Experimental setup ¶

The Pfynwald research platform, encompassing approximately 800 forest pines across 1.2 hectares, is divided into eight plots of 1,000 m² each. Four plots receive the natural rainfall of about 600 mm per year, serving as control plots. The remaining four plots are irrigated to double the average annual rainfall to around 1,200 mm per year.

Additionally, roofs on six of the control plots halve the precipitation to approximately 300 mm per year, with the collected water being drained into the nearby water channel.

By each of the six VPD manipulation scaffolds, 3-5 trees are exposed to a reduced vapor pressure deficit (VPD): they face a nozzle field which releases water under a 70 to 150 bar pressure from April to September. This dry misting only takes places during a main wind direction of 235°-325° in order to prevent the VPD from being reduced in the neighboring control trees as well.

In addition, roofs in six plots reduce precipitation by approx. 50% and drain the collected water into the water channel.

The VPDrought project was implemented in 2024 and will run until 2028.