Task Force probes ‘whys’ behind increased tree mortality

IUFRO has implemented a Task Force to monitor the global tree mortality patterns and trends. This will help to understand the threat for forest health and will support future decision-making.

Photo: [Gerda Wolfrum/IUFRO].

Tree mortality appears to be increasing at unprecedented rates. One may be tempted to think: So what? Trees regenerate. They’ll grow back. But, for a lot of reasons, it’s not quite that simple.

“Forests are incredibly complex ecosystems that have taken centuries – even millennia – to establish,” says Dr. Henrik Hartmann, of the Max-Planck Institute for Biogeochemistry in Jena, Germany. He and four deputies, Adriane Esquivel Muelbert, Aster Gebrekirstos, Nadine Ruehr and Bernhard Schuldt, are coordinating IUFRO’s Monitoring Global Tree Mortality Patterns and Trends Task Force.

Increased tree mortality means that forests can hold less carbon for a shorter period of time. Therefore, there will be more carbon in the atmosphere with known feedback dynamics on climate warming. The accelerating tree mortality rates may indicate a climate change risk for forest survival. And forests are important for the Earth system and to human welfare.

“We need to know how forests will cope with the changes we are imposing on the Earth system.” (The term “Earth system” refers to Earth’s interacting physical, chemical, and biological processes.) That, Dr. Hartmann says, is one of the main drivers behind his Task Force (TF).

The TF reflects a truly global effort. It includes people from many different countries with different cultural and political backgrounds. Their contributions will provide the input needed to make the initiative successful in the different biomes of the world.

“Ideally, by the end of the TF’s five-year ‘lifespan’, we will have accessed and integrated most existing data sources on forest conditions,” Dr. Hartmann says, “and can assess whether and where forest health is threatened at the global, regional and local scale. That can then allow policy makers and forest managers to make decisions that can alleviate those threats.”