Abstract:

To reveal the relationship between species diversity and biomass in Eucalyptus (Eucalyptus urophylla×E. grandis) plantation that located in the Dongmen State Forestry Farm of Guangxi, 18 sample plots were established and the total biomass, arbor layer biomass and undergrowth biomass of communities were subsequently harvested. The results were as follows: 1) Species richness in eucalypt plantation had remarkable positive correlation with biomass of arbor layer, undergrowth and community(α＝0.001), its correlation coefficients was 0.693 5, 0.702 8 and 0.710 6 respectively. 2) LAI(leaf area index) had remarkable positive correlation with species richness and undergrowth biomass(α＝0.001), its correlation coefficients was 0.731 0 and 0.685 6 respectively. 3) Arbor layer biomass had remarkable correlation with soil organic matter and hydrolysable N, its correlation coefficients was 0.641 6 and 0.620 3 respectively. Species richness had remarkable correlation with soil organic matter and correlation coefficient was 0.635 9. Among them, correlation was significant at the 0.1 level. Under growth biomass had little correlation with nine soil nutrients and correlation coefficients was under 0.4 To sum up, species diversity was advantageous to the promotion biomass of Eucalyptus plantation, and the variation of LAI and soil nutrient in small scale could result in the difference of species diversity and biomass in different sample plots. 

Key words: Eucalyptus plantations, species diversity, biomass, soil nutrient, LAI(leaf area index)