The conservation of Bolivian big-leaf mahogany (Swietenia macrophylla King.) forests requires of provenance trials to identify potential seed King.) forests requires of provenance trials to identify potential seed sources. Survival and early growth of seedlings are regarded as key variables in provenance trials. Two provenance trials were installed in an open secondary forest. Five Bolivian mahogany provenances, which belong to the pre-Andean Amazon (A and SC), Chiquitano-Amaon transitional (B and CH) and the Amazon (C) ecoregions, were evaluated. Mixed models with repeated measurement Amazon (C) ecoregions, were evaluated. Mixed models with repeated measurement data were used to analyze survival rate, height growth and root collar diameter of seedlings, as well as seedling vigour. After 12 months of plantation, survivorship of all provenances was much lower at site 1 than at site 2. Height growth was relatively uniform among provenances and sites, ranging from 33-47 cm and from 63-101 cm, respectively. After 19 months at site 2, the provenances from Chiquitano-Amazon transitional (B=84 por ciento, N=288) and pre-Andean Amazon (SC=79,5 por ciento, N=288) showed the highest survival rates, whereas differences in height growth varied from 150 to 216 cm. In general, root collar diameter growth was lower at site 1 than at site cm. In general, root collar diameter growth was lower at site 1 than at site 2. Among provenances, B and CH were significantly different in diameter growth after 4 months at site 1, however, no differences were observed at 12 months among all provenances. At site 2, diameter growth showed that provenances B and CH did better after 4 months while CH did better after 12 and B after 19. In summary, the provenance B from Chiquitano-Amazon transitional showed better characteristics than the rest of tested provenances (84 por ciento survival, 135.1 cm/year height growth and 34.7 mm/year root-collar diameter). Our findings provide useful information o survivl and growth performance of Bolivian mahogany in plantations on secondary forests.

Ingles y Español.