Protection forests in the Northern Limestone Alps: stand regeneration, microclimate, snow cover and ungulates
2010
Prietzel, J., Technische Universitaet Muenchen, Freising (Germany) Lehrstuhl fuer Bodenkunde
Relationships among ungulate pressure, stand regeneration, microclimate, and snowpack dynamics were investigated at three protection forest sites in the mixed mountain forest zone of the Bavarian Limestone Alps. The study was conducted at plots located inside and outside ungulate exclosures which had been established about 35 years ago. Air and topsoil temperatures were recorded for one year in hourly intervals. In winter 2005/2006, the thickness, constitution, and mobility of the snowpack were investigated. Inside the exclosures, which were stocked with dense regeneration of mixed mountain forest, mean air and topsoil temperatures were up to 0.9 °C (air) and 1.9 °C (soils) lower than outside. Maximum daily values of air and topsoil temperatures were up to 1.4 °C (air) and 5.2 °C (soils) lower inside the exclosures compared to the respective outside plots. The temperature differences were dependent on the aspect (NW ESE S). Snowpack thickness during winter increased more slowly inside the exclosures than outside due to snow interception by the young trees which had developed during stand regeneration; in late winter, snowpack melting was retarded. Inside the exclosures the snowpack was more heterogeneous (“column structure") than outside (laminated structure). Consequently, inside the exclosures a large portion of the melting water drained vertically to the bottom of the snowpack and infiltrated into the soil, and the snow gliding activity was significantly smaller than outside. In summary, particularly at S-exposed sites, exclosure of ungulates resulted in a cooler, less extreme microclimate, a more heterogeneous and stable snowpack, and reduced snow gliding. Therefore, an adequate regulation of ungulate density by appropriate hunting activity is a key factor for a sustainable provision of important protection services of the mixed mountain forest in the Northern Limestone Alps.
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Эту запись предоставил Agroscope Reckenholz-Tänikon Research Station