A north-south drought dipole in the United States has long-term effects on the recovery of ponderosa pines after fires, a study finds. Relatively little is known about the large-scale, long-term effects of climate variability on forest recovery from fires. Caitlin Littlefield, Solomon Dobrowski, and colleagues analyzed climate data and Forest Inventory and Analysis data from 989 plots that were burned by 431 wildfires across the US Interior West between 1984 and 2012. The authors also used existing models to predict the likelihood of the presence of juvenile conifers after fires. Every 3-4 years, there was a strong north-south dipole, in which one region was unusually moist while the other region was drier than average. This north-south dipole affected the recovery of ponderosa pines after fires, both in the short term and decades later. For example, juvenile ponderosa pines were less likely to be present after fires in unusually dry northern regions than in unusually moist southern regions, even though northern regions experience cooler temperatures and more precipitation than do southern regions, on average. According to the authors, taking into account the north-south drought dipole could improve long-term predictions of forest recovery from fires under conditions of climate change and reveal opportunities to improve ecosystem resilience.
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Article #20-07434: "A climatic dipole drives short- and long-term patterns of postfire forest recovery in the western United States," by Caitlin E. Littlefield, Solomon Z. Dobrowski, John T. Abatzoglou, Sean A. Parks, Kimberley T. Davis.
MEDIA CONTACTS: Caitlin Littlefield, University of Vermont, Burlington, VT; e-mail: < caitlin.littlefield@uvm.edu >; Solomon Dobrowski, University of Montana, Missoula, MT; e-mail: < solomon.dobrowski@umontana.edu >
Proceedings of the National Academy of Sciences