Biomass harvesting intensity influences above and below ground wood decomposition processes in a northern Ontario jack pine forest

Dead wood decomposition affects provision of habitat, carbon storage and soil nutrients and can serve as a functional indicator of ecosystem integrity. We aimed to assess the effect of increased biomass harvesting practices on wood decomposition processes, hypothesizing that increased harvesting intensity would cause decreased decomposition and altered chemical dynamics in decaying wood. We used a standardized wood stake experiment for tracking above- and below-ground decomposition and chemical dynamics to evaluate the effects of alternative biomass harvesting strategies. We evaluated four biomass harvesting strategies in a second growth jack pine stand: stem-only, full-tree biomass, full-tree with stump removal and, blading. The harvesting effects of these treatments were contrasted with three reference conditions: mid-aged harvest recovery, early post-fire recovery, and old (80 + years), wildfire-origin. Harvesting altered decomposition by slowing above‑ground decay and stalling below-ground decay. Patterns of decay in harvests did not replicate the dynamics of fire. Harvest increased several metals and nutrients and shifting their timing and accumulation patterns compared to references. Biomass harvesting intensity influenced wood decomposition in complex, non‑additive ways, with moderate removals causing variable short‑term increases, intensive treatments suppressing. Increasing biomass removal intensity caused generally modest changes in wood chemistry, including reducing nutrient retention, increasing auxiliary metal accumulation. Responses varied by element, treatment, decay stage, and soil position. Forest management should account for these differential responses to ensure that deadwood stocks are provided, and that environmental conditions support the continued provision of habitat and site productivity.