Research with a broad geographic scope reveals that inexorable climate change is increasing fire frequency, extent, and severity.

In the Pacific Northwest an abrupt harbinger of the effects of future climate warming may have been the unprecedented 110+ degree heat wave of June 2021. This multi-day, extreme heat event scorched green foliage on these maple trees trying to recover from the fire nine months before. The brown, scorched leaves evident in summer 2021 fell to the ground and the treetops died.

Sprouts emerging from the base of maple trees supported a lush crop of foliage in early summer 2021, but the heat wave of late June overwhelmed the trees’ capacity to deliver cooling water to many leaves, so the leaf margins turned brown from heat damage. When the heat wave abated, the shoots put out a flush of dense clusters of small, lighter green leaves.

What challenges will continued climate change and the associated heat waves present to future forests?