2.2.1 Experimental plots
Ten hillslope plots (sizes between
800-4000 m2, and elevation from 2595-2683 m) were
established along two orientations (horizontal or vertical axis)
transect in the Dahuang Mountain Forest Reserve between July and August
in 2014 (Fig. 2). Two plots were on the north-facing slope, and others
on the west/east-facing slopes, and all of the plots were characterized
by heterogeneity of land uses. Basic characteristics of the ten plots
are shown in Table 1. The primary landcover types were grass,
brush-grass, planted forest, planted-natural mixed forest, and natural
forest, representing all stages of landcover changes during plantation
restoration in this region. Plots along the horizontal axis (#6, #7
and #8) were used to determine the relationship between landcover and
SWC for which can exclude differences in SWC caused by slope position;
plots along the vertical axis (#1, #2, #3, #4, #5, #9 and #10)
were used to analyze spatial heterogeneity of SWC and landcover types.
Five spatial sampling intervals (5, 6, 7, 8, and 10 meter) were used for
the investigation, all sampling retained a consistent interval distance
at each transect to satisfy the theoretical model of semivariance
analysis. Four replicates of SWC records were taken at each sampling
point, and the average value was taken for the point after the outliers
were removed. In addition to supporting materials, the SWC survey, stand
structure investigation, soil texture, and landcover species were also
surveyed synchronously.