Wood-specific gravity and carbon proportion of multifunctional agroforestry trees in foothills of Nilgiris, Western Ghats, India

Agroforestry is identified as a potential carbon sequestration strategy, involved in carbon capture and storage in woody perennials. However, the use of default values of wood-specific gravity (WSG) and carbon content (CC) in biomass estimation may lead to over or underestimations. Therefore, the present study attempted to assess the difference in WSG and CC among 25 different species of multifunctional agroforestry (MFA) established at Forest College and Research Institute, Coimbatore, Tamil Nadu, India. Wood core samples were collected using the wood-cutter and incremental borer. Determination of WSG and CC was done by water displacement method and combusting in a muffle furnace. Analysis of variance revealed significant differences for both WSG and CC (P < 0.001). WSG ranges from 0.26 ± 0.01 (Jatropha curcas) to 0.81 ± 0.04 (Santalum album). Out of 25 trees, wood carbon fractions of > 40% were noticed in 21 tree species. Among 25 trees, ten species fall under light wood (WSG < 0.5), eight species in moderately heavy wood (0.5–0.7), and seven species fall under the category of heavy wood (> 0.7). Therefore, documenting WSG and CC will provide better insight in biomass estimations.