SAMPLING STRATEGIES ALONG THE TREE STEM TO DETERMINE THE BASIC DENSITY OF Eucalyptus WOOD

Abstract

Background: There is a need to find a simpler sampling strategy that still maintains the accuracy of the results. This work aimed to assess different sampling strategies for measuring the basic wood density of Eucalyptus clones along the tree trunk.

Results: The basic wood density of most Eucalyptus clones was affected by the sampling strategy employed. The average density varied between samples, ranging from 476.69 to 449.61 Kg m^-3. In this study, the base positions generally showed lower density averages. Traditional sampling best represented the variation trend in Composite sampling due to their similar behavior. Depending on the clone and sampling methodology, the diameter at breast height represented 91.85 to 99.74% of the overall average stem. All adjusted equations were significant, allowing the basic density to be estimated through smaller sampling regions along the tree trunk. When the goal is to evaluate the property at four sample points, the best model corresponds to the heights in the upper half of the stem, which are the higher regions.

Conclusions:  The analyzed base-top sampling strategies did not show significant differences between them, except for the one that only considered the diameter at breast height, which underestimated the basic density value of the wood. Sampling Alternative 1 effectively estimated the average density when considering all clones as a single material, which is the best strategy for measuring basic density under the conditions in the present study. Sampling positions at 50% of the tree's commercial height were more associated with the basic density.