Above-Ground Biomass Production and Nutrient Cycling of Young Plantation of Eucalyptus urophylla

In this paper,the above-ground growth,Biomass accumulation and distribution among different diameter classes and tree components,primary net productivity,nutrient concentration in 4 tree components and litter,nutrient cycling(not include leaching) of 2 to 3 years old plantation of Eucalyptus urophylla were mentioned.The above-ground biomass of the plantation of 2 years old were 22.9 t/hm2 and 40.0t/hm2 of 3 years old,of which therewere 60.2% stem-wood,8.9% stem-bark,14.7% branch and 16.2% leaves at 2 years,and 63.6 stem-wood,7.7% stem-bark,14.1% branch and 14.6% leaves at 3 years.The primarynet productivity of the 2 to 3 years old plantation was 20.5t/hm2,of which more than 50% was stem biomass increment and 16.7% was litter.N,P,K,Ca,Mg,Si,Mn,Zn,Cu and B ac-cumulation was 157.6,5.42,59.3,23.97,9.27,14.16,5.26,0.427,0.125 and 0.588 kg/hm2 at 2 years,and 247.8,8.2,91.1,40.3,17.5,26.3,8.12,0.711,0.22l and 0.981 kg/hm2 at 3years respectively.In the 2 to 3 years old plantation,N,P,K turn-over rates were lower than 0.2 and Cu,Zn and B turn-over rates were lower than 0.3.