Phenology of tree species in Bolivian dry forests

Phenological characteristics of 453 individuals representing 39 tree specie s were investigated in two dry forests of the Lomerio region, Department of Santa Cruz, Bolivia. The leaf, Bower, and fruit production of canopy and s ub-canopy forest tree species were recorded monthly over a two-year period. Most canopy species lost their leaves during the dry season, whereas nearl y all sub-canopy species retained their leaves. Peak leaf fall for canopy t rees coincided with the peak of the dry season in July and August. Flushing of new leaves was complete by November in the Early rainy season. Flowerin g and fruiting were bimodal, with a major peak occurring at the end of the dry season (August-October) and a minor peak during the rainy season (Janua ry). Fruit development was sufficiently long in this forest chat fruiting p eaks actually tended to precede flowering peaks by one month. A scarcity of fruit was observed in May, corresponding to the end of the rainy season. W ith the exception of figs (Ficus), most species had fairly synchronous frui t production. Most canopy trees had small, wind dispersed seeds or fruits t hat matured during the latter parr of the dry season, whereas many sub-cano py tree species produced larger animal- or gravity-dispersed fruits that ma tured during the peak of the rainy season. Most species produced fruit annu ally. Lomerio received less rainfall than other tropical dry forests in whi ch phenological studies have been conducted, bur rainfall can be plentiful during the dry season in association with the passage of Antarctic cold fro nts. Still, phenological patterns in Bolivian dry forests appear to be simi lar to those of other Neotropical dry forests.