The Kroof Experiment—Realization and Efficacy of a Recurrent Drought Experiment and Recovery in a Beech/Spruce Forest

Abstract

Photo 1. View of the roof constructions of the Kranzberg Roof (KROOF) Experiment in a closed state. Mobile parts of the roof close during rain events and automatically open up afterward. During the growing season (April to November) of 2014 to 2018, the experimental plots were artificially drought stressed. Photo 2. View from the crane on the installed scaffolding near two experimental plots during autumn, including the meteorological equipment on the tower tops. Photo 3. Canopy crane at the KROOF site lifting the gondola to allow access to the canopy of the experimental plots, and two PhD students preparing for measurements in the forest canopy (small picture bottom left). Photo 4. An example control plot during the 2019 watering: soaker hoses (black hoses on the forest floor) as a part of the watering system, xylem sap flow sensors (mounted on the tree trunks under green polystyrene, [for details, see small picture on the top left]), stem respiration chambers (gray chambers on tree trunks), a technician measuring soil water content via TDR sensors, and a perforation hose around stems on TE plots to negate stemflow during rainfall (small picture bottom left). Photo 5. Sampling of fine root and mycorrhiza (top left), measuring water potential and pressure-volume curves in a mobile field laboratory (top right), setting up the 60,000 L water tank for the watering (bottom left), and discussing first data in the field (bottom right) by staff of the Technical University of Munich and the Helmholtz Zentrum Munich in 2019. These photographs illustrate the article “The Kroof experiment: realization and efficacy of a recurrent drought experiment plus recovery in a beech/spruce forest” by Hesse et al. published in Ecosphere. https://doi.org/10.1002/ecs2.3399.