Structure and above ground biomass along an elevation small-scale gradient: case study in an Evergreen Andean Amazon forest, Ecuador

The purpose of this study was to examine how tree diversity, richness, and structural characteristics as well as above-ground biomass varies along a small-scale elevation gradient from 601 to 1000 m above sea level (m.a.s.l.) in an Evergreen Andean Amazon forest and their implications in terms of carbon storage. Trees with diameter at breast height greater than 10 cm were surveyed in 20 permanent 0.1 ha plots, five at each elevation site. We determined species richness, density, basal area, aerial biomass and calculated a biomass importance value (BIV). The 1378 trees surveyed were mainly contained in the families Moraceae (17 species) Fabaceae (16) and Meliaceae (10). Species richness significantly increased ( P 0.579). At the highest tree density, the highest BIV of Iriartea deltoidea was found at 601–900 m.a.s.l. The disproportionate contribution of a few species, some being the least abundant but with high AGB in our surveys (e.g., Sterculia sp., Nectandra sp., Ficus sp., and Inga sp.) to carbon stocks is important to consider in furture research on carbon sequestration. As the production of above-ground biomass was concentrated in a few species, some uncommon, decision making in reforestation programs and how species should be selected may have implications when measuring and promoting carbon storage.