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| Effect on biomass of stand density of artificial Black Locust forest in semi-arid region of Loess Plateau |
| Wang Baitian, Wang Ying, Guo Jianghong, Zheng Peilong, Ma Fengbin, Zhang Hua |
College of Soil and Water Conservation, Beijing Forestry University, Key Laboratory of Soil and Water Conservation and Combating desertification,
Ministry of Education, 100083, Beijing, China |
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Abstract Stand volume increment and biomass were respectively investigated by using stem analysis and weighing at 10 permanent sample plots of 18-year artificial black locust（Robinia Pseudoacacia）forest in semi-arid region of Loess Plateau, and the relation between biomass and stand density was analyzed. The results show that there is a good correlation between D2H and stem biomass and leaves biomass while same between D and branch biomass in forest inventory factors, and a closely power function relation of stand density to total biomass, branches biomass, leaves and fructification biomass of individual tree. Meanwhile it is true that there is not significant correlation between total stand biomass and stand density. Stand biomass is higher in lower and higher density than in medium density ranging between 833hm2 and 5000hm2 stand density, moreover higher stem biomass can be obtained to stand density less than 1111hm2. Individual tree biomass of 5000hm2 and 833hm2 stand density is respectively 9.19kg and 56.31kg, while its stand biomass is respectively 45950kg/hm2 and 46906kg/hm2, not significant different. Furthermore, water production efficiency （WPE） of present biomass was analyzed. Annual average rainfall is 487mm for 1986—2003 at the region, WPE of 5000hm2 and 833hm2 stand is respectively 0.5546 and 0.5663, while that of stem biomass is respectively 0.2758 and 0.3965. Obviously, biomass of lower density stands has higher proportion of economic value though higher density stands also harvest more biomass.
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Received: 22 February 2005
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