在六盘山南侧设置2个20m×20m的华北落叶松人工林样地,研究枯落物储量的空间分布。结果表明:枯落物储量空间差异明显,2个样地的枯落物储量平均值为1.80和1.68kg.m-2,最大值为2.96和2.71kg.m-2,最小值为0.35和0.34kg.m-2,最大和最小值的比值变化在8~9之间;在不考虑测点空间位置及取样间距的情况下,2个样地枯落物储量的变异系数为0.41和0.56;枯落物储量的空间分布受空间结构性和随机性的多种因素影响,其中林地微地形能解释枯落物储量空间变异的56%,局部洼地利于更多枯落物堆积;2个样地枯落物储量的空间分布函数曲线的理论模型均符合球状模型,且空间自相关程度较大;当以95%的置信区间准确估计华北落叶松林样地的枯落物储量时,最小取样数量为9个1m×1m的样方。
The spatial distribution of litter mass on forest floor was in detail investigated in two 20 m×20 m sample plots of a pure plantation of Larix principis-rupprechtii in the southern side of Liupan Mountains of the Northwest China. It was shown that there was an obvious spatial variation of litter mass. The mean litter mass for the two plots was 1.80 and 1.68 kg·m-2,the maximum values were 2.96 and 2.71 kg·m-2,and the minimum values were 0.35 and 0.34 kg·m-2,respectively. The ratio of maximum to minimum values varied in a range of 8 ~ 9. Without considering the spatial location and distance of sampling points, the variation coefficient of litter mass was 0.41 and 0.56 for the two plots. This uneven spatial distribution of the litter mass was influenced by many factors, such as the spatial structural factors and random factors. The micro-landform was able to interpret 56% of this spatial variation, which meant that a low-lying landform was more favorable for litter accumulation. The rest spatial variation of litter mass had to be interpreted by other factors. A geo-statistic analysis showed that the semivariograms of litter mass in the two plots were best described by a spherical model, with a moderate spatial self-correlation. For a more accurate estimation of litter mass on forest floor of L. principis-rupprechtii plantation, a minimum sampling amount of 9 sample plots of 1 m × 1 m is required with a confidence interval of 95 %.