Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Hurricanes, high temperatures and drought have caused damage to forests in the Żywiec Beskids. The effect of extreme weather events on the population of Ips typographus was examined in the damaged spruce stands in the period of 2005-2007, using pheromone traps for catching beetles. The daily average number of trapped beetles in a single pheromone trap ranged between 32 and 72 in subsequent growing seasons. It was proved that thermal conditions at different altitudes affected the beginning and the course of I. typographus swarming. Three swarming peaks were observed in each of three consecutive growing seasons. Extremely high temperatures in 2006 did not increase the number of swarming peaks. In 2007 the number of beetles in pheromone traps was twice higher than in the first year of the study.