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

Authors

Daniela Robles, Universite du Quebec en Abitibi-TemiscamingueFollow
Yan Boulanger, Canadian Forest ServiceFollow
Jesus Pascual, Canadian Forest ServiceFollow
Victor Danneyrolles, Universite du Quebec a Chicoutimi
Yves Bergeron, Universite du Quebec a Montreal
Igor Drobyshev, Swedish University of Agricultural SciencesFollow

Document Type

Article

Journal/Book Title/Conference

Landscape Ecology

Volume

40

Publisher

Springer Dordrecht

First Page

1

Last Page

22

Publication Date

1-20-2025

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Abstract

Context 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.

Methods 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.

Results and Conclusions 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.

Recommended Citation

Robles, D., Y. Boulanger, J. Pascual, V. Danneyrolles, Y. Bergeron, and I. Drobyshev. 2025. 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. Landscape Ecology 40:26.