Biomass and Productivity of Eucalyptus urophylla Plantation in New Cultivated Areas

An investigation was conducted into the biomass and productivity of Eucalyptus utophylla at different age stands in Tianlin County where there is a new cultivated area for E.utophylla with the harvest and relative method.The results show that the biomass of E.urophylla stands increases with the increasing of stand age;it is 6.18 t/hm2 in the 0.4-year-old stand,32.09 t/hm2 in the 2.4-year-old stand and 80.59 t/hm2 in the 4.4-year-old stand;that the productivity of the different age stands is 14.83 t/(hm2·a)(0.4 year),13.02 t/(hm2·a)(2.4 years) and 19.90 t/(hm2·a)(4.4 years) respectively;that in the different age stands,there is difference in the biomass distribution of tissues: in the early stage,the rate of branch and leaf is higher and that of stem lower but with the increase of stand age,the rate of stem wood and root becomes significantly greater but the rate of leaf is down;that the biomass distribution of different stands ranges in the following order: branch(37.54%)leaf(31.38%)stem(14.77%)root(11.69%)bark(4.66%) in the 0.4-year-old stand,stem(50.83%)root(18.43%)branch(12.32%)bark(10.23%)leaf(8.20%) in the 2.4-year-old stand,and stem(47.29%)branch(18.42%)root(14.73%)leaf(10.80%)bark(8.75%) in the 4.4-year-old stand respectively; and that the average dieback rate is 84.62% after planting 2 years and 63.46% after planting 3 years,and the rate of dieback length is 21.64% and 27.15% respectively.Although the productivity of Eucalyptus urophylla stands in Tianlin is high,the growth and economic yield are obviously affected because the rate of stem of Eucalyptus urophylla is low,the rate of branch and leaf high and the dieback severe.