FIRE, EASTERN SLOPE.
Fires have done more injury in this reserve than all other causes put together. It is believed that fire has occurred in every township within the reserve and in nearly every section, and it is evident that many hundred thousand feet of timber have been destroyed. Fires increase, in general, proportionately to the extent of human occupation of any region up to the time when a change of public sentiment takes place. After that time the safety of the forest increases in proportion to the density of population. Protection against fire is made difficult at present by the absence of trails and by the nature of the forests.
The larger number of fires on this slope are said to be kindled by campers and Indians. Sheep men have undoubtedly been responsible for many fires in the past, and, as noted by Mr. Coville, the broken character of the forest which permits them to graze their herds on this reserve would not have existed without the agency of fire.
Fires started in heavy timber are often exceedingly difficult to extinguish. Such a fire was burning in the vicinity of the Lake of the Woods, in the southern part of the reserve, August 27 and 28, 1896, and was carefully studied at that time. At 6 p. m., although it was said to have been started on the morning of the same day, it had already burned holes from 2 to 3 feet deep, following, the roots of dead trees, and was slowly spreading along the surface. The vegetable litter on the ground was dry; but, except for the dead timber standing and prostrate in the woods, this fire would have died out of itself. It was kept alive and enabled to spread chiefly by the fallen logs. Where such a log lay on the ground the fire either crept along its under surface near the ground if the bark had fallen, or if the bark remained it moved usually beneath it, reappearing at intervals along the trunk and igniting the dry humus and litter within reach. Half-rotten logs carried the fire with bright flame even when the bark had not fallen. Dead standing stubs from 50 to 90 feet high assisted powerfully in spreading the damage, for the fire ascends such trunks beneath the bark, reappearing at intervals, and burning fiercely under the chimney-like draft established. Instead of falling at once such stubs break off high above the ground from time to time and scatter burning fragments far and wide. In heavy winds the blazing bark is detached and carried far ahead of the main fire, and so forms a powerful factor in carrying and spreading the conflagration. To extinguish this particular fire, which was said to have been wantonly started by a party of campers, would have required the labor of several men for at least a day.
Fires in the open yellow pine do much less serious damage and are far easier to control.
WATER, EASTERN SLOPE.
The effect of forests on irrigation in the lava area of the southern portion is probably not important, since all rain sinks at once into the ground and reappears in the enormous springs which dot the country here and there. Farther north the question is different. The testimony on this point is conflicting, but by far the greater weight of evidence tends to show that the flow of streams has already been seriously influenced by forest fires. The supply of water from this slope is very important to local settlements and should be protected.
MINING, EASTERN SLOPE.
I am not aware that mines of any importance have been developed or that prospects for such development exist.
AGRICULTURE, EASTERN SLOPE.
Agriculture within the reserve can never be important. A few ranches are included by the boundaries, but, so far as known, little cultivation is carried on, as the climate is unfavorable.
GRAZING, EASTERN SLOPE.
The most important question touching the reserve at this time regards the pasturage of sheep. During the past summer about 190,000 sheep were grazed within the reserve, two-thirds of which occupied ranges on the eastern slope. The careful investigation of Mr. Coville, botanist of the Department of Agriculture, the study by Mr. Henry S. Graves under my direction in 1896, and other trustworthy evidence leave no room to doubt that the pasturage of sheep on any area constitutes, so long as it lasts, a prohibitory tax on the reproduction of the forest.
It can not be questioned that sheep grazing in this reserve owes its existence directly to forest fires. Without such fires the openings where the sheep feed would never have been made, nor, after they were made, would many of them have been kept so free from trees. It is almost equally certain that sheep herders in the past have been in the habit of setting fires, although the evidence at hand goes to show that of late years this practice has been largely discontinued. Grazing in fresh burns is apt to be followed by the discoloration and cheapening of the wool.
