Structure and dynamics in a natural, wood-rich forest cell in the Gesäuse National Park

Inventory data were collected in a 52-hectare subalpine spruce-larch-cirbian forest in the Gesäuse in order to derive stock structure types and to quantify the driving factors for tree species composition and the stock structure. In order to be able to assess successive processes, a recording of stock gaps was carried out. In addition, the gap-generating and gap-closing trees were collected and transitional probabilities of the tree species were calculated. In addition, drill cores were extracted from 124 trees to determine the age of tree and stock. On the basis of the annual ring history, exemption events that were triggered by incident events were estimated. With multivariate statistical methods, three structural types could be formed. Structure type 1 was characterised as a “seed-rich, larch-dominated stock” and can be found above all on those areas where forest pastures used to take place with regular waste of greenerle and latches. Structure Type 2 is a “Spruce Dominated Stock” and covers 20 ha. This type of structure is largely located in the north-eastern part of the study area and is only slightly anthropogenic. On the basis of the height and variation of the structural dimensions in type 3, which is stem-number-dominated and spruce-dominated, it can be closed to different phases of stock development. The volume of dead wood on the entire investigation area is 20 % of the total wood supply. Three quarters of the volume of dead wood is to be classified as lying dead wood and are available as a small site that is favourable to the collection from the attainment of a certain degree of degradation of the rejuvenation. Storms are the predominant cause of disturbance on the investigation surface and small stock gaps with a diameter of less than 10 m dominate. On average, an exemption event could be detected from the dendroecological examinations every 20-40 years. In structural type 1 a change of tree species from spruce to larch was observed. Especially in Structureyp 3, falling larchs of spruce are replaced. This trend is reinforced by the abandonment of the alpine industry. Due to the low anthropogenic influence in the north-eastern part of the study area, around 24 ha can be considered a jungle residue. The remaining 28 hectares are to be classified as a natural forest due to the former alpine management, which can develop again in the direction of a primeval forest in the case of portable shell wild densities.