“Forum Future Forest” off to a successful start
It started with two topics in September and October 2021: “Drought and heavy rain – the forest as a buffer” and “Tree species for the forest of tomorrow”.
Wolf von Aufseß (right) explains the conditions in the area of forest before the excursion, supported by Dr. Gregor Aas, Ecological-Botanical Garden/University of Bayreuth.
Wolf von Aufseß is the owner of the Mengersdorf estate and an “unskilled forest owner”. On behalf of the ecology and environmental research conducted at the University of Bayreuth, Dr. Birgit Thies praised the new location of the Mengersdorf estate for the dialogue it facilitates between research and practice on forest issues – the spatial relationship to the topic is closer here than at “Forum Waldkontroversen” (Forum Forest Contoversies) on campus (UBTaktuell reported).
Forest owner Wolf von Aufseß explains what was cleared and planted in the wet, valley floor and on the valley slopes, and why?
Ecologist Andreas von Heßberg moderates the discussion: How can the forest be nurtured specifically in its function as a water reservoir?
On an excursion to the neighbouring area of forest, three sites were visited from the outer to the lower “Pfanne” (Pan), a stream valley with slopes below Neubürg. Could more water be kept in the valley here – should water be actively dammed? What tree species are appropriate there, and what (wood) value does an alder actually have? How significant is the cooling effect of a wet valley floor on the surrounding slopes? These and other questions were discussed in the group – moderated by Dr. Gregor Aas and Dr. Andreas von Heßberg from the University of Bayreuth – in an engaged and sometimes controversial way.
To build up humus, it is important to avoid spruce monocultures and to specifically promote deciduous trees in natural regeneration.
Deliberate waterlogging was discussed: Could this stream be dammed, and what would be the consequences?
Much good can be achieved for the water balance and climate stability of forests with the targeted nurturing of species from natural regeneration.
From the forest we went to the vaulted cellar of the Mengersdorf estate. Dr Stephan Raspe explained the basics of the water balance of forest ecosystems, in particular the role of soil as a complex water reservoir. By increasing the humus content of mineral soil, its water storage capacity can be considerably increased, for example. On the other hand, depending on the weather, every soil can become “saturated” at some point, after which flood peaks caused by rainwater running off the surface can hardly be avoided. At best they can be slowed down.
As a silvicultural conclusion of the lecture, the speaker recommended
- the conversion of pure coniferous forests to mixed and deciduous forests to improve groundwater recharge and the water pumping effect,
- a canopy that is as closed as possible to maintain a cool and humid microclimate in the forest,
- the avoidance of soil compaction, and
- the closure of ditches and drainage pipes.
Dr. Tobias Mette explained how research is trying to identify options for future silviculture based on climatic “analogue areas”. Whar are the tree species prevalent today in areas where the climate corresponds to that predicted for the future in Mengersdorf? The dynamics of developments are becoming clear: At the current pace of climate change, no single tree species offers security for the usual rotation period of around 80 years.
The excursion on Saturday morning focused on climate suitability combined with site conditions. These are mapped in the BASIS site information system , the functioning of which was explained by Ottmar Ruppert. By consulting the forester responsible, forest owners can agree on the best course of action for forest conversion in each case on the basis of the BASIS recommendations, a drill-stock soil comparison, and taking into account the existing trees.
It was exciting to discuss the various questions together at example sites:
- Which trees are more likely not to grow as old as hoped – can timber growth be accelerated through targeted crown clearance?
- Is a single. Crooked, small deciduous tree in a coniferous wood a seed tree worth nurturing for the forest of the future?
- In what cases does natural regeneration act to our benefit?
- What is the benefit of switching to the positive selection of target trees compared to regular large-scale thinning according to negative criteria?
- How might the tree species of the future be introduced on large, damaged areas as efficiently as possible?
Taking the computer into the forest: the BASIS site information system specifically assesses the future risk of different tree species for the selected site.
An assessment of soil conditions using the drill stick is recommended as a comparison with the information system.