Migrating Trees: Forests Shift West with Climate Change
The consequences of climate change are impacting plant species in unanticipated, but logical ways; for instance, conifers and other needle trees are moving northward because they are more sensitive to temperature than flowering, deciduous trees. They already populate the boreal forest of eastern North America, so they’re well-adapted to expand into colder, drier conditions.
Individual trees can’t move, but populations can shift over time as saplings expand into a new region while older growth dies in another. A new study published in Science Advances also shows that about three-quarters of tree species common to eastern American forests, including white oaks, sugar maples and American holly, have shifted their population centers westward since 1980 due to drier conditions in the East.
Global warming has significantly altered rainfall totals. Songlin Fei, a professor of forestry at Purdue University, in West Lafayette, Indiana, and one of the study authors, observes, “Different species are responding to climate change differently. Most of the broadleaf species of deciduous trees are following moisture that’s moving westward.”
Changes in land use, conservation efforts, wildfire frequency and the arrival of pests and blights all play parts in shifting populations. Forest ecosystems are defined as much by the mix of species and the interaction between them as by the simple presence of many trees. If different species migrate in different directions, then ecological communities could eventually collapse.
This article appears in the October 2017 issue of Natural Awakenings.