The Dependence of Volume Increment of Individual Trees on Dominance, Crown Dimensions, and Competition

A study of the volume increment of individual trees over onegrowing season in a 23-year-old stand of Sitka spruce (Piceasitchensis Carr.), indicated that narrow crowned trees weremore efficient producers of increment. Other factors being constant,trees of greater girth at breast height were found to be inherentlybetter producers. Trees of the upper canopy were generally moreefficient than those of the lower canopy under varying conditionsof competition. Shorter periods of growth were recorded in lowercanopy trees and with trees under conditions of greater competition.