Measuring Diameter Increment Caused by Western Spruce Budworm Defoliation in Britisch Columbia : Environmental Influences on Tree and Stand Increment. Mensuration, Growth and Yield Instruments and Methods in Forest Mensuration. Proceedings

1986

2 Abb., 8 Lit. Ang.

Unselbständiges Werk

7453

200017631

Stand surveys to determine diameter loss in Douglas-fir caused by western spruce budworm defoliation are reported. The number of reducedrings and the diameter loss per tree averaged 4.4 rings and 0.8 cm, respective ly. Both were positively correlated with the defoliation level, and were negatively correlated with tree age. Since the standard deviation of the mean diameter loss for the stand was correlated with the mean loss, which in turn was correlated to the tree growth rates, more samples are required to estimate diameter growth loss in faster rather than in slower growing stands.