Can Humans Help Trees Outrun Climate Change?

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April 25, 2019

SCITUATE, R. I. — Foresters began noticing the patches of dying pines and denuded oaks, and grew concerned. Warmer winters and drier summers had sent invasive insects and diseases marching northward, killing the trees.

If the dieback continued, some woodlands could become shrub land.

Most trees can migrate only as fast as their seeds disperse — and if current warming trends hold, the climate this century will change 10 times faster than many tree species can move, according to one estimate. Rhode Island is already seeing more heat and drought, shifting precipitation and the intensification of plagues such as the red pine scale, a nearly invisible insect carried by wind that can kill a tree in just a few years.

The dark synergy of extreme weather and emboldened pests could imperil vast stretches of woodland.

So foresters in Rhode Island and elsewhere have launched ambitious experiments to test how people can help forests adapt, something that might take decades to occur naturally. One controversial idea, known as assisted migration, involves deliberately moving trees northward. But trees can live centuries, and environments are changing so fast in some places that species planted today may be ill-suited to conditions in 50 years, let alone 100. No one knows the best way to make forests more resilient to climatic upheaval.

These great uncertainties can prompt “analysis paralysis,” said Maria Janowiak, deputy director of the Forest Service’s Northern Institute of Applied Climate Science, or N.I.A.C.S. But, she added, “We can’t keep waiting until we know everything.”