Biomass and Biomass Models of Secondary Subtropical Vegetation in Tuojiang River Valley
Liu Xingjiang, Yan Wuxian, Xiang Chenghua, Jiang Junmin
Chin J Plan Ecolo. 1997, 21 (5):
Related Articles |
The biomass and biomass allocation principles of the secondary vegetation in the Qingshuihe tributary of Tuojiang river valley were investigated using field investigation, sample tree and regression analysis (for arbors) and plot harvest (for shrubbery and herbs). The adaptivity of main species was investigated from the viewpoint of biomass distributive coordination in this paper.1. In order to approach the relationships between biomass of main secondary vegetation type and DBH or volume, 11 models of regression analysis were set up. Among the models,Y=aXb was the best with coefficients ranging from 0.946 to 0.999.2. The sequence in which aboveground biomasses varied among different community types was as follows: Quercus variabilis + Cupressus funebris — Rhamnus leptoph ylla + Elaeagnus pungens — Imperata cylindrica var. major community (95.721 t· hm- 2 ) > Cupressus funebris + Alnus cremastogyne — Vitex negundo + Coriaria nepalensis — Imperata cylindrica var. major + Plantago asiatica community (546t·hm-2 ) >Cupressus funebris— Plantago asiatica + Ficus tikoua + Hetero-pogon contortus community ( 38.719t·hm-2 )> Vitex negundo + Coriaria nepalensis + Elaeagnus pungens + Myrsine africana-Imperata cylindrica var. major community ( 11.969t·hm-2)> (Coriaria nepalensis)-Imperata cylindrica var. major+ Heteropogon contortus+ Plantago asiatica community (4.073t·hm-2), The aboveground biomass of two types of Cupressus lusianica were 21.065t·hm-2 and 16.810t·hm-2 ,respectively.3. Stump and thick-roots(>2.0cm in diameter) contributed to 80.42% and 62.09% of their own total root biomass, respectively, in indigenous species and Cupressus lusianica. Under-ground biomasses accounted for 23.89 % and 7.44 % of total biomass respectively,or for 17.67 and 6.9 % of aboveground biomass respectively. This indicates a uncoordination between above-ground biomass and underground biomass of Cupressus lusianica,suggesting potential lodging.4. This paper made a contrasting analysis and evaluation on main secondary vegetation types, the allocations of tree biomass, vertical structure productive potentialities and protective functions, indicating that community types at higher successive stage are the superior model with economic and ecological functions in this region.