16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



of Quercus chrysolepis, never grow within the timbered, or coniferous, 

 belt. These live oaks, therefore, occupy a continuous belt of country 

 which is free from snow except for occasional short periods. This belt, 

 for this reason, is used as a winter range for holding-over stock when 

 feed is scarce in the valleys and deep snows cover the mountains. 

 Sheep and goats are kept in good condition on these live oaks, but 

 cattle and horses do not eat them to any extent until other food can 

 not be obtained. Then this "browse" keeps them in feed until other 

 kinds are available. 



The deciduous oaks, not taking into account the Quercus douglasii, 

 which is of little forage value, are found in the timber belt or above it. 

 The leaves of the deciduous oaks, in contrast to the harsh spinescent 

 ones of the live oaks, are larger, lobed, and soft. This enables cattle and 

 horses to eat them with ease, as is also true of sheep and goats. They 

 actually fatten on the leaves of the Black Oak and White Mountain 

 Oak of these upper ridges and peaks. 



Nutritive Value of the Leaves. From the observations just recorded 

 concerning these several species of oaks, it would seem that the nutritive 

 value increases with the altitude. To verify this, and to ascertain if 

 possible their relative food values, a chemical analysis of each species 

 was made. 



For the purpose of this analysis the leaves were gathered during the 

 month of September, when they were fully mature. Only those which 

 were green and vigorous were taken. These were dried in a room of 

 ordinary temperature, and were then ground to a fine powder. 



It would seem that the irritating and poisonous oil of Poison Oak 

 (Rhus diversiloba) is volatile at a comparatively low temperature. In 

 gathering the specimen the writer was badly poisoned, even though 

 gloves were worn; yet after drying at ordinary room temperature, and 

 the leaves pressed into the mill with bare hands, no poisoning effects 

 followed. 



In the analyses of these oak leaves, the methods for foods, as set forth 

 in Bulletin No. 46, Bureau of Chemistry, U. S. Department of Agri- 

 culture, were followed. In this work, however, some errors appeared in 

 the ether extract and in the nitrogen-free extract. These errors were 

 due to certain peculiarities of composition of the oaks. 



In the determination of fat, or ether extract, quantities of chlorophyll, 

 the green coloring matter in the leaves, remained in the extract. No 

 quantitative method being known for the extraction of chlorophyll, this, 

 together with the gums and resins which are contained within the leaves 

 or on the tomentum and pubescence of the outside, increased the ether 

 extract beyond its true percentage. After determining the nitrogen-free 

 extract, which consists of sugar, starch, pentosans, etc., the percentage 



