Ecosystemic adaptation measures are particularly important in forestry. Strategic planning on the part of politicians and the responsible forestry companies is important for this. This is because even though forest ecosystems have constantly adapted to changing environmental conditions in the past, the extent and rapid progress of climate change can overstretch the adaptive capacity of long-lived tree species.
In addition, the adaptability of the different tree species is pronounced differently. As an example, the spruce, which is widespread in Germany, can be mentioned here. It prefers cool and humid locations and is therefore not very tolerant of drought and heat. Since it is already frequently cultivated outside its natural range due to its rapid growth, its adaptability will continue to decline in the future.
The conversion of pure forest stands - such as the spruce or pine monocultures that are widespread in Germany - into mixed forests that are rich in structure and species, multi-layered and thus close to nature, is a necessary measure to secure the utilization, protection and recreational functions and the biological diversity of the forest in the long term. A broader structural and genetic diversity increases the resilience of forests used for forestry and thus their adaptability. Resilience means that an ecosystem is able to withstand ecological shocks and disturbances such as insect infestation or storms and maintain its basic organization and functionality.
The EU and federal and state governments support forest conversion with financial aid. By 2017, an average of 22,000 hectares of forest had been converted each year.hot p
Natural rejuvenation, in which individual trees are removed from the stand to create clearings for the seedlings of surrounding trees, is the most favorable and natural form of forest regeneration. Often, however, this does not result in a change of tree species, so that the stock is still susceptible to drought and heat. Primarily with the targeted cultivation of heat-tolerant species through artificial regeneration, the forest becomes more resilient.
Forest restructuring measures also help to protect against fires. The danger of forest fires has already increased due to longer and more frequent dry and hot spells. Mixed forests are less prone to forest fires, as they have a more humid interior forest climate. Species-rich mixed forests are also more resistant to insect pests and fungal attack.
The primary goal is to establish multi-level mixed forests, which are based on the tree species composition, dynamics and structure of natural forest communities. Non-native tree species should only be used in exceptional cases and very restrictively after a comprehensive ecological risk assessment has been conducted in advance. In protected areas (nature reserve and special areas of conservation), the introduction of non-native tree species should generally be avoided.
Significant parts of the currently created open spaces should not be cleared or should be cleared only to a limited extent, if this is justifiable due to the forest protection situation. Under protection of the dead, lying or still standing old trees, a diverse and often better adapted subsequent generation can establish itself in the course of natural succession. Due to their high genetic diversity, it can generally be assumed that natural rejuvenation provides better conditions for the establishment of adapted tree individuals than artificial rejuvenation methods.
The water balance plays a key role in the adaptation of forests in response to increasing dry and hot weather events. In all silvicultural interventions, special attention must therefore be paid to preserving or improving the interior forest climate and the soil water supply in order to buffer temperature extremes and reduce the competition for water.
Forest restructuring enables a diversification of the wood supply, which can also bring economic advantages. In addition, mountain forests in particular have the important function of protecting infrastructures and settlements from rockfall and flooding - a function that forest restructuring can also strengthen.
Especially in extremely dry regions, where water is only available to a limited extent during the summer months, forest ecosystems can be supported by technical measures that counteract the increasing water shortage and a drop in the ground-water level. For example, the water balance of soils in wetland forests can be stabilized by rewetting.
Dispensing with large harvester machines helps to reduce soil compaction.
Technical measures can also help against forest fires. Forest fire monitoring can be supported by additional video measures or satellite-based systems, for example.
The German Weather Service daily publishes the so-called Forest Fire Hazard Index on its website. Here, a map shows how high the risk of forest fire is from a meteorological point of view in the individual regions of Germany.
A few years ago, the Thünen Institute of Forest Ecosystems, together with the Humboldt University of Berlin, developed a system for early detection of forest fires.
Legal, political and management measures
As described above, adaptation of forestry to climate change requires consistent risk management to deal with damaging events such as forest fires, storm damage or pest infestation. This is the only way to identify risks in good time, ward them off and successfully manage them.
In addition to short-term crisis management, especially preventive measures such as coordinated water management concepts to reduce the risk of fire are important. They should be coordinated at all planning levels between forest owners, municipalities, landscape associations, forestry administration, fire department and road construction in order to integrate the interests of all parties involved and avoid conflicts of use.
Comprehensive knowledge is important as a basis for the described risk management plans and forest restructuring. Against this background, precise information is needed about which tree species are suitable for the respective location, taking into account future effects of climate change. In addition, planning maps or site mapping are required to provide information on the thriving of the tree species under the relevant environmental and climatic factors. The management of experimental plots, regional recommendations for cultivation by the federal and state governments, regular monitoring and research into the use of wood can also improve the information basis.
Natural forest reserves play a decisive role in this. In the existing non-utilization forests, the climate adaptation potential of tree stands without care and utilization is investigated. On this basis, advice for forestry is given. In mid-2018 a total of 742 natural forest reserves with an area of 35,500 hectares existed in Germany. This is only 0.3 percent of the forest area.
Forest and soil monitoring programs at European, national or country level already provide important information at present, but potential exists for expanding the knowledge base and better networking of actors.
With the Forest Climate Fund, the German government has also created an instrument that has provided over 65 million Euros for adaptation measures since 2013.
With the amendment of the Federal Hunting Act, game populations can be hunted more intensively, since deer eat the sprouts of young deciduous trees and thus prevent the conversion of forests into more natural mixed forests.