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Forestry in the Northwestern United States of America

As Seen by a European Forester on the Staff of the Division of Forestry and Forest Products

ONE of the European members of the staff of the Division of Forestry and Forest Products of FAO has recently visited the forest regions of the northwestern part of the United States.1

1 The Forestry and Forest Products Division wishes to express its thanks, first to the Chief of the U. S. Forest Service, Mr. L. F. Watts, and to the Assistant Chief, Branch of Research, Mr. E. I. Kotok, whose courtesy made possible this trip under the most favorable circumstances; and further to the Chiefs of the Regional Offices and Experiment Stations who arranged the details of this trip, as well as to the many foresters who so courteously guided FAO's representative on his far-flung tour through the forests of Montana, Idaho, Oregon, Washington, and California.

As has been pointed out by the Chief of the United States Forest Service in the first issue of this magazine, these regions support the last virgin timber reserves of this country - reserves on which the United States may have to depend for the continuance of its lumber supply.

The problems which American foresters face are serious and numerous. Viewing these problems through the eyes of a European forester - in the light, of course, of his own experience as a European forester - may help in the evaluation of the situation and may provoke silviculturists to consider their problems from new angles. On the other hand, it should not be forgotten that the present article represents merely the impressions of one month's travel and consequently cannot be expected to exhaust the question or even to present all its aspects.

The following pages will endeavor to set forth the present situation in the forests and timber industries of these regions as well as to review the chief questions posed by these forests and the methods used by American foresters to find solutions.

Stand of Douglas fir, Pseudotsuga taxifolia, abundantly mixed with hemlocks, Tsuga heterophylla, and noble fir, Abies nobilis, in foreground. Oregon, U.S.A.

The first thing about American forests that impresses the European forester is their size. Since the very complete statistics of the United States Forest Service provide a wealth of data on this subject, it is unnecessary to give details here. But it should be borne in mind that until about a century ago all these forests were virgin forests. As can be seen from the extensive virgin forest areas owned and managed by the Federal Government, however, this kind of forest was not necessarily of climax type.

Fire has indeed been the determining influence on the formation of many stands. It is not correct to assume that man is entirely responsible for introducing this scourge. There was, it is true, deliberate burning down of forest to clear land for agriculture. But as soon as regions were settled, the fires caused by men could also be fought by men. Fires from natural causes have been of greater importance. During the two to four very dry months characteristic of summer in the whole northwestern region, fires begun by lightning could spread unchecked over wide areas because of the large amount of debris covering the ground in these unexploited stands. According to many American foresters, such fires determined, with very few exceptions, the character of virgin stands now surviving and of those which were still existing about a hundred years ago.

Fire has in fact produced its normal effect. The new growth is pure and even-aged over large areas, at least in the upper canopy, although in many places the climax forest gradually asserts itself under this canopy as long as fresh fires do not interfere with the process. Intolerant species, experiencing especially favorable conditions during their early stages of growth, have become dominant in the forest: white western pine, Pinus monticola Dougl., in the forests of western Montana and northern Idaho; Douglas fir, Pseudotsuga taxifolia Britt., in Washington and Oregon; ponderosa pine, Pinus ponderosa Laws., or Jeffrey pine, Pinus jeffreyi Grev. and Balf., in California.

This does not mean that these species, and especially ponderosa and Jeffrey pines, are not a part of the climax forest. On the contrary, these two are obviously the chief elements of the climax association over large areas. It seems certain, however, that fire, obviously in conjunction with climatic influences, has greatly modified the composition of the stands by age and diameter classes rather than by species.

These statements are not meant to imply that the northwestern forests are simple and uniform. On the contrary, they are very complex because the species of the climax forest immediately tend to reestablish themselves under the stands appearing after a fire or, as will be shown later, after an insect attack. The result is a great diversity, first in the species found, and second in their relative proportions. These variations are due not only to the wide range of climate and altitude occurring over such large areas, but also to the fact that in one location the stand may have currently reached a certain stage of its evolution that has not been reached in another, even nearby, location.

Silvicultural Consequences

This situation has had several consequences, some of silvicultural and others of economic significance. Since the stands are pure and even-aged and frequent cuttings are impossible, they have in many cases displayed a high susceptibility to disease and insect attacks. The western white pine, a five-needle pine, suffers from "blister-rust," Cronartium ribicola, and, recently, from a canker of unknown origin which spreads rapidly in pole stands. The Douglas fir often shows a troublesome susceptibility to attacks by fungus which cause rotting of the bole. The ponderosa pine and its associates are subject to attack by the western pine beetle, Dendroctonus brevicomis, which has become a very important factor in California silviculture, and by another coleopteron which attacks young plants and has in a few years assumed epidemic proportions.

Another feature, very important from the silvicultural point of view, is the lack of middle-aged stands of those species already mentioned, which, up to now, have been considered as the most valuable. In the virgin forests, fires may have occurred at relatively short intervals of time, but their extent and their effects on the different component parts of the stand probably varied greatly. Probably the trees that were mature enough to be protected by a sufficiently thick bark or that had a young stand of climax species less susceptible to fire established under them did not succumb. One cannot explain otherwise the scarcity of the middle-aged classes of these species, and the great size and age of the trees which are now the tourist attraction of the northwestern forests and are responsible for the commercial renown of the northwestern lumber industries. Many of these trees are 200 to 300 years old, and some are over 1,000 years old, as in the redwoods region, Sequoia sempervirens (D. Don) Endl.

White pines, Pinus monticola, in the virgin forest of Clearwater National Forest, Idaho, U.S.A.

Economic Consequences

The forest conditions found when exploitation began led to the organization, for economic reasons, of the forest industries of each region around one species alone. Up to the last war, the whole forest economy of northern Idaho and western Montana was centered around the western white pine, that of Oregon and Washington around the Douglas fir, that of northeastern California around the ponderosa pine, and that of the coastal region around the redwood. As the stands were composed of very large and relatively inaccessible trees, considerable investment was needed for exploitation so that large firms were in a favored position. Since the stands were also even-aged, clear-cutting methods were almost always used. The remaining trees, very rarely of species considered valuable, were damaged by logging and skidding operations or were unable to survive isolated. The meaning of sustained yield was unknown to the first loggers. Once the land was completely cut over, the sawmills closed down. Settlements which had grown up around big milling plants have frequently degenerated into ghost towns. The former community of Hobart Mills, California, for instance, stands in ruins today, nothing but a gasoline station at a crossroads.

Obviously these extensive clear-cuttings, begun around 1850, have contributed to the gravity of the silvicultural problem. The stands growing on the cut-over lands are still young and the supply of middle-aged trees is limited or nonexistent.

Forest ownership and the lumber industry

The United States Forest Service groups as "National Forests" large forest areas containing not only government-owned forests but also privately owned forests. Frequently the latter are relatively very large.

Large Private Forests and Big Business

The privately owned forests are usually the best and most easily accessible. They are generally big estates belonging to one of the big companies, which exploits them directly or sometimes sells the cutting rights to another company. These large areas contain a certain proportion of virgin forests but also a great deal of completely cut-over land, covered only with young trees. Often natural regeneration has had difficulty in establishing itself or has quite given up the struggle.

Although large enterprises are, generally speaking, none too thoughtful about the future of the forests, the picture traced above fortunately applies mainly to the early days of exploitation. At present, many private companies endeavor to manage their forests on a sustained-yield basis, or at least aim to achieve this result after a conversion period, the necessity of which will be shown later. They have a staff of foresters whose training is the same as that of the federal foresters and who are fully conversant with modern silvicultural methods. Their advice is followed and they usually work closely with the regional forest services and experiment stations. This is particularly the case when the forests are close to Government-owned ones and when supply for their mills is dependent not only on their own cuttings, but also on timber to be sold to them from the forests managed by the federal service.


But this is still not the whole picture. It is only too true that some companies are quite unconcerned about ensuring an even and sustained supply for their mills. Examples can be found everywhere. But it is particularly so in the redwood region, where the Forest Service has little or no opportunity for action since the forests are all privately owned except for a relatively small area very recently acquired by the Federal Forest Service. Though a slight improvement is becoming apparent, exploitation methods as a whole are still definitely destructive, and the future of the forests in this region appears very uncertain.

The big companies confine their activities mainly to the exploitation of the virgin stands. Their prime interest is in high-quality lumber from the very big trees of which the forests are chiefly composed, and their equipment is designed for handling such stock. While their methods of exploitation are sometimes very crude in that they leave the forest unproductive for many years and entail an enormous wastage in timber which might well be put to use, the subsequent processing of the material taken out of the forest is highly efficient. Besides sawmills of the most modern design, drying-kilns, and planing equipment, the plants of some of these big companies include also plywood manufacturing equipment to handle the highest quality logs, facilities for the manufacture of crates to use up the smallest sizes of lumber, plants for briquetting sawdust and for utilizing bark, and even, in the state of Washington, an important pulp mill.

Small Forest Properties

Besides the large forest holdings, there are also small forest estates which vary in importance in the different states. They comprise chiefly farm wood-lots, the average size of which is about 20 hectares (50 acres). These lands, rich and easily accessible, were among the first to be exploited, and now carry new stands, which American foresters call "second growth," that are generally very dense and of rapid growth. These stands are very far from having reached exploitable size, but they should be able, under wise management methods, to yield a return of some value from thinnings.

Small Enterprises

Alongside the big lumber concerns, there are also smaller sawmills. Their number, in fact, considerably increased during World War II. According to regional foresters, these small-scale industries do not have sufficient equipment and capital to cope with virgin forests; they must concentrate their operations on second growth, inducing smallholders to sell their timber before it has reached maturity and full value. During the war, the Forest Service sold stumpage to these small sawmills in order to step up production. Under these circumstances, logging standards were good but wastage during conversion was high. No use was made of the considerable quantity of waste material. Many of these small sawmills, dependent on the National Forests for their raw material, have been obliged to close because they were unable to meet the expenses involved in competition with the big companies.

Virgin stand of ponderosa pine, Pinus ponderosa, mixed with sugar pine, P. lambertiana, in the Stanislaus National Forest, California, U.S.A.

The Timber Market

In closing this summary of the lumber industry situation, it should be noted that in many regions the financial incentive is insufficient to warrant the application of sound silvicultural methods. There is a similarity here between the virgin forests of the northwestern United States and those of tropical regions. It is true that some species have always been marketable for definite uses, such as the western red cedar, Thuya plicata Donn, for shingles, or the incense cedar, Libocedrus decurrens Torr., for pencils. But before World Wear II most of the secondary species were considered worthless. This is still the case in Idaho and Montana except for small quantities of cedar and western larch lumber. There is no market, either in these two states or in California, for pulpwood. Consequently, in these regions, foresters are unable to dispose of timber considered of low value for sowings, nor is it economically feasible to carry out the thinnings which are now necessary and which will become even more urgent when the present young stands reach 30 to 40 years of age. However, construction of a large pulp-mill in the San Francisco area is contemplated, which may help this situation locally.

The problems

The Management Unit

European foresters seldom have to solve the problem of the management unit. The forests they administer are relatively small and are often divided up into different ownerships; and there are enough relatively small sawmills (by comparison with the big American plants). Often the management unit is just the extent of one owner's property. If this is too extensive and it is thought necessary to divide up the area to be cut over in order to provide neighboring sawmills with an adequate supply, the tendency is to divide the coupe into series rather than to form large contiguous blocks. During many centuries a balance has been achieved between forest production and the normal capacity of the sawmills.

The situation is quite different in the northwestern United States. It must be pointed out, however, that in the Balkans, as in the United States, exploitation of the virgin forests has necessitated the creation of big companies. In France, too, for the development of the last virgin forests of the Basque country during the first world war, large areas of forest belonging to various communities had to be grouped together so as to provide a sizable volume of timber for the big companies, to justify the large investments needed for organizing logging operations.

The northwestern forests are difficult of access, covering mountainous country and steep slopes, cut by innumerable narrow canyons. Except for the valleys through which roads and railways pass, most of this region is still very sparsely populated. A few years ago many of the valleys were still considered inaccessible for logging. Going up into them, one finds only scattered logging camps, designed in relative comfort to last a few years but obviously temporary in character. Even some of the big sawmills are built on the expectation of a limited lease on life and the communities that have grown up around them are essentially impermanent.

The selection of a management unit - an area of the forest which will continuously supply a definite amount of timber and consequently a definite amount of work for the inhabitants of a community, mill workers, and loggers - is linked up, therefore, with a real problem of settlement and of the opening up of the forest.

In deciding on the management unit, account must usually be taken of privately owned forests, often interspersed with state-owned forests. The timber resources they can potentially: supply must be combined with those of the public forests to assure the existence of the community which it is desired to create or to stabilize. In fact, recent legislation has authorized the Forest Service to enter into agreements with owners under certain conditions, so as to incorporate into "co-operative sustained-yield management units" private forests adjoining publicly owned forests. These units will be administered under the same rules of management as the state forests. This law, now in operation, will help solve in some cases the problem of the management unit.

Logging and yarding in the redwood, Sequoia sempervirens, region, California, U.S.A.

Generally speaking, the Forest Service divides every National Forest into "working circles," which are chiefly administrative units but which may well serve in the future as management units. In most cases, however, and almost inevitably, the establishment of these management units involves the co-operation of the Forest Service with the big lumber companies. This is so true that, where there are no big enterprises working, the Forest Service must wait for the construction of a big plant in a favorable location or even encourage or facilitate such construction before opening a new exploitation unit or organizing a cooperative unit.

In the United States itself, criticism has been voiced against this policy because it involves a risk of giving to big industry a kind of monopoly over large portions of the publicly owned forests. The risk has been foreseen by the Forest Service and steps have been taken to minimize it. However, it must be understood that, for the rational management of these units, the Forest Service needs the cooperation of the lumber industry and of powerful companies, and vice versa. The first essential of rational exploitation, for instance, is the construction of a complete road network, in order that every part of the management unit can be easily reached. The Forest Service sometimes has a large enough appropriation to open the main road, or "access road"; however, it is unable by itself to open the secondary roads that are required for the regular management of the unit, and these must be very numerous because of the rough terrain to be traversed.

Large industrial plants are or can be focal points, around which important communities grow up. Thus the stability of existing communities or the creation of new communities, which is the object sought in creating management units, is often closely linked with getting the major timber industries on a permanent basis or establishing big new companies.

Cutting Policy and Methods

For a good understanding of the silvicultural policy generally followed by the Forest Service of the northwestern United States, it must again be remembered that the forests it administers are largely virgin forests.

The losses in a normally composed virgin climax forest are, on a statistical average, approximately equivalent to the gross wood increment. In order to harvest a net increment through regular exploitation, it is first necessary to eliminate as quickly as possible the components which are chiefly responsible for the losses, the mature and over-mature trees which are the prey of fungi, insects, and pests of all kinds.

The virgin forests of the Northwest are not climax types, but their composition produces the same results. Where the forests are left to themselves, losses from natural causes are much greater than the gross wood increment, at least as far as the merchantable timber is concerned, without taking into account young and middle-aged stands. It is necessary, therefore, to rid the crop of trees which would in any case be lost before a new cutting could be made on an area already cut over; this is the policy followed by the Forest Service.

The considerable stumpage put up for disposal enables the big operating companies to invest large sums in road construction. The complete network of roads built up facilitates normal management as soon as the "conversion" operation is over. In fact, this policy gets results, and the development of the road network where cutting is in progress or has just been finished is astonishing.

Various methods of cutting are practiced, according to species, maturity of the stand, and its future prospects. Generally speaking, the main trend is towards selection cutting, which approaches the "jardinage" methods of European foresters. Very fine stands can be seen in which the first cutting has taken only 25 percent of the growing stock above 12 inches in diameter, and this proportion is not very far from that of an average "jardinage" cutting. The two kinds of cutting cannot be precisely compared since "jardinage" cutting involves, in principle, every kind of cultural operation in every kind of stand met with on the area involved, while selection cutting is concentrated in general on the trees most likely to die off. But it seems probable that the two kinds of cuttings will become increasingly similar once the growing stock has been regulated, and this trend is already noticeable in some cases.

In adopting selection felling, American foresters hope to be able to extend the harvesting of the old stands of virgin forest over as long a period as possible, so that the young stands now in existence will be ready for exploitation as soon as the old stands become exhausted. Thus the menace threatening the lumber industry from the lack of middle-aged stands could be averted at least in part, and more so if thinning and improvement felling could be carried out economically in the young stands so as to hasten the growth of the best trees. In most areas there is no outlet for thinnings, but the Forest Service is authorized to retain part of the stumpage price of all sales, instead of turning it over to the Treasury, on the condition that this money is used in improvement work. It is thus enabled to carry out local thinnings and prunings which seem very worth while.

Thee types of cutting - clear cutting, clear cutting with scattered seed trees, and selective cutting - in the Willamette National Forest Oregon, U.S.A.

However, selection cutting, even with heavier fellings than indicated above (the normal rate being about 65 percent), is not always possible. Some stands are, as a whole, so over-mature that all marketable trees must be taken out. In the western white pine region some foresters think, perhaps rightly, that clear-cutting is the only way to ensure predominance of this valuable species in the regenerated stand and that the disadvantages of clear-cutting can be avoided if carried out in narrow strips, leaving belts of standing forest. In the Douglas fir region, clear-cutting over relatively small areas under these conditions gives good results from the point of view of regeneration, though selection cutting, with a sufficient opening-up of the canopy, would give the same satisfactory result.

Finally, it must be kept in mind that selection cutting is possible only when suitable logging equipment is available. Most loggers now operate with powerful and easily handled tractors and very mobile cranes for loading the logs on trucks. However where the "slack-line" system is still used, as it is generally throughout the redwood region, selection cutting seems almost impracticable

Even clear-cutting practice has improved considerably in recent years in that quantities of timber previously left at the site are now recovered. One improvement is the practice of "relogging," or going over a previously cut area again to harvest fallen trees or those left standing that are unlikely to survive to be of any use in the forest of the future. Another improvement is the practice of "prelogging" which is the removal, before the main cutting operation starts, of suppressed trees of any value or smaller trees that might otherwise be damaged and probably lost. The logging companies have realized that in many cases these two practices are not only economically feasible, but that they yield a considerable amount of timber, often increasing the volume of the main cut by a quarter or a third.

Following selection cutting, the many access roads opened up make it economically possible to carry out so-called "salvage" cuttings, which roughly correspond to the annual harvesting of windfalls practiced by European foresters. It is to be hoped that this practice will be followed more and more so that the removal of trees that have died after the main crop has been felled may add to the net yield a volume which previously could only be considered as a dead loss of forest capital.

Other Major Problems

The very numerous problems facing American foresters in the Northwest cannot all be discussed within the limited scope of an article such as this. In general, they concern chiefly regeneration, protection, and the silvicultural methods best suited to each type of forest. Three outstanding problems, however, deserve special mention:

Fire. - The first of these problems is fire. American foresters have fought against fire with every means that modern technicians could put at their disposal: a network of trails and roads permitting ready access for fire-fighting crews; numerous "look-out" towers, maimed day and night during the danger season and linked by very complete telephone and radio systems; specially trained mobile teams, with equipment carefully planned down to the last detail; a watch system reinforced by air patrols, generally in co-operation with the Air Force; even the use of parachutists for swift attacks on fires in places otherwise inaccessible; intensive propaganda throughout the country, making the public aware of the danger of forest fires; control of tourist traffic and camping.

These efforts have borne fruit. Obviously, it is too much to say that forest fires in the Northwest will now never get out of hand or spread over large areas. In recent years, however, the number of fires and especially the average area burnt over have been decreasing to such an extent that fires can now be considered as a normal forest hazard just as the risk of windfalls is in European forests. They have ceased to be a constant threat against carefully thought-out management plans.

However, forest administrators must be constantly prepared to meet critical fire situations, for the threat of fire will always remain a characteristic feature of the northwestern forests. It is, indeed, a direct consequence of the climate - of the summer drought, with sometimes a complete lack of rain for weeks, together with violent winds and a very low degree of relative humidity. Perhaps the establishment of a climax forest type would result in stands less sensitive to fire. These are questions that should be carefully studied by experiment stations. Except in the most favorable circumstances the fire threat cannot be entirely eliminated.

Closely tied to the fire problem is the question of slash disposal. It comes as a surprise to a European forester to see the quantities of debris lying around after a felling, but this can be explained by the high proportion of dead or dying timber occurring in virgin forest. If just abandoned, this slash would constitute a grave fire hazard for many years. Even in selection cutting, it must sometimes be burned; but generally, with this method of felling, the slash does not amount to much and is thinly spread over a large area. After tops and branches have been broken down so that everything lies uniformly on the ground, the debris can be left to be covered by the first snowfall, which will hasten decay. Sometimes, however, the slash for some distance on either side of roads, where the risk of a fire starting is greatest, is piled and burned. When more intensive cutting methods have been practiced, the slash must be burned. In some cases, it is done by broadcast-burning, but where advance regeneration or trees left standing need to be protected, the slash may first have to be piled.

Bound up also with fire is the maintenance of plantations, which forms one of the most important activities of the Forest Service. The nurseries are indeed outstanding; it should, however, be noted that while European foresters prefer relatively small nurseries, well distributed in order to avoid too much adjustment for the young seedlings when transplanted, American foresters prefer to concentrate nursery work on large, well-chosen sites. Apparently mortality is no higher than in European nurseries, and this system makes it possible to provide each nursery with excellent equipment - not only for collecting and drying cones and preserving seed, but also for the cultivation of the nursery itself - and to use mechanical methods as far as possible for packing and for storing the seedlings in refrigerator chambers after they are dug up.

Most of the plantations are raised on burnt-over areas. Cost and chances of survival vary greatly with the condition of the soil. Very often burnt-over ground, especially after several fires, is invaded by an abundance of small deciduous trees in the north and, in the south, by thick scrub of various species of Manzanita, Arctostaphyllos spp., chinkapine, Castanea spp., and numerous varieties of Ceanothus. Large areas covered by this type of vegetation were planted up during the depression, but the cost was prohibitive, particularly where the scrub had to be eradicated strip by strip. The Forest Service therefore prefers to concentrate its efforts on the best soils and on areas recently burnt over, where there is no competition from brush. The results are generally excellent.

Blister Rust. - The second problem is "blister rust," Cronartium ribicola. This is particularly serious in Montana and Idaho, because of the importance of the western white pine, but no less so in southern Oregon and in California, where it threatens the sugar pine, Pinus lambertiana, Dougl., a magnificent tree that is locally abundant.

There are not many ways of combatting this disease and all of them rest on the elimination of the various species of Ribes to be found in the understory. It is possible to obtain natural regeneration of white pine by maintaining the canopy so dense, even after the seeding felling, that the Ribes cannot establish itself. It is then usually necessary to protect the pine against the competition of other shade-tolerant species such as hemlock, Tsuga heterophylla (Raf.) Sarg. But it is rarely possible to retain a canopy of sufficient density in stands containing a high percentage of mature trees which have to be felled. Broadcast burning of slash, if carried out two or three years after a clear-cutting, when the Ribes has had time enough to germinate, destroys the pest. The Ribes seeds can remain indefinitely in the soil without losing their germinative powers. But it can be eliminated only over clear-cut areas, and clear-cutting too often has other drawbacks.

The only remaining solution, therefore, is to ensure complete eradication of the Ribes by hand. This is what foresters there have been doing by organizing crews specialized in this kind of work. Some experiments in trying to eliminate Ribes by spraying 2,4 D have been carried out, but the effectiveness of this method is as yet unknown and it is doubtful whether it would be less expensive than extirpation by hand.

Forest fire in Willamette National Forest, Oregon, U.S.A.

Small Forest Holdings. - The third problem is economical and social in character rather than silvicultural: it is the problem of the small private forest holdings.

The position of such forest owners and the danger which threatens them have been pointed out. The foresters' action on this question can take the form only of advice, given through the medium of state organizations. The number of agents assigned to this task, now only two or three in each state, could be increased with great advantage. Wherever these specialists have been able to exert their influence, it is interesting to note that they have been very successful and that many farmers seem very receptive to progressive ideas concerning silvicultural practices.

Forest research

The. attitude of northwestern foresters toward the problems just enumerated and means of solving them is not just a blind groping for practical solutions. On the contrary, it involves the application of scientific methods, carefully tested by experiment stations working closely with the regional forest services in every forest region of the United States. Compared with the organization of European experiment stations, generally concentrated in a limited number of places and having only occasional contacts with the executive services, this type of organization is both original and interesting. Such an organization was a necessity for American silviculture, especially in the Northwest.

The whole ecological evolution of European forests is well known. Their history, against this scale of evolution, is relatively easy to determine because the essential factor has been repeated cutting. The small number of forest species and the similarity of their development over relatively large areas also simplify the picture.

The U. S. Forest Service, on the contrary, has had to deal in the Northwest with forests where only natural factors have influenced the evolution of the stands, and often with a violence unknown in Europe. The diversity of climate, soil, and altitude and the large number of forest species prevented a clear reading of the history of the stands or the determining of the reaction of a given species to a given treatment. The whole ecological history of these forests had to be reconstructed, and this task, which is still on the whole the main task, clearly indicated the necessity for numerous experiment stations spread all over the country.

On the other hand, in Europe, or at least in those European countries which practice the most advanced silvicultural methods, every forest, every exploitation unit, is in itself an experiment which the forester in charge is able to follow very carefully. The most striking example can be found in the forests managed by the "control method," a form of management which enables the forester to know at practically any moment the exact stage in its evolution that the growing stock has reached and permits him to influence the stands at the very place and time that such action will be most useful.

These methods cannot be applied to western forests in the United States for the following reasons. The present composition of the forests, because of their origin, does not lend itself to a slow evolution but necessitates a short conversion period during which European management methods would be meaningless in practice. The forests as a whole still have too few access roads, a situation that could be remedied perhaps by a considerable increase in appropriations for the Forest Service. Their products do not as yet have the outlets which would be needed to make the necessary silvicultural operations profitable. Lastly, these forests are spread over vast areas, and the only remedy for this difficulty would be a great increase in the number of foresters.

Consequently, the best policy was to establish research stations in as many types of forests as possible and to study there the problems presented by each of these types from an economic as well as a silvicultural point of view. As soon as solutions were found and duly tested by scientific methods, they could be applied to scale to all the forests of the particular type.

In other words, one can say that, whereas the method of working European forests is individual in character, since it divides the growing stock into small units with individual characteristics, the treatment of the forests of the northwestern United States is statistical in character. Undoubtedly this is due to the conditions facing the Forest Service of the United States and to the problems which-it has had to solve from the beginning. But it is highly probable that the statistical method of working will remain indefinitely a characteristic feature of silviculture in the northwestern United States, first because all the conditions given above, and chiefly the last one, will never be fulfilled, and second because the statistical method is perfectly justifiable when it is applied to large forest areas. It has already shown astonishing results and its efficiency in these forests is comparable to that of any other method used elsewhere.

The Institute of Forest Genetics, Placerville, California.

It must be further pointed out that these methods have been an important factor in the progress of scientific forestry in its many aspects in the United States and particularly in the northwestern regions.

It would be easy to show many examples of the statistical character of the methods used by American foresters based on the research work of the experiment stations. Two may be quoted as particularly striking.

Cutting in a private forest, Washington, U.S.A. Dark-colored slash has been burned over.

1. The Black Mountain Experimental Forest

The European forester who visits the Black Mountain experimental forest in northeastern California is surprised to find all the elements of the "control method" very strictly applied here. This forest, about 4,000 hectares (10,000 acres) in extent, is managed so as to obtain the highest possible sustained yield. The method of working is very similar to "jardinage," taking into account that it is applied here to an intolerant species, the ponderosa pine, and to virgin stands the composition of which is very far from normal. The management system which determines cutting is as flexible as the "control method," and even more so, since in order to be able to carry out any cultural operation at the appropriate time wherever it may be necessary, the experiment station has its own logging crews and its own logging equipment. Also a complete forestry inventory has been made.

This forest, however, is an experimental forest. The general aim is to determine what silvicultural methods to apply so as to ensure sustained yield, to determine whether such methods are economically feasible, and eventually to evolve silvicultural methods that would be actually applicable from the economic point of view. These rules could then be applied to all forests of this type, which cover nearly 1.5 million hectares (3.7 million acres).

This over-all experiment includes also many other experiments. The complete inventory has been made only to verify the accuracy of the sampling methods currently used in forests of this type. In the management plan, some compartments are ear-marked for cutting according to certain methods in order to determine not only the silvicultural results obtained with every one of them, but also their effect on the cost of harvesting. Elsewhere experiments deal with methods of thinning and pruning.

2. Survey Methods

The second example will be taken from the survey methods used by American foresters, the statistical character of which is particularly apparent. A complete inventory of the large northwestern forests is obviously impossible. However, the sampling methods evolved by the experiment stations, which have been greatly improved by the use of aerial photography and which are used now over the whole forest regions, give the Forestry Service the chance of acquiring as accurate a knowledge of their forests as they wish. And this knowledge can cover all factors: composition by species, by volume, by diameter categories or by tree-class; rate of growth; amount and kind of regeneration; and mortality.

The use of these methods has had a two-fold advantage for American foresters. First it has given them probably a much more accurate knowledge of the whole of their forests than many European countries can boast. If European foresters can say that they know with a high degree of certainty the composition of the forests under their administration - an advantage which they will probably not have very much longer because of the rising cost of complete inventories - they are in almost total ignorance of everything concerning the privately owned forests, over which they have no control. Even in the forests which they administer, they have often only a vague and merely approximate idea of some factors, such as the number and kind of seedlings and young trees not included in the inventories.

Secondly, the use of the sampling method in all public and private forests has familiarized every American forester with statistical methods. These methods again are applicable to all research activities and it is certain that the knowledge thus acquired plays an important part in the achievements in all fields of experimental research, such as the calculation of fire hazard, the planning of the fight against insects and diseases, methods of planting, the study of conditions of natural regeneration for every species, and finally and above all, the study of genetics, to which the Placerville Institute has given such a promising and powerful impulse.

Because many problems of the northwestern forests are similar to those which arise in tropical forests - a similarity which has already been pointed out - a study of the problems of the former ought to be helpful in planning the development of the latter. American foresters, indeed, have perfected methods of forest survey, research, exploitation, and protection which must hold the attention of tropical forest technicians. Also the types of. logging, hauling, and sawing implements used in the northwestern lumber industry should be of interest to technicians in charge of the utilization of virgin tropical forests.

At present the essential feature of northwestern forestry is the conversion of virgin forests into stands which are managed to make them yield determined amounts of wood every year, supplying industry with the most valuable timbers. This is also the essential problem which foresters in charge of the development of tropical forests face. It can be said that the experiment of northwestern forestry is of fundamental interest to these foresters because it will have been completed relatively quickly. In a few decades the population of that part of the United States has increased enormously and this development is continuing, making not only possible but necessary the transition from an extensive to an intensive silviculture, similar in aims if not in methods to European silviculture.

It is obviously impossible, after only a brief visit, to express any valid opinion about the future of the forests of the northwestern United States. Only foresters with intimate local knowledge can make an adequate forecast, though a great many factors, chiefly economic, which may exert a profound influence are beyond even their control. It seems unlikely that timber of such exceptional quality as that now being exploited will be obtained again from the crops which foresters are aiming to grow on a rotation of only 120 to 175 years. This excellent quality is probably due to the great age (200 to 300 years and over) and the slow growth of the timber. On the other hand, increment will probably be much greater and net yield will not be constantly lowered by high mortality. The loss in quality, perhaps exaggerated, may again not be as important as at first appears, in view of probable trends in the lumber industry. However, a period of crisis is to be anticipated, owing to the lack of middle-aged stands. This crisis could be largely averted if the cutting of the old virgin stands could be extended over a sufficiently long period, and especially if in the meantime markets could be created in each region for the species now considered of minor value.

Whatever the future of these forests may be, America's foresters will have accomplished a gigantic task in these regions. Not only will they have opened up the forests, but they will have transformed these timber lands from a prey to disease, decay, and pests into valuable stands which can be managed along rational silvicultural lines. They have developed and are still improving their methods of silviculture, and they have at the same time developed original research methods from which all countries may benefit and have obtained general results which will be of major importance for the future of scientific forestry.

They have a right to be proud of their work and of their national forests.

This article was prepared in the French language and translated by FAO.

Accompanying photographs are reproduced by courtesy of the Forest Service, U. S. Department of Agriculture.

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