Tree species composition and above-ground biomass of a preserved woodland in an agricultural landscape of Southern Nigeria

Abstract

Trees on farmlands occur in various patterns. They are important carbon sinks and provide numerous ecosystem services to local people. In this case study, we estimated the species diversity and the aboveground biomass of trees in the woodland of a commercial farm in Southern Nigeria. Using 10 m wide transects (4 km of total length), we enumerated trees measuring ≥10 cm in diameter at breast height and calculated the stand aboveground biomass (AGB). We recorded a total of 1,221 trees, representing 55 species from 23 families. Total AGB calculated was 124.10 Mg/ha. Gmelina arborea, an exotic species, was the most abundant species and recorded the highest AGB. Smaller stems (<30 cm dbh) were more abundant but larger stems (>30 cm dbh) contributed greater (56%) AGB. These findings show that preserving woodlands in the west African agricultural landscape can contribute substantially to carbon storage and biodiversity conservation.