In Amazonia, oligarchic forests rich in economically important tree species are heavily exploited by rural communities for subsistence and commercial purposes. These trees produce fruits, fiber, thatch, and other useful products, and are important food sources for game animals. Despite the large number of studies that have questioned whether their commercial exploitation can be sustainable, no studies have precisely mapped these very productive forest species to document their actual abundance and extent, which is necessary to conserve these ecosystems and determine the economic value of these forests. This study takes an ecosystems approach, seeking to understand the exact size, spatial distribution and economic value of oligarchic and monodominant forests. The patchy distribution of these non-timber forest species allowed us to map their distribution, estimate tree populations and harvest status with improved accuracy compared to previous studies. GPS and Geographic Information Systems (GIS) were used to delineate and precisely map forest patches of three tree species of high economic and ecological value: Mauritia flexuosa, Myrciaria dubia, and Astrocaryum chambira. We measured commercial fruit yield from M. dubia, fruit production of M. flexuosa palms, and fiber production from A. chambira. Economic values were calculated using prices local extractors received for their products.
Results/Conclusions
Using GPS and ArcMap 10.2, we were able to delineate and document the size of 30 M. flexuosa swamps, 9.55 hectares of M. dubia stands, and 8.29 hectres of A. chambira palm secondary forests. We provide examples of our findings using several maps that illustrate the effectiveness of the GPS field methodology. M. flexuosa swamps covered a smaller area than local residents reported. The size of the swamps was a predictor of fruit producing female palm densities, especially in floodplain landscapes. Stands of M. dubia had much lower fruit production and economic value than found in previously published studies. Secondary forest dominated by A. chambira experienced 1305 leaf spear harvests for fiber, with a higher economic value than found in previous studies. Mapping forest resources with GPS is a very useful tool to implement local conservation programs with rainforest communities and determine their economic value to both rural and urban residents. Remote sensing has so far been unable to distinguish these species from surrounding vegetation. Both researchers and rural communities will find this method useful to enhance forest conservation practices and understanding.