Trees hold secrets to past weather and climate. These photos show how.

A holly tree stands tall in the Sunken Forest at Fire Island National Seashore in Suffolk County, New York.

Tree rings from a holly tree under a microscope.

Spencer Mitchell, small owner forester for Oregon Department of Forestry, holds the core of a healthy Douglas fir tree on Tuesday, April 21, 2026, in Scio, Oregon.

This increment borer is being used to withdraw a core sample small enough to fit inside a paper straw to study this cottonwood tree's rings.

Tree ring scientist Nicole Davi works with a specialized auger to take a cross section of growth rings from a red cedar at Sandy Hook, New Jersey, without harming the tree.

Tree scientist Valerie Prouet, shown doing field research, is among a cadre of scientists collecting historical information from tree rings.

Peter Fule cores a chihuahua pine that survived Rodeo-Chediski Fire in the Sitgreaves National Forest near Overgaard on April 29, 2022.

A healthy core of Douglas fir tree on the left versus a stressed one on Tuesday, April 21, 2026, in Scio, Oregon

A tree core under a microscope in the Laboratory of Tree-Ring Research at the University of Arizona in Tucson on Jan. 6, 2026.

Jeff Perry, founder of Angel City Lumber, points to tree rings as he seals Eaton Fire-damaged tree logs as part of the Altadena Reciprocity Project on December 4, 2025 in Altadena, California. The project is transforming fire-damaged trees collected from the Eaton Fire burn zone into finish-grade millwork lumber to be made available at below market price for fire survivors to rebuild their homes in Altadena.

The rings of this tree, found in a forest in Kimberley, British Columbia, are curved instead of circular which shows that this tree survived and kept growing despite being affected by a wildfire in the past.

Tree-ring specimens in the Laboratory of Tree-Ring Research archive at the University of Arizona in Tucson on Jan. 6, 2026.

A portrait of Director Kevin Anchukaitis in the Laboratory of Tree-Ring Research archive at the University of Arizona in Tucson on Jan. 6, 2026.

Will West talks about counting the rings of the Douglas fir that was cut down on property off of Old Belfair Highway in Belfair, Wash. on Wednesday, Feb. 2, 2022. A community landmark, the tree was likely between 500 to 1,000 years old, according to arborists.