A Jeffrey Pine at High Elevation Signals Unexpected Change at California's Treeline

Safford was hiking at treeline, the forest threshold where trees still grow, but fewer and farther between. Only the toughest species can survive the strong winds, heavy snowpack, and freezing temperatures found there. Safford is a forest and fire ecologist with the University of California Davis Environmental Science and Policy department.

He knows subalpine forests are on the leading edges of climate change — and that this Jeffrey pine (Pinus jeffreyi) didn't belong. So how had it gotten there? Were there others?

And if so, what did that mean? The answers could portend unexpected competition at California's treeline — and a rising threat from wildfire. For people who know their pines, Jeffreys are easy to spot.

That's because their needles come in bundles of three, whereas California's high elevations are still dominated by trees with bundles of five. These high five pines can survive in cold, harsh, windy places where few other trees can.