PORTLAND, Oregon — The largest die-off of fir trees ever recorded in Oregon and Washington state can be blamed on climate change, according to researchers from the U.S. Forest Service, who recently observed over 1.23 million acres of affected forests between the two states. …According to DePinte, the areas most affected range from Central Oregon down to the California border, including the Ochoco, Fremont, Winema and Malheur national forests. But the true catalyst is the region’s ongoing drought. …DePinte said when drought occurs, susceptible species of firs weaken and release terpenes — plant chemicals that produce a distinct smell — which attracts opportunistic insects like bark beetles to attack and populate. …But not all fir species are affected the same. DePinte said the most affected species include white fir, red fir and the Shasta red fir — all of which grow in lower elevations. Higher-elevation species like the noble fir and grand fir are less affected.