On the slopes and summits of the ridges it is sandy, gravelly, and liberally strewn with masses of drift bowlders. The flats largely formed of silting while they still constituted beds of lakes, have a deep soil of fine sand and mold resting on coarse gravel and bowlder drift. Ridges composed of brecciated lavas, which crumble easily under the influence of atmospheric agencies, are covered with soil two or three feet, or even more, in depth, where gentle slopes or broad saddles have favored deposition and prevented washing. The granite areas of the main range and elsewhere have a very thin soil. The flats at the entrance of small streams into Lake Tahoe are covered with deep soil, owing to deposition of vegetable matter brought from the slopes adjacent to their channels. As a whole, the soil of the region is of sufficient fertility to support a heavy forest growth, its depth depends wholly on local circumstances favoring washing and removal of the soil elements as fast as formed, or holding them in place and compelling accumulations.[[11]]
Coniferous species of trees constitute fully ninety-five per cent. of the arborescent growth in the region. The remaining five per cent. consists mostly of different species of oak, ash, maple, mountain-mahogany, aspen, cottonwood, California buckeye, western red-bud, arborescent willows, alders, etc.
Of the conifers the species are as follows: yellow pine, pinus ponderosa; Jeffrey pine, pinus jeffreyi; sugar pine, pinus lambertiana; lodge-pole pine, pinus murrayana; white pine, pinus monticola; digger pine, pinus sabiniana; white-bark pine, pinus albicaulis; red fir, pseudotsuga taxifolia; white fir, abies concolor; Shasta fir, abies magnifica; patton hemlock or alpine spruce, tsuga pattoniana; incense cedar, libocedrus decurrens; western juniper, juniperus occidentalis; yew, taxus brevifolia.
[!-- Note Anchor 11 --][Footnote 11: John B. Leiberg, in Forest Conditions in the Northern Sierra Nevada.]
The range and chief characteristic of these trees, generally speaking, are as follows:
Digger Pine. This is seldom found in the Tahoe region, except in the lower reaches of the canyons on the west side of the range. It is sometimes known as the Nut Pine, for it bears a nut of which the natives are very fond. It has two cone forms, one in which the spurs point straight down, the other in which they are more or less curved at the tip. They grow to a height of forty to fifty and occasionally ninety feet high; with open crown and thin gray foliage.
| A gnarled monarch of the High Sierras,
an aged Juniper, near Lake Tahoe Click photo to see full-sized. |
Western Juniper. This is a typical tree of the arid regions east of the Sierra, yet it is to be found scattered throughout the Tahoe country, generally at an elevation between five thousand and eight thousand feet. It ranges in height from ten to twenty-five or even sixty-five feet. Its dull red bark, which shreds or flakes easily, its berries, which begin a green color, shade through to gray, and when ripe are a rich purple, make it readily discernible. It is a characteristic feature of the scenery at timber line in many Tahoe landscapes.
With the crowns beaten by storms into irregular shapes, often dead on one side but flourishing on the other, the tops usually dismantled and the trunks excessively thickened at base, such figures, whether erect, half overthrown or wholly crouching, are the most picturesque of mountain trees and are frequently of very great age.—Jepson.
Yew. This is not often found and then only in the west canyons above the main range. It is a small and insignificant tree, rarely exceeding forty feet in height. It has a thin red-brown smooth bark which becomes shreddy as it flakes off in thin and rather small pieces. The seeds are borne on the under side of the sprays and when mature set in a fleshy scarlet cup, the whole looking like a brilliantly colored berry five or six inches long. They ripen in July or August.