Where forest may not return in the western United States

Climate-related changes to drought, fire, and insect outbreak regimes have raised concerns that western United States forests, once disturbed, may not return or reattain prior structure and composition.  Many post-fire recruitment studies have documented absence or low densities of seedlings, supporting concerns that altered disturbance regimes may impair subsequent forest succession.  We used existing temporal (2001 – 2016) land cover data with documented data quality in combination with a 2001 – 2019 NDVI time series to estimate an upper bound of 9,150 km2 of disturbed forest which may not return or reattain prior composition and structure.  Using other attributes in the database, we demonstrated how additional information can be used in a professional judgement, relative risk framework to inform where to look and refine the estimate of the total area of impaired forest succession.

Impact/Purpose

Forests provide a wide array of societal benefits from drinking water security to carbon sequestration to flood mitigation.  In the western United States, climate-mediated changes to disturbance regimes (e.g., wildland fire, drought, insect outbreaks) have raised concerns that forests, once disturbed, might not return or re-attain prior composition and structure.  Numerous field-based studies have reported lagging seedling and sapling recruitment at previously disturbed forest sites, but it is not possible to use results from these studies estimate the extent of the problem across the entiret of the 11 western states.  This research undertakes a synoptic approach to estimate the areal extent of impaired forest succession across the western United States.

Citation

Wickham, J., A. Neale, K. Riitters, M. Nash, J. Dewitz, S. Jin, M. Van Fossen, AND D. Rosenbaum. Where forest may not return in the western United States. Elsevier Science Ltd, New York, NY, 146:109756, (2023). [DOI: 10.1016/j.ecolind.2022.109756]

DOI: Where forest may not return in the western United States