Abstract:

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%.

Key words: Larix principis-rupprechtii, litter mass, spatial variation, geostatistics method, Liupan Mountains