Comparative regeneration ecology of three leguminous timber species in a Bolivian tropical dry forest

A comparative study of the regeneration ecology of three lesser-known legum inous timber species was conducted in the seasonally dry forests of Santa C ruz, Bolivia to determine species regeneration strategies and make silvicul tural recommendations for these species. The study included a representativ e from each subfamily of Leguminosae: Anadenanthera colubrina (Vell. Conc.) Benth. (Mimosaceae), Copaifera chodatiana Kunth. (Caesalpinaceae), and Cen trolobium microchaete C. Martius (Fabaceae). After production in the mid-la te dry season, seeds of all species suffered high (> 30%) rates of predatio n. For seeds surviving predation, Anadenanthera germinated within three day s after the first rains and a high germination capacity (82%), but most see dlings died from inadequate light or during subsequent periods of drought. Copaifera germinated more slowly but had high germination capacity (85%). C entrolobium had very low germination capacity (4%) and germinative energy. Most successful regeneration of Centrolobium occurred via sprouting from da maged roots on or near logging roads where it had a density of 261 root spr outs/ha. Anadenanthera regenerated best from seed in areas with soil distur bance or burning. The regeneration of these species will likely increase un der more intensive logging and/or post-harvest competition control treatmen ts in logging gaps. The more shade-tolerant Copaifera is most suited to the current regime of light selective logging, but all three species are likel y to be responsive to post-harvest competition control treatments. Impacts of controlled and natural fire were mixed, but generally seedling regenerat ion and growth were either not significantly affected or were increased by fire.