In Ukraine and Bulgaria, virgin forests still cover large areas. They are important objects of study for researchers at WSL for finding out more about developments in Swiss forest reserves and protection forests.
Nowhere in Europe are virgin beech forests larger than in the Ukrainian Carpathians. In Switzerland, in contrast, where the beech is the most frequent broadleaf species, all beech forests have been managed for hundreds of years. Even today’s beech forest reserves were previously used for a long time. With the demand for large forest reserves on the Central Plateau, interest in virgin beech forests has also greatly increased. This is why, in April 1999, Brigitte Commarmot and Anton Bürgi from WSL visited the Carpathian Biosphere Reserve in West Ukraine for the first time. The two forest scientists wanted to find out whether it would be feasible to carry out a project to compare the natural development of these virgin forests with that in forest reserves and near-natural managed beech forests in Switzerland.
They were able to carry out the planned project and the original trip turned into more than twenty. Since then, Brigitte and other researchers from WSL and Ukraine have dug ever deeper into the secrets of Uholka-Shyrokyi Luh, a virgin forest around 100 km2 in area, which consists almost entirely of beech. There they found trees up to 500 years old and roughly ten times as much standing and lying deadwood per hectare as, on average, in the forests on the Swiss Central Plateau and the Jura. One in three of the living trees had hollows, cracks or other wounds, which provided microhabitats for insects, bats, birds and other animals, such as the blue slug, the most striking slug in these forests. In this virgin forest, researchers at WSL, together with their Ukrainian partners, caught three times as many rare species of beetle dependent on old and deadwood as in old beech forests in Switzerland. They also found rare lichens in high densities that benefited from the presence of old trees.
Virgin forests as a reference for forest reserves
How does this cooperation help Switzerland? “The virgin beech forest in Ukraine is a vast research lab for us,” says Brigitte Commarmot, who for many years coordinated the cooperation for WSL. “Forests largely uninfluenced by humans are an important reference. We use them to assess how close to nature Swiss forest reserves such as Sihlwald near Zürich are, and to find out how management affects biodiversity.” And how does this help Ukraine? Through the cooperation WSL’s partners have obtained access to the international research community. “During the 17 years of collaboration, we have got to know many very motivated and gifted young researchers in West Ukraine,” says Brigitte. Six of them managed to get federal scholarships for extensive periods of study at WSL and at Swiss universities. Several have completed or nearly finished their doctorates. It is moreover important for the Ukrainian researchers not only to receive expert support at WSL, but also to have access to labs with modern equipment, for example, for genetic investigations.
Internationally, the unique data-set, collected over many years, on the development of the largest virgin beech forest in Europe has met with great interest. It probably helped the Ukrainian and Slovakian virgin forests receive the label ‘UNESCO World Natural Heritage’ in 2007. “The label counteracts the pressure from domestic and foreign companies to use the forests and helps to protect them in the long term,” says Brigitte. She retired in May 2017. Peter Brang is continuing her work.
Wind, snow and light in Bulgarian protection forests
Peter Bebi, at SLF in Davos, is investigating how dense or light forests need to be to provide protection against avalanches, debris flows and rockfall. Until recently, he also had no reference to refer to in managing protection forests. Forests with such natural structures can be found in, for example, Bulgaria, where there are still large forest reserves with virgin forests in mountainous regions, as well as conifer forests that have not been managed for a long time. They are similar to typical protection forests in the Alps. The trees often grow very close together and are thus particularly vulnerable to storms and snowbreak. Peter therefore considered it very opportune when he was contacted by Momchil Panayotov from the Forestry University in Sofia. Momchil was interested in studying such forests in Switzerland during a postdoc visit and comparing them with similar forests in his home country.
Ten years later, the two of them have completed several projects in Bulgarian mountain forests and published their results. These have helped Peter estimate the effects of windthrow, bark beetle infestations and other natural events on how well the forests provide protection against natural hazards. The focus is on the influence of overly dense tree stands on the stability of the forest and the natural regeneration of young trees. Peter hopes that the findings from the Bulgarian virgin forests will help to improve recommendations for managing protection forests. Momchil values the cooperation especially as he can then exchange experiences and his team can today be part of an international network of mountain forest researchers.
Achieving a great deal with limited means
The cooperation between scientists from East and West meant, for both sides, first taking an uncertain step into a new research culture. Today, however, all participants consider the cooperation to be extremely valuable. The reference areas in Bulgaria, which have developed naturally, have helped the researchers understand and describe the long-term development of these forests better. “We need to know what extremes states of a forest we should take into account to ensure the best possible protection against natural hazards,” says Peter Bebi with Brigitte Commarmot’s full agreement. “What’s more,” she adds, “we have learnt from our East European partners what an incredible amount we can achieve in often difficult circumstances with limited means.” (Reinhard Lässig, Diagonal 1/17)