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.

Understanding the interplay between environmental conditions and physiological traits is essential to explain tree longevity in resource-limited environments. We studied old (up to 466 years) Thuja occidentalis trees growing on contrasting rock and gravel substrates to assess how substrate type and age influence hydraulic function, resource use, and survival strategies. Using dendroanatomical and physiological measurements, we compared key functional traits across 25 trees of varying ages and site conditions in Duparquet, Quebec, Canada. Our results show that trees on drier rock substrates exhibit smaller xylem tracheids, reduced theoretical hydraulic conductivity, and lower foliage density, enabling them to resist drought stress at the cost of limited growth. These conservative traits become more pronounced as the trees age and are associated with greater longevity, with the age of trees growing on rock substrates exceeding 300 years, whereas those on gravel substrates reaching up to 200 years. In contrast, trees on gravel demonstrate greater hydraulic efficiency and radial growth potential as a result of fewer resource constraints. These findings align with the hydraulic limitation hypothesis and provide valuable insights into how substrate conditions and age-related functional acclimation shape survival strategies in long-lived trees. Moreover, they highlight the importance of local site conditions in tree resilience and underscore the need for further research into the effects of environmental variability on tree physiology and morphology to better predict tree responses to future environmental changes.