直线型线截抽样在森林资源综合监测中的应用

线截抽样是稀疏总体的调查方法,是一种有放回不等概抽样方法.系统梳理了直线型线截抽样的倒木蓄积总值、密度、均值、长度以及估计精度、方差、估计区间等计算公式,将直线型线截抽样应用于研究区域的倒木调查,探讨不同截线长度对调查精度的影响,从而确定最佳的截线长度为50 m.此时,倒木蓄积总量为536.85m3,蓄积密度为27.53 m3·hm-2,倒木总条数为5 887条,抽样精度达90.05％(可靠性为95％),为森林资源综合监测地面样地设计提供理论与实践依据.

Straight-line intersect sampling with comprehensive forest resource monitoring

Line intersect sampling is an inventory method for rare populations using unequal probability sampling with replacement. For ecological management, the formula to calculate total volume, density, and mean and total number, as well as to of fallen dead woods estimate precision, variance, and the estimate interval was systematically deduced. Then, straight-line intersect sampling was applied to the inventory of fallen dead woods in the fourth small section of the first section of checking method in China. The effect of different transect length on inventory precision was discussed. The best transect length was determined to be 50 m taked inventory time and precision into consideration, for which the total volume of fallen dead woods was 536.85 m3, the volume density was 27.53 m3·hm-2, the total number of fallen dead woods was 5 887, and the sampling precision gained was 90.05% （with a reliability of 95%）. These results could provide scientific and practical applications for ground plot designs with comprehensive forest resource monitoring. Ch, 7 fig. 4 tab. 19 ref.}