Wild boar (Sus scrofa scrofa L) rooting and forest regeneration on podzolic soils in the Netherlands

Phenology and the effects of rooting by wild boar on soil chemistry and forest regeneration were studied by stratified sampling, in deciduous and coniferous forests on acidic, podzolic soils in the central part of the Netherlands. At increasing degrees of soil scarification, three types of rooting were distinguished. Rooting phenology was dominated by superficial rooting in the litter layer, with highest frequencies in deciduous forests. Mast availability increased rooting activities in winter and summer, but the effects of season, soil morphology, or root abundance could not be established. No effect of rooting on soil pH, organic matter, and N-contents could be established. No evidence was found that singular, very intensive rooting, resulting in mixture of soil horizons, favoured conditions for germination and growth in stands of beech (Fagus sylvestris), Douglas-fir (Pseudotsuga menziesii), Japanese larch (Larix kaempferi), and pedunculate oak (Quercus robur). In practice, the boar visited the same spots regularly, and no effect of rooting could be established on regeneration of European black cherry (Prunus padus), American black cherry (P. serotina), birch (Betula pubescens and B. pendula), rowan (Sorbus aucuparia), holly (Ilex aquifolium), Scots pine (Pinus sylvestris), Douglas-fir, Norway spruce (Picea abies), and Japanese larch. Regeneration of oak (Quercus robur and Q. petraea), red oak(e. rubra), and beech was negatively correlated with rooting frequency.