The park is now under the management of a military commander as acting superintendent, aided by a detachment of United States troops, who maintain order, prevent acts of vandalism, and see that the rules and regulations of the park are obeyed. No one except the troops is allowed to bring firearms into the park, and the wild animals, now carefully protected by law, have greatly multiplied. Through subsequent acts of Congress two forest reserves have been added to the park proper, the Madison Forest Reserve in 1902 and the Yellowstone Forest Reserve in 1903. These additions make the total area reserved from settlement about seventeen thousand six hundred square miles.
The only living beings that are permitted to fell as many trees as they wish are the beavers, which use them in constructing their dams. The grizzly and the black bear flourish in the park and have become quite tame. In the neighborhood of the camps and hotels they have become an intolerable nuisance because of their propensity to break into tents and buildings in search of food.
The lordly elk nourishes here and numbers of them may be seen at almost any time of day. A herd of buffaloes is jealously protected, and food and shelter are provided for them during the winter when necessary. These animals are increasing in numbers. Many antelope, deer, and mountain sheep are seen in the park.
The mountain lion and the coyote are two animals that the authorities of the park feel justified in killing in order to preserve the other game, but the wild ruggedness of the territory, which affords these pests ample opportunity to multiply unmolested, prevents their extinction.
During the fall of the year wild geese and ducks frequent the park in great numbers; some of the latter remain all winter long in places where the hot springs keep the water of the streams from freezing. The United States Fish Commission has taken special care in stocking the fishless streams with trout, and now the Yellowstone Park furnishes the finest trout-fishing in the whole world. Visitors to the park are granted full license to fish, but they must use only hook and line.
About one-fifth of the reservation consists of tracts suited for grazing, but for agricultural purposes the park is worthless, since frosts occur every month of the year.
The forests consist of a variety of trees, but only one kind, the Douglas spruce, is suitable for good lumber. The quaking aspen is the only deciduous tree that is abundant. Elk and deer browse about these trees and keep them trimmed at a uniform distance from the ground.
During the long rainless season the distant hills and mountains are bathed in an atmosphere of soft purple and blue in ever-varying intensity, while later in the season Jack Frost with his magic brush paints the mountain-sides with the most varied and gorgeous colors, and the aspen changes to rich autumnal tints.
At the proper season Yellowstone Park is a vast garden of wild flowers which are dense and rich in colors even up to the snow line. Several varieties of the lupine and the larkspur clothe the hillsides with every shade of color, while the modest violet seeks secluded spots in which to bloom. Forget-me-nots, geraniums, harebells, primroses, asters, sunflowers, anemones, roses, and many other plants are abundant.
The climate puts new life and energy into the visitor. Contrary to the general opinion, the climatic conditions in the park are not extreme, notwithstanding its high elevation. The average temperature at the Mammoth Hot Springs in January, the coldest month, is 18° F., and in July, the hottest month, 61°. In the plateau regions, averaging fifteen hundred feet higher, the temperature is 8° in January and 51° in July.