Scientists used aerial imagery from the U.S. Department of Agriculture to map pinyon-juniper forests over nearly 2 million acres in northern Arizona, including Grand Canyon National Park and Flagstaff-area national monuments.
Forty-three percent of areas classified as alive in 2015, were dead or dying in 2021. Wupatki National Monument saw a tree mortality of 47%.
The project’s investigators say more research is needed to pinpoint the causes of the die-off, including longer-term monitoring to see the effects of climate. The Southwest is in the midst of a decades-long drought and experiencing warmer temperatures from global climate change.
Junipers are typically drought-tolerant trees. Federal land managers began to raise concerns about the widespread die-off last year.
