where 



Y = 0.661X + 0.143 



Y = tree specific gravity 



X = specific gravity at breast height 



The correlation coefficient is 0.754; the standard error of estimate is 0.021 



Figure 2. --Relation of mean tree specific gravity calculated by the 

 stem section method to core specific gravity at breast height. 



There is a growing need for information on wood quality and weight both by indus- 

 tries that manufacture and use wood products and by public and private agencies re- 

 sponsible for forest production. Wood users are interested in specific gravity because 

 it is related to strength properties. For example, reliable estimates of hardness, 

 static and impact bending, and compression can be derived from specific gravity values. 

 Also, reasonably good estimates of the paintability and gluability of wood can be made. 

 In management planning, conversion of forest inventories and yield estimates from a 

 volume to a weight basis is contingent upon a reasonably accurate method of determining 

 the specific gravity of standing trees. 



Because of the basic utility of a knowledge of wood specific gravity and the in- 

 creasing use of lodgepole pine for lumber, poles, and pulp, future research in this 

 species should include determinations of specific gravity for the entire range of sites, 

 ages, and tree sizes. 



4 



