Dendroecological analyses of deciduous forest relics in the Gößgraben (National Park Hohe Tauern) Diploma thesis

As part of this study, the growth and development of deciduous forest relic stocks in the Gößgraben (approximately 1150-1 500 m MH, Carinthia, Austria) were investigated using dendroecological techniques. These are intraalpine deposits of maple-ulmen (Ulmo-Aceretum pseudoplatani Beger 1922) and beech stock (Asperulo-Fagetum Sougnez et Thill 1959, Luzulo luzuloides-Fagetum Meusel 1937). The south-exposed stocks are located in the outer zone of the Hohe Tauern National Park. The maple-Ulmen stocks are among the rare forest societies in Austria and form the only stock south of the main alpine ridge. The beech trees reach the highest intra-Alpine deposits in Austria in the Gößgraben. Above all, the maple-ulmen stocks have a high proportion of dead wood, thus emphasising the primal forest-like character of the stocks. The sub-oceanic local climate, as well as avalanche and rockfall events, play an important role in the preservation of stocks, as they ensure a positive selection of the deciduous woods compared to the spruce. The tree species examined are mountain maple (Acer pseudoplatanus), mountain ulme (Ulmus glabra), beech (Fagus sylvatica) and spruce (Picea abies). Four stocks with different tree species composition were selected. For each stock, approximately 15 cores were taken from the existing tree species, with the exception of stock 2 (28 maple cores) (in sum n=140). Since much of the mountain populations are affected by the Dutch elm welve, only dead Ulmus glabra individuals were sampled to prevent further spread. The year ring width was measured at a resolution of 1 & 956;m. The growth chronologies obtained by dating and indexing were correlated with meteorological records of monthly precipitation sums and mean air temperature (monotone Spearman-Rank Correlation Coefficient Analysis). In addition to the year ring widths, the age structure of the dominant tree species was determined, whereby the age of core rotten individuals was estimated by extrapolation. On the basis of the growth of the base area, long-term changes in growth were analysed.