KLIWAFOR

Limitation of the CO₂ sink strength of forests by ground-level ozone pollution as an intrinsic component of climate change

KLIWAFOR – Limitation of the CO₂ sink strength of forests by ground-level ozone pollution as an intrinsic component of climate change – Validation of an ozone-uptake model and implementation in the physiological tree growth model "BALANCE" for processoriented risk assessment.

The objective of the project is to determine the restriction of carbon storage function of forests under elevated O3 regimes, for the first time, in order to present a forest risk assessment for Germany. Therefore, an ozone module will be developed, validated and integrated into the process-oriented forest growth model "BALANCE". Model simulations for different forest regions and climate scenarios will form the basis for the development of forestpreventive adaptation measures. From the beginning, the project development will be accompanied by representatives from the forest administration. Processes and results will further be discussed and communicated with decision-makers to guarantee an effective forest risk management.

The calibration and validation of the ozone module as part of the forest growth model "BALANCE" will be carried out based on the measurements of the Kranzberger Forst site, a beech/spruce mixed stand in Southern Germany. The module will be developed for individual trees in particular for beech (Fagus sylvatica), with the possibility to scale-up to the stand level. We will utilize extensive data material from previous projects as well as newly generated data at the research site. In order to estimate stomatal ozone uptake, additional measurements will be performed to evaluate the effect of leaf temperature versus air temperature on vapor pressure deficit.

Phytotron climate chambers will be used to simulate realistic radiation and climate conditions. Subsequently, the influence of leaf temperature will be validated under canopy conditions and integrated in the ozone module. As a basis for the simulation study on forest growth and carbon sequestration, different scenarios including, stand structure, climate conditions, ozone concentrations and extreme events, representative of "virtually designed" forest sites will be generated, exemplifying the most important forest regions of Germany.

From the beginning of the project, the interaction with representatives from forestry practice will be in cooperated. Workshops will accompany the model development and the modalities for scenario simulations. In this way we will assure the generation of realistic scenarios and acceptance for the developed "virtually designed" forest sites, for the model prototype.

• 2018-04-01 - 2020-12-31

• Prof. Dr. Thomas Rötzer

• Technical University of Munich (TUM) - Chair for Ecophysiology of Plants

• Waldklimafonds