Neighbour's identity of commercial tropical tree species in a tropical rainforest near Manaus, Brazil.

The use of spatially explicit neighbourhood approach helps to understand the processes which structure and guide tree communities over space and time, contributing for the conservation and forest management. We investigated the neighbours of Brosimum spp., Eschweilera coriacea, Ocotea cernua and Protium hebetatum, hypothesizing that there is a taxonomic pattern around these focal species, been important information for the maintenance of the forest?s structure submitted to the management actions. We used a 2-ha plot in a tropical rainforest in Brazil where all trees with diameter at breast height (DBH) ?10 cm were stem-mapped in 2005. First, we determined how focal species were spatially structured by using Ripley?s K function. For the neighbourhood analysis, the nearest 20 trees around focal trees were identified to compute the mean richness, mean proportion of conspecifics, relative frequency distribution and the number of neighbour species by distance from focal trees. Our findings demonstrate that conspecific neighbours are occurring associated with focal trees, mainly at shorter distances for all focal species with possible more intra-specific interactions as a very few heterospecific neighbours were associated with focal trees. The spatial structure, more than abundance of focal species, may have contributed for the conspecific encounters, mainly for Brosimum spp. and Ocotea cernua. Rare species were found frequently associated with focal species, calling our attention for the effects of the forest management of commercial trees on community structure in order to prevent local extinctions