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Highlights: [•] Decay fungi translocated diverse forms of 15N from soil to their wood inocula. [•] 211% more N accumulated in inoculated wood blocks vs. un-inoculated after 78days. [•] The majority of accumulated N was acquired from underneath wood blocks. [•] Woody debris will accumulate more N if in close contact with the forest floor. [ABSTRACT FROM AUTHOR]

Reports that the rate of mass loss of three standard substrates (pine needle litter, aspen leaf litter, and forest floor material) was measured in forests and adjacent clearcuts throughout British Columbia to test the hypotheses that (i) rates of mass loss are greater in clearcuts than in forests and (ii) clear-cutting would stimulate decomposition most in colder zones. Range of mass loss; Mass loss from pine needles that was significantly slower in clearcuts throughout the incubation; Aspen leaf litter and forest floor material that lost mass at similar rates in forests and clearcuts; Effect of clear-cutting that did not vary between relatively cold and warm sites; Effect of clear-cutting that was not related to the size of the clearcuts.

Reports on the measured rates of decomposition at three sites representing the major mixedwood forest types of British Columbia: (i) boreal forests of white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuloides Michx.), (ii) coastal forests of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and red alder (Alnus rubra Bong.), and (iii) a wet interior forest of Douglas-fir, paper birch (Betula papyrifera Marsh.), and lodgepole pine (Pinus contorta Doug. ex Loud.). Mass loss of litter of each species (both pure and in combination with the other species) that was measured in forests of each species to determine (i) if broadleaf litter decomposed faster than needle litter, (ii) if litter decomposed faster in broadleaf or mixedwood forests than in coniferous forests, and (iii) if mixing with broadleaf hastened decomposition of needle litter; Broadleaf litters that decomposed faster than needles during the first year but, thereafter, decomposed more slowly; Litter that tended to decompose faster in the broadleaf forests than in the coniferous forests; No evidence to indicate that the addition of broadleaf litter hastened decomposition of needle litter; Results that indicate that the mixing of needle litter with broadleaf litter is unlikely to hasten decomposition in mixedwood forests of British Columbia.

Reports on the incubation of forest floor samples from a three tree species (Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), and paper birch (Betula papyrifera Marsh.)). Rates of N mineralization in the forest floors of Douglas-fir that was significantly greater than either birch or lodgepole pine; Douglas-fir forest floors that also mineralized more N per unit of either N or C than the other species; Nitrogen mineralization rates that were positively correlated with the N concentration of the forest floor; Nitrogen concentration of foliar litter that were poor predictors of N mineralization rates resulting from Douglas-fir litter having the lowest N concentrations in litter but the highest rates of net N mineralization in the forest floor; Nitrogen mineralization in the forest floor that was negatively correlated with the lignin concentration in foliar litter; Douglas-fir litter that had low lignin concentrations, which may allow more of the mineralized N to remain in inorganic forms rather than being bound in humus; Results that suggest that a component of Douglas-fir might improve N availability in coniferous forest floors.