Structural analysis of carbonate larch forests in Gesäuse National Park

The Gesäuse National Park is the easternmost distribution area in the Northern Limestone Alps of Austria, where the pine is formed. In order to find out more about these refuges and to observe their further development, this project was carried out. As part of the project, four permanent test areas were created in the Gesäuse National Park in 2014 and 2015. The areas were laid out in the pine-focused areas of the National Park. Two areas were fully folded to one hectare each and in two areas were taken along a line N15 samples (15 next trees). General forest parameters such as breast height diameter, height, age, etc. were collected during the full shots as well as in the N15 samples. In addition, dead wood, rejuvenation, shrub influence as well as solitaires were included. The abundance of data was evaluated with regard to the central questions in the project. Thus, it was of particular importance the influence of the latches on the survival of the herds and what other tree species occur in these areas and exert competitive pressure on the pine (larch). From the current point of view, the spread of larch-circle forests upwards through the latches is strongly limited. The latches form a striking, seemingly insurmountable boundary for the trees. It is clearly recognizable that where the latches occur massively, trees only have a chance on open spaces and only until they are not overgrown by the latches. Apart from the shrubs, larch and spruce exert the greatest competitive pressure on the pine. The low occurrence of birdberry and fir is not a competitive pressure for the pine, but an increase in diversity in these areas. The survival of the stocks is currently only ensured with very little rejuvenation. Although pine rejuvenation could be collected in all areas, the number of stems per hectare in the areas was very small. With the installation of these areas, a first important step for the monitoring of the pine stocks in the groom is given, however, how these stocks will develop will show the future.格塞乌斯国家公园（Gesäuse National Park）是奥地利北石灰岩阿尔卑斯山脉（Northern Limestone Alps）最东端的自然分布区域，境内自然分布有松属林木。为深入探究这类庇护生境并观测其后续演化进程，本项目正式启动。作为项目的核心组成部分，研究团队于2014年与2015年在格塞乌斯国家公园内设立了4个永久监测样地。样地均选址于公园内以松树为优势种的区域：其中2个样地为完整的1公顷监测样方，另外2个样地则沿预设样线设置了15个采样点，每个采样点选取紧邻样线的1株树木，共15株。在完整样方与15株采样树木中，均采集了胸径、树高、树龄等常规森林监测参数。此外，研究还纳入了枯木蓄积、天然更新状况、灌木干扰以及孤立木分布情况等观测指标。 针对项目核心研究问题，研究团队对所获海量监测数据开展了系统性评估分析。其中两项内容尤为关键：其一为林隙（latches）对林木种群存活的影响，其二为该区域内其他哪些树种会对松属林木（此处特指落叶松）构成竞争压力。 基于当前观测结果，落叶松群丛通过林隙向上扩张的进程受到了极强限制。林隙为林木的向上扩张形成了一道显著且看似难以逾越的物理屏障。可以清晰观测到，在林隙大规模分布的区域，林木仅能在开阔地带存活，且存活时长不会超过其被林隙完全覆盖之时。 除灌木外，落叶松与云杉对松属林木的竞争压力最为突出。花楸（birdberry）与冷杉（fir）在该区域的分布占比较低，并不会对松属林木构成竞争压力，反而能提升区域内的物种多样性。 当前，该区域松属林木种群的存续仅能依靠极少量的天然更新维持。尽管所有样地均采集到了松属林木的天然更新个体，但样地内每公顷的幼茎数量仍处于极低水平。 通过设立上述永久监测样地，本研究为该区域松属林木种群的长期监测工作迈出了重要的第一步。不过该种群的后续演化趋势，仍有待未来的观测结果予以验证。