Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties. 1. Basic density
Raymond, CA and Munari, A, Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties. 1. Basic density, Wood Science and Technology, 35, (1-2) pp. 27-39. ISSN 0043-7719 (2001) [Refereed Article]
A non-destructive sampling strategy for basic density, based on removing 12 mm bark-to-bark cores, was developed in E. globulus and E. nitens. Fifty trees of each species, aged 5 to 9 years, were sampled across a range of sites. Core samples were removed on both a north-south and an east-west axis from 6 fixed heights in the base of the tree (0.5 m, 0.7 m ..., 1.5 m). Whole-tree values were calculated from disc samples removed at eight percentage heights (0, 10, 20, ..., 70%) and correlations between the cores and whole-tree values were used to determine the optimal sampling height. Core samples were found to be reliable predictors of whole-tree density, explaining between 84% and 89% of the variation between trees. Core sampling of E. globulus and E. nitens to estimate basic density of whole-trees and stands is feasible; cores from trees at all E. globulus sites gave high correlations with whole-tree values. For E. nitens, site differences were apparent, and it is recommended that a small destructive sa mpling program should be undertaken prior to commencing a major sampling program. Recommended optimal sampling heights are 1.1 m for E. globulus and 0.7 m for E. nitens. Core orientation was not important and density was not related to tree size. Six whole-tree samples or eight core samples are required for estimating the mean density of a stand at a specific site to an accuracy of ±20 kg m-3 with a 95% confidence interval.