Systems dominated by trees would appear to be resistant to rapid environmental change. The obligate persistence of trees, because of the inability of individuals to purposely move over space, induces lagged responses and a level of resistance to turbulent global change. Rapid warming, increased climatic variability, and the increased frequency of severe weather events would appear to challenge this concept of resistance. As a result, a key question in ecology is, “what tipping points exist in a tree’s resiliency and to what degree might acute climatic events affect that resiliency?” Newly developed and more readily accessible datasets of high-resolution measures of climate allow us to investigate the impact of severe weather events on trees. Given that such events are historically rare, tree-ring records provide scientists a larger window to potentially study more than one of these extreme events. Explicitly here, we first utilize high-resolution climate records to investigate the influence of extreme events and narrower windows of time on the radial growth trees in the eastern US temperate forest. We then review existing literature on the strange days that appear to have had a legacy on the dynamics of tree growth, carbon uptake, canopy disturbance, and forest development.
Results/Conclusions
Regarding extreme events, our strongest finding is that a late frost (a ‘false spring’) in 1968 constrained the growth of Acer saccharum in New York State’s Adirondack Mountains and in southwestern New Hampshire, an event that also reduced the New Hampshire’s apple crop that year. We have also identified potentially narrower ‘seasons’ when climate constrains growth. Examining 22 drought-related eastern US mortality events during the 20th century, we find that 10 are associated with severe frosts or cold events. Going farther back, ring structure in three tree genera indicated a possible frost event in 1774. A review of diaries and other historical documents reveal farmers, communities, political figures, and military personnel reporting a late, severe, and widespread frost event on May 4th and 5th of that year. Not only did this event cascade through populations of humans, wildlife, and trees, it appears to be the proximal driver of six years of elevated forest dynamics that continues to have a legacy on a large swath of southeastern US forests. Together, these pieces of evidence indicate that the rare combination of extreme events, some as ephemeral as a few days, can impact temperate mesic forests for centuries.