Study On Biomass And Nutrient Of Phoebe Bournei Plantation In Heterogeneity Spatiality Of Density And Site

The biomass and nutrient of P. bournei plantationss of 37 years, which had similar managements in Shunchang of Fujian provinace, were studied in heterogeneous spatiality of density and site. Results indicated that the heterogenous spatiality of density and site effected heavily on biomass, nutrient absorption and accumulation in Phoebe bournei plantations ecosystem.In lower density spatiality (1500-1650 trees/hm²), the average biomass of single tree was 56.52 kg/tree, which was as large 1.39 times as higher density spatiality. The averager biomass in differernt organs of single tree decreased with the increase of density. The biomass allocation ratio of root, stem and bark raised with the increase of density, but decreased of branch and leaf.The community total biomass of P. bournei plantations was 104.48t·hm^-2 in lower density spatiality, which nearly equalled with that in higher dentsity spatiality. The biomass of tree layer increased with stand density increasing, but its biomass ratio of tree layer decreased with the increase of density. Oteherwise, the biomass allocation of shrub layer and herb layer was different with tree layer.The average biomass of single tree was different greatly in heterogeneous spatiality of site. The average biomass of single tree was 73.03 kg/tree in II site, which was higher 57% and 177% than that in III and IV site, respectively. The average biomass in every organ declined with the site quality becoming worse, the biomass ratio of stem was also declining with the site becoming worse, other organs had no obvious tendency with the site changing.In heterogeneous spatiality of site, the community total biomass in II, III and IV site was 149.12t.hm^-2, 112.28t.hm^-2and 65.29t.hm^-2, respectively. The total biomass of P. bournei plantations in II site was as larger 1.34 times and 2.28 times as that in III and IV site, respectively. In P. bournei plantations community, the biomass of tree layer decreased with the quality decline of site, while the biomass of shrub and herb layer were the largest in III site and the least in IV site.Studied on biomass in different organs and two regression models which include the parameter of biomass , diameter and height with equations W=aD^b, W=a(D²H)^b were built up. The results show that the two equations all can be used to calculate the biomass of tree layer. As to the practice, the equation W=aD^b was better than the other.In heterogeneous spatiality of density, the content of all elements except Cu were decreased with the density increasing in ecosystem of P. bournei plantations. The average content of all elements except Mn were larger 4% (Cu) to 60% (N) of tree layer in lower density spatiality than that in higher density spatiality. The average content of all elements except Mg and Cu were larger 16% (P) to 90% (N) of...