FORESTRY AND THE FOREST
Whether the lumberman's judgment of economic influences leads him to be optimistic or otherwise as to the profit of forestry in general, he is most interested in the particular forest with which he has to deal. He can neither accept nor dismiss the proposition intelligently, much less put his ideas into actual practice, without knowing something of the capability of his land to respond to his effort. "What methods are best, what will they cost, and what will be the result?" are questions which arise at the very outset. They lead at once into the domain of technical forestry.
With us forestry has not been practiced long enough to furnish demonstrated examples with which to answer such questions. We can, 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.
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.
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.
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.
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 windfall or accidental destruction when we burn the slashing. It cannot be denied, however, that fire after planting would result in complete loss, while seed trees might restock the area again and again after such accidents.
Natural Reproduction.
On the other hand, natural reproduction does not always require the leaving of merchantable timber on the cutting area. Frequently there are enough crooked or conky trees to serve the purpose. These defects are not directly transmissible through seed to the offspring, although conk is infectious and the young crop should be protected by the removal of the diseased parents after it is well started.
Again, seeding from adjacent timber can often be relied upon. This is a question of economy in logging operations, lay of the ground, prevailing wind direction, fertility of the stand and other local considerations. A valley with healthy fir woods on either side is likely to seed up promptly even if a half mile wide. So is a flat at the leeward foot of a hill timbered on the summit where the wind strikes. A cutting on a ridge is correspondingly unlikely to restock. Theoretically if a tract of timber were large enough, it could be opened up by logging operations which, instead of proceeding steadily from one edge, might skip every other landing or so until the most remote portion was reached after a few years, and then work back again, cleaning up the neglected portions after they had seeded the first openings. The same effect sometimes results from actual accidental practice.
It is apparent that rules cannot be laid down for general application. Generally speaking, a logger interested in fir reforestation should study his ground to see if naturally, or, with inexpensive aid, the cut-over area will not reseed from the sides and from the cull trees he will leave uncut. If not, he may leave a few merchantable seed bearing trees provided the soil is such as to make them deep-rooted and wind-firm. Groups are better than single trees because less likely to be blown down and easier to protect from the slashing fire. More should be left toward the windward edge. But before tieing up any considerable sum in merchantable trees he should consider the cost and safety of supplementing any shortage of natural supply by artificial seeding.
WESTERN HEMLOCK (Tsuga heterophylla)
Since hemlock is so frequently associated with Douglas fir, the principles governing its reproduction and its relative promise as a second crop have necessarily been largely covered in the preceding discussion of fir. The following remarks are merely additional.
We have seen that the perpetuation of hemlock is advisable only where fir reproduction is difficult to obtain or will be at too great a sacrifice of valuable existing hemlock. The first of these conditions is confined chiefly to pure hemlock stands and to coast regions where the fir is often too old to seed well. The second may exist on the coast or in certain moist interior regions where there is a heavy hemlock undergrowth. In either case natural hemlock reproduction will be counted upon, both because it is practically certain to occur and because if it were not certain and artificial aid were necessary, we would abandon hemlock entirely and devote our efforts to fir. In short, discussion of hemlock as a second crop need not include systematic attempts to seed the ground but may be confined to protection of what we have to begin with.
In a straight hemlock proposition, the protection question may differ considerably from that involved by deciding between fir and hemlock. In the latter case, because of the assistance of fire to fir, the growth already on the ground must have considerable value to warrant foregoing the several advantages of slash burning. In the former, slash burning has no object except to reduce future risk. The inference is that a much less promising stock of young growth is worth protecting.
While this is true, there is danger of overestimating its value, especially if care is not taken in logging. It has been remarked that suppressed misshapen hemlock is not apt to make a healthy growth, that windfall is a peril, and that if the previous shade has been heavy, sudden opening to sunlight may be fatal. It should also be remembered that even slightly injured young hemlock is worthless, for it is almost certain to be attacked by borers. Anything which deadens a small portion of the bark like axe blazes, fire scorch, or scars from strap leads, is dangerous. Hemlock is more liable than fir to general defects like black streak, borers, fungous disease and mistletoe, therefore investment in reforestation needs the maximum safeguard against them. In many instances better results may be obtained from a new healthy seedling stand following a purifying fire, even at some loss of time, than from well started young growth which is unhealthy and likely not only to fail itself but also to infect any seedlings which may come in among it. Consequently if the slashing is not large, and reproduction from the sides may be counted on, the above considerations, coupled with the reduction of future fire risk, may suggest slash burning just as in the case of fir. The remarks apply particularly if it is considered necessary to log as clean as possible.
With a good, healthy start toward a new forest, however, it will usually be best to keep fire out, for the material saved will warrant greater expense in protection during the growing period. Representative tracts, both on the coast and in the Cascades, have been studied which showed that, with care in lumbering, enough good young hemlock too small for logs or skids could be saved after present-day logging of a heavy mixed fir and hemlock stand to produce in fifty years 11,000 or 12,000 feet of timber over 14 inches in diameter. This would not be wholly additional to the second crop of seedlings which might be produced if these trees were not preserved, for the ground and light they use would be denied to the seedlings, but undoubtedly the yield would be greater than could be secured if they were destroyed.
This means that under similar conditions we may go still further and actually apply the selection system, especially if the original stand is nearly pure hemlock. So far we have discussed areas left by present-day logging methods. Suppose, however, the owner of a good tract of hemlock, having decided that conditions do not warrant trying to get fir, is willing to modify his methods for the sake of better hemlock returns at some future cutting. He would probably do best to take out only the mature trees, leaving everything which is still growing with fair rapidity. Greater light will stimulate these immensely as well as encourage further seeding of the ground. The few merchantable trees he spares, together with those now unmerchantable, will, in perhaps twenty years, make another excellent crop. By leaving a fairly dense stand he prevents the windfall danger which threatens the survivors of too vigorous cutting, and also prevents them from assuming the branchy form of trees which receive too much side light. The fire danger is much reduced by resultant shading of the ground and slightly by the lesser cover of debris. In short, he makes the most economical use of the ground, and the capital represented by the trees he spares is well invested.
To sum up, hemlock lends itself to almost every form of management. Determination as to which is most advisable is governed by its extremely variable manner of occurrence and by the local promise offered by associate species. The foregoing discussion can only serve as suggestive when considering given conditions.
WESTERN CEDAR (Thuya plicata)
Except for small swamp and river bottom areas, where the land is likely to be more valuable for agriculture than for forest culture, pure cedar stands are not common. Therefore it is as a component of mixed stands that cedar is likely to become a problem in conservative management. To some extent it presents a peculiar question by being taken out alone for special purposes, such as poles and bolts, independent of ordinary logging of sawtimber.
Western cedar is a typically shade-bearing tree and also endures much ground moisture. Its occurrence as an under story and in swamps does not indicate that it always requires such conditions, however, but more often means merely that they protected it from competition or from destruction by fire. Charred remains of very large, fine cedar are often found on comparatively dry slopes where fire has resulted in complete occupation by fir at present. Cedar's failure to reappear there after removal is probably because its thin bark and shallow roots allowed its destruction by a fire which was survived by some better protected fir seed trees. Nevertheless, cedar must be classified as a moisture-loving species and occupies dry soils only in coast or mountain localities where there is a compensating heavy rainfall.
Reproduction and management of western cedar have not been sufficiently studied to warrant very positive conclusions. This neglect is probably due to a wide belief that in spite of its present commercial importance, its place in the future forest will be small. It most commonly occurs with other trees in heavy stands, which make the preservation of any young cedar difficult because of the destructiveness of logging. Being of comparatively slow growth, also persistent in retaining branches when grown in the light, it is not as promising for artificial reproduction as Douglas fir or white pine. To let it become old enough for good shingle material will be too expensive to pay, for roofing is one of the wood products easiest to substitute for. While cedar is adapted for poles, posts and other underground use, less decay-resisting species can be made equally durable by chemical treatment. In other words, as a second crop it is probably below other species in ease of establishment, rapidity and quantity, and will not have sufficient peculiar value to compensate for consequent less economical use of the ground.
There may be exceptions to this rule. Good young cedar in forests which are to be handled under the selection system should be carefully protected. It can always be utilized and may bring revenue before anything else can be cut. For the same reason it has been suggested for planting with fir and white pine, either simultaneously as a small proportion or later in blank spaces where the others fail. Under such conditions the main stand will not be modified and the cedar will afford a valuable adjunct.
Although found in the moister mountain regions, this exceedingly valuable tree seldom occurs to a commercially important extent except along the coast, where it is common on swales and fertile benches and in river bottoms often forms pure stands of great density. Yields of 100,000 feet an acre are not unusual and the trees are very large. It is also common, although of small size, in swamps.
This spruce reproduces readily in openings, whether made by fire or cutting. Unthrifty specimens may be found under shade, but considerable light is necessary for successful development. Even then, height growth in youth averages slower than that of fir or hemlock. The leader shoot is likely to die, so that hardly more than 25 per cent of the young trees establish a regular form of growth before a height of 20 or 30 feet is reached. After this stage spruce grows uniformly and rapidly, still somewhat slower than fir in height but exceeding it in diameter. The branches are slow to die, however, so that the tree remains bushy for most of its length until it reaches 60 or 80 feet in height, and even afterward a dense stand is required to clear it. In many pure spruce forests the larger trees have been able to withstand the pruning influences and remain limby, while the smaller ones, being pushed in height growth to reach sufficient light for survival, have cleared themselves with remarkable rapidity.
The natural occurrence of Sitka spruce, except in Alaska, is probably limited chiefly to situations where it escapes competition, in youth at least, with the more hardy and rapid-growing species. It has the greatest advantage over these on river bottoms and flats where there is a dense growth of deciduous brush and where the soil is very wet in spring. In considering it as a possible second crop, the same competition must be remembered. Whether seeding is natural or artificial, the extent to which it will hold its own with any considerable quantity of other species is doubtful. If such are present and the situation is adapted to them, any expensive effort to get spruce merely by modifying methods of logging or handling the slash is certainly likely to be disappointing. Under the conditions mentioned as peculiarly favorable for spruce, gradual natural restocking may be expected if some seed supply is preserved, but since the growth is rather slow and a thin stand will remain limby, it may pay to hasten returns by supplementary artificial planting. Some authorities question the financial practicability of this on the ground that since spruce is of slower growth it will pay better to use the ground for fir, but the latter is unlikely to be true of bottom land.
After summing all its advantages, the peculiar merits of spruce for certain purposes should be weighed, for sufficiently higher stumpage value will compensate for delay in harvesting the crop. Moreover, Sitka spruce has not been as thoroughly studied by foresters as the more prominent Western trees, and while the foregoing notes represent general present opinion, further figures on rate of height growth may be more encouraging. There is no doubt that diameter increase is rapid from the start. Most of the disadvantages mentioned also decrease toward the southern limit of the spruce range, the growth on the Oregon Coast being rapid.
In this species we have the important western conifer which most often permits the selection system of management. With certain exceptions in which the entire stand is mature, the object of conservative logging should be to remove trees past the age of rapid growth and foster those that remain for a later cut. When comprising the entire stand, or at least clearly dominating it, with all ages fairly evenly represented, successful in reproduction, and not so dense as to present mechanical difficulties, it is ideally adapted to this form of management. The important underlying principle is that, since for a period of its life the normal individual tree increases in wood production and then declines, it is bad economy to cut it while it is still growing rapidly or to allow it, after slowing down, to occupy ground which might be used by a tree still in the vigor of production. For example, if at 100 years old it contains 500 board feet, it has averaged an addition of 5 feet, a year throughout its life. If at 125 years old it contains but 560 feet, the average increment will be but 4-1/2 feet a year. It will not give equal return for the soil, moisture and light it monopolizes during these 25 years. At the same time, probably there are young trees nearby which hitherto have averaged below the maximum, but if released from its competition will forge ahead for a period at the end of which they will give a greater annual return than if cut at present. It would be as bad economy to cut these today as to spare the over-mature tree. In short, the production of the forest is not only sustained, but actually increased, by removing the oldest trees at just the proper time; and is decreased by taking out young trees either not yet at the natural age of greatest mean annual increment or capable of artificial stimulation by thinning.
By studying the relation of age to production in the particular locality, the proportion of different age classes, and also finding the approximate average diameter which corresponds to the age at which he desires to cut, the professional forester can make a very accurate selection of the trees which can be removed to best advantage at present and also fix the time and yield of the next cutting. Fortunately, however, commercial and silvicultural considerations accidentally coincide so nearly under average yellow pine conditions as to make certain rough rules which can be laid down entirely consistent with logging methods now in practice. Diameter is far from exact indication of age, for the location of the forest and the situation of the individual tree, especially as it affects the relation between height and diameter growth, are potent factors, but as a rule merchantability for saw-material is not far from maturity.
In a great majority of cases the approximate minimum diameter for cutting which would be fixed by it forester would be somewhere between 16 and 30 inches, but say it were 18 inches, for example, it would not arbitrarily apply throughout the stand. Most trees with yellow, smooth bark and small heavy-limbed tops, perhaps partially dead, are mature regardless of their size. If small, they have been crowded or stunted and may as well be cut. Trees with large, healthy crowns composed of many comparatively small branches, and with rough dark bark showing no flat scaling, are sure to be growing rapidly, even if quite large. They are also less desired by the lumberman, who often calls them black pine or black jack, so may often be spared, without much sacrifice, for seed trees or in order to continue their rapid wood production.
The seed tree problem in such a pine forest and under such a system as has been described is comparatively simple, for there are likely to be enough young trees of fruiting age left to fill up the blanks between existing seedlings. The density of the latter determines to a large extent the number and location of seed trees necessary, but there should always be two to four to the acre, even if this requires leaving some that would otherwise be logged.
Under this system recurring cuts may be made at periods of perhaps 30 or 40 years, taking out each time the trees which have passed the minimum diameter since the last previous cut. It is obvious, however, that if the process is to continue indefinitely, protection must be absolute. Destruction of young growth will stop the rotation at the time the surviving older material is harvested. At each cut the brush should be disposed of with this end in view. If the stand is very thin it may not add much to the danger of fire and, especially if reproduction is difficult and requires shelter, may best be left spread on the ground at some distance from remaining trees. Otherwise, and this is the rule, it should be piled and usually burned. In this process and in logging every effort should be made to protect existing young growth from injury. Ground fires should be prevented now and always hereafter.
So far, however, we have been considering how to make the most of a stand of many ages, due to constant reproduction permitted by the light supply in a fairly open forest. On the other hand, yellow pine sometimes produces a mature stand so heavy that there is little young growth beneath it, or even a thin old stand with either little reproduction or an invasion of lodge-pole pine. Such conditions are usually due to fire at some period. In the first of these cases, usually the dense stand has resulted from a fire which destroyed its predecessor not so completely as to remove the seed supply, but sufficiently to afford light for a more uniformly dense crop of seedlings than would occur in the normal forest. These have been thinned out as the stand grew old, but never to a degree which allowed much reproduction beneath them. The natural cycle will be begun again in time, for toward the end of the life of this unusually heavy stand, seedlings will begin to appear gradually as individual old trees die and admit more and more light. The other exceptions described are due to more recent ground fires which have destroyed only the less hardy young growth and perhaps also encouraged the lodge pole which, within its range, is always quick to take burned ground.
The same result is almost sure to follow the "Indian" method of forest protection sometimes advocated, which consists of purposely running ground fires frequently in order to prevent accumulation of sufficient debris to make an accidental fire fatal to timber of commercial size. While such immunity may be secured, and perhaps without sacrifice in stands so heavy as to have no reproduction or when the latter has already been destroyed, it is obviously at the expense of young growth if any exists. The counter argument that a small proportion escaping will be sufficient for the second crop is fallacious, because good timber will not be produced from these scattering seedlings subjected to strong light by later logging. Other means are necessary if the forest is to be reproduced.
This brings us to the possible management of yellow pine as an even-aged forest. Thoughtful foresters are beginning to suspect that while the "Indian" system of fire protection will usually be fatal if ordinary logging practice is followed, it may serve as an adjunct to a system which, if carefully applied, will be better than selection cutting for some of our pine areas. This plan is suggested where there is little young growth worth protecting and consists of depending upon seed trees almost entirely for reproduction, protecting carefully until the resultant even-aged second growth is large enough to stand Blight fire, and then burning periodically at such a season and with such safeguards as will prevent the fire from being injuriously severe.
Not only are there many existing forests where absence of small trees will permit clean cutting without sacrifice, but the same condition is likely to occur eventually in stands following selective logging if the second cut is long delayed. Although a good representation of all ages under the diameter limit remains, the density of this may become too great to allow further reproduction, and in time the dominant trees will shade out all smaller growth. To allow this purposely, choosing heavy cuts at intervals long enough to mature the crop from seed rather than frequent light cuts of a constantly replenishing stand, thus reducing the necessity of fire prevention, is the aim of those who favor clean cutting as the most practicable system. They assume that additional investment in seed trees, or planting to insure prompt starting of a new crop after cutting, will be unnecessary or at least offset by the smaller fire charge and greater economy of logging.
Theoretically, such practice with a species adapted to the selective method is uneconomical, for the ground is not fully utilized. Accidental open places in the stand are not occupied by young trees which would otherwise fill them. Time is lost by not starting the second crop until after logging, for were there no fire previously there would be considerable seedling growth which, although perhaps dormant because of shade, would begin to amount to something much quicker than that supplied by seed trees afterward. Nor is the system feasible where there is much fir or other species less fire-resisting than pine. It is dangerous in practice except where there is very little combustible matter on the ground and fire is generally easy of control, and exceedingly dangerous to advocate because serves as a pretext and example for indiscriminate carelessness with fire under all conditions. Finally, the alleged immunity of pine from injury by ground fires is exaggerated. As a matter of fact, while the whole stand is seldom perceptibly hurt, the immediate or gradual death of a good tree here and there thins the stand very considerably in a few years and it is such a thinning process in the past which makes many pine tracts bear but 5,000 feet to the acre where otherwise they would yield two or three times as much. Scorching also retards the growth of trees not actually injured otherwise.
The technical objections given above may sometimes be offset by practical advantages and the system is likely to receive expert approval for certain conditions provided it is not used as a cloak without taking sincere steps to replace the destroyed second growth by adequate seed trees or artificial seeding. The latter danger may easily warrant public alarm manifested by restrictive laws. Universal ground burning of green timber will distinctly reduce the prospect of unassisted natural reforestation on the great area of potential timber land in which, as a resource, regardless of ownership, the public is vitally interested. Under present conditions at least, a large proportion of this is likely to be logged without any view to a future crop. It is questionable whether any state should, or will, legally approve ground burning except under stipulation of proper management thereafter.
Unfortunately, it is necessary, in concluding this discussion of yellow pine, to admit that while an attempt has been made to outline the methods which will insure a second crop, the promise of satisfactory financial return is more doubtful than that offered by some other species. Compared with the typical coast trees, such as Douglas fir, spruce and hemlock, the growth is slow and the yield small. The chief circumstances in its favor are low land values, lesser fire risk, cheapness and certainty of reproduction and excellent market prospects. Less investment compensates somewhat for longer rotation and smaller yield. Low taxation, however, is an absolute essential.
Although as a distinct forest type this valuable tree is limited chiefly to Idaho, it occurs occasionally in mixture or small tracts over a wide range, and no reason appears why its commercial importance should not be extended by planting on cut-over lands. Its high value, rapid growth and heavy yield make it a particularly promising species for growing under forestry principles. Its chief requirements for success are fairly good moist land, access by the seed to mineral soil and ample light for the young seedlings.
Except that it is more fastidious as to soil, white pine usually demands about the same treatment as that prescribed for Douglas fir, including clean cutting, slash burning and establishing a new even-aged stand by seed trees or artificial restocking. Under favorable conditions the stand is nearly even-aged, with little undergrowth except of undesirable species. What small pine may exist is seldom thrifty enough to be worth saving, so the best thing is to clean off the ground for the double purpose of removing weed trees and favoring valuable reproduction. Like that of fir, the natural rotation of white pine forests seems to have been accomplished often by the aid of fire, and where not given this aid it suffers from lack of suitable seed-bed and from the competition of other species already established.
Individual seed trees left in logging are not successful because of shallow root system and almost certain windfall. Replacement must be by seeding or planting, or by leaving small tracts of pine surrounded by cleared fire lines to protect them when the slashing is burned. The size and distance apart of these must be determined by their situation and exposure to wind, considering both the danger of windfall and the carrying of seed. Especially in younger growths, the quantity of merchantable material tied up in this way is not so great as is sometimes necessary in the case of red fir, where single seed trees may contain several thousand board feet. On the other hand, stumpage value may be high. For this reason artificial replacement may often be more profitable, especially where there is reasonable safety against recurring fire.
A thing to be borne in mind is that white pine seems to reach a healthier and better development when mixed with a small proportion of other species, such as cedar, tamarack, spruce, lodgepole pine and Douglas fir, so there is no object in trying to produce an absolutely pure stand. Some authorities think that 60 per cent of pine, with the rest helping to prune it, is an ideal mixture.
Present interest in private reproduction of this species hardly warrants treating it at length in this publication, although unquestionably it will eventually occupy a higher place in the market than at present and its readiness to seize burned land in many regions will make it a factor whether desired or not. Where yellow pine will grow, the problem is most likely to be to discourage lodgepole competition.
In strictly lodgepole territory, however, it may be the only promise of a new forest. Generally speaking, an even-aged growth should be induced by clean cutting if the entire crop can be utilized. Slash burning in such cases is desirable. The chief difficulty is in providing seed supply, for either individual seed trees or small groups are almost certain to be blown down. Experiments so far indicate that heavy strips must be spared, chosen to afford the least present loss and safeguarded by fire lines.
In some lodgepole stands, especially where only certain sizes are marketable, the cutting practically amounts to thinning. Here obviously the effort should be to prevent over-thinning and to remove debris with the least damage to the remaining stand. Piling and burning is essential.
This extremely valuable pine, commercially limited to the Oregon and California mountains, is fastidious in its choice of conditions. Not a frequent or prolific seed bearer, it still insists on a moist loose seed-bed and prefers the natural forest floor to burned-over land. It cannot stand drought when young and except on cool northern slopes seedlings may be killed or stunted by exposure to full sunlight. On the contrary it demands more and more light as it grows older and will be suppressed or killed if unable to secure it. Under natural conditions it perpetuates itself best by filling open places in the forest.
For the above reasons, sugar pine is naturally a component of mixed forests and it is doubtful whether it will be successfully grown as a pure stand. Unfortunately, also, logging methods which are both the simplest and most favorable to the reproduction of its associates may be discouraging to sugar pine reproduction. Nevertheless, its value warrants strong efforts to favor it and is an argument, where considerable young sugar pine exists, against either clean cutting or the use of fire.
The Forest Service, for which authority much of the above discussion of this species was taken, offers the following general outline for management in California:
"Since the forests in which sugar and yellow pine occur vary greatly in composition, the method of treatment must also vary. For this the forest types already distinguished may form a basis.
"On the lower portion of the sugar pine-yellow pine type, where sugar pine forms but a small proportion of the stand, only the yellow pine should be considered for the future forest. All merchantable sugar pine may therefore be removed. It will be necessary to leave only a few seed trees of yellow pine to restock the ground, although usually it will be a wiser policy to leave a fair stand, since this can be removed as a second cutting when reproduction is established. This procedure would also hold for areas on which yellow pine occurs in nearly pure stands. In these localities dense stands of second-growth yellow pine occur. It will often be profitable, where there is a market at hand, to thin these stands when they are about 30 years old, removing the suppressed trees for mine props. Trees 6, 8 and 10 inches and up are used for this purpose, and sell for from 5 to 6 cents a running foot.
"On the upper portion of the sugar pine-yellow pine type, where both species have about an equal representation in the stand, seed trees of each should be left, wherever practicable, in the proportion of two sugar pines to one yellow pine."
In the fir belt, where sugar pine and fir are the principal species, the fir should be cut clean wherever possible and sugar pine should be relied upon for the future forest.
"On all lands, the Douglas spruce, white fir and incense cedar should be cut whenever possible, and chutes, skidways and bridges should be constructed from the two last named species."
The following specific instructions are issued for marking timber on National Forest sales in the sugar pine-yellow pine type:
"Owing to the large size of the trees, marking in this type of forest should be done with special care, since a slight mistake involves a comparatively large amount of timber.
"On nearly all of the lands included in this type the ground is now but partly and insufficiently stocked with young timber, the areas of forest are constantly becoming more accessible to markets, and there is every indication of a strong future demand at greatly increased prices. On nearly every tract, a second cut can be made within thirty years. All marking under present sales should be done strictly with reference to two points:
"1. Stocking the cut-over land as fully as possible with sugar and yellow pine.
"2. Securing a second cut within thirty years.
"All cutting should be done under the 'selection system,' which requires a careful choice of the individual trees to be removed. Fixed diameter limits and the leaving of any specified number of seed trees per acre can be very largely disregarded.
"The condition of every sugar and yellow pine on the sale area should be studied closely to determine whether that tree will be merchantable thirty years hence, by which time a second cut is probable. As a rule the trees which will remain merchantable for another thirty years should be left. Suppressed and crowded trees which cannot develop should be removed. Under this system of marking, ordinarily about one-half of the present stand of merchantable pine would be left uncut. Will it pay?
"On areas where practically all of the pine is over-matured and would be cut under the rule given above, a sufficient stand must be left to reseed thoroughly the cut-over land. This requires not less than four full seed-bearing trees, at least 25 inches in diameter, per acre. The strongest and thriftiest trees available should be selected for this purpose, but not less than the number specified must be left even if every tree will be a total loss before a second cut is possible.
"Extensive areas of pine timber which are not yet fully mature should be excluded from the sale. On patches or small areas of immature pine, which it is not practicable to exclude from the sale, cutting should be very light, limited to one-third or less of the largest trees, or omitted altogether.
"No attempt to discriminate sharply between sugar and yellow pine should be made, as both trees are almost equally desirable. Where a choice is necessary, sugar pine should be favored on moist situations, as in canyons, moist pockets, or benches and on northerly exposures. Yellow pine should be favored on dry situations, including exposed ridges and southern exposures.
"Fir and incense cedar should be marked, as a rule, to as low a diameter as these trees are merchantable in order to reduce the proportion of these species in coming reproduction. It is essential, however, that no large openings be made in the present stand since the exposed ground is in danger of reverting to chaparral or of becoming so dry from evaporation that no reproduction will follow cutting. Where the stand of pine is insufficient to reseed thoroughly and protect the cut-over area, enough sound, thrifty fir and cedar should be left to form a fairly even cover with openings less than a quarter of an acre in size.'"
The under current of all opinion upon sugar pine up to date is that reproduction will not be very successful unless enough growth to shelter the seedlings remains after logging. Where the fire risk permits, the same end may be furthered by leaving the tops scattered on the ground.
Little experimenting has been done in planting sugar pine, but there are many indications that except where conditions strongly favor natural reproduction it will be resorted to eventually if any particular attempt is made to get this species. Leaving large seed trees is not only expensive, but rather uncertain, because heavy seed years are several years apart and squirrels consume a large portion of an ordinary crop. Transplants which have received nursery shelter until past the greatest danger of drying out should prove most successful on heavily-cut south slopes.
Although probably the most rapid-growing of all American commercial trees and also of high market standing, redwood has been little studied by foresters. The layman is still more confused by its many peculiarities. Growing to a size of 20 feet in diameter and 350 feet high, reaching an age of well over 1,000 years and seldom reproducing by means of seed, it is not surprising that it was long regarded as ill-adapted to second crop management. Although observing that suckers sprout from the stumps with great rapidity, the lumberman generally regarded these mushroom growths as abnormal and temporary, and believed his virgin timber to be the finally-vanishing remnant of a prehistoric species unsuited to present-day conditions.
It was next discovered that the suckering habit is no new one, indeed that the majority of the present stand, however old, began as sprouts from roots or stumps of its predecessors. This is evident from the circular arrangement of several trees around the spot where their parent stood. These old sprouts were of very slow growth, for they were shaded by a forest of extreme density. As seedlings they could have neither germinated nor grown, but as suckers they were kept alive by the parent until light supply became available through their increasing height or through thinning of the forest. Under such conditions centuries were required to produce large trees.
The owner of today, by cutting down the old stand, gives the suckers conditions hitherto unknown to the redwood. The vigor and susceptibility to the aid of light, which originally was necessary in the sprout growth to perpetuate the species at all, now respond to entire freedom and light in an astonishing manner. Even after severe slashing fires char the stumps, the latter throw out clusters of sprouts which grow several feet a year. Logging works 30 or 40 years old have come up to trees nearly 100 feet high. Naturally such timber has a heavy percentage of sapwood and is soft and brittle, but it is already suitable for piling, box lumber and like purposes and improves constantly.
Since reproduction by seed does not enter into the problem, financial possibilities depend almost wholly on the nature of the original stand. There are many types of redwood forest, pure and mixed, flat and slope. If the old trees are few to the acre, the sprout clusters will be so far apart that excess of side light will produce clumps of swell-butted, short limby trees, of little use for lumber; that is, unless there is also a seedling growth of fir or other species to fill the blanks and bring up the density. Where such a nurse growth is to be counted on, or where the redwood trees are small and close together, ideal conditions for a certain, rapid and well formed second crop exist.
The thinner the original redwood stand, the greater the effort necessary at the time of logging to obtain the required density. The leaving of seed trees of other species, with as many as possible small trees of both redwood and other species and the maximum protection of all from fire, should then be the means employed. On some tracts the proportion of redwood will not warrant this effort; on some it is not even required. The question of whether it pays to hold redwood land is therefore almost wholly local, but when conditions are favorable it can be answered affirmatively, because of the extremely rapid growth, with less doubt than of almost any other species.
There is some tendency to over-production of sprouts by redwood stumps. Removal of the excess with an ax, saving those closest to the ground and not over-thinning to the extent of reducing the density conducive to height growth and shedding of low branches, improves the chances of those remaining.
It has been shown in a previous chapter that the owner of deforested land who desires to secure a second crop may find it necessary or cheaper to adopt artificial measures wholly or in part instead of depending upon natural reproduction. These measures may be of two kinds—direct seeding, in which the seed is sown where the trees are to stand permanently, and the planting of trees grown in nurseries.
Whether artificial reforestation is accomplished by means of sowing seed or planting trees, the first requisite is a supply of tree seed of the desired species and of good quality. Unfortunately for the timber owner who wishes to enter upon extensive seeding operations, the business of collecting and preparing forest tree seed for market has received but little attention from old-established seed firms, and it is not always possible to purchase the species and quantity desired. Moreover, the prices charged are often excessive.
In the Pacific Northwest, however, the demand for seed of Douglas fir and Sitka spruce has led to the establishment of a considerable trade in these species, and at reasonable prices, so that where these species are to be used, or only small quantities of other species, the timber owner will probably find it to his advantage to purchase the seed rather than to attempt collecting it himself. Douglas fir seed is quoted at $1.40 to $2.00 per pound and Sitka spruce seed at $2.25 to $3.00.
In purchasing seed it is common practice to specify that it shall be of the new crop, because tree seed kept in ordinary storage loses its vitality materially. When properly stored in air-tight receptacles, however, as is now done by some seed dealers, it will retain its germinative power for several years with only slight depreciation. Moreover, fresh seed, if improperly treated, may be of very poor quality, so that the age of the seed is of little value in the determination of its worth and the only sure method of ascertaining this is by means of germination or cutting tests. The latter method is the quickest and most simple and consists of cutting open a number of the seeds and ascertaining the per cent whose kernel is sound, plump and moist. Seed of good average quality should contain not more than 25-30 per cent of infertile seed.
When seed cannot be purchased, it is necessary to collect. Since no species of coniferous trees bear abundant crops of seed each year and often several seasons will elapse between good crops, it is necessary to gather sufficient seed when the supply is abundant to provide for succeeding years when the crop is apt to be a failure.
The seed ripens in the fall, usually during August or September, and the cones should be collected at that time. Pines require two years in which to mature the seed; that is, the cones are not fully formed and the seed ripe until the second fall after the fertilization of the flowers in the spring. Most of the other important conifers ripen their seed in the fall of the same season. Shortly after the seed is ripe, the cones open and allow it to disseminate, consequently they must be gathered before this occurs.
The cones are gathered either by climbing the trees and cutting them off from the branches, by picking from the tops of felled trees, or by robbing squirrels' hoards. Where squirrels are abundant in the forest, the last method is the cheapest. Climbing trees is practiced only where the trees are small. When this method is employed, the workmen should be equipped with linemen's belts and climbers. Picking from felled trees is readily carried on except where dense underbrush interferes, as is the case in the ordinary Douglas fir forest.
Trees growing in the open, with large crowns extending down the greater part of the bole, bear cones more abundantly than trees in dense forests, and for this reason collecting from scattered open growths can be done more cheaply than on logging areas. Often large quantities of cones can be purchased from settlers who will collect and deliver them at central points at a stipulated price. When this method is employed, however, frequent examination of the cones should be made to ascertain that they contain the full number of seed, for often opened cones from which a part or all of the seed has been disseminated will be offered for sale. Insect larvæ also often destroy a large proportion of the seed, particularly when the crop is light and care should be taken that the cones purchased are not infested. The prices paid for cones vary from 25 cents to 50 cents per sack for the larger cones, like yellow and white pine, and 50 cents to $1.00 for Douglas fir and spruce, depending upon the abundance of the crop.
After the cones are gathered the seed must be extracted and cleaned. Where climatic conditions in the fall of the year will permit air-drying, the cones may be spread out on sheets or blankets where they will be exposed to the sun and wind. Under this treatment they will open in from 3 to 6 days, depending upon the weather and the species. Where bad weather will interfere with air-drying, the cones must be dried undercover by artificial heat. This is the method usually employed by professional seed collectors, and where large quantities of cones are to be treated each year special dry houses are constructed and fitted with elaborate drying apparatus. The work can be done most cheaply with such an establishment, but for the ordinary timber owner who expects to collect seed only occasionally, a makeshift dry-house which will answer the purpose can be fitted up inexpensively in any unused building. The essential features are shelves or trays 4 feet wide arranged around the walls of the room, one above the other and separated about 8 inches apart, and a heating stove placed in the center of the room. The shelves may be made of burlap stretched tight, or, better still, of wire screening of 1-1/2 inch or 3/4-inch mesh.
After being subjected to a temperature not exceeding 110° Fahr. for from 24 to 48 hours, the cones will open, allowing the seed to fall out when shaken or pounded. The seed when separated from the cones is then mixed with a coarse gravel in about the proportion of 4 to 1 and churned to remove the wings. Finally, all foreign matter is removed by screening and hollow seed blown out by passing it through an ordinary fanning mill.
The selection of the method of reforestation to employ, whether direct seeding or planting, depends primarily upon the character of the area to be restocked. Direct seeding is usually considerably cheaper when the results are satisfactory, but only on the more favorable sites where moisture and soil conditions are right is there any assurance of success. Even in such cases partial or total destruction of the seed often results from birds and rodents. In exposed situations where the soil is shallow, or where because of climatic conditions soil dries out several inches deep during the growing season, the seed may not germinate at all, or the young seedlings may be killed before they have time to send their roots down to the permanent moisture level. In such situations, planting is the only reliable method. If the plant material is of the proper kind and the work well done, satisfactory results are almost certain to follow. Direct seeding is a much more rapid method than planting, and where extensive areas are to be restocked within a short period and seed is abundant, the work can be completed quickly. On the other hand, this method is wasteful of seed because a large proportion fails to germinate and the young seedlings often succumb to adverse conditions, so that where seed is scarce or its cost high, planting is the more practical method.
Because planting is the most reliable method it has been the one most largely employed in extensive operations, both here and in most European counties, but thorough tests are now being made of direct seeding and under proper conditions it promises to be fairly satisfactory. The Douglas fir region west of the Cascade Mountains offers the most favorable conditions for direct seeding and except on badly exposed south slopes, or where the growth of brush is exceedingly dense, it is believed this method will prove a satisfactory one for the timber owner to employ.
In the yellow pine regions conditions are not so satisfactory for direct seeding, since this tree occurs largely in a region of deficient rainfall. However, natural reproduction is abundant throughout many portions of this type, and it is probable that direct seeding will prove fairly successful if the proper methods are employed and if forest conditions have not been too greatly disturbed. That some method of successfully employing direct seeding with yellow pine be found is greatly to be desired, since yellow pine seedlings do not withstand transplanting well, but there is need for careful experimentation before extensive seeding operations in this type by private timber owners would be justifiable.
Western white pine, it is believed, will be easy to reproduce in most of its native situations by direct seeding, though the greater scarcity of its seed and the fact that it will be more subject to destruction by birds and rodents because of its larger size may make planting the more practical method.
Trees for planting can either be purchased from commercial nurserymen or grown in nurseries established for that purpose near the planting site. When only a few thousand trees are needed it is cheaper to purchase them, but when extensive operations are contemplated, covering hundreds of acres in which millions of trees will be needed, it is far preferable for the owner to grow the trees in his own nursery. Some initial outlay for the establishment of the nursery will be necessary and a practical nurseryman should be employed, but the saving in the cost of the trees will fully compensate for these.
One, two and three year old trees, the latter once transplanted, are usually employed in planting, the older trees being used for the less favorable sites. In planting they are placed in rows equidistant apart, the spacing varying from 4 to 12 feet, with a general average of about 6 feet. The work may be done either in the fall after growth has ceased or in the spring before growth commences.
The cost of planting, of course, will vary greatly with the age of the trees, the number planted per acre and the accessibility and character of the planting site. With young trees and wide spacing, the cost may be as low as $6.00 per acre, while in more unfavorable situations where older plants are used and planting is more laborious it may be as high as $16.00. A fair average, however, for those areas which a timber owner would be most likely to plant up is about $8.00 to $10.00 per acre.
In direct seeding, several different methods may be employed, such as broadcasting over the entire area with or without previous preparation of the soil, sowing in strips, or sowing in seed spots; but observation and experiment have shown that it is necessary for seed such as Douglas fir, yellow pine and western white pine to come in close contact with the mineral soil in order that it may germinate and the seedlings live; consequently only those methods should be used which will accomplish this. Where the area has been burned over previous to sowing and the mineral soil laid bare, broadcast seeding may be employed. Where the ground will permit the use of a harrow good results are obtainable by scarifying the soil in strips about 10 feet apart and sowing the seed in these strips. On unburned areas covered with a dense growth of fern, salal, moss, grass, or other plants, this covering must be removed by the seed spot method. This consists in removing the ground cover with a grub hoe or mattock in spots of varying diameter (6 inches to 3 feet) and of various distances apart (6 to 15 feet), and sowing the seed in these spots. The advantages of this method are that a minimum amount of seed is used; the ground can be prepared and the seed covered to whatever extent is desirable, and the soil pressed down. This method is believed to be the one best suited to the greatest variety of sites.