Thetaprobe ml2

After each flux measurement was completed, soil temperature and moisture within the collar were measured at 5 cm depth using a digital thermometer (E.T.I. Ltd., West Sussex, UK) and a Theta probe (ML2, Delta‐T Devices, Cambridge, UK), respectively. In the mire and surrounding lichen heath, 30 dipwells (5 cm diameter PVC tubes) were established and water‐table depth was measured manually during each set of CH₄ measurements. Additionally, weekly measurements of water‐table depth at all locations were made to permit flux modelling. Soil temperature was also monitored continuously (thermistor probe connected to a CR10x datalogger, Campbell Scientific, Leicestershire, UK) within the wetland and birch forest.

The experiment was conducted at the Swiss Canopy Crane facility in a diverse mixed forest in the vicinity of Basel, Switzerland (47°28′N, 7°30′E), at an elevation of 550 m a.s.l. The forest is a mix of needle- and broad-leaved tree species with individuals about 130 years old and stocking on a rendzina-type soil on calcareous bedrock^{34 (link)}. The climate is humid temperate with mean July temperatures of 19.2 °C and two thirds of the 900 mm mean annual precipitation falling during the growing season. Yet, the site is prone to summer drought^{18 ,35 (link),36 (link)}. This destructive experiment took place shortly before the study site was abandoned and the crane became dismantled. Weather data were available from the close weather service station in Binningen (c. 8 km distance; Supporting Fig. 8). On-site soil moisture was measured with a TDR probe (ML2 ThetaProbe, Delta-T Devices, Cambridge, UK) at −10 and −20 cm at three different spots within freshly trenched soil profiles of −20 cm depth. Throughout the whole study period, soil water content did not drop below 25% vol.