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

by E. T. Allen

BRUSH PILING

In the more open pine stands of the interior, where both logging debris and original combustible ground cover are small, slashings threaten the adjacent timber less than in denser forests, but are of peculiar danger to the valuable young growth usually left on the area itself. As we have seen in a previous chapter on western yellow pine, reproduction in dry localities may require scattering the brush over the ground and keeping fire out, and there may be abnormally dense stands suggesting clean slash burning, but as a rule brush piling is the best course. In view of the importance of this subject the following extracts are taken from a circular issued by the Forest Service:

"Advantages of Brush Burning

"The greatest advantage of brush burning is the protection it gives against fire. In many cases brush burning is the only practicable safeguard against fire. After the average lumbering operation the ground is covered with slash, scattered about or piled, just as the swampers have left it. This, in the dry season, is a veritable fire trap. Probably 90 per cent of all uncontrolled cuttings are burnt over, which retards the second crop at least from fifty to one hundred years and perhaps permanently changes the composition of the forest. Fires may be set by loggers while still at work on the area or several years after by lightning, campers, or locomotives. By piling the brush and burning it in wet weather, or in snow, when there is no danger of the fire spreading, all inflammable material is removed, and the second growth can come up without serious risk of being destroyed. Even where only part of the brush is burned and the rest is piled, as when the piles in open places, along ridges, streams, or laid off lines are burned, very much is gained in case of fire, since these cleared lanes form bases from which a fire may be fought.

"Besides lessening the danger from fire, brush burning has certain minor advantages. When the brush on the ground is removed it is much easier for rangers and others to ride or walk through the forest. This may be very important in case of a fire or in rounding up cattle. It is also much easier to cut and handle ties, cordwood, or other timber which may later be taken from the cut-over areas if the slash is out of the way. By piling and burning the green brush as it is cut from the trees by the swampers, as is now being done in Minnesota and parts of Montana, the ground is cleared and skidding is made easier and cheaper. Again, careful piling and burning of brush improves the appearance of the forest. There is nothing much more unsightly than a recently cutover area where no attempt has been made to dispose of tops and lops. Near towns or resorts and along roads or streams frequented by tourists this point should be carefully considered, but as a general rule the utility of the forest should not be sacrificed for beauty.

"Disadvantages of Burning

"The disadvantages of burning brush are many and, with the one exception of protection from fire, far outweigh the advantages. If protection can be had in some other way, as with more efficient patrol service or more stringent laws, the practice should in many cases be abandoned. In many places, especially in the yellow pine type, the best, and often the only, reproduction comes up under a fallen treetop or other brush. Where there is little of the old stand left, the straggling open top protects the seedlings from the direct heat of the sun. Yet brush not only protects the seedlings from the sun but, what is more important, the leaves and broken twigs form a cover which retards evaporation of moisture from the soil. Over the greater part of the West the soil dries out very rapidly during the dry season, and this serious retards or even prevents the growth of seedlings. Even in the moister regions, such as that of the Engelmann spruce type, it is very necessary to conserve the moisture in the soil after logging to prevent the remaining trees from being killed through lack of soil moisture. A third reason why seedlings so often come up only under the down treetops is that they are protected from stock. Next to drought, sheep are perhaps the most serious menace to reproduction, and though it would be best to keep all stock off the area for several years after logging, in many cases this is not practicable, and on many areas the leaving of the tops on the ground is the only way to protect reproduction from injury.

"In many places after the timber has been cut off gullies and washes start in the old wheel ruts, log slides, etc., and these and other forms of erosion can best be prevented by leaving the brush on the ground, either laid in the incipient washes or scattered over the soil that is likely to wash. Brush burning destroys the valuable soil cover, and on the spots where the piles are burned the soil is loosened, which renders it even more liable to erosion.

"It is well known that where the forest is burned each year the soil becomes poorer and poorer, because nitrogen, the chief fertilizing ingredient of the soil, is given off in the smoke, and only the mineral elements go back to the soil in the ashes. And, what is more injurious, the humus—i. e., the decomposed vegetable matter in the top soil—is destroyed. In burning brush after logging all the fertilizing and humus-forming leaves and twigs are destroyed just when most needed, for another good crop or leaves cannot be expected for many years.

"The added cost, both to the lumberman and to the Government, is another argument against brush burning. The cost of piling brush has varied all the way from 15 cents to $1 or more per thousand, with an average or 40 or 50 cents, while the cost or burning may be from 5 cents to 25 cents per thousand, averaging about 15 cents. By abandoning the practice of brush piling this 60 cents a thousand will not be entirely saved, as is claimed by some, for the brush will still have to be lopped and disposed of in some other way, which will cost, it is estimated, at least half as much as piling and burning. But even a saving of 25 or 30 cents a thousand is a strong argument against the practice.

"Thus, from a silvicultural viewpoint, the disadvantages of brush burning far outweigh its advantages. Yet, as a general policy, it seems unwise, until other methods have proved their efficiency, to abandon brush piling and burning to any great extent at present. The fire danger is a known quality, and, though it is being reduced each year, it is still a menace. Therefore changes from the present practice should be made with caution. Brush piling and burning is certainly not advisable in all cases, and extensive experiments should be made to determine what is the best method of brush disposal for the different types and conditions.

"Brush Piling and Burning

"The cost of piling varies with the cost of labor, the methods of logging, the type, the topography, the kind of trees cut, and the time of the year it is done. A few figures will illustrate this variation. In the yellow pine type in Montana an addition to the swampers' wages of 15 cents a thousand would, it is said, enable them to pile the brush, as they have to handle it anyway. Usually, however, the piling is done by a separate crew. Much of the work is thus duplicated. In yellow pine in the Southwest, brush piling costs from 45 to 50 cents, while in Montana it can be done for 25 cents. One operator in lodgepole in Montana says it is cheaper for him to pile than not to, because he can get his skidding done so much cheaper, yet on other operations it has cost from 50 cents to $1 a thousand, depending on how thoroughly it is cleaned up. In the sugar pine type of California the cost of piling averages from 25 to 35 cents, while the cost in the Douglas fir type, in Montana and Idaho, averages about 40 cents, and in Engelmann spruce type the cost is only about 25 cents a thousand. It is certain, however, that the cost of piling will everywhere be materially reduced when the operators begin to look on piling as part of the swampers' regular work and not as an entirely separate job.

"Dry brush should never be burned during the dry season, unless absolutely necessary for the suppression of an insect invasion. Green brush in some places may be burned at any time, but as a rule it is unsafe to burn it in dry weather. The best time to burn brush is in the fall, just after the first snowfall. Then the piles are dry, and there is no danger that the fire will get beyond control. Brush may also be burned at the beginning of or during the rainy season, when the ground is damp enough to prevent the fire from spreading, and the brush dry enough to burn readily.

"The cost of brush burning varies like the cost of piling. It varies even more in the same localities, with weather conditions and methods of piling. Brush that can be burned for 10 or 15 cents a thousand at a favorable time, as just after the first snow, will cost five or ten times as much to burn in dry weather, or when the piles are very wet. Brush can be burned more easily the first fall after cutting than it can the second year, when many of the leaves have fallen off. Brush burning has been done for 13 cents a thousand in lodgepole, in the Medicine Bow National Forest, while it has cost 22 cents in similar timber in the Yellowstone, and estimates of 40 cents a thousand have been made for it in the Rockies. It is generally admitted that brush can be most economically burned by the same people who pile it. Recently several contracts have been made in which the purchaser of the timber is required to pile and burn the brush under the direction of forest officers, as has been the practice in the Minnesota forest for some time. This will lighten the total cost, and when the weather allows the brush to be burned, as logging proceeds, the cost of burning will be offset by the subsequent reduction in the cost of skidding.

"Piling Without Burning

"Brush piled properly, even though it is not burned, is a great protection to the forest. Inflammable material is removed from among the living trees, and should a fire occur it would be much easier to fight. This is especially true where reproduction is dense. Where openings are scarce piles should be made in the most open places, and may be larger than those made to be burned."