Forests of Crater Lake National Park
The Forest Cover.
Second to the wonderful blue lake in the crater of the former Mount Mazama, the most attractive feature of the park is its heavy mantle of beautiful coniferous forests. Within the confines of the park there are represented more than a dozen cone-bearing species—pines, firs, hemlocks, and others—growing in pure bodies or mingled together, forming a confused, broken cover. The few broad-leaf trees that climb this high in the mountains are mostly small and shrubby, forming all underbrush in the open forests and thickets in the moist ground along the streams.
The various trees of the southern Cascades are not generally scattered throughout the mountains, but are distributed in fairly well defined zones at different altitudes, depending upon the temperature and amount of moisture they require. East of the Cascade Range the general elevation of the south-central Oregon plateau is between 4,000 and 5,000 feet, and here the climatic conditions are widely dissimilar from those that prevail on the western side, where the surface is several thousand feet lower in the valleys of the Rogue and Umpqua Rivers. For this reason the typical forests on the east and west slopes differ greatly in composition, and from each side merge into a nearly common type of forest on the summit of the range.
Crater Lake National Park, on account of its position, therefore, has mainly the characteristic forest cover of the higher mountains, but within a few hours’ ride from any entrance the tree species found are those common in the lower portion of either the eastern or western Oregon region.
At the lowest elevations in the Rogue River Valley and on the Klamath side the forests are composed of species that endure warm summer temperature and thrive in the dry and powdery soil. Here the predominating tree is western yellow pine, which on the west slope occurs mainly with scrubby oaks, madrona, and small Douglas fir. On the Klamath side, where the general elevation is higher, yellow pine is very abundant and forms magnificent forests either alone or associated with Douglas fir, white fir, lodgepole pine, sugar pine, and incense cedar.
As one ascends the west side the composition of the open yellow-pine forest changes at middle elevations to more dense stands, in which Douglas fir is the most abundant tree. Here also are other species, such as western hemlock, western red cedar, white fir, and lodgepole and sugar pine, that prefer the cooler and more moist situations.
By the time the park is reached many of these trees become fewer in number, and their place is taken by trees of the higher altitudes. The dense forests around the edges of the park and on the lower slopes of the former Mount Mazama have a large number of species, among them several of the true firs, Douglas fir, lodgepole pine, Engelmann spruce, mountain hemlock, and western white pine.
Climbing still higher, to the very rim of Crater Lake, and up the slopes of the surrounding peaks, the forest becomes more scattered and the trees smaller and more stunted. Only a few species endure the low temperature, high winds, and deep snows at these altitudes, the principal ones being alpine fir, mountain hemlock, and white-bark pine.
Very often scattered trees are found far above or below the general limits of their range. Alpine species descend cool, moist canyons far down into the drier yellow-pine region, and the trees of the lower country occasionally reach far up into warm favorable areas at the higher altitudes.
No matter which route may be taken to reach the park, this gradual change from one forest type to another is very evident, and this transition offers much to excite the curiosity and interest of the observer.