A team of scientists from the US Geological Survey, UC Berekeley and the National Parks Service seek to find out.
Via SFGate:
Anthony Ambrose, a tree ecologist at UC Berkeley, is leading the team’s field effort and says the level of dieback among the trees is the worst that has ever been observed in recorded history.
“It’s an unusual situation where the trees are actually showing signs of drought that they’ve never displayed before,” Ambrose said in an interview. “These trees have dealt with drought in the past but now with global temperatures increasing rapidly we think the heat is tipping the scales.