The functioning of perched water tables and their impacts on tree growth are still poorly documented while soils with temporary waterlogging are very frequent in France. How does perched water table change during winter? Are these changes influenced by the forest stand features? Is this perched water table a disadvantage or an advantage for the growth of mature trees? In order to brighten these questions, an internship supervised by Nathalie Korboulewsky (DR, Irstea Nogent-sur-Vernisson) and Jordan Bello (Phd Student, Irstea Nogent-sur-Vernisson) began the 3rd of april 2017 for five month (Anna-Karine Jean, Université de Jean Monnet Saint-Etienne). This internship will attempt:
- to characterize the perched water table regime during winter for the different silvicultural treatments of the OPTMix experiment;
- to link oak (Quercus petraea) and pine (Pinus sylvestris) growth with different variables of the perched water table (minimum depth, time of presence, date/speed of apparition, withdrawal)
To reach these objectives, data recorded since 2014 on each plot with soil moisture sensors, automatic and non-automatic piezometers will be used (see plot below).
Clay layer depths are mean values of the measured clay layer depths of each plot having the same species composition (pure Oak, pure Pine or Mixture). Groundwater table depth values are the mean values of the manually collected piezometric measurements in each plot having the same species composition (pure Oak, pure Pine or Mixture) and at the same date.
