"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."
SLASH BURNING
In many regions, especially in western Oregon and Washington, logging debris is too great to make piling practicable. But except for the damper localities close to the Pacific, the danger from these immense accumulations is all the more excessive and, as we have seen elsewhere, their removal is often desirable in order to further reforestation by desirable species. Here the only course is to burn the slashing clean.
This is a dangerous process unless every safeguard is employed. Burning must be at a time in spring or fall when the slashing is dry enough but the surrounding woods are not. Spring burning is theoretically preferable, for it leaves less inflammable material during the fire season. The first fire is also easier to control then, because repeated experiments may be made, as the slashing dries, until just the right conditions exist. On the other hand, it is dangerous if there are many old stumps and logs in which fire may smoulder to make trouble later. The exponents or fall burning also argue that with care they can be ready to fire a very dry slashing safely at the beginning of a rainstorm. Spring burning seems to have the most advocates, but it is doubtful whether any rule for all localities and conditions can be given with confidence. Frequently failure at one season leads to postponement until the next.