Ecological studies on soil nematodes, enchytraeids, collembolans and mites in a 1948 Pseudotsuga menziesii plantation at Shawnigan, British Columbia were made from March 1971 to March 1972. The plantation was thinned to 1,900 stems/ha and urea was applied at 0, 224 and 448 kg N/ha just before faunal sampling. Monthly samples were extracted in high-gradient apparatus, Murphy split funnels and simple wet funnels. Fifty-two and 53% of collembolans and mites, respectively, occurred in the top 5.3 cm of the 17.5-cm soil profile studied. The Pearson and Hartley power function test indicated that for intramonth sampling to show statistical significance of treatment, at least 10 samples per treatment would be required for any of the groups under experimental conditions similar to the one reported here. Collembolans and mites exhibited significant downward seasonal distribution, and urea treatment accentuated this phenomenon for all four groups, suggesting that sampling below 6 cm would be required to observe the full impact of urea fertilization on the soil fauna. Except for enchytraeids, seasonal population fluctuation contrasted with the generally observed pattern in temperate regions of spring and fall peaks and showed increases through the spring, culminating in summer and autumn maxima. Urea fertilization increased annual mean population of nematodes by 1.41 and 2.51 times the control for 224 and 448 kg N/ha, respectively, and decreased enchytraeids by 0.52 and 0.28 times the control for the same two fertilizer rates; collembolans and mites were not significantly affected.