Trees and forests in the 21st century – is a 385 million year-old success story coming to an end?

Henrik Hartmann

Date: July 10, 2019
Time: 2 pm
Place: F 0.1 (Büsgenweg 1)

Trees are simply wonderful! Some tree species can live for several thousand years or weigh as much as 12 adult blue whales, others grow to over a hundred meters high. Probably the largest individual on earth, a poplar clone, covers an entire valley and is estimated to be well over 10,000 years old. But despite their size and longevity, trees had to fight hard against adverse environmental conditions over the course of their 385 million years of existence on earth. They were not spared from ice ages and massive species extinctions, but they always returned from their refuges to reconquer the continents. However, in contrast to the geological changes in climate, modern human-induced climatic change is unprecedented in speed and extent, our planet warms up faster than ever before. Extreme events like prolonged drought and heat spells have been increasing significantly since the 1980s, making the environmental conditions for trees unpredictable. This can lead to the death of individual trees and large forest stands and, when pest populations are boosted by drought and heat, declines of entire forest landscapes can occur.
Although human welfare is tightly linked to the survival of forests, our fundamental understanding of tree functioning is still patchy. These knowledge gaps both hamper mitigation measures in forest management and prevent realistic predictions of vegetation dynamics under ongoing climate change. In this talk I will present some of our work on mechanisms of drought-induced tree mortality and highlight how research on resource allocation provides fundamental insights into tree responses to environmental change. I will also talk about forest health in a changing world and present a new initiative for monitoring global tree mortality.