Crown Cover Is Correlated with Relative Density, Tree Slenderness, and Tree Height in Lodgepole Pine

Abstract

Abstract The objective of this study was to investigate the relationship between tree height, bole slenderness, and relative density with crown shyness (crown interstitial space) in even-aged lodgepole pine. In 10 lodgepole pine stands in Alberta, Canada, ranging in height from 5.6 to 22.1 m, 9–23 triangular plots were established. A plot consisted of three trees that formed the corners of the triangle; all plots were at theoretical crown closure. Within each triangle, the percentage crown closure (% CC) was related to the mean height, slenderness coefficient (SC, tree height/diameter), and relative density (RD) of the trees that defined the triangle. Within the stands less than 12 m in height, % CC was positively correlated with RD. Within most of the stands greater than 15 m, % CC was negatively correlated to SC. Mean % CC declined with increasing stand height. Results suggest that RD is strongly related to % CC in short stands but as trees grow in height, biomechanical issues related to stem form (i.e., SC) probably play a large role in determining the amount of canopy coverage. We suggest that taller trees with high SC are more flexible, resulting in intense crown collisions, crown abrasion, and crown shyness. FOR. SCI. 50(3):356–363.