KlimaQuer: Conservation of drought tolerant and ecological valuable sessile oak forests through natural regeneration

The predicted accumulations of droughts and other weather extremes as a result of global climate change strongly affect vitality of Central European forests. Accordingly, silvicultural adaptation measures are necessary to ensure the presence and distribution of drought-tolerant tree species. In this context, sessile oak (Quercus petraea) is considered as a tree species of the future. However, the regeneration of sessile oak is associated with significant silvicultural difficulties and high costs. These include the regulation of competing shade-tolerant tree species, browsing control and a high efforts for tending measures.

The aim of this project is to provide forest managers with recommendations regarding the minimum size of canopy openings as well as the timing and extent of tending measures in oak-dominated forests. These recommendations are intended to ensure the successful establishment of a regeneration of sessile oak. Accordingly we are try to identify optimal light conditions allowing sessile oak a) to regenerate and b) to be competitive enough to minimize costs for measures usually needed to regulate concurrent vegetation.

In this project, the growth and competitiveness of sessile oak regeneration will be investigated by applying light measurements, along a maximum radiation and site gradient. In addition, a relationship between height growth and vitality of oak regeneration and the size of canopy openings will be analyzed. The value of this research project lies in the description of the oak regeneration process over the largest possible radiation gradient (light availability); the quantification of competing vegetation over several developmental stages of regeneration; the description of the importance of sunflecks for oak regeneration and its responsiveness regarding root growth after liberation from competition and shade.

In the media

FNR press release

Publications

1. Modrow, T., Kuehne, C., Saha, S., Bauhus, J., Pyttel, P. (2020): Photosynthetic performance, height growth, and dominance of naturally regenerated sessile oak (Quercus petraea [Mattuschka] Liebl.) seedlings in small-scale canopy openings of varying sizes. European Journal of Forest Research 139: 41–52.