Biomass Production and Energy Conversion Efficiency by Eucalyptus in Energy Planlnations

Studies on growth, assimilation rate, biomass production, solar energy conversion efficiency and seasonal energy conversion efficiency by Eucalypts under energy plantation practices (short spacing, 13m × 13m) have been carried out at six monthly intervals for a period of 36 months under semi-arid non-irrigated conditions in Gujarat. The results show that there exists considerable variation among the population of the trees which increase with increasing age. The total biomass ranged from 5 dt/ha at 12 months to 66 5 dt/ha at 36 months,the utilizable biomass (wood, bark, branch) ranging from 2.25 dt/ha to 43 5 dt/ha for the same periods. There existed a direct correlation between, the leaf biomass and total biomass by different categories of trees. The results on various growth parameters, viz,net assimilation rate, relative growth fate and crop growth fate is also presented. The relationship between D²H and total as well as utilizable dry malter production by trees has been worked out and presented. The solar energy conversion efficiency as found to be maximal at 36 months of the age being 126. The seasonal energy conversion efficiency showed two peaks, one 18-24 ond another 30-36 month., the values being 1.77 and 3.16 per cent of PAR coinciding with lhe period of moisture availability. The high biomass production by trees under energy plantation practices as related to the CO₂ profile and energy conversion efficiency is briefly discussed.