The impacts of partial cuts on carbon stocks remain uncertain due to elevated post-harvest windthrow mortality that may counteract the positive effects of thinning on stand growth. This study evaluated the effects of partial cuts and tree mortality on aboveground carbon stocks eight years after harvest in jack pine forests. The experimental design included 24 sites with varying harvest intensities: unharvested control, moderate (30–35 %), and heavy (40–50 %) thinnings. Dendrochronological analyses and allometric equations were used to quantify carbon in live and dead biomass (snags, broken, and uprooted trees). Increases in individual tree carbon stocks between the pre-harvest year and the eighth year post-harvest were lower in controls and similar among partial cut treatments. Eight years after harvest, live carbon stocks per hectare were 41 % lower in the heavy thinning than in unharvested stands but remained similar between moderate thinning and control treatments. Larger trees and those growing closer to skidding trails showed greater increases in carbon stock, with the latter exhibiting a 33 % higher increase on average. Mean total deadwood carbon stocks were 55 % higher in the control than in the partial cuts due to reduced snag carbon in harvested stands. Uprooting was influenced by harvest treatment and proximity to skidding trails, while stem breakage was driven by tree characteristics (height, age, and competition) and distance to trails. The proportion of snags was explained by mean annual wind speed. These findings suggest that moderate thinning could sustain forest carbon stocks with prescriptions aiming at maintaining snag carbon stocks.

Wood processing, mining, and recreational infrastructures facilitate the transport and establishment of woodboring insects. Longhorn beetles (Coleoptera: Cerambycidae) are woodborers that typically develop in stressed or dead trees and are inadvertently transported in wood products, creating opportunities for exotic species to invade and expand their range around infrastructures. To understand how these infrastructures influence longhorn diversity, abundance, and potential invasions, we sampled longhorn beetles in 2021 and 2022 from 11 sawmills, 10 mines, 11 campgrounds, and 12 control (unmanaged) forest sites throughout northwestern Quebec (Canada) using broadly attractive blends of pheromone and host volatiles to assess infrastructure-related shifts in community composition compared to undisturbed forest stands. The most abundant species observed across all infrastructures was Monochamus scutellatus scutellatus Say, comprising over 60 % of the total individuals collected, followed by Monochamus mutator LeConte (17 %) and Tetropium cinnamopterum Kirby (7 %). We did not record any exotic species; this absence may reflect community-level resistance from diverse native longhorn assemblages. Sawmill sites had the highest diversity and evenness and showed increased abundance of several common native species. However, longhorn communities varied more with forest composition than infrastructure type. NMDS distinguished longhorns linked to balsam fir from those associated with Jack pine, like M. mutator and Rhagium inquisitor Linnaeus, and separated beetles in white spruce and pine, such as Tetropium cinnamopterum Kirby and T. schwarzianum Casey, from those in early-succession hardwoods. Increased abundance of longhorns near sawmills came from diverse forest types. We do not find evidence for increased invasion risk near infrastructures, but ongoing surveillance remains crucial.