Journal Article

Timber harvesting was the most important factor driving changes in vegetation composition, as compared to climate and fire regime shifts, in the mixedwood temperate forests of Temiscamingue since AD 1830

Drobyshev, Igor, Robles, Daniela, Pascual, Jesus, Danneyrolles, Victor, Boulanger, Yan, Bergeron, Yves

2025

Overview

The vegetation composition of northeastern North American forests has significantly changed since pre-settlement times, with a marked reduction in conifer-dominated stands, taxonomic and functional diversity. These changes have been attributed to fire regime shifts, logging, and climate change. In this study, we disentangled the individual effects of these drivers on the forest composition in southwestern Quebec from 1830 to 2000 by conducting retrospective modelling using the LANDIS-II forest landscape model. The model was run based on pre-settlement forest composition and fire history reconstructions, historical timber harvest records, and climate reanalysis data. We compared counterfactual scenarios excluding individual factors to a baseline historical scenario. Our results indicated that timber harvesting had the greatest impact on forest dynamics over the past centuries. In the absence of timber harvesting, pre-settlement species abundances were largely maintained, preserving key functional traits like fire and shade tolerance that contribute to ecosystem resilience. Increased fire activity during the settlement period contributed to the increase of early-successional aspen (Populus tremuloides), but timber harvesting played the dominant role. Fire exclusion had no influence on vegetation composition, suggesting mesophication unfolds over longer timescales than those captured in this study. Climate change, characterized by modest increases in temperature and precipitation, had a minor effect on vegetation shifts, as increased precipitation might have mitigated the adverse effects of rising temperatures. However, future climate change is projected to become a more significant driver of forest composition. These findings underscore the importance of forest restoration and continued research on past forest dynamics to better understand current and future changes. The online version contains supplementary material available at 10.1007/s10980-025-02043-x.

• Publisher: Springer Nature B.V,Springer Netherlands
• Subject: Agricultural and Veterinary Sciences / Agriculture, Forestry and Fisheries / botanical composition / climate / Climate change / Composition effects / Earth and Related Environmental Sciences / ecological resilience / Ecosystem resilience / Environmental restoration / fire history / fire regime / forest dynamics / Forest ecosystems / Forest harvesting / forest restoration / Forest Science / Forests / functional diversity / Fysisk geografi / Geovetenskap och relaterad miljövetenskap / Jordbruk, skogsbruk och fiske / landscapes / Lantbruksvetenskap och veterinärmedicin / Logging / Natural Sciences / Naturgeografi / Naturvetenskap / Physical Geography / Populus tremuloides / Precipitation / Quebec / shade tolerance / Skogsvetenskap / species / Temperate forests / temperature / Temperature tolerance / Timber / Vegetation / Vegetation effects