The Hölstein site is located in in the eastern part of the Swiss Jura mountains (47°26’16.4’’, 7°46’31.1’’; 540 m a.s.l.), in a mixed, temperate forest with an exceptionally high biodiversity and a vigorous tree regeneration. The research plot has a size of 1.6 ha and comprises 540 mature trees. The main tree species are Fagus sylvatica and Picea abies with an admixture of Abies alba, Quercus petraea, Pinus sylvestris, Acer pseudoplatanus, Carpinus betulus, Fraxinus excelsior and Sorbus torminalis. A canopy crane is installed in the center of the research area to access the tree canopies for in situ measurements and for sampling of leaf material. Rainout shelters will be installed in 2019 for conducting a long-term throughfall exclusion experiment.

'Tyrolean Mountain Grassland and -Forest' currently consits of 'Stubai - combination of Neustift meadows and Kaserstattalm' (DEIMS.iD: https://deims.org/324f92a3-5940-4790-9738-5aa21992511c). Additional forested research locations may be added in the future.

The site Bily Kriz (Bílý Kříž) is located in Moravian-Silesian Beskids Mountains. Ecosystem type: Managed secondary pure Norway spruce stand. Prevailing species: Norway spruce (Picea abies [L.] Karst.) Height of the stand: 17 m (2016) Understory: Vaccinium myrtillus L. Year of plantation: 1981 by 4 years old seedlings

As the largest contiguous pine forest in Switzerland, the Pfyn forest in Canton Valais (46° 18' N, 7° 36' E, 615 m ASL) offers the best conditions for such measurements. In light of this, a WSL research team installed a long-term experiment of 20 years duration in the Pfyn forest. The average temperature here is 9.2°C, the yearly accumulated precipitation is 657 mm (average 1961-1990). The pines in the middle of the forest are about 100 years old and 10.8 m high. The test area has 876 trees covering 1.2 ha divided into 8 plots of 1'000 m2 each (Image 4). Between the months of April and October four of these plots are irrigated by a sprinkler system providing an additional 700 mm of water, annually. In the other four plots, the trees grow under natural, hence relatively dry conditions.