Growth and Yield Models of Four Year Old Eucalyptus Clones K7 and K62 at the Sa Kaeo Plantation, Sa Kaeo Province

Abstract

            The objective of this study was to estimate the survival rate and construct a growth-yield model of Eucalyptus clones K7 and K62 at the Sa Kaeo plantation located in the Sa Kaeo province. The sampling fraction of the forest resource inventory, as estimated by the systematic sampling rows method, was 1.125%. The mean survival rate of eucalyptus clones K7 was found to be 97.15±1.37%, the mean height was 12.61±0.06 m., and the average diameter at breast height (DBH) was 8.63±0.08 cm. The eucalyptus clones K62 had a mean survival rate of 93.53±5.28%, an average height of 12.91±0.07 m., and DBH of 8.77±0.10 cm. Best fit equations from the statistical analysis were used to assess the fresh weight (Mt), biomass (Wt), and volume (V) of eucalyptus. The optimal equations for estimating the growth and yield of K7 were: fresh weight (Mt) = 0.0993(D²Ht)^0.8661 (R² = 0.991), biomass (Wt) = 0.0527(D²Ht)^0.8661 (R² = 0.991), and volume (V) = 0.0001(D²Ht)^0.852 (R² = 0.989). The best fit equations for eucalyptus clone K62 were: fresh weight (Mt) = 0.0854(D²Ht)^0.9127 (R² = 0.998), biomass (Wt) = 0.0542(D²Ht)^0.9127 (R² = 0.984), and volume (V)= 0.00009(D²Ht)^0.871 (R² = 0.995). The mean weights of K7 and K62 clones were 10.662±0.383 tons/rai and 13.367±0.481 tons/rai, respectively. The mean volumes of K7 and K62 clones were 0.033 and 0.048 cubic meters/tree, respectively. The average volume of the sample plots were 10.340±0.035 and 12.3850±0.043 m³/rai, respectively. The t-test was used to compare the weight and volume of the K7 and K62 clones and we found a significant difference (P<0.05). We conclude that the eucalyptus clone K62 can be recommended to farmers as their fresh weight, biomass, and volume was higher than the K7 clone.