Effects of thinning on development of southern pine beetle infestations in old growth stands

Abstract

A study was conducted to quantify the relationship between southern pine beetle infestation growth and the intertree spacing in old growth pine stands. The problem with extrapolating the results of previous studies to old growths tands is that it is unclear whether the same mechanism will operate in stands of older trees characterized by double the diameter (20-25 cm vs. 40-60 cm). In this study we focused on experimentally answering the question of how three levels of thinning (resulting in different average intertree distances) affect the rate of SPB infestation growth in mature loblolly pine stands, over 60 yr old and over 40 cm average dbh. We also included a hardwood removal treatment. Both intermediate and severe thinning had a strong negative effect on the rate of infestation growth. The effects of intermediate and severe thinning were similar; there was no statistically detectable difference between these two treatments. Hardwood removal appeared to decrease infestation growth rate compared to no thinning, but this effect was not statistically significant.

Citation

Turchin, Peter; Davidson, James; Hayes, Jane Leslie. 1999. Effects of thinning on development of southern pine beetle infestations in old growth stands. South. J. Appl. For. 23(4):193-196.