856 A NATIONAL PLAN FOR AMERICAN FORESTRY 



the larger merchantable trees without harm to the seedlings, saplings, 

 and immature trees that are usually present. However, these types 

 are not immune to destruction. Fires in slash following logging can 

 and do destroy all tree growth. 



An outstanding example of the effect of man on the forest is found 

 in Eldorado County, Calif., where the ponderosa pine belt is being 

 pushed back and up the Sierra slopes. Because of man and his 

 occupation of the land, there has 'been a retreat of nearly 10 miles 

 from the 1,000-foot to the 2,500-foot level on a 30-mile front, leaving 

 a deforested area of about 160,000 acres. In addition, there is an 

 area of second growth nearly as large, three fourths of which is less 

 than half stocked. And this condition is typical not only of the 

 entire western front of the pine belt in the Sierra Nevada but of the 

 Douglas fir belt of the California coast ranges. The change from 

 forest to deforested land has come about very gradually. Some of the 

 deforestation may be attributed to the Indian, but undoubtedly the 

 larger part has occurred since the advent of the white man, whose first 

 inroad probably began with the establishment by Capt. John Sutter 

 of a sawmill at Coloma. By 1870 the lower ponderosa pine belt had 

 been largely logged off. Successive fires have completed the change. 



In the redwood type, high-speed power logging and severe fires, 

 as a part of the logging operation for slash disposal and subsequent 

 fires resulting largely from carelessness, leave cut-over areas in bad 

 condition, but the sprouting capacity of redwood is insurance against 

 complete devastation in all but the exceptional cases. 



Insects are a contributing factor in rendering softwood lands non- 

 productive. When extensive outbreaks of insects develop in forest 

 types composed chiefly of one species of tree or several species that 

 are subject to attack by the same insect, a high percentage of the 

 stand may be destroyed. The standing dead trees go down in the 

 course of a few years, making an impenetrable tangle of tree trunks 

 and tops through which reproduction is struggling. Fire starting at 

 this stage is difficult to control. Outbreaks of the mountain pine 

 beetle in lodgepole pine have been followed by fires which left great 

 areas destitute of timber for many years. Outbreaks of defoliating 

 insects in the spruce-fir type of the Rocky Mountains frequently 

 destroy every tree, even down to an understory of reproduction. 

 Fire that starts under these conditions likewise leaves barren land 

 in its wake. Many bald ridge tops and barren scars in the mountains 

 of Arizona and New^ Mexico are unquestionably the result of out- 

 breaks of defoliating insects followed by fires. 



Available data indicate that new areas are being devastated at the 

 rate of about 850,000 acres each year; but against this annual increase 

 should be credited an allowance for the new forests that are growing 

 up slowing on areas long ago devastated. It may, indeed, be doubted 

 whether there is any net annual increase in the total area of devas- 

 tated forest land. Protection from fire, abundant seed crops, and 

 moisture conditions favorable for the establishment of seedlings fol- 

 lowing the period of germination are among the influences tending to 

 reestablish tree growth on areas long unproductive. In the Lake 

 States, for example, with better protection from fire in effect in 

 recent years, much of the cut-over forest land is being restocked 

 naturally with tree growth of some kind, usually jack pine, maple, 

 and aspen. In the South and in other regions, there is a similar 



