PRACTICAL FORESTRY IN THE PACIFIC NORTHWEST PROTECTING EXISTING FORESTS AND GROWING NEW ONES, FROM THE STANDPOINT OF THE PUBLIC AND THAT OF THE LUMBERMAN, WITH AN OUTLINE OF TECHNICAL METHODS TEXT

however, profit by experience gained elsewhere, for the laws which govern tree life are as universal as those which govern the life of men and animals. In dealing with new species and new environments we have no great difficulty in judging their future from their past, which lies written plainly for those who care to study it. While to some extent trees require elements obtainable only from the soil, they are more independent in this respect than most other forms of vegetation. Soil influences forest trees mainly by its physical character, especially as this determines the moisture contents. Very little nourishment is actually taken out of the soil for, as someone has said, wood is nothing but air solidified by sunshine. A tree's immense and complicated foliage system is the laboratory with which it effects this transformation. Since air exists everywhere and the chemical quality of the soil is comparatively unimportant, the requirements of different species for light, heat and moisture are what mainly determine their distribution and habits of growth. And since heat and moisture are largely climatic factors and fairly uniform in given localities, it follows that the demand of a species upon light may practically fix its habits and possibilities in those localities. The very great variance of species in light requirement accounts to a large extent for the composition of most primeval forests. It is of peculiar importance in the management of forests by man because he cannot control it as he may be able to control some of the other agencies which affected the primeval forest, such as fire or seed supply. SELECTION FORESTS It would be unprofitable to discuss here all the many methods of forest management which have proved to be best, technically, for given species and combinations of species. Where market and transportation facilities are highly favorable, as in Europe, the timber owner can adopt the method which will bring the best results, but here he has no such choice. He can but bear in mind certain fundamental principles, uniformly applicable to large areas for considerable periods of time. Roughly, however, our Western forests can be classified by their adaptability to the two directly opposite systems, known as clean cutting and selection cutting, of which almost all methods are modifications. A selection forest is one in which all ages of trees exist, from seedling to maturity. It is the natural growth of species which are tolerant of shade. In a natural state, undisturbed by cutting, it maintains much the same aspect continuously, for as the oldest trees die, their place is taken by younger ones. Obviously such a forest must be composed of species, whether one or several, which can grow beneath its own shade. The understories of varying ages are as dense as their light requirements and the density of the overwood permit. The common hardwood forests of the East illustrate one type of the natural selection forest. On the Pacific slope an example is afforded by hemlock, either practically pure or mixed with white fir, but probably the most typical is the ordinary Western yellow pine under certain conditions. At its best this tree composes a forest so dense that all young growth is shaded out, but everyone is familiar with the frequent opener stand containing all ages. The younger trees are often called blackjack. EVEN-AGED FORESTS On the other hand, trees extremely intolerant of shade occur only in what the forester calls even-aged forests. Being unable to start in the darkness of an existing stand of any considerable density, they must seize opportunities to recover openings. The Douglas fir of the Northwest, more commonly called red or yellow fir, is an excellent illustration. In the interior states this species reproduces under cover to some extent, because there is a stronger light average throughout the year and because the stand is not so dense. In the typical Douglas fir forests of Oregon and Washington, discussed in this booklet, it never does so. While hemlock, cedar and white fir undergrowth may be abundant, Douglas fir seedlings are seldom seen except in burns, slashings, roads, or open spots in the woods. And the fir trees composing the dominant stand are of nearly the same age. How, then, did this even-aged fir forest begin? Close scrutiny will practically always find the answer in fragments of charred wood. Long ago another similar forest occupied the ground until lightning or an Indian's fire started a new cycle. Possibly recurring burns swept the area many times before wind-blown seeds began to start advance groups of fir, which, when fifteen or twenty years old, themselves fruited and filled the blanks between them. Perhaps destruction was not so complete and surviving trees made the process a swifter one. Except in the very oldest forests, where remains of the original stand have entirely rotted away, the history in either case may be read in ancient snags and fallen logs. Suppose, however, that fire had not come to aid the fir in perpetuating itself? This, too, we can answer from the signs today. Every Northwestern woodsman knows tracts of varying size (usually small because fire has been almost universal) covered with big old hemlock, white fir and cedar, with here and there a dying giant fir, perhaps, but mainly showing fir occupancy only by rotting stumps and logs. No sign of fire is seen. When this fir forest was approaching middle age, the shade bearing species began to appear beneath it. As the firs began to crowd themselves out, the later comers shot up with the increased light and filled the open places. At last the even-aged fir forest was completely transformed into a selection forest of other trees, which will remain until some accident again gives fir a chance if any survives near enough to reach the spot with seed. Douglas fir is not the only Western tree which usually grows in even-aged stands. Lodgepole pine has the same habit, often supplanting yellow pine after fire or logging. Western white pine is perhaps more tolerant than Douglas fir, hence more likely to hold its own without artificial aid, but is also more certain to compete successfully if it has such aid. The same is true of tamarack. NATURE AS A MODEL We thus see that if economic reasons suggest it, we may use the selection system as a basis for artificially managing the shade bearing species such as hemlock, white fir, cedar, spruce, and even Western yellow pine. We may cut the largest and oldest trees and still have a well started second crop. If there is not much young growth to leave, even a little is valuable. It may be decidedly best to leave medium sized trees, which otherwise we would cut, because they are still growing rapidly. On the other hand, we see that this method would not be of any advantage at all in insuring a second crop of Douglas fir, for there is no young growth of this species to protect. The small and medium sized trees, instead of being immature, are merely stunted specimens of the same age as their larger brothers and unlikely to gain in size if left. Selection cutting here would save for future use only such understory of shade-bearing species as may exist. Unless this is an object, the best plan is to cut clean and get all we can. If we leave any fir at all it is for the purpose of reseeding, not to secure better utilization of the trees themselves, and whether we do so depends, theoretically at least, upon whether it is better than artificial seeding or planting. In short, selection cutting harvests the ripest trees of a perpetual forest, while clean cutting destroys the forest in order to start an entirely new and more rapid growing one. Clean cutting is therefore necessary as well as natural in dealing with intolerant trees. But it does not follow that the selection system, although natural to tolerant species, is the only one adaptable to them. While the one class demands light, the other does not demand shade. It is merely capable of enduring it. Indeed, except for the greater susceptibility of some species to extreme heat and dryness when very young, as a rule shade bearing trees grow much better if they do have ample light supply. Consequently clean cutting may be the best system for these also under certain economic conditions. Besides its influence upon the occurrence of species in the forest, light practically governs the physical form of the individual tree. If grown in an opening and not artificially pruned, a tree will have a conical trunk and living branches almost down to the ground. The denser and consequently darker the forest, the more cylindrical the trunk, the smaller the crown of branches and the greater the clear length. The individual tree has no object in assuming a desirable commercial form and does so only when deprived of side light by numerous neighbors. Then it sacrifices diameter growth to height growth in reaching for the top light necessary for its life. At the same time the lower branches are killed by shade and drop off, the scars being healed and eventually buried. The pin knots near the center of a big clear log are the remains of branches which when living were at the top of the young tree. This is why, if it is to produce good timber, any forest must be dense enough to cover the ground throughout the early part of its life at least. When we see an excellent clear stand of mature Douglas fir, for example, we may know that it consists of the comparatively few survivors of a close sapling growth in which the weak were gradually killed out after serving their office of pruning and forcing the vigorous. Had only the trees we now see been on the ground they would be worthless except for firewood. For the same reason artificial forest planting must be thick, although the fillers or nurse trees may be of inferior species if not of so rapid growth as to gain the mastery. Nature teaches many lessons which we must recognize in artificial management or fail, but she is no more the best grower of forest crops than she is of agricultural crops. We have to study natural methods of forest perpetuation to see how they may be improved upon as much as to adopt them as models. As a rule the virgin forest is exceedingly wasteful of ground. The possibilities under intelligent care are not indicated by nature's average, but by her accidental best, and usually they far exceed even this. A fair comparison is that of scientific farming with unsystematic gleaning from wild and untended fields. The foregoing general principles of forest growth have been purposely outlined very briefly so as to serve as a mere introduction to their application or modification in concrete cases. MANAGEMENT OF SPECIFIC TYPES DOUGLAS FIR (_Pseudotsuga taxifolia_) Compared with most important commercial trees, the Northwestern Douglas fir is remarkably easy to reproduce. It is an abundant seeder, grows very rapidly, and inhabits a region with every climatic advantage. In the typical fir districts of Oregon and Washington deforested land which escapes recurring fire is usually restocked naturally and with astonishing rapidity. The exceptions to this rule are where the destruction of seed trees has been wide and absolute, where already established competing species are not removed with the original forest, and where the surviving fir is too old to seed. The two latter conditions are most prevalent near the coast, where the wet climate not only tends to protect slashings from fire and thus preserve the undergrowth of shade bearing species which escapes logging, but has also prevented the accidental destruction in the past of the original fir stand by fire. In considering these natural results as they bear upon proposed methods, we find actual destruction of seed supply the easiest to avoid. If the original stand contains suitable seed trees we can protect a sufficient number of them. If not, or if it is less expensive, we can secure seed elsewhere. More frequent difficulty will lie in determining whether the reproduction of fir should be the sole effort, or whether it should not be sacrificed, if necessary, in order to utilize an existing start toward a second crop of other species. This is of peculiar and early importance, for it usually also decides the question of protecting the slashing from fire. If the present stand is nearly pure fir, or if other species are represented almost wholly by merchantable trees, there will be no young growth worth saving. A new crop must be started from seed, and since fir is the quickest and easiest to grow, as well as probably the most valuable, it should be given every encouragement. _Slash Burning and Its Exceptions._ In most cases this requires burning the ground after logging, not only to reduce the future fire risk but also to provide a suitable seedbed. Fir much prefers mineral soil to start in, as is easily seen from the far greater frequency of seedlings on road grades than on adjacent undisturbed ground covered with humus and rotten wood. Hemlock has no such fastidiousness, even preferring rotten wood as a seedbed. To protect the slashing from fire, therefore, both preserves the most unfavorable conditions for fir and subjects it to unnecessary competition by its rival. Hemlock seedlings already established, seeds lying on the ground, and surrounding or surviving trees which may scatter more seed, are all encouraged to shade and stifle the struggling fir seedlings already handicapped by dislike for their situation. On the other hand, a large proportion of what we now consider typically fir forest has a vigorous ground cover of hemlock and cedar which may become merchantable many years before an entirely new fir crop can be grown. The presumably greater value of the latter may be consumed by the heavier carrying charge before returns are available. Certainly if the promise of profit from other species and the difficulty of establishing fir both reach the extreme, protection of the growth already started is the best forestry if it is practicable. Moreover, there may be considerable young growth of other species under conditions which do not preclude satisfactory additional reseeding by fir. When the owner is in position to plan far into the future, like the Government or State, he may seek a temporary compromise, although expecting eventually to secure pure fir. In such a case it may often be best to utilize a first new crop of hemlock, but on harvesting this a few decades hence to burn clean and start the next rotation with fir only. _Conditions Vary Methods._ Between conditions clearly suggesting one course or another, all gradations will present themselves and no written rule can be given for determining the dividing line. Much depends upon future relative values of species, upon which the owner will have his own opinion. More depends upon the character of existing young growth and consequent adaptability to changed conditions after logging. Even a very thick stand of young hemlock is unlikely to produce much if the overwood has been very dense, for much of it may be so old and stunted by shade that sudden advent of strong light will result merely in distorted worthless branch growth or in killing it outright. Occasional vigorous young trees just under present merchantable size are of doubtful value because they are likely to blow down. The most promising class of undergrowth found in fir forests of the Northwest is where there has been sufficient light to produce a fairly thick stand of young hemlock or cedar from five to fifty feet high. If the undergrowth from which any second crop may develop is insufficient to be worth much consideration, and reseeding must be depended upon entirely, there may still be a question as to species. If ample natural supply of fir seed can be expected, slash burning is indicated. But if not and the owner is not prepared to undertake the expense of artificial seeding, while at the same time there is a promising natural hemlock supply, burning has no object except the reduction of future fire risk. It may even retard hemlock reproduction, both by destroying part of the seed supply and by encouraging the growth of brakes on the area. The question here is a really financial one. The cost of planting fir under these conditions may be more than reimbursed by the resultant more valuable and rapid growing crop. The owner must do his own conjecturing as to future comparative values of the species. So far we have discussed slash burning only in its sylvicultural relation, finding that it encourages Douglas fir reproduction and is consequently advisable in Northwestern Douglas fir types unless there is an exceptionally promising second growth already started. The balance will be further in its favor, in doubtful cases, because of the protective feature. This is discussed more fully in another chapter, but it is well to recall here that immunity from recurring fire is the first essential of profitable reforestation. To secure second growth by treatment which threatens its destruction later is bad management unless the original saving is ample to cover subsequent greater cost of protection. This is seldom the case. _How to Reseed the Area._ Dismissing the exceptions noted, and returning to our rule that another crop of Douglas fir is usually the best secured by following nature--cutting practically clean, burning the ground and starting a new even-aged stand--we have still to consider means of getting this stand started. We may depend upon natural reseeding from trees preserved for the purpose or from the surrounding forest, or we may resort to planting. What are the comparative advantages of these two methods and the circumstances governing choice between them? Hitherto, students of the subject have inclined to favor natural reproduction. The very general second growth on deforested land where no aid has been given indicates that excellent results will follow slight assistance. Red fir fruits frequently and profusely, and the seeds carry well in the wind. Burns have been known to restock fully from seed blown from forested hills a mile or more away. Moreover, while planting always involves initial expense, sometimes much may be done to insure natural seeding with little or no actual outlay. There is danger, however, that in many instances this economy will be more apparent than real if it is effected by actually leaving much value in seed trees. Abroad and in the East there is comparatively little loss in leaving even a fourth or fifth of the original stand to furnish seed. The individual trees left may be good seeders, although small. Little capital is tied up in them and they may be utilized later to equal advantage. A mature fir forest of the Pacific coast may have no small fruiting trees at all, and if left such are likely to be knocked down in logging. To leave 20 per cent of the large trees standing would sometimes tie up 20,000 feet to the acre, worth $40 or $50. Age and windfall may cause loss equal to stumpage increase; moreover, they can never be utilized without the same expense for roads and machinery that is necessary in the original logging. The second crop will not be allowed to reach a size requiring such equipment. In considering possible windfall loss, not the normal wind but the possible maximum storm within the entire life of the second crop must be reckoned with. It is probably safe to say of mature Pacific coast fir that leaving enough merchantable timber on a cutting area for adequate seeding costs more than to use it and restock. Restocking can be done for $2 to $10 an acre, which would leave a decided margin for profit on the seed trees. And if we undertake to reduce this balance by leaving very few seed trees, we decrease the certainty of successful reproduction and increase the danger of entire failure through