The impact of forest fertilization on wood decomposition will be studied on six sites located in Idaho and Washington. These sites have been established in various forest types on soils developed from widely different parent materials. Wood stakes will be installed in two microplots on three of the standard fertilizer treatment plots used by the Intermountain Fertilization Cooperative (lbs/ha): 300 N/200 K, 300 N/0 K, 0 N/200 K, and in an unfertilized control. Soil moisture and temperature data collectors will be placed on one of the fertilizer treatment plots at each site.

Mineral soil – twenty-five stakes (2.5 x 2.5 x 30 cm) of both loblolly pine and aspen will be placed at each microplot/site - for a total of 2400 stakes (25 stakes x 2 species x 4 fertilizer treatments x 2 microplots x 6 site locations). Douglas-fir stakes will also be installed as a third species on sites that Douglas-fir is a dominant tree species. Five stakes of each species will be removed from each microplot every 6 months starting in 2003. Soil moisture and temperature will be measured at the 10 cm depth, and gas samples will be taken at 10, 20, and 30 cm soil depths in each plot for CO₂/O₂ determination.

Litter layer (forest floor) – fifty wood stakes (2.5 x 2.5 x 15 cm) of each tree species will be installed at each microplot - 25 stakes at the forest floor/mineral soil interface, and 25 stakes on the litter layer surface - for a total of 4800 stakes (25 stakes x 2 species x 4 fertilizer treatments x 2 microplots x 2 litter layer locations x 6 site locations). Temperatures will be measured at the mineral soil/litter interface and on the soil surface.

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