Journal of Global Ecology and Environment

Bangali Babool, Acacia auriculiformis (Family-Leguminosae & Sub-family-Mimosoideae) is an evergreen fast growing exotic tree species and it grows in different parts of India. This species is mainly used for making furniture, fuel wood and as minor timber. The present study aims at determination of volumetric equation for A. auriculiformis in South Gujarat. The study was carried out in different land-use systems like plantation, road side and canal side plantation, etc. in Navsari and Valsad districts of Gujarat during 2022-24. In this study, a total of 120 A. auriculiformis trees belonging to different diameter classes viz., D₁: 10-15 cm, D₂: 15-20 cm, D₃: 20-25 cm, D₄: 25-30 cm, D₅: 30-35 cm, D₆: 35-40 cm, D₇: 40-45 cm, D₈: 45-50 cm, D₉: 50-55 cm, D₁₀: 55-60 cm, D₁₁: 60-65 cm and D₁₂: 65-70 cm were considered. A total of four different regression models such as Linear [V₁ = a + b D], Power (V₂ = a D^b), Logarithmic [V₃ = a + b ln(D)] and Quadratic polynomial [V₄ = a + b D + c D²] models were tested using DBH as an independent variable. Among them, based on higher R² and lower RMSE values, the quadratic polynomial model [V₄ = a + b D + c D²], followed by linear model [V₁ = a + b D] were found to be the best fitted regression equations. Further, based on cross verification of actual values with predicted values of volume 11 trees tested with four equations, Quadratic polynomial model recorded higher RMSE value than others; thus, it is suggested to use volumetric equation: V=-0.468+0.046*D+0.000087*D² for estimating volume of standing trees of A. auriculiformis with DBH which falls between 10 and 70 cm.