With climate change becoming an ever increasing problem and our forests at risk from a variety of diseases and infestations, scientists around the world are working to learn more about how trees can survive these changing conditions. One of these conditions, which is becoming more commonly seen around the world, is drought. Finding out which trees can resist drought is essential for maintaining our global forests.
In April, a team including Princeton University researchers and Willian Anderegg of the University of Utah released the results of a study about determining which trees can resist drought. Previously, scientists struggled to determine how climate change was affecting various trees and how to predict which trees would survive changing weather and climate conditions.
After collecting data on drought-induced tree deaths from 33 individual studies performed around the globe, including data on 475 species and over 760,000 individual trees, the team chose to examine key traits of trees to see which ones the survivors had in common. Things like tree species, type of tree, water hydraulics, rooting depth, and leaf characteristics were all taken into consideration.
Anderegg and his team found that trees that can better withstand stress to their water transport system – ‘water pipes’ known as xylem – can better survive drought.
“A Heart Attack for a Tree”
Regularly, trees pull water up from the ground through the xylem in the trunk to the leaves. This natural pulling creates tension within the tree. When there is a drought, the tree has to pull much harder on the xylem to bring up the water from the ground. This intense pulling allows air bubbles to infiltrate the pipes and cause blockages. Anderegg and his team call these blockages “like a heart attack for a tree”.
Trees with a larger hydraulic safety margin are more capable of withstanding this stress caused by the xylem’s pulling.
With these results, scientists and those involved in fighting climate change can more accurately determine which trees should be planted in certain areas to ensure they will survive times of drought. Making smart decisions about what trees to plant where will help curb the effects of climate change on our trees.