22 STATE BOARD OP FORESTRY. 



San Diego. The localities in which the groves measured are situated 

 are mentioned in tables 4 to 10. No plantations are growing in other 

 sections of the State from which data upon growth and yield can be 

 obtained, but the tables will undoubtedly indicate closely the growth of 

 blue gum throughout its planting range. 



The majority of the groves measured were situated in Southern Cali- 

 fornia, and the data were collected after the succession of exceptionally 

 dry years in that section from 1898 to 1903. The growth of plantations 

 was considerably retarded during that period of very low rainfall, the 

 sites, occupied by the groves giving the lowest yield, being generally 

 those most unfavorably affected by the drought. The majority of the 

 groves when measured were less than eight years old, hence their 

 growth does not represent the maximum productive capacity of their 

 sites. It is believed the tables are very conservative for the growth of 

 blue gum in California. 



Tables 1 to 3 show the volumes of blue gum trees in cubic feet, cords 

 and board feet. For these tables measurements of seedlings and sprout 

 trees were combined, since they differ but little in form and habit of 

 growth. The cubic foot and cordwood tables are based on the computa- 

 tion of the contents of entire trees. The volume and the clear length 

 only, scaled by the Scribner rule, was used for the board foot table. 

 Owing to the scarcity of plantations of older and larger trees, volumes 

 tan not be given for trees over 160 feet in height, 24 inches in diameter, 

 and 30 years of age. 



In both the volume and yield tables for cordwood, the New England 

 cord of 128 cubic feet is used. The results were obtained by dividing 

 the figures given in the cubic foot tables by 90 cubic feet, which repre- 

 sents very closely the average solid contents of a cord of Eucalyptus 

 wood. However, the New England cord is little used in California, a 

 cord of 96 cubic feet, or about 65 cubic feet solid contents being in 

 general favor. To change from New England to California cords, the 

 amounts should be increased one-fourth. 



Tables from 4 to 10 record the growth and yield of individual blue 

 gum plantations. Separate tables have been constructed for seedling 

 and sprout plantations upon different types of soils. Portions of many 

 sprout groves have been cut at different periods, and represent the 

 growth at different ages. Therefore, different portions of the same 

 groves are often separated in the tables to permit arrangement of the 

 sample plots by successive ages, and to show the progress of growth 

 and yield. 



In the sprout yield tables the number of trees in the column showing 

 the present stand per acre is often several times as great as would 

 result from the spacing mentioned. This is due to the number of 



