分别为明尼苏达州北部的低、中、高立地质量的白云杉(Picea glauca(Moench)Voss)人工林,建立了生物量估计方程。立地质量由地位指数确定。这些指定立地质量的方程之间的回归系数具有显著的统计差异(P<0.005)。根据这些方程估计的优势木地上生活量与根据全部数据的总方程估计的地上生活量有差别。随着林木的长大,总方程的 (Picea glauca (Moench) Voss) plantations of low, medium and high stands in northern Minnesota, respectively, and established the biomass estimation equation. Site quality determined by the status index. The regression coefficients between these nomographies have significant statistical differences (P <0.005). There is a difference between the estimated above-ground living biomass of wood on the basis of these equations and the aboveground biomass estimated from the total equation of the total data. With the growth of trees, the total equation