The rejuvenation of the white fir in the area of the Kalkalpen National Park

Silver fir (Abies alba Mill.) is an important tree species in Austria and is considered to increase the stability of forest ecosystems. Yet it has a lower proportion in the Austrian forests compared to what would be expected naturally, which makes it particularly important to understand the factors limiting the regeneration of silver fir. The objective of this thesis was to provide information on the limiting factors for the regeneration of silver fir in unmanaged forests, and to contrast these factors to a commercial forest. Study areas were the Kalkalpen National Park and the neighbouring Steyrtal enterprise of the Austrian Federal Forests. Circular Study plots were created in areas requiring regeneration, and regeneration success was recorded on 223 sample plots in the national park and 43 sample plots in the commercial forest enterprise. I investigated whether the effect of game on Fir regeneration can be influenced by hunting. Furthermore, the influence of seed trees, exposure and canopy cover was examined. Response variables were the presence of Silver Fir Regeneration and the Height of Regenerating Silver Fir. The proximity of a Fir seed tree was found to be the major factor influencing the presence of Silver Fir in the regeneration (p. 001). When a seed tree was within a 25 m radius of the plot the probability for silver fir regeneration increased from 12.8 % to 55.6 %. Browsing had an influence on the tree height of silver fir in the regeneration but did not influence its presence significantly. Furthermore, canopy cover had a significant influence on the height of silver fir trees in the regeneration. When comparing Kalkalpen National Park and the Steyrtal forest enterprise, a trend (p =.059) emerged show that the probability of finding a seed tree area is higher in the national park. Canopy cover differed significantly, canopy cover in the national park on average 19.20 % higher than that of the Steyrtal forest enterprise (p. 001), special attention should be paid to its ecology and needs.银冷杉（Silver fir, Abies alba Mill.）是奥地利的重要乡土树种，可有效提升森林生态系统的稳定性。但相较于其自然分布的预期占比，其在奥地利森林中的现存占比偏低，因此探明限制银冷杉更新（regeneration）的关键因子尤为关键。本研究旨在阐明未经营森林中银冷杉更新的限制因素，并将其与商业化经营森林的相关影响因子进行对比。研究区域选取卡尔卡彭国家公园（Kalkalpen National Park）以及奥地利联邦林务局（Austrian Federal Forests）下属的相邻施泰尔塔尔林场（Steyrtal enterprise）。在具备更新潜力的区域设置圆形样地，分别在国家公园内的223个样地与商业化林场内的43个样地中记录森林更新成效。本研究探讨了狩猎活动是否能够调控猎食动物对银冷杉更新的啃食（browsing）影响，同时考察了母树（seed trees）、生境朝向以及林冠覆盖度（canopy cover）的作用。本研究的响应变量（response variables）包括银冷杉更新苗的存在与否，以及更新苗的株高。研究发现，银冷杉母树的空间邻近性是影响样地内银冷杉更新出现与否的核心因子（p<0.001）。当样地25米半径范围内存在银冷杉母树时，银冷杉更新的发生概率从12.8%提升至55.6%。动物啃食行为会对银冷杉更新苗的株高产生显著影响，但并未显著影响其更新出现概率。此外，林冠覆盖度对银冷杉更新苗的株高存在显著影响。对比卡尔卡彭国家公园与施泰尔塔尔林场的结果发现，国家公园内存在银冷杉母树的样地占比呈现出更高的分布趋势（p=0.059）。二者的林冠覆盖度存在显著差异：国家公园内的林冠覆盖度平均较施泰尔塔尔林场高出19.20%（p<0.001），后续研究应重点关注银冷杉的生态学特性及其更新需求。