Zeitliche und räumliche Umsetzung des Sanierungskonzeptes

1998

S. 330-342, 365-366

Unselbständiges Werk

200065999

The current situation for forest regeneration is analyzed on the basis of inventory data. In the scenarios it is assumed that all timber and old growth stands - 510 of 841 inventory plots - should be regenerated naturally in the future decades. The desirable stand composition is oriented toward the potential ntural vegetation. The analyses show that the current dominant species in mature stands is Norway spruce. This species also dominates the regeneration of almost all plots. The next most frequently occurring species is European larch. However, in the vegetation association "Homogyno Piceetum", larch can only be found in 55% of the inventory plots on unstable steep slopes. In this situation, a higher percentage would be desirable in regenerating stands. Mature Silver fir can only be found in 5% of Abietetum plots (17 of 340 plots) in old stands. 10% of the plots have fir in the regeneration. Fir occurs only in the regeneration of 15% of the slopes classified as unstable. Mature trees of European beech grow on only 4% of the sites where their presence would be expected. European beech regeneration can be found on 16% of these sites. Mature Sycamore maple is almost non existent in the old stands, but can be found in 12% of plots where it would be expected. While the most important measure for fir regeneration will be game regulation and protection, beech and maple will have to be underplanted and where necessary, fertilized. Pioneer species like European mountain ash, birch and willow grow in the regeneration of almost half of the plots. If natural regeneration is favoured in the future, the competition of grasses will be an increasing problem. In 35% of the inventory plots where regeneration is still missing or only sparsely developed, Calamagrostis sp. occurs as part of the ground cover vegetation. In such stands, weed control measures in the future will be necessary. In another 36% of the stands, where Avenella flexuosa dominates the ground cover, regeneration is insufficient. Light regime has to be regulated carefully and soil treatment may be necessary to get sufficient natural regeneration. The analysis of plots in the regeneration, sapling or thicket stage shows, that these stands again will be dominated by Norway spruce. A mixture of larch can be found in 46% of the plots. Larch is however, under-represented on unstable slopes. Fir can be found in approximately 15% of mesotrophic to eutrophic Abietetum sites, but is almost missing on dystrophic sites. Beech and maple grow on 12 respectively on 16% of the suitable sites, pioneer species grow in 57% of the regeneration plots. From these data a slow shift in stand composition can be considered for the future. Extrapolation of foliar analyses to the inventory plots by multiple linear regression equations shows that nutrient deficiencies, could potentially exist on 52% of the plots. Nitrogen (42%) and potassium (22%) deficiencies are most common. Deficiencies of more than one element occur on 30% of the plots. Fertilization should, however, only be planned together with other silvicultural measures like thinning and regeneration. These measures can be scheduled over several decades within a given watershed, minimizing harmful side effects. Ferilization will be most important if nutrient demanding species are to grow in the next generation. Apart from needle analyses, other parameters, like humus form and soil status, should also be included in the decision process.