Circular Distribution of Branches from Plantation Grown Black Spruce in Ontario

Abstract

Abstract The literature is not consistent in descriptions related to branch location around a stem and, consequently, few models exist to predict distribution of branch azimuth. The objective of this study was to determine if branches in black spruce are uniformly distributed around the stem at the tree, log, and whorl levels with respect to branch size. Branch size limits were selected to reflect the largest branch per whorl and knot size limits were established by visual grading rules for 2 × 3 and 2 × 4 dimension lumber. Using Rayleigh's test of uniformity, branches are considered to be uniformly distributed around the stem for all branch size limits: between 40 and 80% at the tree level, over 70% at the log level, and virtually 100% at the whorl level. The findings of this study indicate that a simple random assignment (from a uniform distribution) of branches around the stem within each whorl is sufficient to properly describe branch location within black spruce tree growth models.