The district of Ludwigsburg is located in a wine-growing climate characterized by comparatively high average temperatures and low rainfall. According to current knowledge, wine-growing regions will be characterized by a climate that may be four degrees warmer than today as a result of climate change by the end of the century. Trees that are planted today will have to cope with these conditions. This scenario poses enormous challenges for forest owners and foresters.
In the Ludwigsburg district, foresters are relying on the latest scientific findings. Anne Klama and Katharina Obermeier, both currently employed by the forestry department as part of their trainee training, recently took part in a training course that dealt with the silvicultural options for adapting our forests to climate change. The focus was on the correct handling of the Douglas fir tree species. Prof. Dr. Ulrich Kohnle, Head of the Forest Growth Department at the FVA and a renowned scientist in the field of silviculture, was invited as an external speaker.
"Old trees have adapted perfectly, young trees are more adaptable." Kohnle opened his lecture with this statement, in the course of which he discussed the current models of climate change and the associated conclusions for the forest in the Ludwigsburg district, as well as the repeatedly discussed topic of alternative tree species. "The theory that the forest should be left to its own devices and nature will take care of it is not tenable from a scientific point of view," said Kohnle, explaining: "The loss of water through cell respiration and leaf evaporation in trees is significantly greater than evaporation from the bare ground. Regular maintenance interventions therefore help the forest to adapt to the drought."
A relatively new scientific finding, but one that is of great importance for forestry work, goes in the same direction: when young trees grow up in dense clusters, they invest more in height growth, i.e. the fight for light. In doing so, however, they tend to neglect root growth. Once this imbalance has occurred, however, it only corrects itself very slowly later - if at all. This is particularly problematic in years of drought, when a large, deep root system is best able to supply trees with water. However, trees can also shed their leaves prematurely in such years in order to bring their water requirements back into line with the water supply. Although this allows them to survive, the premature cessation of growth means that fewer reserves can be formed, which weakens the trees in subsequent years. Parts of the crown can also die - in severe cases even the entire tree.
Professor Kohnle's lecture was followed by an excursion to various forest stands that Anne Klama and Katharina Obermeier had selected and measured in advance. The scientific findings were discussed with the Ludwigsburg foresters in a very practical way and the changes that need to be made compared to the previous maintenance measures were considered.
"Climate change presents the forest with an unprecedented challenge. Our aim is to adapt the forest to climate change as best we can with our decisions and thus preserve it with all its various functions. The support of science is of the utmost importance to us as decision-makers on the ground. We are therefore particularly pleased that we were able to attract Prof. Dr. Kohnle, a renowned scientist in the field of silviculture, for a training course," explains Dr. Michael Nill, Head of the Forestry Department at the District Office, in conclusion.
