Trends in Outbreaks of Defoliating Insects Highlight Growing Threats for Central European Forests, and Implications for Eastern Baltic Region

To identify general patterns in the effect of climate-driven changes outbreak frequency forest defoliating species, we examined 60 years records (1950–2010) outbreaks five species. Data on Lymantria dispar, monacha, Bupalus piniarius, Panolis flammea, and Operophtera brumata from Central European countries (Slovakia, Czech Republic, Austria, Hungary, Germany), where current climate is comparable with projections for Eastern Baltic region by end 21st century, were analyzed. Time series approach was applied to estimate linkage between warming. Mean annual, summer, winter deviations period 1850 1900 assessed as proxies legacy effect, warming lagged one year. Among those tested, showed a outbreaks. Three significant occurred analyzed (at beginning period). During middle part period, magnitude low, implicating higher insect risk Europe. In latter more frequent yet smaller occurred, which supports one-year lag, annual temperatures.