Carbon sequestration potential of nitrogen-fixing tree stands

We compared the C storage of two nitrogen-fixing trees in mixed and monospecific plantations to investigate the C sequestration potential after 10 years of their establishment. The study was carried out in three types of plantation, Dalbergia sissoo Roxb. ex DC. pure (P₁DS), Leucaena leucocephala (Lam.) de Wit pure (P₂LL) and mixed plantation of D. sissoo and L. leucocephala (P₃DS.LL). The results of the study indicated that, P₃DS.LL sequestered 34.30 ± 0.24 t yr^-1 ha^-1 CO₂ compared to 27.35 ± 0.19 t yr^-1 ha^-1 in P₁DS and 19.81 ± 0.44 t yr^-1 ha^-1 in P₂LL. Total carbon storage was also maximum in P₃DS.LL (93.47 ± 0.67 t ha^-1) followed by P₁DS (74.54 ± 0.53 t ha^-1) and P₂LL (53.98 ± 1.21 t ha^-1). This indicates that L. leucocephala has synergetic effect with D. sissoo to enhance the carbon sequestration potential when interplanted together. The study revealed that mixed plantation of N-fixer trees have potential to sequester more carbon than same species in monoculture. The study concluded that in reforestation or afforestation program the synergic effect of N-fixer trees can be helpful projects to offset more C emissions.