Water Repellency of Mountain Forest Soils in Relation to Impact of the Katabatic Windstorm and Subsequent Management Practices

Even though massive winds are significant disturbing factors for forest ecosystems, studies assessing topsoil properties in relation to wind-induced changes in forest floor and, specifically, works dealing with soil water repellency are lacking. On the other hand, the majority of works aimed at the wettability of soil have been carried out on soils from arid or semiarid climatic regions. Besides that, much less attention has been dedicated to soil water repellency in boreal-temperate regions and mountainous areas in particular. Here we report on water repellency of topsoil in mountainous region of the High Tatras of northern Slovakia (central Europe), where katabatic windstorm have blown down app. 12,500 hectares of forest canopy. Different management practices applied on windblown areas together with fire impact have resulted in four types of sites in the area: harvested, reference, left on self-recovery and struck by wild-fire. In order to cover the diversity of topsoil conditions, samples were taken at four representative sites. Results of WDPT and MED measurements show that a great portion of samples exhibited considerable degree of water repellency. It was found that there are significant differences in actual water repellency and field water contents between particular groups of samples taken at individual sites. Results of multiple regression analysis showed that water repellence of topsoil material is significantly controlled by water and organic carbon contents. Besides, for fire-unaffected soils it was found that the degree of water repellence is closely related to detected values of soil reaction as well. Explained portions of WDPT and MED variances ranged from 45 up to 72%. [References: 32