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Gewählte Doctoral Thesis:

Gisela Pröll (2016): Regeneration patterns and ecophysiology of tree seedlings on dry, nutrient-poor sites in the Calcareous Alps.
Doctoral Thesis - Institut für Waldökologie (IFE), BOKU-Universität für Bodenkultur, pp 119. UB BOKU obvsg

Data Source: ZID Abstracts
Abstract:
Natural tree regeneration is frequently poor in mountain forests of the Calcareous Alps. Shallow, rocky organic soils with low water holding capacity and nutrient supply typically result in periodic drought and long-term nutrient stress. Multiple factors impair tree regeneration on extreme sites in the Northern Calcareous Alps, but so far studies on the seedling/sapling establishment, ecophysiology and biomass allocation are scarce. During the thesis, tree regeneration was quantified and factors which drive tree regeneration processes on extreme sites in mountain forests of the Calcareous Alps were quantified. Effects of different substrates (organic soil on limestone – OL, mineral soil – MS, organic soil on dolomite – OD) on photosynthesis, water relations, biomass allocation and root morphology of seedlings of sycamore (Acer pseudoplatanus L.), beech (Fagus sylvatica L.), spruce (Picea abies [L.] Karst.) and larch (Larix decidua Mill.) were tested in a pot experiment. Moreover, drought stress measurements were conducted during a summer heat wave in the field. On extreme sites in the Northern Calcareous Alps, unfavourable microsites, browsing and dense competing vegetation restrict tree regeneration. Drought stress affected sycamore, spruce and larch more severely on OD compared with the other substrates in the field. Lower above- and belowground biomass of seedlings, reduced photosynthesis and leaf conductance of spruce on MS compared with OL/OD was mainly due to the different nutrient availability. Low nutrient availability was compensated by beech and spruce with increased root biomass and/or root morphological changes. Our results demonstrate the sensitivity of seedlings to nutrient stress and episodic droughts, a potential consequence of climate change, but also their ability to acclimate to unfavourable conditions.

Betreuer: Katzensteiner Klaus
1. Berater: Hietz Peter
2. Berater: Kikuta Silvia

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