Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Abstract The investigations were carried out in selected Scots pine (Pinus sylvestris L.) stands in Gidle, Koszęcin, and Złoty Potok forest districts (Regional Directorate of State Forests in Katowice). The majority (89.2%) of analyzed 212 Scots pine tree-tops and branches, left in the forest after cuttings, were infested by cambio- and xylophagous insects (Curculionidae – 19 species, Cerambycidae – 4 species). The mean number of brood galleries in a single piece of the examined material was 64. The following insect species were characterized by the highest values of dominance, frequency, and dominance structure: Pityogenes bidentatus, Pogonocherus fasciculatus, Pissodes piniphilus, Pityogenes quadridens, Pityophthorus pityographus, and Magdalis frontalis. Three different insect communities and 63 associations of a definite dominance structure were distinguished. Also preferences of the most abundant species in respect of diameter and bark thickness of 0.5-meter-long sections of tree-tops and branches were determined. The majority of insect species infested top and branch segments 2.6-4.5 cm in diameter with the bark 2 mm thick. Treatments aiming at reduction of reproduction of secondary insect pests on Scots pine cut off tree-tops and branches are proposed.