Summary Report No. 62


Bewertung ausgewählter Waldfunktionen unter Klimaänderung in Brandenburg

A. Wenzel (August 2000)

Future climate change will most likely affect the composition of plant communities in the forests of Brandenburg. Results from the forest simulation model FORSKA show significant vegetation changes for climatic warming scenarios. The objective of this investigation was to analyse how these vegetation changes impact forest functions.

The impacts on the forest functions were evaluated based on the change of the simulated species composition of the potential natural vegetation. The forest functions were evaluated using empirical and statistical methods, which were previously used primarily for landscape planning under current climatic conditions. Forest functions considered were species and habitat conservation, groundwater recharge, and carbon sequestration. Species and habitat conservation was divided into several components: species richness, structural variety, spatial diversity and vegetation endangerment. An aggregated diversity index was calculated for biogeographical subregions with similar climate and site characteristics.

The results indicated a shift of plant communities towards a greater share of drought tolerant species in response to climatic warming. The assessment of forest functions showed that the aggregated diversity index, groundwater recharge and carbon sequestration decreased significantly with climate change. No characteristic regional pattern was recognizable.

The applied methods used to evaluate the impacts of climate change were developed for current climate conditions. This must be considered when the results of the regional impact assessment are interpreted. In further groundwater recharge studies, consideration should be given to the influence of higher temperatures and CO2 content in the air. These change the evapotranspiration and water use efficiency of the plants. The habitat diversity function was evaluated using data from representative forest ecosystems. It should be noted that there is high uncertainty how ecosystems characteristics such as species richness and stand structure will develop under a changing climate.

This was a first attempt to analyse the impact of climate change on different forest functions. The results indicate that the investigated forest functions are quite sensitve to climate change in Brandenburg. It is concluded that the evaluation of forest functions is important in developing management strategies to mitigate negative impacts of climate change on forests in Brandenburg.