Effects of different forest recovery management on runoff and soil erosion in an area affected by Vaia storm

The current study was carried out in a wind damaged forest area and it aims to estimate the effects of management strategies after storm events on runoff and sediment yield. In order to achieve the goal, four experimental plots have been established on an area hit by two windthrows in 2003 and 2018 (Vaia storm). Each plot bound an area of 27 m2 (4.5 m x 6 m) and is located on a 40% slope facing East, previously covered with subalpine spruce forest at about 1650 m asl. The considered forest treatments were (1) salvage logging and natural regeneration, (2) no intervention, and (3) salvage logging and artificial regeneration. We measured runoff and sediments yield from September 2020 to September 2022. Water and sediments mobilized in the experimental plots are convoyed in a 1 m3 tank where the content is weighted by a load cell, and a pressure transducer records the water level. An in-situ radar rain gauge measures cumulative precipitation and intensity. Moreover, sediments samples were collected twice a year, dried and sieved to obtain the percentage of organic material and the texture of the eroded soil. The first results show a contrasting behaviour in terms of runoff/sediment yield between the four plots upon the occurrence of an intense precipitation event. The differences could be explained by the time passed after the windthrow, and the different forest treatments applied. These and future outcomes will be of paramount importance for adapting management strategies to an increasing frequency of subsequential extreme events (windthrow and precipitation).