Sheffield
	USDA Forest Service	USDA Forest Service
	Washington, DC	Asheville, NC

July, 2000

NOTE: This document contains a brief overview of the forest resource situation in the United States based upon data compiled for 1997. A separate document with more detailed trend analysis is in preparation. 

INTRODUCTION

For this analysis, the United States has been divided into four regions; North, South, Rocky Mountains, and Pacific Coast. The subregions and States that make up the regions are shown in Figure 1.

Rocky
Mountains

Alaska

North

Great
Plains

Inter-
mountain

North Central

Pacific
Northwest

Northeast

Pacific
Coast

Pacific
Southwest

Southeast

South Central

Hawaii

South

Figure 1–Resource reporting regions and subregions.

FOREST LAND BASE

Of the United States 2.3 billion acre total area, 33 percent (747 million acres) is forest land and 67 percent (1,516 million acres) is non-forest land (Table 1). Forests are found in abundance in every region of the Nation. They vary from sparse scrub forests of the arid, interior west to the highly productive forests of the Pacific Coast and the South, and from pure hardwood forests to multi-species mixtures, and coniferous forests.
About two-thirds (504 million acres) of the Nation's forests are classed as timberland, productive forests capable of producing 20 cubic feet per acre of industrial wood annually and not legally reserved from timber harvest. An additional 52 million acres of forest, reserved for non-timber uses, are managed by public agencies as parks or wilderness areas (table 2). There are also 191 million acres of other forest lands not capable of producing 20 cubic feet per acre of industrial wood annually, but of major importance for watershed protection, wildlife habitat, domestic livestock grazing, and other uses. Almost all of the other forests are in the South and West, over half are in Alaska. Although these other forest lands produce little industrial roundwood, they do produce other wood and tree products which are often important for local use. Fuelwood is a primary use in many areas having non-timber forests, such as the pinyon-juniper forests of the southwestern portion of the country.

Table 1. Land area in the United States, 1997

Type of land	Total area	Proportion	
	(Million acres)	(Percent)	
Timberland	504	22	
Reserved Forest	52	2	
Other forest land	191	8	
   Total forest land	747	33	
Other land	1,516	67	
Total area	2,263	100	

Ownership
In 1997, about 67 percent (500 million acres) of the total forest area was owned by State and county agencies, forest industry, and other private individuals (Table 3). The Federal lands are administered primarily by five groups -- Forest Service, Bureau of Land Management, National Park Service, Fish and Wildlife Service, and Defense/Energy Departments.

Nonfederal forest lands are concentrated in the East--some 351 million acres. National Forest and other public lands are concentrated in the West; 250 million acres of these western public lands are classified as forest land.

Table 2. Land area in the United States, by type of land and region, 1997.

Type of land	
Total	
North	
South	Rocky
Mountains	Pacific Coast	
	(Million acres)	
Timberland	504	159	201	71	72	
Forest land, reserved	52	8	4	18	22	
Other forest land	191	3	9	54	125	
 All forest	747	170	214	143	219	
Other land	1,516	243	321	598	354	
  Total, all land	2,263	413	535	742	573	

Reserved Forest 
There is worldwide interest in the extent of protection of representative ecosystems so as to maintain a pool of biodiversity for future generations. There are various ways of classifying the degree of protection given to an area.  The classification scheme used by the International Union for the Conservation of Nature (IUCN) includes the following categories: I. Strict nature reserve/wilderness area; II. National Park; III. National monument; IV. Habitat/species management area; V. Protected landscape/seascape, and VI. Managed resource protection area

The IUCN classification scheme is based on the concept of protection by legal statute and thus does not apply well to private lands and some public lands in the United States. Individual landowners may have no intention to harvest timber, but subsequent owners may choose to harvest timber or otherwise develop the land. Some organizations such as the Nature Conservancy own land with the intention of preservation, but this protected status may change as organization objectives change over time. In 1997, some 52 million acres of forest land were classed as reserved and include wilderness areas on Federal and State lands and National Parks. This estimate does not include any allowance for private lands in conservation easements or held by private groups such as the Nature Conservancy, Ducks Unlimited, etc. The reserved forest land area in 1997 amounted to 7 percent of the total forest land area and is more than double the area classed as reserved in 1953.

Table 3. Area of forest land in the United States, by region and ownership, 1997.

Region	Total	National Forest	Other Federal	State and local	Private	
	(Million acres)	
North	170	12	2	27	129	
South	214	12	7	6	189	
Rocky Mountains	143	72	26	6	38	
Pacific Coast	219	50	64	30	74	
  Total, all regions	747	147	100	70	430	

Productivity
Productivity of forest land is defined as the amount of wood per acre that can be produced in fully stocked natural stands. The natural potential has been used because measures of the potential are available for most regions of the United States, and they provide a uniform means of describing productivity of forest land in the United States. While no single measurement adequately describes the productivity of forest land for uses other than timber, this estimate of biological productivity is sometimes useful in helping to determine the forests relative capacity for other uses. Chief among the factors that influence productivity are soil, climate, and topography.

Most of the Nation's high productivity forest lands are located in the South (91 million acres) and in the Pacific Coast region (44 million acres). The East (North and South) also has about 73 percent of the medium productivity forest lands whose growth potential range from 20 to 85 cubic feet per acre annually (Table 4). The Pacific Coast has the greatest area of low productivity lands. Alaska has 105 million acres of interior forests with the potential of producing less than 20 cubic feet per year of industrial wood. The Rocky Mountains also has large areas of low productivity forests dominated by pinyon-juniper.

In the West, the largest areas in the high productivity class are in the coastal Douglas-fir and hemlock-sitka spruce types. In the East, the highly productive sites are found in the loblolly-shortleaf pine and oak-gum-cypress ecosystems of the lower Mississippi drainage and the Atlantic coastal plain.

Table 4. Area of forest land in the United States, by region and productivity class, 1997.

		Productivity class 1	
Region	Total	High (85+)	Medium (20-85)	Low (<20)	Reserved 2	
			(Million acres)			
North	170	34	126	3	8	
South	214	91	110	9	4	
Rocky Mountains	143	12	59	54	18	
Pacific Coast	219	44	29	125	22	
 Total, all regions	747	181	323	191	52	
1 A measure of mean annual growth in cubic feet per acre per year obtainable in fully stocked natural stands.
2 Reserved forest lands are not classified for timber productivity.

Stand Size
The average size of trees on timberland provides insight to changing forest landscape in the U.S. In 1953, 60 percent of the nation’s timberland was in stands that were poorly stocked or averaged less than 10 inches in diameter. In 1997, 49 percent of the nation’s timberland was in stands averaging over 10 inches in diameter (see detailed RPA table 16). 

TIMBERLAND TYPES

The timberlands of the United States span a wide range of latitudes, elevations, precipitation, and soils. Consequently, the species composition of the forests found on these timberlands is quite diverse, ranging from pure stands of ponderosa pine in the semi-arid west to the complex multi-species hardwood forests of the Northeast.

Eastern Hardwood Forests
The eastern hardwood forests in total account for 53 percent of the timberland area of the United States, and 74 percent of the timberland area in the East. This group of multi-species types covers the majority of timberland in all four eastern subregions - North Central, Northeast, South Central, and Southeast. The most widespread forest type is oak-hickory, which is found throughout the South to Southern New England, and west to the Great Plains; timberlands in this type total 124 million acres (Table 5).

The oak-gum-cypress forests, which total 29 million acres, are a mainstay of the southern hardwood industry. The conversion of bottomlands to agriculture reduced the extent of this type substantially from pre-settlement conditions. In the past two to three decades, the area of oak–gum–cypress has stabilized.

Elm-ash-cottonwood forests are bottomland forests of the North. They account for nearly 12 million acres, mostly in the North Central and Northeast regions. White ash from these forests is used for a number of specialty wood products. These bottomland forests provide habitat for furbearers and many other animals.

Maple-beech-birch forests are found on 51 million acres of timberland in the East, predominantly in the Northeast and North Central regions. These forests, which have apparently expanded in area in recent years, contain a number of prized hardwood species, including sugar maple and the birches. This is the forest type famed for fall color.

Most of the 17 million acres of aspen-birch forests are in the North Central region. This forest type is made up of pioneer species, which often take over areas following disturbance or removal of other forest types. This type is a major source of fiber for the pulpwood industry in the North and a key habitat species for grouse and deer management.

Table 5. Area of timberland in the United States, by forest type, 1997.

Forest type	Total area	Proportion	
	(Million acres)	(Percent)	
Eastern:			
  Loblolly-shortleaf pine	52	10	
  Spruce-fir	15	3	
  Longleaf-slash pine	13	3	
  White-red-jack pine	11	2	
  Oak-hickory	124	25	
  Maple-beech-birch	51	10	
  Oak-pine	33	7	
  Oak-gum-cypress	29	6	
  Elm-ash-cottonwood	12	2	
  Aspen-birch	17	3	
  Other types	2	1	
    Total, Eastern	360	72	
			
Western:			
  Fir-spruce	25	5	
  Douglas fir	37	7	
  Ponderosa pine	29	6	
  Hemlock-sitka spruce	11	2	
  Lodgepole pine	12	2	
  Other softwood types	8	2	
  Western hardwoods	21	4	
    Total, Western	143	28	
All types	504	100	

The oak-pine forests of the East are found primarily in the South. Many of these stands on Southern timberlands have emerged following selective cutting operations in pine stands; many regenerated stands are also a mix of pines and hardwoods early in their development. The acreage in this type has remained stable during the last decade.

Eastern Softwood Forests
The eastern softwood forests, though occupying a much smaller area of timberland than the hardwood forests, are the most important timber resources throughout much of the East in terms of timber production. Nowhere is this more true than in the pine region of the South. In both the Southeast and South Central subregions, the longleaf-slash pine and loblolly-short leaf pine forests, which combined account for 65 million acres of timberland, provide the raw material for the South's huge and still growing forest products industries. Loblolly-shortleaf pine forests account for over half of the 91 million acres of conifer-bearing timberlands in the East. These forests also provide critical habitat to rare species like the red cockaded woodpecker and serve as prime habitat for white-tailed deer, wild turkey, bobwhite quail, and mourning dove .

Longleaf-slash pine forests, which account for less than one-quarter of the southern pine type acreage, are found in States bordering the South Atlantic and Gulf coasts, but most of the area in this type is concentrated in Florida and Georgia.

The white-red-jack pine and spruce-fir forests are the softwood forests of the North. Combined they account for 29 percent of the softwood forests of the East, but only 5 percent of all of the Nation's timberlands. The spruce-fir forests of the Northeast are an important source of pulpwood in that region.

The white-red-jack pine forests total 11 million acres. The species composition of this forest type varies; in the Northeast, white pine predominates, while red and jack pines are the common pines of the North Central region.

Western Forests
The timberlands of the West are forested primarily with softwood species. Eighty-four percent of the timberland area in the West is forested with softwoods; 15 percent has hardwood stands, and 1 percent is currently non-stocked.

Three forest types combined account for almost two-thirds of the forests on the West's timberlands. The Douglas-fir type, which is found in the Rocky Mountains, Pacific Northwest and Pacific Southwest regions, totals 37 million acres, and is the most abundant species in the West. The Douglas-fir forest on the Pacific Slope in the Northwest are perhaps the most productive softwood forests in the United States in terms of fiber production.

Ponderosa pine forests occupy about 29 million acres of timberland in the West, over 54 percent of which is in the Rocky Mountains. This species is also abundant east of the Cascade Range in the Northwest region, and in the Southwest region - California. The ponderosa pine forests of the West are a major source of raw material for the manufacture of lumber.

The fir-spruce forests are found on 25 million acres of Western timberlands. These forests, found at medium to higher elevations throughout the forested West, have gained in value and use for wood products in recent decades, with tightening supplies for other species. The area of fir forests has increased in some areas such as California, due in part to selective harvest of pine in mixed conifer stands.

Hemlock-sitka spruce forests are found primarily on the Pacific slope in Oregon and Washington, and in coastal Alaska. These forests account for about 8 percent of the West's timber forests, and are important timber species, providing raw material for lumber products, pulping, and log export on the Pacific Coast.

Lodgepole pine is another significant forest type on Western timberlands. Lodgepole stands total almost 12 million acres. Although present throughout much of the West, this species is most abundant in the Rocky Mountains where three-fourths of the type is found. It is also present in significant quantities in the ponderosa pine subregion of the Northwest.

The other western softwood types - larch, redwood, western white pine, and other minor species total less than 6 million acres, and are much more localized in occurrence than the major forest types of the West.

There are about 21 million acres of hardwood forests on Western timberlands. In California, oaks predominate in hardwood stands; in the Rocky Mountains, aspen is the most abundant hardwood. In the Northwest region, red alder is the most abundant hardwood species. In recent years this species has declined slightly in area, volume, due to increased value to the wood products industry. It is currently used for fuelwood, lumber and specialty millstock, and pulp chips for both domestic use and export.

VOLUME OF TIMBER

The Nation's timberlands contain trees of a large variety of species. Variability in the condition of these trees has considerable bearing on their value for use in wood products. It is estimated that the Nation's timberlands contain about 906 billion cubic feet of timber, of which 92 percent is in growing stock--live, sound trees suited for roundwood products (Table 6). About 6 percent of all timber volume is in live cull trees that traditionally, because of form or rot, are not suited for the production of roundwood products. However, new technology using chipped wood is making these trees more marketable for product use. About 2 percent of the volume of all timber is in dead trees that are sound enough to have value for some product uses. Softwood species have a higher proportion (95 percent) of all timber volume in growing stock; hardwood volume is 88 percent growing stock. The remainder of this discussion on timber volume will focus on growing stock.

Softwood Timber Volume
The Nation's softwood growing stock volume totals 484 billion cubic feet or 58 percent of all growing stock (Table 7). Softwood growing stock volume is concentrated in the West. The Pacific Coast alone accounts for 44 percent of all softwood growing stock, despite its relatively small timberland base. The West contains most of the United States' remaining forests of old-growth; these stands have high per acre volumes. Many of the young forests on the Pacific Coast also have high per acre volumes due to the high productivity of much of the timberland. Most of the remainder of softwood timber is evenly distributed between the South and the Rocky Mountains; the North has only 10 percent of the Nation's total softwood timber volume.

Douglas-fir is the most abundant softwood species; it totals 113 billion cubic feet or 23 percent of all softwood timber volume in the United States (Table 8). Sixty-two percent of all Douglas-fir volume is in Oregon and Washington.

Table 6. Volume of trees on timberland in the United States, by condition
class and species group, 1997.

		Species group	
Condition class	All species	Softwoods	Hardwoods	
	(Billion cubic feet)	
Growing stock trees	836	484	352	
Live cull trees	50	8	42	
Sound dead trees	21	17	4	
  Total, all classes	906	509	398	

Table 7. Volume of growing stock in the United States, by region and
species group, 1997.

		Species group	
Region	All species	Softwoods	Hardwoods	
	(Billion cubic feet)	
North	214	49	165	
South	256	105	152	
Rocky Mountains	125	115	11	
Pacific Coast	240	215	25	
  Total, all regions	836	484	352	

Other important western softwood species in order of volume abundance are True firs (49 billion cubic feet); ponderosa and Jeffrey pine (39 billion cubic feet); western hemlock (32 billion cubic feet); lodgepole pine (27 billion cubic feet); and spruce (23 billion cubic feet). The location of volume concentrations of these species follows closely the distribution of the namesake forest types discussed earlier.

Eastern softwood species are found primarily in the South, an area that has become a focal point for new forest industrial investment in recent years. This shift in the level of timber harvest and industrial development between the Pacific Coast and the South has resulted in part from the declining supplies of large old timber on private lands on the Pacific Coast along with increased demands for other nontimber uses of public forest lands. Eastern softwoods account for nearly one-third of the Nation's softwood timber; Southern pines alone account for 20 percent.

Loblolly and shortleaf pines total 70 billion cubic feet or 66 percent of all softwood timber volume in the South and 45 percent of all softwood volume in the East. Other important Eastern softwoods are: longleaf and slash pines (16 billion cubic feet); red and white pines, located in the Northeast and North Central region (17 billion cubic feet); spruce and balsam fir, located in the North (14 billion cubic feet); and other yellow pines (12 billion cubic feet)

Hardwood Timber Volume
Hardwoods account for 42 percent of all growing stock timber volume in the United States (Table 8). Fully 90 percent of all hardwood timber volume is in the eastern United States, almost evenly distributed between the North and the South. Most of the remaining ten percent is on the Pacific Coast.

The hardwoods of the East are numerous, and their unique characteristics warrant tracking many of them as separately identifiable species. The oaks total 108 billion cubic feet. The higher economic value select species, which include select white and red oaks, hard maple, yellow birch, sweet gum, yellow poplar, ash, black walnut, and black cherry, total 138 billion cubic feet or 39 percent of all hardwood growing stock in the United States. Although there is an apparent abundance of select species, much of the volume is in relatively small trees, which limits their usefulness for many products where clear, wide surfaces are important. In the East, 52 percent of all hardwood timber volume is in trees less than 13 inches in diameter.

The volume of western hardwoods is small relative to the vast softwood resources in the West, or the hardwood resources in the East. But locally, western hardwoods are important, and their use is growing as softwoods become more limited in supply. Red alder, with an inventory of 8 billion cubic feet, has risen for nearly three decades but has declined due to increased use in recent years. It is located almost entirely in the Douglas-fir subregion of Oregon and Washington. The aspens in Colorado and other states in the Rocky Mountains are becoming increasingly popular with tourists in the fall when the aspen foliage changes to a fluorescent gold against the backdrop of mountains and emerald green softwood forests.

Table 8. Volume of growing stock in the United States,
 by species, 1997.
	
Species	Volume	Proportion	
	(Billion cubic feet)	(Percent)	
Eastern softwoods:			
  Loblolly-shortleaf pine	70	8	
  White-red-jack pine	19	2	
  Longleaf-slash pine	16	2	
  Spruce-fir	14	2	
  Other yellow pines	12	1	
  Eastern hemlock	9	1	
  Cypress	6	1	
  Other softwoods	9	1	
    Total	154	18	
			
Eastern hardwoods:			
  Red and white oaks	108	13	
  Soft maple	32	4	
  Hard maple	22	3	
  Yellow poplar	21	3	
  Sweetgum	17	2	
  Cottonwood and aspen	16	2	
  Other hardwood	99	12	
    Total	316	38	
			
Western species:			
  Douglas -fir	113	14	
  True fir	49	6	
  Ponderosa and jeffrey pine	39	5	
  Western hemlock	32	4	
  Sitka and other spruces	32	4	
  Lodgepole pine	27	3	
  Other softwood	39	5	
  Hardwoods	35	4	
   Total	365	44	
Total, all species	    836	100	

Ownership of Timber Volume
The pattern of ownership of timberland area is not a good indication of distribution of timber volumes among the same owner groups. Because of many factors, among them; history of use, land productivity, and degree of management, timber volumes are distributed unevenly among owners. National Forests, which account for only 19 percent of the Nation's timberland, have 30 percent of all timber volume, and 46 percent of all softwood timber volume (Table 9). The National Forests still have a considerable area in old softwood stands with high per-acre volumes, but little hardwood volume relative to the other owner groups.

Other Public Owners - States, federal agencies other than the Forest Service, counties and municipalities - account for about 11 percent of all timber, 58 percent of which is softwoods. The hardwood volume in this owner group is concentrated in the North; the softwood volume is mostly in the West, the largest share in Oregon and Washington.

Forest industries account for about 12 percent of all timber volume in the United States, and 14 percent of all softwood volume. This group of timberland owners accounts for a small part of total timberland and timber volume in most regions, but is locally important in many states and areas. In all areas having industry timber, it is important beyond its relative abundance, because industry owners hold and manage timber for harvest. Inventory turnover - the rate of harvest and replacement of timber inventories - is higher on forest industry land than on other ownerships.

Table 9. Volume of growing stock in the United States, by ownership
and species group, 1997

	Species group	
Ownership	All species	Softwoods	Hardwoods	
	(Billion cubic feet)	
National Forest	252	222	30	
Other public	88	51	37	
Forest industry	100	66 	34	
Other private	396	144	252	
  Total, all ownerships	836	484	352	

Other private timberlands account for 47 percent of all growing stock volume in the United States, a proportion less than the timberland area share of this owner group might indicate, but nevertheless a large and important resource. This owner group controls 30 percent of all softwood timber, and 72 percent of all hardwood timber. Both softwood and hardwood timber volume in this owner group are concentrated in the eastern United States, softwoods in Northeast, Southeast, and South Central regions; hardwoods are abundant in this ownership throughout the East.

ELEMENTS OF CHANGE IN TIMBER VOLUME

Timber inventories are dynamic. The net change in timber volume is affected by a number of factors, some within owners or managers control, and some beyond their control. When timberland is shifted from one owner to another, is converted to another use, or withdrawn from timber production (for example, park or wilderness use) volume is removed from the inventory of one owner group, and may or may not be added to another. The impacts on timber volume change are not always precisely known, but if the average volume on the lost acres is representative of average volume for the entire ownership class, the volume loss/gain due to timberland transfer or withdrawal is proportional to the timberland area lost. While such inventory losses can be estimated, they tell us little about the dynamics of forests and their uses as timberland. The focus here will be on the elements of dynamic change within forests - mortality, growth, and harvest.

Mortality
Timber mortality is commonly defined as the net volume of timber dying annually or for some other period, due to insects, disease, suppression, fire, and catastrophic or other weather events. Mortality is a part of every living forest. Usually, losses due to endemic levels of insects, disease, and suppression occur at a low and predictable rate. Little of this type of timber loss is captured for harvest because the dead trees are widely scattered, not providing economic concentrations of timber volume needed to support profitable harvest operations.

Timber volume loss to mortality can also occur in high concentrations in localized areas, through epidemic insect infestations, wildfire and windstorms. Timber killed but not destroyed in such catastrophic events is often salvaged and utilized for the production of timber products. In such cases, the volume of this loss would be recorded as removals to avoid double counting.

The volume of mortality totaled 6 billion cubic feet in 1996 (Table 10), about 0.76 percent of the growing stock volume in the United States. The distribution of mortality is generally consistent and very predictable, absent periodic catastrophes. For softwoods and hardwoods combined, the mortality rate (mortality volume as a percent of growing stock) varied between 0.73 and 0.81 percent. The highest mortality rates in 1996 were on private forests; the lowest were on public forests. The largest volume losses to mortality generally occur where the largest concentrations of timber are found. However, even in areas of high timber volumes, mortality is usually so dispersed at the per acre level, that barring catastrophic loss, trying to capture mortality for harvest is not a realistic option. For the United States as a whole, mortality averages only 13 cubic feet per acre annually. On the Pacific Coast, mortality averages about 20 cubic feet per acre annually; in the eastern regions, it averages 10 to 11 cubic feet per acre.  While mortality is viewed as a loss from a timber perspective, dead trees provide valuable wildlife habitat, insect breeding areas, decaying organic material to improve forest soils, and perches for predatory birds. 

Table 10. Mortality of growing stock in the United States, by ownership
and species group, 1996.

		Species group	
Ownership	All species	Softwoods	Hardwoods	
	(Million cubic feet)	
National Forest	1,835	1,593	242	
Other public	643	326	317	
Forest industry	808	509	299	
Other private	3,034	1,198	1,836	
  Total, all ownerships	6,320	3,626	2,694	

Net Annual Timber Growth
Net annual growth is a commonly used measure of productivity and performance of timber resources. Net annual growth is annual growth of timber volume, less the mortality volume and increase in cull volume. In other words, it is the net effect of natural gains and losses to timber volume. Although net growth is frequently used as an indication of timber available for harvest, this simple concept of harvest availability is at best a coarse filter for measuring availability and can be misleading. Spikes in mortality due to catastrophic losses, sharp increases in forest planting, and many other factors must be put into perspective to get an accurate assessment.

Net annual timber growth (net growth) totaled 24 billion cubic feet in 1996 (Table 11). Fifty-five percent of all timber growth and 74 percent of all hardwood growth was on other private timberlands. Forest industry accounted for 19 percent of all timber growth, and 25 percent of all softwood growth, percentages much larger than their share of timberland and timber volume.

On a per acre basis, net growth on forest industry timberlands is averaging 65 cubic feet annually, far in excess of any other ownership. This high level of growth reflects the inherently high productivity of timberlands in this owner-group, as well as the age, stocking levels, and management levels of timber stands. National Forests have lands of poorer productivity and many old stands with relatively slow growth. As a consequence they generally have the lowest per acre growth of any owner group (43 cubic feet).

Table 11. Net annual growth of growing stock in the United States,
 by ownership and species group, 1996.

		Species group	
Ownership	All species	Softwoods	Hardwoods	
	(Million cubic feet)	
National Forest	4,104	3,430	674	
Other public	2,145	1,207	938	
Forest industry	4,368	3,382	986	
Other private	12,933	5,375	7,558	
  Total, all ownerships	23,549	13,393	10,156	

Timber growth is unequally distributed among all the regions of the country. The South accounts for about 45 percent of all timber growth, softwood growth, and hardwood growth (Table 12). The South and North combined account for most (89 percent) of total hardwood growth. The Rocky Mountains and Pacific Coast combined have 47 percent of all softwood growth.

On a per acre basis the Pacific Coast has the highest rate of growth (69 cubic feet) of all regions of the country. The Rocky Mountains and North have the lowest per acre growth rates (each at 34 cubic feet per acre), considerably lower than those for the Pacific Coast and South.

Timber Removals
Removals from timber inventories are losses that occur by other than natural causes (mortality). Removals, mortality, and land dedication to non-forest uses are the negative elements of change that, with growth as a positive element, determine the direction or trend in timber volume over time. Timber removals from growing stock volume include:  (1) harvest of roundwood products; (2) logging residues; and (3) other removals, such as non-commercial thinning, and land clearing with resultant loss of timber. Not included in the removals discussed herein are the timber inventories on timberlands withdrawn intact for parks and wilderness. We have focused here on timber removals from growing stock inventory that are or can be potentially used for wood products.

Timber removals from growing stock inventory in 1996 totaled over 16,021 million cubic feet (Table 12). Almost 64 percent of all timber removals came from the forests of the South, which continued to increase its share of timber harvest in the United States as harvest levels on public forests in the West decline. Only 16 percent of all removals came from the Pacific Coast forests in 1966; 17 percent came from the North and only 3 percent from forests in the Rocky Mountains.

Softwoods accounted for 63 percent of all growing stock removals in 1996. The forests of the South accounted for 64 percent of all softwood removals, the Pacific Coast 24 percent, the Rocky Mountains 5 percent, and the North 7 percent. Hardwood removals in 1996 were centered in the North and South, which together accounted for 98 percent of the United States total. Southern hardwoods continue to grow in importance as a commercial crop and accounted for 62 percent of all hardwood removals from growing stock in 1996, up from 58 percent in 1986.

Table 12. Net annual growth and removals of growing stock in the United States,
by region and species group, 1996.

Region and		Species group	
item	All species	Softwoods	Hardwoods	
	(Million cubic feet)	
North:				
  Net growth	5,420	1,169	4,251	
  Removals	2,772	668	2,104	
  Ratio growth to removals1	1.95	1.75	2.02	
				
South:				
  Net growth	10,712	5,889	4,823	
  Removals	10,185	6,478	3,707	
  Ratio growth to removals1	1.05	0.91	1.30	
				
Rocky Mountains:				
  Net growth	2,434	1,963	471	
  Removals	532	501	31	
  Ratio growth to removals1	4.57	3.92	15.26	
				
Pacific Coast:				
  Net growth	4,983	4,373	611	
  Removals	2,532	2,417	115	
  Ratio growth to removals1	1.97	1.81	5.32	
				
United States:				
  Net growth	23,549	13,393	10,156	
  Removals	16,021	10,065	5,956	
  Ratio growth to removals1	1.47	1.33	1.71	
1 Refer to caveats in the discussion on Net Annual Timber Growth and Timber Growth-Removal Balances
before using this ratio.

Timber removals were concentrated on private ownerships in 1996. Other private owners had 59 percent of all timber removals; industrial forests accounted for 30 percent (Table 13). The National Forests accounted for only 5 percent of total growing stock removals in 1996, down from 13 percent in 1986. Other public, with 6 percent of total removals, echoed the decline in removals on all public forest lands.

The ownership distribution by species group was somewhat different than the all species distribution due to the differences in species volume distribution between the owner groups. Forest industry accounted for 37 percent of all softwood removals, other private 52 percent, National Forests 6 percent, and other public 6 percent. Hardwood removals came primarily from other private forests (73 percent).

Table 13. Net annual growth and removals of growing stock in the United States,
by ownership and species group, 1996.

		Species group	
Ownership and item	All species	Softwoods	Hardwoods	
				
	(Million cubic feet)	
National Forest:				
  Net growth	4,104	3,430	674	
  Removals	828	629	199	
  Ratio growth to removals1	4.96	5.45	3.39	
				
Other public:				
  Net growth	2,145	1,207	938	
  Removals	946	561	385	
  Ratio growth to removals1	2.27	2.15	2.44	
				
Forest industry:				
  Net growth	4,368	3,382	986	
  Removals	4,733	3,683	1,050	
  Ratio growth to removals1	0.92	0.92	0.94	
				
Other private:				
  Net growth	12,933	5,375	7,558	
  Removals	9,514	5,191	4,322	
  Ratio growth to removals1	1.36	1.04	1.75	
				
United States:				
  Net growth	23,549	13,393	10,156	
  Removals	16,021	10,065	5,956	
  Ratio growth to removals1	1.47	1.33	1.71	
1Refer to caveats in the discussion on Net Annual Timber Growth and Timber Growth-Removal Balances
before using this ratio.

Timber Growth - Removal Balances
Comparisons of net growth and removals provide a spot check of the balance between the two, and by inference an indication of what will happen to the inventory for the year of comparison. However, growth-removal comparisons should be used with some caution. While annual growth for any one year gives an index to expected growth for the next few years, it should be noted that growth estimates are often based upon growth rates measured for a period preceding that year; thus, growth that actually occurs in a given year may be different than the average because of changing weather patterns, changing mortality rates, and shifts in management intensities for the forests. Likewise, the removals for any given year, such as 1996, can be substantially different than the year preceding or the year following due to the overwhelming impact of market demand on levels of timber harvest, which is the major component of removals. So, although these comparisons are interesting, they should not be used to draw inferences about long-term growth-removals balance and their effect on trends in timber inventories. In addition, the comparisons used here pertain to aggregate forest areas and species and may not be indicative of local conditions. A positive balance for hardwoods as a whole means nothing with reference to individual highly prized species such as black walnut. Any individual species or a state or local area may have a far different growth-harvest balance than the aggregate in which it occurs.

Growth-removals balance can be expressed as a ratio of growth to removals. A ratio exceeding 1 means that growth exceeds removals for the year in question; a ratio of less than one indicates removals in excess of growth and--for that year--a resulting decrease in inventory volume.

The growth-removals balance for the United States is positive for all species (1.47), for softwoods (1.33), and for hardwoods (1.71) (Table 12). The ratios in the North are very high, indicating continued substantial increases in growing stock volume if harvests and removals remain at 1996 levels. The softwood ratio in the South is just under 1.00--marking a continued tight supply/demand relationship for softwoods in the South. The growth-removals ratio in the Rocky Mountains exceeds 4 due largely to increased growth and low relative removals. The ratio on the Pacific Coast is 1.97; for softwoods it is 1.81, reflecting the sharp drop in harvesting on public lands in this region over the last few years.

The current ratios by ownership are positive for all owner groups but forest industry (Table 13). The 1996 growth-removals ratio for National Forests is 4.96; for other public forest it is 2.27 for all species and 2.15 for softwoods; other private lands have a ratio of 1.36 for all species, 1.04 for softwoods, and 1.75 for hardwoods. For forest industry forests, the 1996 ratio of growth to harvest for all species is 0.92; for softwoods it is 0.92, due to higher timber harvest levels in recent years as supplies shift from public lands in the west to private lands in the east. The hardwood growth-removals ratio for this owner group is 0.94 as demand for Southern hardwoods also rises.

TIMBER PRODUCTS OUTPUT

Timber products output from growing stock accounts for most of the timber removed from timberlands (Table 14). In 1996, 90 percent of all softwood growing-stock removals and 79 percent of all hardwood growing-stock removals were in the form of roundwood used as raw material for manufacture of wood products

Table 14. Roundwood products, logging residue, and other removals from growing stock
on timberlands in the United States, by species group and region, 1996.

		Region	
Species group	United			Rocky	Pacific	
and item	States	North	South	Mountains	Coast	
	(Million cubic feet)	
Softwoods:						
  Roundwood products	9,102	629	5,773	455	2,245	
  Logging residue	615	31	368	45	170	
  Other removals	348	8	337	1	2	
    All softwoods	10,065	668	6,478	501	2,417	
						
Hardwoods:						
  Roundwood products	4,708	1,790	2,787	23	109	
  Logging residues	677	225	444	2	6	
  Other removals	571	89	476	5	0	
    All hardwoods	5,956	2,104	3,707	31	115	
						
All species:						
  Roundwood products	13,810	2,419	8,560	478	2,353	
  Logging residues	1,292	256	813	47	176	
  Other removals	919	98	813	7	2	
    Total, all species	16,021	2,772	10,185	532	2,532	

Roundwood products accounted for 89 to 94 percent of softwood growing-stock removals in all regions of the country. Hardwood roundwood products accounted for 85 percent of the total hardwood growing-stock removals in the North and 75 percent in the South.

Logging Residues
Logging residues are materials removed from growing stock in the process of timber harvest, which are left unutilized at the harvest site. Theoretically they represent usable raw material that could be used in the manufacture of wood products. But the size, species, concentrations, and/or condition of the material have rendered it unsuited for manufacture of products at that time, or simply not economical to transport to the processing facilities. Thus logging residues are not unjustified waste, but they may be a source of raw material in the future as products, the price of raw materials, or the economics of manufacturing changes.

Logging residues accounted for 6 percent of all softwood growing stock removals and 11 percent of all hardwood removals in 1996 (Table 14). In the Rocky Mountains and Pacific Coast, softwood logging residues were 9 and 7 percent, respectively, of total removals; but in the South and North, softwood logging residues were only 6 and 5 percent, respectively of total removals. The higher proportion of removals left as logging reside in the West is due in part to breakage and other factors associated with logging of old timber, and due to operation in steep, remote terrain.

Hardwood logging residues as a percent of total removals varied from 5 percent in the Pacific Coast to 12 percent in the South. In the eastern part of the United States, where hardwood removals are concentrated, hardwood logging residues totaled 669 million cubic feet, and accounted for 11 percent of hardwood removals in the North and-, 12 percent in the South. Although logging residues cannot be considered an immediate raw material resource, the economics and technology of harvest and manufacture and the nature of raw material used for wood products do change with the passage of time. As in the past, technology change has resulted in an increase in the degree of utilization and a decrease in the proportion of growing stock left as logging residue.

Other Removals
Other removals consist largely of growing stock cut and burned or otherwise destroyed in the process of conversion of forest land to nonforest uses. A secondary source of other removals is growing stock killed and not utilized in forestry cultural operations such as precommercial thinning. These removals, like logging residues, are not a potential immediate source of raw materials, but changing economics may some day make more of this material available for product manufacture. In 1996, 6 percent of all growing stock removals fell into the category, but fully 10 percent of hardwood removals were so classified. Almost all the hardwood growing stock lost to other removals was in the South and the North where hardwood forests have continued to be moved into land uses such as residential development and pasture. Most of the softwood growing stock classified as other removals in 1996 was in the South. When timberland is converted to nonforest use, some wood raw material is usually lost in the process. But wood that is valuable for product manufacture, if in economic concentrations, is usually utilized, and is included in the roundwood products category of removals.

Products from Growing Stock and Other Timber
Roundwood timber products come largely from growing stock. Most attention is focused on roundwood products from growing stock because of the overwhelming importance of that source, and because harvest from growing stock has an effect on growing stock inventories, which are tracked and studied because of their commercial importance. But roundwood products also come from such non growing stock sources of wood raw material as dead trees, live cull trees that are largely rotten or are rough in form, very small trees, trees of seldom used species, and trees from nonforest land (fencerows, etc.).

In 1996 roundwood products from all domestic sources in the United States totaled 16,431 million cubic feet, of which growing stock accounted for 84 percent, other sources 16 percent (Table 15). Only 9 percent of all softwood roundwood products came from nongrowing stock. But the situation was different for hardwoods; 26 percent of all hardwood roundwood products came from nongrowing stock sources.

The major reason for the high proportion of nongrowing stock in total hardwood harvest is fuelwood. Hardwoods accounted for 78 percent of all roundwood harvested for fuelwood in 1996. And nongrowing stock accounted for 66 percent of all hardwood used for fuelwood. For fuelwood use, species, tree form and size are of minor importance to the value of wood. Location, availability, and low cost are primary concerns; as a consequence much fuelwood comes from species of lesser value for other roundwood products, and small trees or trees that are too poorly formed for timber and other products. Nongrowing stock accounted for a minor part of the wood supply for all other products. The fuelwood harvest was concentrated in the eastern United States.

Sawlogs (including veneer logs) accounted for 51 percent of total roundwood harvest in 1996. This roundwood product, used in the production of lumber, accounted for 63 percent of all softwood harvested, but only 33 percent of all hardwood. The sawlog harvest was concentrated in the South Central and Southeast regions, and in the Pacific Coast; these regions combined accounted for 79 percent of the timber harvested for sawlogs.

Pulpwood roundwood (including composites) accounted for 33 percent of total timber harvest in the United States in 1996. Nearly 55 precent of the pulpwood harvested was softwoods. Ninety-eight percent of all pulpwood roundwood was harvested in the Eastern United States, the South alone accounting for 75 percent. Although the Pacific Coast has a substantial pulp industry, most of the wood raw material is chips produced as byproduct from the manufacture lumber.

Other products include roundwood harvested for cooperage, mine-timbers, poles, pilings, posts, shakes, shingles, and logs for export. In 1996, timber harvested for these products totaled 342 million cubic feet or 2 percent of all roundwood harvests. Eighty-seven percent of the harvest for these products was softwoods. Forty-six percent of the harvest for other products was concentrated on the Pacific Coast, the majority of which was logs for export. Most of the remainder of harvest for other products was in the North (18 percent) and the South (27 percent).

Table 15. Volume of roundwood harvested in the United States, by source of material,
Species group, and product, 1996.

		Product	
Source of material	All	Veneer &			Other	
and species group	products	sawlogs	Pulpwood	Fuelwood	products	
	(Million cubic feet)	
Growing stock:						
  Softwoods	9,102	5,999	2,646	187	270	
  Hardwoods	4,708	1,934	2,125	612	39	
    Total, GS	13,810	7,932	4,770	799	309	
						
Other sources:						
  Softwoods	935	283	319	306	27	
  Hardwoods	1,686	186	315	1,178	7	
    Total, other	2,621	469	634	1,484	33	
						
All sources:						
  Softwoods	10,036	6,282	2,965	493	296	
  Hardwoods	6,395	2,120	2,440	1,790	45	
    Total, all sources	16,431	8,402	5,405	2,283	342	

GLOSSARY

Annual mortality--The average annual volume of sound wood in growing stock trees that died from natural causes during the period between inventories.
 
Annual removals--The net volume of growing stock trees removed from the inventory during a specified year by harvesting, cultural operations such as timber stand improvement, or land clearing.
 
Bureau of Land Management (BLM)--An ownership class of Federal lands administered by the Bureau of Land Management, U.S. Department of the Interior. 
 
Coarse materials--Wood residues suitable for chipping, such as slabs, edgings, and trimmings. 
 
Commercial species--Tree species suitable for industrial wood products. 
 
County and municipal--An ownership class of public lands owned by counties or local public agencies, or lands leased by these governmental units for more than 50 years. 
 
Cull tree--A live tree, 5.0 inches (12.7 centimeters) in diameter at breast height (d.b.h.) or larger, that is unmerchantable for sawlogs now or prospectively because of rot, roughness, or species. (See definitions for rotten and rough trees.) 
 
Diameter class--A classification of trees based on diameter outside bark measured at breast height (4-1/2 feet or 1.37 meters above ground). D.b.h. is the common abbreviation for "diameter at breast height."  With 2-inch diameter classes, the 6-inch class, for example, includes trees 5.0 through 6.9 inches d.b.h. (12.7 through 17.5 centimeters).

Federal--An ownership class of public lands owned by the U.S. Government. 

Forest industry--An ownership class of private lands owned by companies or individuals operating wood-using plants. 

Forest land--Land at least 10 percent stocked by forest trees of any size, including land that formerly had such tree cover and that will be naturally or artificially regenerated. Forest land includes transition zones, such as areas between heavily forested and nonforested lands that are at least 10 percent stocked with forest trees and forest areas adjacent to urban and built-up lands. Also included are pinyon-juniper and chaparral areas in the West and afforested areas. The minimum area for classification of forest land is 1 acre. Roadside, streamside, and shelterbelt strips of timber must have a crown width at least 120 feet (30 meters) to qualify as forest land. Unimproved roads and trails, streams, and clearings in forest areas are classified as forest if less than 120 feet wide. 
 
Forest type--A classification of forest land based on the species presently forming a plurality of the live-tree stocking. 
 
Major eastern forest type groups: 
White-red-jack pine--Forests in which eastern white pine, red pine, or jack pine, singly or in combination, comprise a plurality of the stocking. Common associates include hemlock, aspen, birch, and maple. 
 
Spruce-fir--Forests in which spruce or true firs, singly or in combination, comprise a plurality of the stocking. Common associates include white cedar, tamarack, maple, birch, and hemlock.

Longleaf-slash pine--Forests in which longleaf or slash pine, singly or in combination, comprise a plurality of the stocking. Common associates include other southern pines, oak, and gum.
 
Loblolly-shortleaf pine--Forests in which loblolly pine, shortleaf pine, or southern yellow pines, except longleaf or slash pine, singly or in combination, comprise a plurality of the stocking. Common associates include oak, hickory, and gum.
 
Oak-pine--Forests in which hardwoods (usually upland oaks) comprise a plurality of the stocking, but in which pine or eastern redcedar comprises 25-50 percent of the stocking. Common associates include gum, hickory, and yellow-poplar.
 
Oak-hickory--Forests in which upland oaks or hickory, singly or in combination, comprise a plurality of the stocking except where pines comprise 25-50 percent, in which case the stand is classified as oak-pine. Common associates include yellow-poplar, elm, maple, and black walnut. 
 
Oak-gum-cypress--Bottomland forests in which tupelo, blackgum, sweetgum, oaks, or southern cypress, singly or in combination, comprise a plurality of the stocking except where pines comprise 25-50 percent, in which case the stand is classified as oak-pine. Common associates include cottonwood, willow, ash, elm, hackberry, and maple.
 
Elm-ash-cottonwood--Forests in which elm, ash, or cottonwood, singly or in combination, comprise a plurality of the stocking. Common associates include willow, sycamore, beech, and maple.
 
Maple-beech-birch--Forests in which maple, beech, or yellow birch, singly or in combination, comprise a plurality of the stocking. Common associates include hemlock, elm, basswood, and white pine.
 
Aspen-birch--Forests in which aspen, balsam poplar, paper birch, or gray birch, singly or in combination, comprise a plurality of the stocking. Common associates include maple and balsam fir.
 
Major western forest type groups: 
Douglas-fir--Forests in which Douglas-fir comprises a plurality of the stocking. Common associates include western hemlock, western redcedar, the true firs, redwood, ponderosa pine, and larch.
 
Hemlock-Sitka spruce--Forests in which western hemlock and/or Sitka spruce  comprise a plurality of the stocking. Common associates include Douglas-fir, silver fir, and western redcedar.
 
Redwood--Forests in which redwood comprises a plurality of the stocking. Common associates include Douglas-fir, grand fir, and tanoak.

Ponderosa pine--Forests in which ponderosa pine comprises a plurality of the stocking. Common associates include Jeffrey pine, sugar pine, limber pine, Arizona pine, Apache pine, Chihuahua pine, Douglas-fir, incense-cedar, and white fir.
 
Western white pine--Forests in which western white pine comprises a plurality of the stocking. Common associates include western redcedar, larch, white fir, Douglas-fir, lodgepole pine, and Engelmann spruce.
 
Lodgepole pine--Forests in which lodgepole pine comprises a plurality of the stocking. Common associates include alpine fir, western white pine, Engelmann spruce, aspen, and larch.
 
Larch--Forests in which western larch comprises a plurality of the stocking. Common associates include Douglas-fir, grand fir, western redcedar, and western white pine.
 
Fir-spruce--Forests in which true firs, Engelmann spruce, or Colorado blue spruce, singly or in combination, comprise a plurality of the stocking. Common associates include mountain hemlock and lodgepole pine.
 
Western hardwoods--Forests in which aspen, red alder, or other western hardwoods, singly or in combination, comprise a plurality of the stocking. 

Chaparral--Forests of heavily branched, dwarfed trees or shrubs, usually evergreen, the crown canopy of which at maturity covers more than 50 percent of the ground and whose primary value is watershed protection. The more common chaparral constituents are species of Quercus, Cercocarpus, Garrya, Ceanothus, Arctostaphylos, and Adenostoma. Types dominated by such shrubs as Artemisia, Chrysothamnus, Purshia, Gutierrezia, or semidesert species are not commonly considered chaparral.
 
Pinyon-juniper--Forests in which pinyon or juniper, or both, comprise a plurality of the stocking. 

Other softwoods--Forests in which other softwood species not mentioned above comprise a plurality of the stocking. These are primarily black spruce forests in interior Alaska.

Fuelwood--Wood used for conversion to some form of energy, primarily residential use. 
 
Growing stock--A classification of timber inventory that includes live trees of commercial species meeting specified standards of quality or vigor. Cull trees are excluded. When associated with volume, includes only trees 5.0 inches (12.7 cm) d.b.h. and larger. 
 
Hardwood--A dicotyledonous tree, usually broad-leaved and deciduous. 

Industrial wood--All commercial roundwood products except fuelwood. 
 
Land area--The area of dry land and land temporarily or partly covered by water, such as marshes, swamps, and river food plains; streams, sloughs, estuaries, and canals less than 200 feet (60 meters) wide; and lakes, reservoirs, and ponds less than 4.5 acres (1.8 hectares) in area. 
 
Live cull--A classification that includes live, cull trees. When associated with volume, it is the net volume in live, cull trees that are 5.0 inches (12.7cm) d.b.h. and larger. 
 
Logging residues--The unused portions of growing-stock trees cut or killed by logging and left in the woods. 
 
National Forest--An ownership class of Federal lands, designated by Executive Order or statute as National Forests or purchase units, and other lands under the administration of the Forest Service including experimental areas and Bankhead-Jones Title III lands. 
 
Net annual growth--The average annual net increase in the volume of trees during the period between inventories. Components include the increment in net volume of trees at the beginning of the specific year surviving to its end, plus the net volume of trees reaching the minimum size class during the year, minus the volume of trees that died during the year, and minus the net volume of trees that became cull trees during the year. 
 
Net volume in cubic feet--The gross volume in cubic feet less deductions for rot, roughness, and poor form. Volume is computed for the central stem from a 1-foot stump to a minimum 4.0-inch (10cm) top diameter outside bark, or to the point where the central stem breaks into limbs. 
 
Noncommercial species--Tree species of typically small size, poor form, or inferior quality, which normally do not develop into trees suitable for industrial wood products. 
 
Nonforest land--Land that has never supported forests and lands formerly forested where use of timber management is precluded by development for other uses. (Note: Includes area used for crops, improved pasture, residential areas, city parks, improved roads of any width and adjoining clearings, powerline clearings of any width, and 1- to 4.5-acre areas of water classified by the Bureau of the Census as land. If intermingled in forest areas, unimproved roads and nonforest strips must be more than 120 feet (30m) wide, and clearings, etc., more than 1 acre (0.4 ha), to qualify as nonforest land.) 

Nonindustrial private--An ownership class of private lands where the owner does not operate commercial wood-using plants.
 
Nonstocked areas--Timberland less than 10 percent stocked with all live trees. 
 
Other Federal--An ownership class of Federal lands other than those administered by the Forest Service or the Bureau of Land Management. 
 
Other forest land--Forest land other than timberland and productive reserved forest land. It includes available and reserved forest land, which is incapable of producing annually 20 cubic feet per acre of industrial wood under natural conditions because of adverse site conditions such as sterile soils, dry climate, poor drainage, high elevation, steepness, or rockiness. Urban forest land is also included. 
 
Other land--Nonforest land less the area in streams, sloughs, estuaries, and canals between 120 and 200 wide feet and lakes, reservoirs, and ponds between 1 and 4.5 acres in area. 
 
Other private--An ownership class of private lands that are not owned by forest industry or farmers. 
 
Other products--A miscellaneous category of roundwood products that includes such items as cooperage, pilings, poles, posts, shakes, shingles, board mills, charcoal, and export logs. 
 
Other public--An ownership class that includes all public lands except National Forest. 

Other red oaks--A group of species in the genus Quercus that includes scarlet oak, northern-pin oak, southern red oak, bear oak, shingle oak, laurel oak, blackjack oak, water oak, pin oak, willow oak, and black oak. 
 
Other removals--Unutilized wood volume from cut or otherwise killed growing stock, from cultural operations such as precommercial thinnings, or from timberland clearing. Does not include volume removed from inventory through reclassification of timberland to productive reserved forest land. 
 
Other sources--Sources of roundwood products that are non-growing stock. These include salvable dead trees, rough and rotten trees, trees of noncommercial species, trees less than 5.0 inches d.b.h., tops, and roundwood harvested from nonforest land (for example, fence rows). 
 
Other white oaks--A group of species in the genus Quercus that includes overcup oak, chestnut oak, and post oak. 
 
Ownership--The property owned by one ownership unit, including all parcels of land in the United States. 
 
Planted forest- Planted forests are areas deemed to be forest by RPA definition and comprised of at least 40 percent of its composition in planted trees of either native or exotic species. Planted forests may be divided into two groups:
Plantations- Forest stands consisting almost exclusively of planted trees, of native or exotic species, and intensively managed to maintain this composition to maturity. Management practices may include extensive site preparation prior to planting and suppression of competing vegetation.

Augmented forest- Forest stands consisting of at least 40 percent planted trees, of native or exotic species, but not intensively managed to assure dominance of these trees in the stand at maturity. Management practices may include suppression of competing vegetation at the time of planting.

Poletimber trees--Live trees at least 5.0 inches (12.7cm) in d.b.h., but smaller than sawtimber trees.

Primary wood-using mill-- A mill that converts roundwood products into other wood products. Common examples are sawmills that convert sawlogs into lumber and pulpmills that convert pulpwood into wood pulp. 
 
Productivity class--A classification of forest land in terms of potential annual cubic-foot volume growth per acre at culmination of mean annual increment in fully stocked natural stands. 
 
Pulpwood--Roundwood, whole-tree chips, or wood residues that are used for the production of wood pulp. 

Reserved forest land--Forest land withdrawn from timber utilization through statute, administrative regulation, or designation. 

Removals (annual)--The net volume of growing stock trees removed from the inventory during a specified year by harvesting, cultural operations such as timber stand improvement, or land clearing.
 
Residues-- Bark and woody materials that are generated in primary wood-using mills when roundwood products are converted to other products. Examples are slabs, edgings, trimmings, miscuts, sawdust, shavings, veneer cores and clippings, and pulp screenings. Includes bark residues and wood residues (both coarse and fine materials) but excludes logging residues. 
 
Rotten tree--A live tree of commercial species that does not contain a saw log now or prospectively primarily because of rot (that is, when rot accounts for more than 50 percent of the total cull volume). 
 
Rough tree--(a) A live tree of commercial species that does not contain a saw log now or prospectively primarily because of roughness (that is, when sound cull due to such factors as poor form, splits, or cracks accounts for more than 50 percent of the total cull volume) or (b) a live tree of noncommercial species. 
 
Roundwood products-- Logs, bolts, and other round timber generated from harvesting trees for industrial or consumer use. 
 
Salvable dead tree--A downed or standing dead tree that is considered currently or potentially merchantable by regional standards. 

Saplings--Live trees 1.0 inch through 4.9 inches (2.5 through 12.6cm) d.b.h.

Saw log--A log meeting minimum standards of diameter, length, and defect, including logs at least 8 feet (2.4m) long, sound and straight, and with a minimum diameter inside bark of 6 inches (15.2cm) for softwoods and 8 inches (20.3cm) for hardwoods, or meeting other combinations of size and defect specified by regional standards. 

Sawtimber--A classification of timber inventory that is composed of sawtimber trees of commercial species.

Sawtimber trees--Live trees containing at least one 12-foot saw log or two noncontiguous 8-foot (2.4m) logs, and meeting regional specifications for freedom from defect. Softwood trees must be at least 9.0 (22.9cm) inches  d.b.h., and hardwood trees must be at least 11.0 inches (27.9cm) d.b.h. 

Seedlings--Live trees less than 1.0-inch (2.5cm) d.b.h. and at least 1 foot (0.3m) in height.

Select red oaks--A group of species in the genus Quercus that includes cherrybark oak, northern red oak, and Shumard oak.
 
Select white oaks--A group of species in the genus Quercus that includes white oak, swamp white oak, bur oak, swamp chestnut oak, and chinkapin oak.
 
Softwood--  A coniferous tree, usually evergreen, having needles or scale-like leaves. 
 
Sound dead--The net volume in salvable dead trees. 
 
Stand size class--A classification of forest land based on the size class of all live trees in the area. The classes include:

Nonstocked stands--Forest land that is stocked with less than 10 percent of full stocking with all live trees. Examples are recently cut-over areas or reverting agricultural fields.

Seedling-sapling stands--Forest land that is stocked with at least 10 percent of full stocking with all live trees with half or more of such stocking in seedlings or saplings or both.

Poletimber stands--Forest land that is stocked with at least 10 percent of full stocking with all live trees with half or more of such stocking in poletimber or sawtimber trees or both, and in which the stocking of poletimber exceeds that of sawtimber.

Sawtimber stands--Forest land that is stocked with at least 10 percent of full stocking with all live trees with half or more of such stocking in poletimber or sawtimber trees or both, and in which the stocking of sawtimber is at least equal to that of poletimber.

State--An ownership class of public lands owned by States or lands leased by States for more than 50 years. 
 
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 producing or is capable of producing crops of industrial wood and not withdrawn from timber utilization by statute or administrative regulation. (Note: Areas qualifying as timberland are capable of producing in excess of 20 cubic feet (1.4m3) per acre per year of industrial wood in natural stands. Currently inaccessible and inoperable areas are included.)  

Unreserved forest land--Forest land that is not withdrawn from harvest by statute or administrative regulation. 

Veneer log--A roundwood product from which veneer is sliced or sawn and that usually meets certain standards of minimum diameter and length and maximum defect. 
 
Metric equivalents for various units of measure

1 acre = 0.404686 hectares
1,000 acres = 404.686 hectares
1 board foot = 0.00348 cubic meters
1,000 board feet = 3.48 cubic meters
1 cubic foot = 0.028317 cubic meters
1,000 cubic feet = 28.317 cubic meters
1 inch = 2.54 centimeters or 0.0254 meters
1 foot = 30.48 centimeters or 0.3048 meters
1 mile - 1.609 kilometers
1 square foot = 0.0929 square meters
1 square foot per acre basal area = 0.229568 square meters per hectare
1 ton = 0.90718 metric tons
Breast height = 1.37 meters above ground level

Although 1,000 board feet is theoretically equivalent to 2.36 cubic meters, this is true only when a board foot is actually a piece of wood with a volume 1/12 of cubic foot. The International 1/4-inch log rule is used by the Forest Service to estimate the product potential in board feet. The reliability of the estimate obtained by conversion will vary with the size of the log measured. The conversion given here, 3.48 cubic meters, is based on the cubic volume of a log 16 feet long and 15 inches in diameter inside bark (d.i.b.) at the small end. This conversion could be used for average comparisons when accuracy of 10 percent is acceptable. Because the board foot unit is not a true measure of wood volume and because products other than dimension lumber are becoming important, this unit may eventually be phased out and replaced by the cubic meter.

HISTORIC REFERENCES

  Reference
      Year					Document
	
1630, 1907	The Timber Supply of the United States. Forest Resource Circular No. 166. Washington, DC: U.S. Department of Agriculture; Forest Service; 1909. 24p. (R.S. Kellogg)

1938	Forest Lands of the United States, Report of the Joint Committee on Forestry. 77th Congress, 1st Session, Document No. 32 presented to Congress March 1941. Clapp Report.

1953	Timber resource for America's future. Forest Resource Report No. 14. Washington, DC:  U.S. Department of Agriculture; Forest Service; 1958. 713p.

1963	Timber trends in the United States. Forest Resource Report No. 17. Washington, DC:  U.S. Department of Agriculture; Forest Service; 1965. 235p.

1970	The outlook for timber in the United States. Forest Resource Report No. 20. Washington, DC:  U.S. Department of Agriculture; Forest Service; 1973. 367p.

1977	An analysis of the timber situation in the United States 1952-2030. Forest Resource Report No. 23. Washington, DC:  U.S. Department of Agriculture; Forest Service; 1982. 499p.

1987	Forest Statistics of the United States, 1987. Resource Bulletin PNW-RB-168. Portland, OR:  U.S. Department of Agriculture; Forest Service; 1989. 106p. [Waddell, Karen L.; Oswald, Daniel D.; and Powell, Douglas S. ]

1992	Forest Resources of the United States, 1992. Gen. Tech Rep. RM-234. Ft. Collins, CO:  U.S. Department of Agriculture; Forest Service; 1993  142p. [Faulkner, Joanne L.; Powell, Douglas S.; Zhu, Zhiliang; and MacCleery, Douglas W. ]

LIST OF STANDARD 1997 RPA TABLES

Tables

Table 1.	Land and water areas in the United States by major class, region, subregion, and state, 1997.
Table 2.	Forest land area in the United States by ownership, region, subregion, and State, 1997.
Table 3.	Forest land area in the United States by productivity class, region, subregion, and State, 1997.
Table 4.	Forest land area in the United States by average d.b.h. class and forest type group, 1997.
Table 5.	Forest area in the United States by region, subregion and State, for 1997, 1987, 1977, 1963, 1953, 
             	1938, 1907, and 1630.
Table 6. 	Area of planted and natural forest land in the Eastern and Western United States by forest type 
	group and major ownership group, 1997.
Table 7.	Forest land area in the eastern and western United States by rural-urban continuum class and forest 
	Type group, 1997.
Table 8. 	Forest land area in the Eastern United States by forest type group, region, subregion, productivity 
 	class, and ownership group, 1997.
Table 9.	Forest land area in the Western United States by forest type group, region, subregion, productivity 
 	class, and ownership group, 1997.
Table 10.	Timberland area in the United States by ownership, region, subregion, and State, for 1997, 1987, 1977, 1963, and 1953.
Table 11.	Timberland area in the United States by ownership group, region, subregion, and State, 1997.
Table 12.	Timberland area in the United States by forest type group, subregion, and stand size class, 1997.
Table 13.	Timberland area in the United States by major geographic region and forest type, 1997, 1987 ,1977, 1963, and 1953.
Table 14.	Timberland area in the Eastern United States by forest type group, subregion, and stand-age class, 1997.
Table 15.	Timberland area in the Western United States by forest type group, subregion, and stand-age class, 1997.
Table 16.	Timberland area in the United States by stand-size class, region, and subregion, 1997, 1987, 1977, 1963, 1953. 
Table 17.	Net volume of timber on timberland in the United States by class of timber, species group, region, subregion, and State, 1997.
Table 18.	Net volume of softwood growing stock on timberland in the United States by ownership group, region, subregion, and State, for 1997, 1987, 1977, 1963, and 1953.
Table 19.	Net volume of hardwood growing stock on timberland in the United States by ownership group, region, subregion, and State, for 1997, 1987, 1977, 1963, and 1953.
Table 20.	Net volume of all growing stock on timberland in the United States by ownership group, region, subregion, and State, for 1997, 1987, 1977, 1963, and 1953.
Table 21.	Net volume of softwood growing stock on timberland in the Eastern United States by species, subregion, and State, 1997.
Table 22.	Net volume of hardwood growing stock on timberland in the Eastern United States by species, subregion, and State, 1997.
Table 23.	Net volume of growing stock on timberland in the Western United States by species, subregion, and State, 1997.
Table 24.	Net volume of softwood growing stock on timberland in the United States by diameter class, region, and subregion, for 1997, 1987, 1977, 1963, and 1953.
Table 25.	Net volume of hardwood growing stock on timberland in the United States by diameter class, region, and subregion, for 1997, 1987, 1977, 1963, and 1953.
Table 26.	Net volume of growing stock on timberland in the United States by diameter class, region, and  subregion, for 1997, 1987, 1977, 1963, and 1953.
Table 27.	Net volume of softwood growing stock on timberland in the Eastern United States by species, subregion, and diameter class, 1997.
Table 28.	Net volume of hardwood growing stock on timberland in the Eastern United States by species, subregion, and diameter class, 1997.
Table 29.	Net volume of growing stock on timberland in the Western United States by species, subregion, and diameter class, 1997. 
Table 30.	Net volume of all growing stock on timberland in the Eastern United States by species, and subregion, 1997, 1987, 1977, and 1963. 
Table 31.	Net volume of growing stock on  timberland in the Western United States by species, and subregion, 1997, 1987, 1977, and 1963. 
Table 32.	Net volume of growing stock on planted and natural timberland in the Eastern and Western United States by forest type group and major ownership group, 1997.
Table 33.	Net all live biomass on timberland in the Eastern and Western United States by forest type group and urban rural continuum category, 1997.
Table 34.	Net all live biomass on timberland in the United States by tree component, region, subregion, and State, 1997. 
Table 35.	Annual mortality of growing stock on timberland in the United States by ownership group, region, subregion, and species group, 1996, 1986, 1976, 1962, and 1952.
Table 36.	Net annual growth of growing stock on timberland in the United States by ownership group, region, subregion, and species group, for 1996, 1986, 1976, 1962, and 1952.
Table 37.	Annual removals of growing stock on timberland in the United States by ownership group, region, subregion, and species group, for 1996, 1986, and 1976.
Table 38.	Net annual growth, removals, and mortality of growing stock on timberland in the United States by species group, region, subregion, and State, 1996.
Table 39.	Volume of roundwood products harvested in the United States by source of material, species group, region, subregion, and product, 1996.
Table 40.	Roundwood products, logging residues, and other removals from growing stock and other sources by species group, region, and subregion, 1996.
Table 41.	Weight of bark and wood residue from primary wood-using mills by type of material, species group, region, subregion, and type of use, 1996.

Board foot tables 

Table b1.	Net volume of softwood sawtimber on timberland in the United States by ownership group, region, subregion, and State, for 1997, 1987, 1977, 1963, and 1953.
Table b2.	Net volume of hardwood sawtimber on timberland in the United States by ownership group, region, subregion, and State, for 1997, 1987, 1977, 1963, and 1953.
Table b3.	Net volume of softwood sawtimber on timberland in the Eastern United States by species, subregion, and State, 1997.
Table b4.	Net volume of hardwood sawtimber on timberland in the Eastern United States by species, subregion, and State, 1997.
Table b5.	Net volume of sawtimber on timberland in the Western United States by species, subregion, and State, 1997.
Table b6.	Net volume of softwood sawtimber on timberland in the United States by diameter class, region, and subregion, for 1997, 1987, 1977, 1963, and 1953.
Table b7.	Net volume of hardwood sawtimber on timberland in the United States by diameter class, region, and subregion, for 1997, 1987, 1977, 1963, and 1953.
Table b8.	Net volume of softwood sawtimber on timberland in the Eastern United States by species, subregion, and diameter class, 1997.
Table b9.	Net volume of hardwood sawtimber on timberland in the Eastern United States by species, subregion, and diameter class, 1997.
Table b10.	Net volume of sawtimber on timberland in the Western United States by species, subregion, and 
	diameter class, 1997.