Top-down view of a mixed forest with many dead trees, whose dead, bare branches appear white in between the green of the healthy trees.

Plant Allocation

Plants are sessile organisms and face particular challenges in a rapidly changing environment because they generally cannot escape unfavourable conditions by migration, at least not within the life span of an individual. Plants require very efficient mechanisms to resist or avoid harsh environmental conditions – usually by allocating resources to specific plant organs and functional pools. In the Plant Allocation group we investigate carbon fluxes within the plant in response to environmental stress like drought and how such fluxes are altered during resource limitation.

Another focus of our work lies on tree and forest responses to global changes at large spatial scales. For example, we investigate whole-tree responses to experimental drought and heat and how this leads to tree death. I am the coordinator of the IUFRO (International Union of Forest Research Organizations) task force on monitoring patterns and trends in global tree mortality ( and founding member of the International Tree Mortality Network (

Research questions

Global trends in tree mortality
Henrik Hartmann
During the last decade, I have pursued several initiatives to address trends in global tree mortality. Already in our 2015 Science paper we highlighted the need for long-term monitoring of forest condition, and we further developed this concept into two international scientific initiatives, the IUFRO task force on Monitoring global tree mortality patterns and trends and the International Tree Mortality Network. more
Carbon allocation priorities in spruce trees
Jianbei Huang
Our experiment provides mechanistic evidence that trees faced with severe photosynthetic limitation strategically regulate storage allocation and consumption to ensure survival at the expense of growth. Understanding such allocation strategies is crucial for assessing and predicting how trees may respond to extreme events. more
Wood anatomy and non-structural carbon dynamics
David Herrera
In this project we are interested in understanding how some wood traits such as the formation of living fibers and the proportion and size of parenchyma cells, fibers and vessels affect the storage and use of NSC in trees under starvation to help them survive. more
Bark beetle ecology and host selection
Linda Lehmanski
Bark beetles are one of the major threats to coniferous forests. Severe droughts or windthrow can increase the vulnerability of spruce to bark beetles, therefore supporting increased mortality of forest. To address this timely threat, we are studying different intersections between the bark beetle Ips typographus and its host Norway spruce. more
The left side of the collage is image A, the right side is image B.
Image A is a close-up of a tree trunk. A narrow strip of bark has been removed in a ring shape. A few centimeters below, several instruments are strapped to the trunk. Picture B also shows a tree trunk with instruments attached at several heights, but the bark is intact everywhere.
Juliane Helm
I want to understand reduced CO2 emissions from tree stems and the post-respiratory fate of CO2 in stems. I am using a novel respiration chamber system for measuring CO2 and O2 repeatedly and fully autonomous in the field.  more

Methods and techniques

Construction and maintenance of experimental setups
Martin Goebel
In order to answer the research questions of the group, appropriate instruments often have to be developed or established methods or setups have to be adapted to our specific needs. Currently, my focus is on the measurement of gas emissions from trees, for example emissions of Volatile Organic Compounds (VOCs) and the respiration of trees. more
Anett Enke / Savoyane Lambert / Iris Kuhlmann
The sugar and starch concentrations in plants are a good indicator of the carbon balance of the plant. We can thus record how plants respond to environmental changes. To do this, we extract the various plant parts and determine the sugar and starch concentrations using high-performance liquid chromatography, or HPAEC-PAD for short. more
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