It is probably no news for anyone that climate change poses a threat to forests and the fulfilment of their ecological functions. Forests are threatened by the effects of climate change, such as rising average annual temperatures, more drought, higher concentrations of CO2 in the atmosphere, declining and uneven precipitation, higher nitrogen depletion and much more. How trees respond physiologically determines their survival, growth and spread. However, the action of other organisms also comes into play, in addition to insect pests, especially game.
It is a well-known fact that mixed forests are more resistant to external influences (which play a large role in times of climate change) than monocultures. In addition to higher resilience to disruption, they also perform better ecosystem functions and are more productive. On the other hand, they are more endangered by game pressure. This fact is especially important at the present time, when the numbers of ungulate populations reach very high numbers in our forests.
The aim of this study, which was prepared by scientists from the Faculty of Forestry and Wood Sciences, is to increase knowledge about mixed stands with a dominant representation of promising beech. The research area of ??the study was rubble forests and florid beech forests in the Broumovsko Protected Landscape Area. The assessed factors in the stands included their structure and production, radial growth of trees (i.e. analysis of annual rings) and the influence of game on natural rejuvenation.
And what do the results of the study say? The results of the analysis of annual rings were especially interesting. They showed that the year-on-year growth differed for individual tree species and reflected the effects of various abiotic and biotic stressors. In the case of beech, it was mainly damage caused by late frost, drought or attack by beech scale (Cryptococcus fagisuga). The situation was similar in other monitored species, for example sycamore maple showed a decrease in growth in the years affected by drought or attack by sycamore tarspot fungus. However, beech and sycamore showed the highest degree of resistance to environmental fluctuations of all the monitored tree species, while Norway spruce was the most sensitive to adverse environmental factors. Relatively large damage to natural rejuvenation by browsing was also found in the areas of interest in the monitored species. It averaged up to 30%, with the highest losses observed in white fir (up to 53%) or wych elm (51%). Beech showed damage of about 23%.
The conclusion of the study highlights the fact that although there is a lot of speculation about the consequences of climate change, we do not yet know what the real impacts will look like. However, it leans towards the potential of mixed forests and confirms the importance of beech in European forest ecosystems. The importance of successful natural regeneration cannot be overlooked for the future of forests. In the Czech Republic, there is currently a lot of pressure from game in many localities, and in some species of trees it is practically impossible to grow back without fencing, because game damages regeneration by browsing or peeling of bark. For this reason, the study emphasizes that for the future of forests it will be necessary to significantly reduce the ever-increasing numbers of hoofed game.
Vacek S., Prokůpková A., Vacek Z., Bulušek D., Šimůnek V., Králíček I., Prausová R., Hájek V. (2019): Growth response of mixed beech forests to climate change, various management and game pressure in Central Europe. Journal of Forest Science 65: 331–345.
prof. RNDr. Stanislav Vacek, DrSc.
Professor Vacek (* 1954) studied geobotany at the Faculty of Science, Charles University and then worked as a researcher at VÚLHM in Opočno. In 2005, he returned to the university grounds, where a year later he was appointed professor of forestry at the CULS Faculty of Forestry and Wood Sciences. He still works as a teacher at Department of Silviculture.
Prepared by: Dagmar Zádrapová