By Kai Zhu, Christopher W. Woodall, Souparno Ghosh, Alan E. Gelfand, and James S. Clark
Durham, NC (September 13, 2013) – A new study led by Duke biologists and published in Global Change Biology, finds that many trees aren’t shifting their ranges northward in response to warmer temperatures as quickly as was previously expected.
The study looked at 65 different species in 31 eastern states, and found that 80 percent of the species weren’t yet shifting their ranges to higher latitudes. Instead, the trees were speeding up their life cycles, with younger trees replacing older trees at a higher rate.
The study’s findings suggest that most young trees have higher optimal temperature and precipitation levels than older trees, which means they thrive more in warmer, wetter climates than older trees do. That, coupled with longer, wetter growing seasons which encourage growth and competition among older trees are likely reasons why trees are staying put and speeding up their life cycles rather than spreading farther north.
Analysis suggests that tree species might respond to climate change by having faster turnover as dynamics respond to longer growing seasons and higher temperatures, before there is evidence of poleward migration at biogeographic scales.