Brazil nut (Bertholletia excelsa Humb & Bonpl.) is now the most economically important species in several Extractive Reserves and other similar community forestry land uses in Amazonia. However, despite its economic and social importance, there is very little quantitative information on the population ecology and management of this species. Several earlier studies suggested an apparent lack of regeneration of Brazil nut.
We conducted a participatory research on the ecology and management of Brazil nut populations in extractive areas in Xapuri, State of Acre, in the western part of Brazilian Amazonia. We studied the demography of natural populations in 51 transects of 1 ha each (1000 x 10 m) to assess the sustainability of current management systems and analyzed different alternatives to increase productivity of Brazil nut in different sites within the extractive reserves.
Our surveys indicate that while the density of adults with highest nut production (80 cm < DBH < 160 cm) was only 1.18 plants/ha, the combined density of juveniles (< 40 cm DBH) and small adult plants (40 cm < DBH < 120 cm) was 4.55 plants/ha. Most (83.7%) juveniles had either small or very small canopy openings. A considerable proportion (23.3%) of small adult plants also experience unfavorable light levels.
The most rapid and inexpensive way to increase productivity of Brazil nut in the study area seems to be liberation thinning. Liberation thinning of suppressed individuals is relatively inexpensive (US$ 0.08/plant) and can increase the size of the adult population through increased recruitment from the large pool of juveniles and increase the production of Brazil nuts through more favorable light regimes for small adult plants. We argue that increasing productivity of Brazil nuts is a key strategy to promote forest conservation in Extractive Reserves through increasing the interest of extractivists in maintaining the forest cover and avoiding conversion to pastures and agriculture.
Key words: Amazonia, Brazil nut, management, non-timber forest products (NTFPs), extractive reserves.
Correspondence: Virgilio M. Viana, Center for Internationational Forestry Research (CIFOR) and Dept. of Forest Sciences, University of Sao Paulo, Esalo, Piracicaba, SP 13400, Brazil
E-mail: vimviana@carpa.ciagri.usp.dr