Jeffrey Wood, University of Missouri – Changes in Forest Behavior after Crossing a Drought Threshold

How forests react to droughts might be key to planning for a warmer future.

Jeffrey Wood, assistant professor of biometeorology at the school of natural resources at the University of Missouri, examines this issue.

I’m an Assistant Professor in the School of Natural Resources at the University of Missouri. My research is broadly aimed at improving scientific understanding and prediction of how ecosystems interact with weather and climate. A major area of recent interest is focused on how forest behavior is influenced by drought. I use a variety of techniques to measure the “breathing” and the “pulse” of trees and the whole forest. My research is highly collaborative and involves scientists from different fields of study.

In a recent study, I worked with collaborators from Oak Ridge National Laboratory, CalTech and UCLA on research where we discovered what we called the “ecosystem wilting point”, a threshold defining changes in whole-forest behavior under drought.

Changes in Forest Behavior after Crossing a Drought Threshold

Forests are critical global resources that support a variety of life on Earth. They act as buffers between humans and climate change by taking up carbon dioxide from the air, filtering rainwater, and providing fiber and timber as well as being sanctuaries for recreation. As warmer temperatures fueled by a changing climate affect ecosystems globally, forests are under pressure to adapt to these changes to ensure survival in a warmer world.

In a recent study, we discovered what we called the “ecosystem wilting point.” This concept helps scientists understand how forests behave during drought and will ultimately help achieve the goal of predicting how they will adjust to a changing climate.

We studied a drought-prone oak-hickory forest in mid-Missouri at a local state research observatory. We analyzed data from a particularly intense drought year, finding that when the forest crossed the “ecosystem wilting point” threshold, it became much less responsive to changes in the environment. We then looked at long-term data records and determined that the forest is often only two to four weeks without rainfall away from crossing the threshold and experiencing severe stress.

This study provides a basis for scientists to assess how extreme drought might affect forests by using the ecosystem wilting point threshold concept to examine and fine-tune how models perform globally during periods without rain.

Projecting climate, the carbon cycle and how forests respond to environmental change is important for a variety of reasons: It provides insights that inform on how to better manage these crucial natural resources, helping scientists and managers develop adaptation strategies. It’s vital to study forests and their make up because they’re connected to weather and the climate in ways that we still don’t fully understand.

Read More:
[Google Scholar] – Jeffrey Wood
[University of Missouri] – MU researcher discovers threshold that triggers drought response in forests
[Missouri Agricultural Experiment Station] – Baskett Forest