Comparison of various linear and non-linear functions for estimating biomass and volume of Dalbergia sissoo grown under rainfed conditions

Abstract

An experiment was initiated during 1996 at Jhansi for selecting progenies of Dalbergia sissoo Roxb. ex DC with high growth and timber yield. Ten-year-old trees planted under rainfed conditions were harvested and biomass/ volume data were recorded/ computed. Linear and non-linear functions were constructed for bole biomass, total wood biomass and bole volume. The functions fitted using variable ‘D2H’ were found better than those fitted using variable ‘D’ alone on the basis of mean square error and R2 criteria, where D – diameter at breast height and H – height of tree. The logistic function B = 87.45 (1+ exp (2.052 –9.982 D2H))-1 was adjudged best fit (R2=0.893, mean square error=21.689) and may be used for estimating bole biomass. On the other hand, the linear function B = 9.834 + 293.335 D2H (R2= 0.916, mean square errore= 36.365), where B – biomass (kg) was found good fit for aboveground wood biomass. For clean bole volume, the best fitted linear function V = 0.0021 + 0.3002 D2H (R2= 0.921, mean square error=0.0002), where V – volume in m3, may be used for estimating the volume of D. sissoo tree in this region