Integrating disturbance to improve our understanding of range-wide patterns in tree species abundance and demography

Abstract

Climate and topography have long been recognized as the primary drivers of broad-scale geographic patterns in tree species abundance, demography, and occurrence, but within species ranges, forest disturbance regimes also play a fundamental role by affecting mortality, growth, and recruitment of tree species. Although forests are generally adapted to certain levels of disturbance, the intensification of disturbance regimes over recent decades highlights a pressing need to move beyond a purely climate-based understanding of tree species dynamics and to integrate the role of disturbance into macroscale considerations of forest ecosystems. Here, we review the independent and interactive impacts of four primary disturbance agents — extreme weather events, insect pests and tree diseases, human modification of the landscape, and fire — on North American forests, with considerations for the ongoing and expected effects of changing climate conditions. In particular, we emphasize how contemporary disturbances vary and interact across spatial and temporal scales, as well as how disturbance regimes may shift with future climate change. We show that forests in the eastern and western regions of the USA are largely governed by different sets of dominant disturbances and interactions, such that eastern forests tend to have higher levels of pest incidence and landscape modification by humans, whereas western forests are impacted by greater amounts of areas burned by fire and have experienced greater drought intensity in recent decades. Given this regionalization of disturbance regimes, we discuss how contemporary disturbances can be incorporated into statistical models of tree species abundance and demography to better understand future species trajectories. We summarize the main challenges of modelling disturbances with statistical models but highlight recent advancements and development of new data products that provide opportunities to tackle novel research questions, implement modelling approaches in innovative ways, and generate insights that can be used to inform forest management actions.

Citation

​Gougherty, Andrew V.; Clipp, Hannah L.; Prasad, Anantha M.; Peters, Matthew P.; Matthews, Stephen N. 2025. Integrating disturbance to improve our understanding of range-wide patterns in tree species abundance and demography. Forest Ecology and Management. 593: 122875. 10 p. https://doi.org/10.1016/j.foreco.2025.122875.