1. We examined the relation between bark thickness and girth in a larg
e sample of trees from evergreen and semi-evergreen rain forest. 2. Th
ere is a significant tendency for bark thickness to increase with tree
girth. Removing this tendency, we find a significant trend for specie
s from more disturbed habitats to possess thicker bark. 3. Species fro
m more disturbed habitats also have a greater propensity for secreting
gums and resins, 4. Nine of the 29 species occurring in more than one
habitat type and with a sample size of at least 11 individuals show a
tendency for possession of a thicker bark by individuals in the more
disturbed habitats. 5. We conclude that bark thickness and occurrence
of gums and resins are physiognomic-structural attributes of value in
characterizing tree communities created by different levels of disturb
ance.