INTRODUCTION 



Tree crowns are a vital component of forest biomass and the functioning of forest 

 ecosystems. The capability to estimate tree crown biomass is needed for evaluating 

 fire behavior potential of forest fuels, productivity, nutrient cycling, fiber utiliza- 

 tion, and interception of rainfall and radiation. The study reported here, initiated 

 out of the need to appraise forest fuels, deals with estimation of weights and sizes of 

 crowns for commercial conifer species in the Rocky Mountains. 



Objectives of the study were to: 



1. Determine relationships for predicting weight of both dead and live tree 

 crowns, from d.b.h., crown length, tree height, and crown ratio. 



2. Determine the fractions of crown weight for foliage and branchwood by diameter 

 size classes of to 0.24 inch (0 to 0.63 cm), 0.25 to 0.99 inch (0.64 to 2.53 cm), 

 1.00 to 2.99 inches (2.54 to 7.61 cm), and 3.00 inches (7.62 cm) and larger (fig. 1). 

 Determine the relationships among the fractions, species, and d.b.h. 



Figure 1. — Foliage and 

 branchwood size classes ^ 

 for determining moisture 

 content and size frac- 

 tions of crown material. 



1 



