Ponderosa pine, Jeffrey pine, mixed conifer, and white fir forests of the Cascade and Sierra Nevada Ranges of California have been important resources and were extensively altered by timber harvest between 1850 and 1950. Many historical logging operations were small in size and of short duration. Other operations encompassed thousands of acres and existed for relatively long periods of time. Before settlement of California by Europeans, there were extensive forests in the Cascade and Sierra Nevada Ranges of California, much of it suitable for timber production. The forests were dominated by a variety of tree species depending on factors such as elevation, precipitation, aspect, and soils of the particular location. Tree species found as monocultures or in mixed assemblages include ponderosa pine (Pinus ponderosa), Jeffrey pine (P. jeffrey), sugar pine (P. lambertiana), lodgepole pine (P. contorta), California white fir (Abies concolor lowiana), incense-cedar (Calocedrus decurrens), and California black oak (Quercus kelloggii). The forests, especially those dominated by ponderosa and Jeffrey pine, generally were composed of small stands of even-aged trees interspersed with other even-aged patches of different ages. Vegetation found under the forest canopy was generally composed of perennial grasses with few shrubs. The logging industry evolved from the labor-intensive and inefficient days of the 1850's to the relatively efficient railroad logging methods of the 1930's and later. Annual production of timber ranged from as little as 500,000 board feet in the early 1850's to nearly 5 billion board feet by 1950. By 1950, at least 20 percent of the forests in the Cascade and Sierra Nevada Ranges bad been harvested as least once. Because of their value as lumber and the susceptibility of sugar pine to white pine blister rust (Cronartium ribicola), ponderosa and sugar pine declined, and incense-cedar and California white fir increased over those parts of the forest where they coexisted. At present, trees are, in general, younger and smaller in diameter and height; however, occasional larger, older trees that were left after logging can still be found. Also, grasses have declined and higher amounts of shrubs and small trees are now found under the tree canopy.
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