Temperate, mesic forests are generally viewed as being relatively stable at broad spatial scales. This view and the biodiversity of these forests would suggest a resistance and resilience to the impacts of Anthropogenic climate change, even at large scales. Recent research within multiple old-growth temperate mesic forests in the eastern U.S., however, reveals two synchronous, large-scale disturbances within the last 350 years—tree recruitment over ~1.4 million km2 in the late 1600s and a severe canopy mortality over ~61,000 km2 in the 1770s. One conclusion that can be drawn from this work is that severe and synchronous large-scale disturbance can simultaneously kill trees at broad scales. If such an event happened, the hypothesis that these forests would resistant and resilient in the face of climate change would be challenged..
Another observation that can be drawn from this finding is that smaller events, like individual tree death, lightning strikes, ice storms, etc, do not remove the legacy of large-scale events like those identified in the 1600s and 1700s. Therefore, another hypothesis that can be drawn from this work is that that the impact of synchronous, large-scale disturbance on the development of temperate, mesic forests is greater than the more frequent disturbances at regional (or greater) scales.
Finally, analysis of the two large-scale events indicates that extreme climate events or decadal-scale climate dynamics were one of likely several drivers of these events. For example, repeated drought and an extreme frost that defoliated trees were drivers of the 1770s event. A hypothesis that can be drawn from these analyses research is that climatic extremes are an important driver of the long-term development and dynamics of temperate, mesic forests. Overall, these findings indicate that the legacy of climate-induced forest dynamics across broad spatial scales in temperate, mesic forests is profound and underappreciated.
Documentation of large-scale disturbance in extant temperate, mesic forests came to light through tree-ring research that was conducted from regional- to subcontinental-scales. Our research project here is to investigate temperate, mesic forests at these scales using tree-ring and ecological methods. Gaining insight to the potential dynamics of temperate, mesic forests at large-scales is crucial because these species-rich, highly productive forests are important drivers of regional water and carbon cycles for a total of approximately one billion people.