Spatial variability of soil organisms, pH, moisture, O-horizon depth, and temperature in differentiated conifer stands in the Western Cascades, Oregon

Geostatistical tools, the semi-variogram and correlogram, were applied in anecological setting to test for differences in spatial heterogeneity patterns of soilmicroarthropods, nematodes, pH, moisture content, 0-horizon depth, and temperature intwo contrasting forest stands. Two adjacent research plots, with varied densities of old-growth and 80-year re-growth trees, were selected in coniferous forest near Blue River inthe Western Cascades of Oregon. One plot consisted of a heterogeneous mix of age classeswith a high density of old-growth trees; the other plot contained homogeneous re-growthwith a low density of old-growth trees. Means and standard deviations of soil propertiesand organism counts were similar in both plots. Spatial analysis results, however, revealeddistinguishable differences between treatment areas. Short range (5-8 m) patch-to-patchpatterns, especially in pH, moisture, 0-horizon, and faunal census, were more pronouncedin the re-growth homogeneous plot, whereas long range patterns (17-22 m) were morepronounced in the old-growth heterogeneous plot.