Altitudinal distribution of Swiss stone pine (Pinus cembra) in the Styrian Alps as facilitator of silvicultural stability and resilience strategies

Stockholm

2024

1443

Bandaufführung

40005312

Alpine forest ecosystems dominated by Norway spruce (Picea abies) in the Austrian Alps are facing increasing threats through bark beetle (Ips typographus) infestations. The situation calls for immediate diversification of the tree species spectrum in order to create stable and resilient forest stands for providing multiple ecosystem services for the presence. The project Dynamic Forest Type Classification in the Austrian province of Styria created an empirical database resulting from 1800 forest site investigation plots. Analyzed data show that in the Western Styrian Alps Swiss stone pine (Pinus cembra) may be dominant or sub-dominant in many forest stands across six forest vegetation zones (FVZ), currently from the moderate cool mixed forest zone up to the very cold conifer forest zone. This corresponds to an altitudinal gradient of more than 1000 m, ranging from about 1300 m up to 2300 m ASL. The actual presence of Swiss stone pine (SP) in the analyzed forest plots could at least partly have been facilitated through the occurrence of Rhododendron species, which co-host Chrysomyxa rhododendri, a fungus which infects Picea abies and decreases its vitality in the alpine forest ecosystems. Together with forest management this might be one of the reasons for the presence of SP in such a wide altitudinal range. In the current situation SP turns out to be a suitable alternative for the diversification of the tree species spectrum in Styrian and Austrian alpine forest ecosystems, as it can successfully grow on most of the given forest sites within the relevant FVZ. From acidic siliceous to loamy carbonate bedrocks SP is able to establish on forest sites as dominant or subdominant tree species. Additionally, tree species suitability of SP is high in the FVZ, with increasing growth in the lower FVZ. Both the high presence and suitability on various forest sites define SP as prominent tree species in alpine forest ecosystems for increasing their stability and resilience. For a successful establishment of SP, its competition with Picea abies, Larix decidua and Abies alba has to be silviculturally regulated in order to maintain its share.