STUDIES IN NORTHERN CALIFORNIA 199 



the season of greatest injury, the relative damage to the various 

 important timber species, the extent of injury both from brow- 

 sing and trampHng, and under what conditions grazing may aid 

 forest reproduction. From the facts ascertained it was hoped 

 to develop a plan of grazing which would prevent serious injury 

 to the young growth. 



Based upon three examinations in 191 1 and 191 2 of plots con- 

 taining 11,040 plants, consisting of sugar pine, white fir, Douglas 

 fir, yellow pine, and incense cedar, all of a size subject to injury 

 by grazing, the following results were recorded of the damage 

 caused by sheep and by cattle, respectively: 38.3 per cent and 

 8 per cent of the yellow pine reproduction, 21.8 per cent and 19 

 per cent of the Douglas fir, 48.3 per cent and 11 per cent of the 

 white fir, and 26.9 per cent and 12.5 per cent of the sugar pine. 

 These figures include all types of injury, much of which was so 

 sHght that most of the reproduction recovered fully in later years. 

 For the period of observation, only .03 per cent of 10,888 speci- 

 mens on the plots were killed by grazing. During this time, 155 

 young tree plants were killed by other agencies than stock. The 

 factors chiefly instrumental in the destruction of the stand were 

 drought, disease, and rodents. The only serious injury noted 

 was on goat and sheep ranges, and this was due entirely to faulty 

 management of the stock. 



As early as 1897, Coville^ investigated the injuries from sheep 

 grazing on forest growth in the Cascade Mountains of Oregon. 

 It was found that over most of the reserve of 4,493,000 acres, em- 

 bracing the main ridge of the Cascade Mountains, the actual 

 damage to the growth of timber was confined chiefly to small 

 areas, such as bed grounds and trails. On heavily overgrazed 

 range, where the forage was badly trampled, the stunted growth 

 of pine seedlings was frequently seen. 



Working on the National Forest range lands of Oregon gen- 

 erally, Munger^ concluded that the timber reproduction was 



1 Coville, Frederick V., "Forest Growth and Sheep Grazing in the Cascade 

 Mountains of Oregon." U. S. Dept. of Agr., Div. of Forestry, Bui. 15, 1898. 



2 Munger, Thornton T., "Western Yellow Pine in Oregon." U. S. Dept. of 

 Agr. Bui. 418, 1917. 



