© 2001 Heron Publishing—Victoria, Canada
Crown structure and leaf area index development in thinned and unthinned Eucalyptus nitens plantations
Jane L. Medhurst (1, 2) and Chris L. Beadle (1, 3)
1. Cooperative Research Centre for Sustainable Production Forestry, GPO Box 252-12, Hobart, Tasmania, 7001, Australia / 2. Department of Plant Science, University of Tasmania, GPO Box 252-55, Hobart, Tasmania, 7001, Australia / 3. CSIRO Forestry and Forest Products, GPO Box 252-12, Hobart, Tasmania, 7001, Australia / Received August 18, 2000
Summary
The crown structure of Eucalyptus nitens (Deane & Maiden) Maiden 6 years after thinning, and the development of stand leaf area index both immediately and 6 years
after thinning, were investigated. Thinning did not alter branch angle, branching density or the relationship between branch
size and branch leaf area. However, larger branches were found in the lower crown of thinned trees and the increase in leaf
area as a result of thinning occurred on the northern aspect of the crown. The vertical distribution of leaf area in unthinned
trees was skewed toward the top of the crown and correlated with live crown ratio. The vertical distribution of leaf area
in thinned trees tended to be less skewed and was unrelated to tree size or dominance. Leaf area index, as estimated from
light interception measurements, increased at a constant rate soon after thinning regardless of residual stocking. In the
longer term, residual stocking had a strong influence on leaf area increase per tree and was correlated with changes in crown
length.
Keywords:
branch angle, branch size, branching density, thinning, vertical leaf area distribution.
