Allometric equations to estimate volume, biomass and carbon of Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby in a commercial stand in southwestern Amazonia

Forest plantations with tropical species lack allometric equations to estimate yield. This study aims to test allometric models for estimation of volume, biomass and carbon stock for stems of Schizolobium parahyba var. amazonicum, a species with great potential for using in homogeneous stands. A plantation of S. parahyba was inventoried, rigorously cubed and wood disks with bark were collected to obtain the biomass and carbon stock of the stem. Allometric models were fitted using as independent variables diameter at 1.30 m from the ground, total height, basic wood density and carbon content. The biomass and carbon stock of the stand were 124 Mg ha-1 and 58 Mg C ha-1, respectively. The selected equations for volume estimation with and without bark were V=exp⁡(-9.600+0.937*ln⁡d^2 h) and V=exp⁡(-9.622+0.938*ln⁡d^2 h), respectively; for biomass. the selected equation was B=exp⁡(-9.566+0.936*lnd^2 h+1.014*lnρ). and to estimate carbon stock C=exp⁡(-9.797+0.937*lnd^2 h+1.026*lnρ+0.699*lnt). The allometric equations for volume, biomass and carbon stock fitted in this study can generate more accurate yield estimates for S. parahyba plantations in the Amazon region. Brazil’s commitment under the Paris Agreement to reforest 12 million hectares by 2030 makes improving estimates of volume, biomass and carbon a high priority.