Speaker
Description
The regeneration of pedunculate oak (Quercus robur L.), a light-demanding tree species crucial for Central European forest biodiversity, is hindered by homogenised, shaded conditions of dense forest stands. However, rising tree mortality caused by climate extremes and pathogens may provide a window of opportunity for oak regeneration.
In the meliorated Leipzig floodplain forest, we investigated how recent canopy dieback affects understorey structure and microclimate, and whether this could facilitate oak regeneration. Over two years, we monitored planted oak saplings and recorded microclimatic air and soil conditions under varying canopy cover resulting from tree mortality. These conditions were studied with and without small-scale understorey thinning of flood-intolerant tree species (16 × 16 m), and compared to silvicultural cuttings of up to 0.7 ha.
High tree mortality in the overstorey alone did not create favourable conditions for oak regeneration, as fast-growing, shade-producing maple species further limited light availability in the understorey. The combination of high mortality in the overstorey and removal of flood-intolerant maples in the understorey enhanced the growth and vitality of planted oaks. While increased light availability generally promoted oak development, this effect was weakened under increasing drought stress, as indicated by leaf carbon isotope ratios (δ¹³C).
We found that soil moisture tended to be higher on silvicultural cuttings than in the forest. However, air humidity was lower, and vapour pressure deficit (VPD) emerged as the strongest microclimatic predictor of drought stress.
Our results suggest that small-scale, selective interventions offer a promising strategy to support pedunculate oak regeneration under changing environmental conditions, by improving both light and microclimatic conditions compared to dense stands or larger cuttings. The study underlines the need for adaptive management as a complement to hydrological revitalisation measures in order to maintain biodiversity and ecosystem functions of floodplain forests.
| Status Group | Doctoral Researcher |
|---|---|
| Poster Presentation Option | Undecided/No preference |
