Decline of radial growth in red oaks is associated with short-term changes in climate

Comparison of basal area increments of paired healthy and declined oak trees shows a marked disjuncture beginning in the early 1950′ at 3 of 4 sample locations across the southeastern United States. An argument is presented that the change in growth was caused (or accelerated) by a series of severe regional droughts in the early 1950′s that impacted the trees which then responded by forming two distinct populations consisting of: 1. relatively healthy trees, and 2. declined trees. Both populations produced less annual basal area increment after several subsequent short-term droughts, but marked crown deterioration and death appeared in the declined population after a moderately severe drought in the early 1980′s.