Appropriateness of Non-Destructive Measures of Young Pine Tree Performance in Weeding Experiments

SYNOPSIS The objective of this work was to compare several commonly used measures of tree performance in three commercially grown pine species (Pinus patula, P. taeda and P. elliottii) during the first growth season in a weeding experiment. Both tree mortality and above-ground tree biomass measures indicated that there was significant tree suppression by weeds for all three species. Using above-ground biomass as an absolute measure of tree performance it was clear that root collar diameter was far more sensitive to treatment effects than height. A derived index combining both height and root collar diameter was consistently the most closely correlated with above-ground biomass. Leaf: stem ratios were significantly different between the three species, and between different weed regimes.