The Kids Aren’t Alright: Saplings Reveal How Changing Climate May Undermine Forests


UArizona researchers studied how young trees respond to a hotter, drier climate. 

UArizona researchers studied how young trees respond to a hotter, drier climate. Their findings can help shape forest management policy and our understanding of how landscapes will change.

As climate scientist Don Falk was hiking through a forest, the old, green pines stretched overhead. But he had the feeling that something was missing. Then his eyes found it: a seedling, brittle and brown, overlooked because of its lifelessness. Once Falk's eyes found one, the others quickly fell into his awareness. An entire generation of young trees had died.

Falk – a professor in the UArizona School of Natural Resources and the Environment, with joint appointments in the Laboratory of Tree-Ring Research and the Arizona Institute for Resilience – refers to this large-scale die-off of the younger generation of trees as a recruitment failure. This is particularly devastating for a population of trees because the youngest are essential for forest recovery following massive die-off events, such as severe wildfires and insect outbreaks, both of which will become more frequent as the climate continues to change, he said.

To better understand how extreme climate conditions might trigger recruitment failure, Falk and his co-authors examined how five species of 4-year-old trees responded to extended drought and heat.

Read more at University of Arizona

Image: A University of Arizona-led experiment exposed different species of trees to heat and drought to study how young trees respond to climate change. After 20 weeks of drought and a one-week heat wave, this Douglas fir sapling was dry and brittle. (Credit: Alexandra Lalor via University of Arizona)