Long-term compositional changes following partial disturbance revealed by the resurvey of logging concession limits in the northern temperate forest of eastern Canada

Land use changes that are linked to European settlement of North America have transformed northeastern temperate forest landscapes. Many studies report a regional increase of young early-successional forests due to high disturbance rates since the preindustrial era (fire, land clearing, and clear-cuts). In this study, we document specific compositional changes to present-day mature forest landscapes, which have only been managed with partial cutting (high-grading and diameter-limit cuts) since the preindustrial era in southwestern Quebec. We resurveyed 108 forest observations that were extracted from logbooks of former logging concession limits (surveyed between 1870 and 1890). Results highlight an increase in mid-to late-successional shade-tolerant taxa (Betula alleghaniensis Britton, Thuja occidentalis L., Acer saccharum Marsh.) at the expense of preindustrial dominant conifers (Abies balsamea (L.) Mill., Pinus strobus L.). Former logging activities and spruce budworm (Choristoneura fumiferana Clemens) outbreaks appear to be the main drivers of these changes, which were also strongly structured across the topographic gradient. To some extent, these results highlight the relevance of partial cutting management, as it has allowed long-term maintenance of a mid-to late-successional forest composition, while also pointing the need for P. strobus restoration. We conclude that by allowing site-specific comparisons, the resurvey of historical observations greatly improve the analytical strengths of historical reconstruction.