Wpływ postępowania ochronnego na występowanie kornika drukarza Ips typographus (L.) w Dolinie Kościeliskiej w Tatrzańskim Parku Narodowym

In the end of 2013 the Norway spruce stands in the Kościelska Valley in the Tatra National Park (S Poland) were severely damaged by the wind. In the next year about 22,000 m3 of timber from broken and fallen trees was processed and removed from the active protection zone, whilst in the strict protection zone those trees were left. In 2014, when the presented survey started, the infestation of lying and surrounding standing trees was very low, but starting from 2015 an intensive bark beetle Ips typographus outbreak affected the survived stands. No−intervention strategy was implemented by the national park in both zones, regardless their formal status at that time as well. In 2015 a set of 10 observation plots (200 trees in total) was established in both active and passive (strict) protection zones (5 plots in each zone). In 2017 a new set of 12 plots (240 trees in total) was installed (6 plots in each zone). On each plot the breast height diameter of all trees was measured and the relative mortality of trees (share of attacked spruces) was recorded each year. The infestation density and sex ratio were defined on the 25×25 cm bark samples taken from 138 trees in 2 trunk sections located 1.5−2.0 above the ground and in the midway between tree and crown bases. The bark beetle attack on living spruces in 2015 differed between the active and strict protection zones. The relative tree mortality was lower in active than in passive protection zone (20 and 39% respectively), but later it gradually came to be similar in both parts of the area (73.3 and 77.5%, respectively in 2017). In the initial outbreak phase, thinner (weaker) trees were attacked, and in the following years – stronger ones, although in the active protection zone the opposite pattern occurred initially. The attack density decreased in subsequent years, being higher in active protection zone, with gradually decreasing difference between zones. Thicker trees were attacked with lower intensity. The share of females, higher in active protection zone (68.2 vs. 63.9%), gradually decreased to (57.9 vs. 51.2%). The initial decrease of bark beetle attack intensity in the active protection zone gradually disappeared after the no−intervention strategy was applied. The resulting extended bark beetle infestation and its increasing intensity in both parts of the area, demonstrate the appropriateness and effectiveness of active protection measures applied in 2014.