Soils were collected from 18 of the 21 DIRT plots on November 2 and 3, 1995. Control plots 15, 18, and 20 were not sampled. There were three sampling locations in each plot; duplicate O and M horizon samples were taken at each sampling location for a total of 6 O and 6 0-10 cm mineral samples taken per plot. No O horizon samples were taken from the three -OA plots (plots 7, 5, and 21).

O horizon: Each sample consisted of a 20 cm x 20 cm square of Oea material cut from the forest floor of each plot. There was some disagreement about the O/A boundary. It was decided to err by possibly including A material in the O sample, rather than leave O material out of the O sample.

Mineral horizon: Mineral 0-10 cm cores were taken directly beneath the locations from which O samples were collected. Cores measured 10 cm in length by 4.8 cm in diameter. Some compaction of the soil may have occurred during coring, possibly affecting bulk density values.

Three unsieved O and M cores from each plot were reserved for microbial and microfaunal analysis. Fresh weight was recorded for the other three O and M samples per plot, and these were subsequently passed through a 5.6 mm sieve. The weight of the sieved material was recorded. Subsamples were analyzed for moisture content, pH, %C, and %N. The sieved material was split into portions for gross N flux determination (using ¹⁵N pool dilution) and for a laboratory incubation study which monitored CO₂ release, DOC release, and net N mineralization and nitrification.