Bark- and wood-boring beetles on Scots pine logging residues from final felling: effects of felling date, deposition location and diameter of logging residues

Abstract

To reduce the risk of bark- and wood-boring beetle pests, the extensive removal of logging residues is conducted in forests; however, this practice can lead to a loss of saproxylic insect diversity. Thus, finding a better pest management strategy is needed and requires additional information on the actual effects of various, differently treated logging residues for pest multiplication. In the present study, a total of 2,160 fragments of Scots pine ( Pinus sylvestris L.) logging residues generated during final felling in a single stand in the Drahanska Highlands in the Czech Republic were examined for bark- and wood-boring beetles. The felling occurred on four dates in 2006 (in February, May, August and November). The logging residues from each felling were left scattered on the clear-cut area or were gathered into piles. The fauna inhabiting the logging residues were investigated by peeling off the bark during the first six months of the vegetative period following the felling. The logging residues hosted species-rich assemblages of bark- and wood-boring beetles (25 species were identified). Beetle occurrence was significantly affected by felling date, logging residue type (trunk fragment or branch and branch thinner or thicker than 1 cm), diameter and the manner in which the logging residues were deposited (freely scattered, top pile layer, or bottom pile layer). The Scots pine logging residues were a substrate for the significant multiplication of several potentially significant pests (particularly, Pityogenes chalcographus [Linnaeus], Ips acuminatus [Gyllenhal] and Pityophthorus pityographus [Ratzeburg]). The results indicated that the risk of pest reproduction can be minimised by felling the trees in August (and probably also September and October). For I. acuminatus and P. pityographus , the risk can be minimised by gathering the logging residues into piles.