A long-term field experiment was established in 1995 in the Stuart Dry Warm Sub-Boreal Spruce (sbsdw3) biogeoclimatic variant in the Vanderhoof Forest District to study the interactions between Sitka alder (Alnus viridis (Chaix) DC. ssp. sinuata (Regel) A.&D. Löve) and lodgepole pine (Pinus contorta Dougl. ex Loud.) in a 1987 cutblock. The main objective of the study was to determine the effects of differing levels of Sitka alder retention (0, 500, 1000, and 2000 clumps per hectare) on lodgepole growth after the pine stands were thinned to a uniform density of 1000 stems per hectare. Ancillary studies were planned to measure: (1) the nitrogen fixation rate of Sitka alder, using 15N isotope dilution, (2) the long-term changes in soil nutrient pools, and (3) the decomposition rates and nutrient concentration changes in Sitka alder and lodgepole pine litter. This establishment report details the methods used and documents the initial soil and stand condition at the time of installation of the experimental treatments.