【摘要】 以黄土高原半干旱地区的山西省方山县人工刺槐林为对象,采用树干解析与称重法,设立标准地对10个不同密度人工刺槐林进行了生长与生物量调查,分析密度对单木和林分生物量的效应。结果表明:18年刺槐林分的地上现存生物量与测树指标D2H和D有很好的相关性,其中树干和叶的生物量与D2H关系密切,而枝条生物量与D关系密切。刺槐单木总生物量及各部分生物量都是密度的幂函数,但是对林分而言,低密度林分和高密度林分的总生物量都比较高,而处于中间密度林分的生物量较低;林分现存总生物量也呈同一趋势。从总生物量来说,林分的水分利用效率与密度不存在线性关系,但是其干材的水分生产效率是随着密度降低而增加的,反映出不同密度水分利用效率的经济价值不同。更多还原

【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 D~2H 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 833hm~2 and 5000hm~2 stand density, moreover higher stem biomass can be obtained to stand density less than 1111hm~2. Individual tree biomass of 5000hm~2 and 833hm~2 stand density is respectively 9.19kg and 56.31kg, while its stand biomass is respectively 45950kg/hm~2 and 46906kg/hm~2, 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 5000hm~2 and 833hm~2 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.更多还原