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Coarse woody debris (CWD) serves a variety of ecological functions in forests, and the understanding of its decomposition is needed for estimating changes in CWD-dependent forest biodiversity, and for the quantification of forest ecosystem carbon and nutrient pools and fluxes. Boreal forests are often intensively managed, so information is needed on the effects of timber harvesting on wood decomposition, and the factors controlling the decomposition process. Therefore, decomposition of standard wood stakes of Scots pine, loblolly pine, and aspen were monitored in an uncut forest and in an adjacent clear-cut in Finland. Stakes of each species were placed horizontally on the top of the surface organic layer, at the organic layer-mineral soil interface, and vertically in the mineral soil to depth of 20 cm in both the uncut forest and in the clear-cut. Five stakes of each tree species were taken every year from each stake location for five years. Mass loss of wood stakes from all three species was greater in the clear-cut than in the uncut forest during the five-year decomposition period, losing an average 59.8% of their mass in the clear-cut, which was greater than mass loss by both pines (19.8±3.0SE %) and aspen (43.3±5.1SE %) in the uncut forest. Aspen wood stakes decomposed faster than both Scots and loblolly pine stakes in the uncut forest during the whole study period, but after two years there were no differences between the three species in the clear-cut. In the uncut forest, mass loss of stakes on the surface of the organic layer was 6 to 10 % faster than those at the mineral soil interface or in the mineral soil. In contrast, mass loss of stakes, placed on the top of organic layer in the clear-cut was 32 to 35 % lower than those deeper in the soil probably due to low moisture conditions at the soil surface. Wood stake mass loss was positively correlated with the sum of soil temperature degree days (r≥0.94). In the uncut forest mass loss was positively correlated with wood stake N accumulation, indicating that N availability was also a factor in decomposition before harvesting. Our study indicates that wood decomposition in this boreal forest is more sensitive to increased soil temperatures and N availability after clear-cut harvesting than found in earlier studies.

Douglas‐fir [Pseudotsuga menziesii var. glauca (Beissn.) Franco] seedling success on harvested areas in northern Idaho is often limited on harsh sites because of moisture and nutrient stress. This study was conducted to determine the importance of soil source, seed source, and organic matter on seedling growth and nutrition. Soil and seed were taken from both high‐ and low‐elevation sites at the Priest River Experimental Forest, Priest River, ID. In a greenhouse, seed was sown in both home‐source soil (taken from local seed‐collection zone) and nonsource soil (taken from opposite seed‐collection zone) mixes. Soil mixes included 100% organic, 50% organic/50% mineral, or 100% mineral soil. Seedlings were measured for height, bud length, root collar diameter, dry root and shoot weight, total N, total P, K, and number of ectomycorrhizal roots tips g−1 of dry root. Both soil and seed sources had similar nutrient and growth characteristics for each of the three soil mixes. One hundred percent organic soils, after only one growing season, produced seedlings that were significantly taller and had greater bud length, root collar diameter, and biomass than those growing in either mineral soil or the organic/mineral mix. Total N and P uptake was greater in the organic soil than in the mineral soil or the mix, but K uptake was greater in pure mineral soil. Low‐elevation seed‐source trees were always taller than their high‐elevation counterparts, an apparent result of adaptation to longer growing seasons. The best ectomy‐corrhizal colonization took place in the mineral soil mix. Ectomy‐corrhizae were most prolific on seedlings grown in nonsource soil when compared with those grown in home‐source soil. Regeneration success in the Inland Northwest will be substantially improved by maintaining the integrity of organic horizons on harvested areas and by adhering closely to seed‐transfer‐zone guidelines.