TREE GIRDLING TREATMENTS FOR TIMBER STAND IMPROVEMENT IN BOLIVIAN TROPICAL FORESTS

Abstract

The efficacy and costs of three tree girdling treatments to remove non-commercial trees were evaluated in both dry and humid Bolivian tropical forests that were recently harvested. The treatments included chainsaw girdling only and chainsaw girdling immediately followed by application of two different herbicide solutions (glyphosate and 2,4-D) to the girdled surfaces. Two years following the application, girdling + 2,4-D killed more than 75% of the crown on 75% of treated trees, while girdling + glyphosate and girdling only treatments killed 61 and 14% respectively. No significant differences in treatment efficacy were observed between forest types, although there were differences
between tree species in response to treatments. Glyphosate killed trees more slowly than 2,4-D. Treatment costs were $0.16 / tree for girdling + 2,4-D, $0.32 / tree for girdling + glyphosate and $0.09 / tree for girdling only.