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.本研究以奥地利克恩顿州（Carinthia）Gößgraben区域（海拔约1150~1500米）的落叶林残遗林分为研究对象，采用树木年代生态学（dendroecological）技术开展生长与发育相关调查。该区域包含两类阿尔卑斯内陆植被群落：分别为槭榆林（Ulmo-Aceretum pseudoplatani Beger 1922）与糙苏-山毛榉林（Asperulo-Fagetum Sougnez et Thill 1959）、 Luzulo luzuloides-山毛榉林（Luzulo luzuloides-Fagetum Meusel 1937）。南向林分位于高地陶恩国家公园（Hohe Tauern National Park）的外围区域。槭榆林是奥地利境内的珍稀森林群落之一，同时也是阿尔卑斯主脊以南仅存的该类残遗林分。Gößgraben区域的山毛榉残遗林分是奥地利境内海拔最高的阿尔卑斯内陆山毛榉群落。尤为关键的是，槭榆林分的枯木占比极高，进一步凸显了其原始森林的自然特质。亚海洋性局地气候、雪崩与落石事件对林分的保存起到了核心作用：相较于挪威云杉（Picea abies），这些环境因子对落叶木本植物形成了正向筛选。本次调查涉及的树种包括桐叶槭（Acer pseudoplatanus）、欧洲白榆（Ulmus glabra）、欧洲山毛榉（Fagus sylvatica）以及挪威云杉（Picea abies）。研究共选取了4个树种组成存在差异的林分，每个林分采集对应优势树种的树芯约15枚，仅林分2例外，其采集了28枚桐叶槭树芯，总样本量为n=140。鉴于多数山地种群受荷兰榆树病影响，为防止病害进一步扩散，本次仅采集已死亡的欧洲白榆个体。树轮宽度以1微米（μm）的分辨率进行测量。通过定年与索引构建的生长年表，与月降水量总和及月平均气温的气象记录开展了单调斯皮尔曼秩相关系数分析（Spearman-Rank Correlation Coefficient Analysis）。除树轮宽度指标外，本研究还测定了优势树种的年龄结构：对于树芯腐朽的个体，通过外推法估算其树龄。最后，基于断面积生长量，分析了树木生长的长期变化趋势。