Effect of pruning and thinning intensity on Eucalyptus nitens leaf area

Abstract

Eucalyptus nitens is an important commercial fast growing species planted mainly in Chile and Australia (Tasmania). In Chile there are not previously published studies quantifying leaf area in adult forest plantations of E. nitens. This study presents the effect of pruning and thinning intensities, applied at age 6 in a E. nitens stand, and on the amount of leaf area sustained at 15 years old. A factorial experiment considering pruning (0 m, 3.5 m and 7 m height) and stocking (1,100, 800 and 400 trees ha-1) was established in 1989 near Los Álamos town in central Chile. Using the average tree method, 27 trees were sampled destructively for biomass and leaf area assessments. Projected leaf area, leaf area index, and specific leaf area were estimated for each sampled tree. The results indicate that projected leaf area and leaf area index reached a maximum of 64.7 m2 tree-1 at 400 trees ha-1 stocking and 3.48 m2 m-2 at 800 trees ha-1 stocking respectively. Specific leaf area was higher (43.2 cm2 g-1) at higher stocking (1,100 trees ha-1). For all treatments projected leaf area and leaf area index were higher in the central section of the crown. Allometric relationships were obtained using diameter at the base of the live crown and stump diameter. The information presented in this study allows giving a more functional explanation of the horizontal and vertical behavior of the leaf area, at different stocking.