Colonization of disturbed Scots pine trees by bark‐ and wood‐boring beetles

1. In a single stand, the colonization of 128 girdled Scots pine trees (Pinus sylvestris L.) by bark‐ and wood‐boring beetles was examined during two vegetation periods after treatment. The trees were girdled on four different dates in April, July, October and January.
2. The time elapsed from girdling to the first attack of bark‐ and wood‐boring beetles was 1–19 months (mean = 10.7) and differed significantly among trees girdled on different dates.
3. The part of the tree and the date and wave (rank) of colonization were the most significant factors that explained a considerable portion of the variability in the occurrence of bark‐ and wood‐boring beetles.
4. The species composition changed dramatically from the tree base to its top and branches. The colonization of trees was initiated most frequently in the upper thin‐barked part of the trunk and in thick branches.
5. In total, 32 species of bark‐ and wood‐boring beetles colonized the studied trees. Particular species were significantly associated with certain periods of tree dieback and colonization (colonization waves). Phaenops cyanea (F.) and Pissodes piniphilus (Hbst.) were by far the most aggressive first‐colonizing species. Pityogenes chalcographus (L.), Ips acuminatus (Gyll.) and Tomicus minor (Htg.) were shown to be moderate‐aggressive species, followed by Tomicus piniperda (L.), Monochamus galloprovincialis (Germ.) and Pissodes pini (L.). The remaining species were designated as not harmful and saprophagous.