2.2 Field estimation of litter storage and retention dynamics
In a second experiment, samples of litter were collected before and after precipitation events and weighed in situ to assess the litter-layer retention capacity. We used standard coffee filters to collect broadleaf and needle litter grab samples of approximately equal volume at different time steps after precipitation events (see supplementary Figure S1 for pictures of the procedure). Coffee filters are well suited for this purpose, as they retain the drip water of the litter with only minor losses, and they also can be dried in the oven with the litter inside. For three rainfall events we took 20 broadleaf and 20 needle litter samples for at least four timesteps: before the event, 2 hours after the event, 24 hours after the event, and around 40 to 48 hours after the event. We weighed the samples directly on site and dried them for 24 hours at 70 °C as suggested in Carnol and Bazgir (2013) to evaluate the water content for each sample. In a third experiment, we measured soil moisture at two pairs of 1x1 m plots at 10 cm and 30 cm depths, to evaluate how water retention in the litter layer affects soil-water content dynamics. Each pair had one plot covered with the naturally present broadleaf-litter layer, and one plot from which we regularly removed all litter. Volumetric water content in the soil was measured with 5TE dielectric permittivity sensors and recorded using EM50 Loggers (formerly Decagon, now Meter Group). The sensors were installed in the middle of each plot to minimize boundary effects. Data were recorded at 10-minute intervals.