R. C. WILSON
Chief, Forest Survey Branch, and
GEORGE VITAS
Forestry Information Specialist, Forest Service, United States Department of Agriculture
THE United States is fortunate in having supplies of timber sufficient to support large and diverse forest industries. Timber products in the United States comprise about one fourth of all raw materials used for manufacturing and for construction. Nearly 80 cubic feet of wood products, or more than 2 cubic meters, is used by the average American each year.
America's rapidly expanding population - which is likely to double before the end of the century - is making increasing claims on its forest, not only for greater wood production but also for nontimber uses of the forest such as recreation and water. Moreover, substantial withdrawals of timber land for such purposes as highways, reservoirs and agriculture are in prospect. Thus American foresters face a real challenge in continuing to supply in the years ahead enough wood of the right quality at reasonable prices and enough other forest services to meet potential demands much larger than those of today.
For a closer look at the timber situation in the nation that is host to this year's World Forestry Congress, attention should be directed to some of the details revealed by a recent appraisal of America's timberlands (1) and the latest results of the comprehensive forest survey conducted by the United States Forest Service in co-operation with state agencies an forest industries.
The United States of America has eight percent of the forested area of the world - some 770 million acres (312 million hectares). Fourteen percent of the world's growing stock (including 18 percent of the softwood growing stock) is in the United States. This country cuts about one fifth of the timber removed from the world's forests. Although some forest products are exported, most of this cut is for domestic consumption. The United States also imports more forest products than she exports. Imports are primarily softwood lumber, newsprint paper, wood pulp and pulpwood (2).
One third of the United States is forest land. The forests are extremely variable in character, since more than 800 native tree species (and a number of exotics) occur within the country. These grow under a wide range of conditions.
Northern and southern limits of forests: from stunted spruce to lush hardwoods
At America's northern limits of forest in the State of Alaska most of the trees are stunted white and black spruces (Picea glauca and P. mariana), paper birch (Betula papyrifera) and willows (Salix spp.) growing on permafrost. In contrast, trees near the southern limits of forest are baldcypress (Taxodium distichum) and various subtropical hardwoods forming a luxuriant canopy over the swamps in the states of Louisiana, Mississippi and Florida.
Western and eastern limits: from tropical hardwood to temperate pines
The western limits of America's forest in the island State of Hawaii, where koa (Acacia koa), ohia (Metrosideras polymorpha) and other tropical hardwoods cling to the lava, contrast with the eastern limits where clumps of pitch pine (Pinus rigida) accent the low sand dunes of the Atlantic Ocean shoreline.
Contrasts in adjacent forests
Hardly less striking are contrasts in forest types growing in much closer proximity. In the State of California, for example, dense and towering stands of redwood (Sequoia sempervirens), with per acre timber volumes greater than those of any other forest in the world, blanket the moist seaward slopes of a mountain range. In contrast, scrubby stands of chaparral (including species of Ceanothus, Cercocarpus and Arctostaphylos), valuable mainly as protective forest for the watershed, shield the sunbaked interior slopes of the same mountains.
The State of Montana, sitting astride the continental divide of the Rocky Mountains, offers another contrasting example. West of the divide are extensive reaches of pure conifers - pine, spruce, fir and larch -characteristic of the western mountain states. But immediately east of the divide - where the plains begin that stretch across mid-continent to the Appalachian mountains - are only patches of forest. These are mainly cottonwoods (Populus spp.) and other native hardwoods strung out along the water courses.
Two thirds of the forest, or 530 million acres (215 million hectares), is commercial timberland; that is, it will produce, or is physically capable of producing, industrial wood and is not reserved from cutting. The other 240 million acres (97 million hectares) are classed as noncommercial forests, either because they are too unproductive to manage for wood production or because they are reserved in the public interest for recreation, watershed protection or other paramount values. The national parks are examples of such reservations.
Timberlands mainly near the coast
Most of the timberlands are in coastal states, although every one of the 50 states in the Union has at least small acreages of commercial forest (Figure 1). One fifth of the commercial area lies within the four Pacific Coast states of Alaska, Washington, Oregon and California. Douglas fir (Pseudotsuga menziesii), ponderosa pine (Pinus ponderosa) and several species of spruce (Picea) and hemlock (Tsuga) are the most valuable components of the timberlands in those states. Another fifth of the commercial timberland is within the five southern states of Louisiana, Mississippi, Alabama, Georgia and Florida. Several species of pines - Loblolly pine (Pinus taeda), Longleaf pine (P. palustris), Slash pine (P. caribaea), Shortleaf pine (P. echinata) - and intermingled hardwoods are important components of the forests in the South.
The commercial area supports about 550,000 million cubic feet (15,600 million cubic meters) of growing stock, in trees which are 5 inches (12.7 centimeters) or larger in diameter and meet merchantability specifications for wood products. Two thirds of the growing stock volume is in softwoods, primarily Douglas fir, pines, spruces, firs, and hemlocks. Most of the volume of hardwood growing stock is in oaks, mainly white and red oaks (Quercus alba, Q. prinis, Q. borealis, Q. falcata var. pagodaefolia and Q. shumardii). Nearly half of the nation's growing stock, or 260,000 million cubic feet (7.4 billion cubic meters) is in the four Pacific Coast states. About one third of this is one species, Douglas fir.
Nearly 10,000 million cubic meters of sawtimber
A supply of more than 2,000,000 million board feet of live sawtimber1 (nearly 10,000 million cubic meters of roundwood) is standing in America's forests. Three quarters of this supply is softwood, of which Douglas-fir sawtimber constitutes approximately one quarter of the total. The largest concentration of this sawtimber volume is in the old-growth stand of the State of Oregon (Figure 2).
1
Not volume of live sawtimber in board feet, International ¼-inch rule, in live trees of commercial species, containing at least one merchantable saw log with the following minimum diameters at breast height: eastern softwoods, 9 inches (22.9 centimeters); western softwoods and all hardwoods, 11 inches (27.9 centimeters).
Mostly private holdings
Nearly 70 percent of the commercial timberland area is in private ownership (Figure 3). Farm holdings represent the largest class of owners, controlling approximately 31 percent of the timberland (Figure 4). Twenty-five percent is held by a variety of miscellaneous private owners - businessmen, professional people and housewives, for example - who are not directly associated with either agriculture or forest industries. There are four and a half million individual ownerships in these two classes. More than three million of these are farm holdings. There are also about 23,000 industrial owners (those engaged in the manufacture of lumber, pulp or other wood products) who hold 12 percent of the commercial forest area.
FIGURE 3. - Chart to represent the division of ownership of commercial forests in the United States.
Small forests, of less than 100 acres (approximately 40 hectares) each, comprise 86 percent of the total number of private ownerships (3).
National government controls most of public timberlands
Most of the 32 percent of commercial forest lands in public ownerships are administered by the national government, primarily through the United States Forest Service and the United States Bureau of Land Management. About four percent is administered by state agencies and two percent by counties, cities or other local governments.
In the eastern states, over four fifths of the timberland is privately owned. In the western states, however, more than two thirds is in public ownership and most of this is within the national forests administered by the United States Forest Service.
Two thirds of the 240 million acres (97 million hectares) of noncommercial forests are in public ownership. These, also, are mainly in western states.
Fifty-five percent of the volume of growing stock and half the volume of sawtimber is in private ownership. In the eastern states, about 90 percent of the timber volume (both growing stock and sawtimber) is on private land; in western states, by contrast, only 40 percent of the timber volume is in private ownership. More than 90 percent of the growing stock on western public lands is on national forest or other areas managed by the national government.
Private holdings contain most (nine tenths) of the hardwood sawtimber but public holdings embrace most (55 percent) of the softwood sawtimber in the nation.
Most of the forests in the United States are accessible and the moat accessible timber is largely on private holdings. Due to the character of the land, the economy of the eastern states is more developed than in the west and forests are generally more accessible. In parts of western states, accessibility is still a serious problem, mainly on public lands in mountainous areas. An expanding program of road building, however, promises to insure reasonably good access to the old growth timber on such areas within the near future. The virgin, remote timberlands of interior Alaska, estimated to contain 32 billion cubic feet (nearly a billion cubic meters) of growing stock, are today the only truly frontier forests in the United States.
One quarter of timberland inadequately stocked
Nearly half of the commercial forest land is well-stocked (70 percent or more) with trees presently or potentially suitable for merchantable wood products. One tenth of the commercial area is nonstocked or is less than 10 percent stocked. However, nonstocked areas, together with areas only poorly stocked (10 to 40 percent), comprise about one quarter of the commercial acreage, and offer some of the best possibilities for increasing the timber supply. Much of this acreage of inadequate stocking is the result of heavy cutting and forest fires in past decades.
Some timberlands are restocking naturally and satisfactorily under protection from fires and other hazards. But planting or Seeding is needed on approximately 50 million acres (20 million hectares) if these areas are to be restored to productivity within a reasonable time. Nearly 85 percent of this plantable area is in eastern states and about the same percent of the total is in private ownership.
Appraisal of recent cuttings
Since the condition of a forest after logging greatly influences growth, the results of an appraisal of the productivity of recently cut lands is of interest, particularly since in the United States between 10 and 20 million acres (4 and 8 million hectares) of forest are cut over each year. This appraisal of lands logged within a recent five-year period considered the following four significant factors to determine a productivity index:
1. present stocking;
2. prospects for stocking where stocking was deficient;
3. species composition;
4. stand age at the time of felling. Results of the appraisal showed that within the gross forest area of current cutting operations about two thirds of the acreage of recent cuttings was in the upper productivity class (index of 70 to 100), 24 percent in the medium class (index of 40 to 69), and 11 percent in the lower class (index of 0 to 39).
Industrial and public holdings in best growing condition
The recent cuttings on private lands managed by forest industries and those on public lands are in much better condition than those on farm and other private holdings. On forest industry and public lands about four fifths of the recently logged areas are in the upper productivity class; on other lands less than half are in that class. Regardless of ownership, large holdings are generally in better growing condition than small holdings. For example, on all large private ownerships over 50,000 acres (20,000 hectares) in size, nearly 80 percent qualify in the upper productivity class; on all small ownerships less than 5,000 acres (2,000 hectares) in size, only 40 percent qualify in the upper class.
Growing stock increasing: softwood sawtimber volume decreasing
For a proper evaluation of timber supplies a look at the trends in volume and growth is needed. The volume of hardwood growing stock in the United States has been increasing by about 2 percent a year, and that of hardwood sawtimber by about I percent annually. The volume of softwood growing stock is apparently being maintained. However, the volume of softwood sawtimber (from which the largest amounts of forest products are produced) has been decreasing at a rate of about ½ percent annually.
Current annual net growth of timber i.e., volume growth on growing stock trees after deductions for losses through mortality due to fires, insects, diseases and other causes, was about 14 billion cubic feet (nearly 400 million cubic meters) in 1952, a favorable 4 percent higher than it was about ten years before. In the same year, net annual growth of sawtimber was about 47 billion board feet (210 million cubic meters of roundwood), 9 percent higher than it was 10 years previously.
Forty percent of sawtimber growth in southern pines and Douglas fir
Most of the timber growth is in eastern states where the large majority of timber stands are relatively young, generally less than 50 years of age. Most of the stands in western states are much older, many are several hundred years of age. About 30 percent of the total sawtimber growth, and 25 percent of the growth in growing stock, is that of southern pines. Douglas fir, the most widely used wood in the country, also contributes a large amount of the growth. The annual growth of this species is now nearly 10 percent of the national total in sawtimber and more than 5 percent of the total in growing stock. Annual growth of Douglas fir and of other western species is expected to increase as more virgin forests in the west are converted to young, managed stands.
Quality of growth declining
Although details are lacking on quality of growth nationwide, some indications point to significant declines in supplies of high-value material. In the eastern states, for example, about 40 percent of the hardwood sawtimber volume and approximately 70 percent of the softwood volume is in trees no larger than 15 inches (about 38 centimeters) in diameter. Therefore, sawtimber growth in the eastern states is mainly on trees too small to yield high-quality lumber, veneer and other products for which there is a sustained demand. Also, a large proportion of the growth is on the less desirable species. Among the oaks, for example, which contribute three eighths of the hardwood growth, more than half of the growth is in species which are least valued by the market. Striking decreases are also occurring in the volume of such valuable trees as sugar maple (Acer saccharum) and yellow birch (Betula alleghaniensis).
Annual mortality at 100 million cubic meters
Three and a half billion cubic feet (100 million cubic meters) of growing stock were killed during 1952 in America's forests by such destroyers as insects, diseases and fires (Figure 5). Nearly 13 billion board feet (60 million cubic meters of roundwood) was sawtimber; only one quarter of this was salvaged for wood products. Two thirds of the growing stock losses and four fifths of the sawtimber losses were in softwoods.
Insects destroy most timber
In 1952, insects destroyed twice as much sawtimber as diseases, and they killed nearly seven times as much as fires (Figure 6). Losses from weather, animal damage and other causes were about one third of the total mortality of sawtimber.
One half of the average annual kill in growing stock and three quarters of the kill in sawtimber was in western states where overmature, and thus more susceptible, trees comprise large proportions of the stands.
Mortality by various causes continues to have a serious impact on the nation's growing stock, although the amount of mortality varies from year to year with fluctuations in weather, insect populations and incidence of disease.
Growth low is double that of mortality
Less spectacular than outright kill of trees above 5 inches in diameter, but nevertheless extremely serious, is the growth loss due to diseases, fires, and insects. Examples of such growth losses are those caused by delay in restocking, by changes in timber types, by defoliation, by reduction in tree vigor, by increase in decay or by reduction in soil productivity after a damaging attack. It is estimated that such losses in annual growth are now double those due to mortality, and that diseases account for nearly half this growth loss.
In effect, the net growth of America's forests could probably be boosted by 50 percent (and that of sawtimber could be doubled) if all the damage now caused by destructive agents could be eliminated.
In America, there are almost 6,000 uses for wood. About 50,000 plants are engaged in primary manufacture of forest products from roundwood in the United States.
Most of America's wood-using plants are sawmills
About 46,000 of these plants are sawmills which form parts of the lumber industry. They vary from small mills situated close to the forest, each employing only a few people (Figure 7), to huge plants with facilities for turning out finished, seasoned and graded lumber, The large plants are located mainly in cities or on main transport routes. Each may employ several hundred full-time workers and produce 100 million board feet or more of lumber annually. Sawmills are found in every state in the Union. Small sawmills are particularly numerous in the states along the eastern seaboard. Most of America's large mills are located in the Pacific Coast states of Washington, Oregon and California.
Pulp and paper industry growing
The pulp and paper industry has been growing faster than any other forest industry in the country. It is concentrated mainly in the southern and Pacific Coast states. A recent canvass indicated that 75 of approximately 300 pulp mills in the United States are situated in 12 southern and southeastern states2. These have a combined pulping capacity of more than 44,000 tons per day and represent over half the national pulping capacity. Most of these plants, in addition to turning out raw pulp, produce a variety of derived products including newsprint, other papers and paperboard (Figure 8).
2
States of Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia.
Many other forest industries
Other important industries are those processing roundwood into veneer (plywood), cooperage, piling, utility poles, railroad ties, mine timbers and chemical wood. Many other plants, such as those, producing furniture, are engaged in the secondary manufacture of forest products.
All together, it was estimated in 1952 that timber-connected activities (growing, protecting, harvesting, processing, transportation, distribution and fabrication of timber products) contributed nearly 15,000 million dollars to the national income or some 5 percent of the total.
About 11,000 million cubic feet (311 million cubic meters) of growing stock is harvested annually. More than 80 percent of the cut is from sawtimber-size trees. About three quarters of that is for saw logs and veneer logs and bolts. The other one quarter is harvested for pulpwood and other products. Three quarters of the sawtimber cut is from softwoods. In the western states, virtually all the cut is softwood; in the southern states, about three fifths is softwood; but, in the northeastern states, more hardwoods than softwoods are cut.
Sawtimber cut increasing in western states
The western states have recently been furnishing an increasing proportion of the national sawtimber cut. Last year, they furnished over half the volume of saw-logs and about two thirds of the softwood lumber produced in the country. In contrast, the sawtimber out of southern softwoods has been dropping. This trend is expected to be reversed as the high-volume old growth stands in the western states are cut over and the distribution of timber cut is more closely related to areas of forest and to growth capacities of the land. Since the demand by the market for softwoods is expected to increase, maintenance of the surplus growth of southern softwoods will be essential until these adjustments in the out of western softwoods can be completed.
About one quarter of the timber cut is not utilized. It is either lost as residues in logging or as unused plant residues. Losses from these sources are approximately equal. In 1952, about 1,400 million cubic feet (nearly 40 million cubic meters) of unused residues were estimated from each source. Utilization of timber cut varies significantly by kind of product produced. Only two thirds of the timber cut for lumber and 75 percent of the cut for veneer is used, but nearly all the cut for pulpwood is used.
Trend is to integrated industries for better utilization
In recent years utilization has been improving. More efficient logging and manufacturing equipment has been developed and widely adopted. Production of new wood products such as particle boards and greater use of by-product materials for pulp and paper have helped to reduce the amount of unused residues. The trend toward integrated industries - where a pulp mill, fibreboard plant or other facility for relatively complete wood utilization is located adjacent to a sawmill or veneer mill - is notable in increasing utilization in both woods and mill (Figure 9). Companies with integrated plants can better afford to bring in relatively low-value wood from the forest along with high-value material. By grading and sorting at the plants before manufacturing, all logs are sent first into a plant which demands the highest- quality material, for veneer or lumber. The residues from that operation are sent along with other lower quality wood for essentially complete manufacture into byproducts such as pulp, wood chemicals, or fibreboard.
Potential demand for wood products in the United States is expected to rise along with anticipated growth of population and economic activity. The United States Forest Service recently developed three projections of potential future timber demand, low, medium and high, based on specific assumptions of prices for wood products and increases in population and gross national product. The medium demand projection - the basic projection - indicates that by the end of the century demand for timber in the United States may be nearly twice as great as it was during mid-century (about 83 percent higher in the year 2000 than in 1952).
Greatest demand is for lumber and pulp
The two main product components of this estimated demand are lumber and pulpwood. Per caput consumption of lumber has been declining. Total consumption, however, has held up well in the past and future increases are anticipated, as much as 25 to 50 percent over that in 1952 by 1975. Per caput consumption of pulpwood has tripled in the last three decades and total consumption has increased about five times. Projected total demand for pulpwood to supply United States markets for paper and paperboard in 1975 indicates increases of at least 100 percent over 1952 and 50 percent over 1959. A large increase in the demand for ply-wood is also expected.
Consumption of fuelwood is dropping
Fuelwood is the only wood product for which a significant drop in demand is anticipated. This is a continuation of the downward trend of fuelwood consumption for several decades past. On the other hand, the demand for miscellaneous wood products is expected to hold its own or possibly increase.
In view of potential demand for wood, it is highly desirable that timber growth in the United States be considerably increased within the next half century.
The Forest Service has indicated a goal of raising the net annual growth of growing stock from 14,000 million cubic feet (nearly 400 million cubic meters) in 1952 to 22,000 million cubic feet (over 620 million cubic meters) in 2000. For sawtimber the goal is to increase the net from 47,000 million board feet (210 million cubic meters of roundwood) in 1952 to 105,000 million feet (nearly 470 million cubic meters of roundwood) in 2000.
Whether desired increases in growth can be obtained depend largely on the rate of progress in forest management and utilization practices. There are several indications of good recent progress in this field, including the relatively good productivity of recently logged lands on large industrial and public holdings referred to earlier.
Improved fire protection
Fire protection on timberlands is continually being improved and is now adequate to guard nearly 70 percent of the timberlands in normal fire seasons. Organized fire protection is increasing at a rate which is expected to reduce the average area burned annually to less than 9 million acres (3.6 million hectares) within a decade. This would be 2 million acres (some 800 thousand hectares) per year less than the area burned in the early 1950's and would be only one fifth of the average annual bum three decades ago.
Better control of insects and diseases
Detection and control of insects and diseases is now under way on an organized basis, encouraged by such actions as the passage of the National Forest Pest Control Act of 1947. Increased research in forest genetics also aims at developing strains of trees that will resist attacks by forest pests.
Big increases in plantations
Tree planting is also being stepped up remarkably (Figure 10). The rate of planting has increased more than five times within the past quarter century. About 1.5 million acres (over 600 thousand hectares) of land were planted to trees in 1958 and over 2 million acres (more than 800 thousand hectares) in 1959. Some of these plantations were on land diverted from farming as a conservation reserve under provisions of the National Agricultural Act of 1956 (Soil Bank). The latest nationwide appraisal, in 1952, showed more than 5 million acres (over 2 million hectares) of acceptable plantations in the country. About equal acreages were on private and public lands. Most of the acreage was in southern and northeastern states.
Seeding accelerated
Direct seeding of trees, where climate, soil and tree species are favorable, has been greatly encouraged by development of a chemical dip for coating the seeds with a repellent to prevent birds and rodents from eating them. Both aerial and hand methods were used for seeding 109,000 acres (44,000 hectares) in 1959, more than twenty times the acreage seeded annually only five years before.
Stand improvements
Stand improvements - by removing worthless or less desirable trees, by pruning desirable trees to improve their quality and by actions to encourage stand regeneration - are being used increasingly, particularly by forest managers of large industrial and public holdings (Figure 11). Timber stand improvement probably offers the greatest opportunity to secure added growth and quality.
Timber is reasonably abundant in the United States today. The annual growth of hardwood growing stock exceeds the annual cut by a wide margin while the growth and cut of softwood growing stock is nearly in balance. The growth of sawtimber nearly equals the annual cut; a surplus growth of hardwoods of approximately 7,000 million board feet (35 million cubic meters of roundwood) almost equals the deficit of approximately 9,000 million board feet (45 million cubic meters of roundwood) in softwoods. Although no timber famine is in prospect, shortages of some preferred species and quality timbers may be expected as old growth timber supplies of Douglas fir and other western species are reduced. These provide a large part of the cut of softwood sawtimber which comprises three quarters of the national sawtimber cut. The job ahead is to keep the growth of the kind of timber used in balance with the total annual harvest and, at the same time, build up the level of growing stock sufficiently so that it will be able to supply the needs of the future.
The increasing demand for woods products from the forests of the United States is expected to rise strikingly with growth of population, and the demand for wood by the year 2000 may well be double that of today. Unless the recent rate of progress in forest management, substantial though it is, can be greatly accelerated, the projected growth will be less than the projected demand. Within a few decades that increased demand could not be met without cutting deeply into forest capital.
American foresters, therefore, are faced with a great challenge: to take action during the next few years to insure an abundant continuing supply of wood on all timberlands, particularly on the small private woodlands held in about four and one half million different ownerships which must supply nearly half of the nation's timber needs in the future. The United States must look forward to intensified actions such as the following:
1. a mounting acceleration of tree planting - in terms of thousands of millions of trees per year - to insure restocking of idle and cutover timberlands;2. increased care in cutting of commercial products and supplementary stand improvement measures to improve the productivity of stands by encouraging growth and regeneration of the most desirable trees;
3. more intensive control of forest diseases, fire and
insects;4. more conversion into useful wood products of the timber cut now left as logging and mill residues.
These actions offer some of the most promising prospects for rapidly increasing the timber supply of the United States of America.
(1) UNITED STATES DEPARTMENT OF AGRICULTURE, FOREST SERVICE. Timber Resources for America's Future. Forest Resource Report No. 14, 713 pp., illus. (based on a nationwide appraisal made in 1952). 1958.
(2) FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS. World Forest Resources, Rome, Italy, pp. 1-120, illus.; 1957.
(3) FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS. "Improving Small Woodlands in the United States," UNASYLVA, Vol. 13, No. 2, 1959.
