![]() ![]() Then something else happened that moved the investigation along: A University of Washington graduate student named Jacob Betzen decided to base his master’s degree research on the question of bigleaf maple decline. Signs were pointing to climate-related causes for the trees’ plight. The precious little snowpack that did accumulate melted early, and the following summer saw some of the hottest and driest conditions ever recorded in the state. Although the winter had seen roughly average total precipitation, it had been very warm, so almost all of it had fallen as rain, not snow. That’s because 2015 was, at the time, a record drought year in Washington. Ramsey says 2016 was an especially deadly year for young maples, and that may have actually helped the team to narrow down the possible causes. One by one, these were ruled out, and as the true culprit remained elusive, the scale of the damage only got worse. Early on, they considered all sorts of causes - fungal infections, root diseases, even chewing damage from squirrels. The DNR team started collecting samples and partnered with local laboratories to begin eliminating suspects. ![]() ”We had to really scrap it together at the beginning, without much budget.” “It was really just a couple of people prioritizing bigleaf maple,” says Ramsey. Amy Ramsey, a forest pathologist with the department, started investigating these early reports along with a few others in the office. Calls started coming in to the Washington Department of Natural Resources (DNR) reporting declining maples on both private and public land across the region - whole trees were going bare of leaves and many, especially younger trees, were dying. The first signs of trouble appeared in 2010. A new paper in the journal Forest Ecology and Management explores why. But this widespread and ecologically important tree species is in serious long-term decline. Among Northwest hardwood trees, it is second in abundance only to the ubiquitous red alder. ![]() It’s become something of a meme to post pictures of the huge leaves, often well over a foot wide, with a relatively puny human hand next to it for scale. Even if you’ve never had the pleasure of standing in the dappled shade of this tallest North American maple, you’ve probably seen its namesake leaf. The bigleaf maple ( Acer macrophyllum) is an iconic deciduous tree of the Pacific Northwest. ![]()
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