Meteorological extremes and their impacts on forests in the czech republic

Abstract

Meteorological extremes in the Czech Republic (CR) cause considerable damage to forest stands. The effects of such extremes has increased conspicuously in the latter half of the present century, with salvage felling due to meteorological factors accounting in some years for more than half of the total timber cut in the CR. The most important reason for this salvage felling is damage due to wind (61 %), followed by damage due to snow (16 %), drought, air pollution and ice deposits. Using data from four professionally-maintained weather stations and one special station, time series for maximum wind gusts are analysed as well as the frequencies of days with ice deposits, maximum mass of ice, heights of new snow ≥ 10 cm and, for areal precipitation series from Bohemia and Moravia, precipitation sums for the year, the summer half-year and the frequencies of occurrence of dry months. The problems of measuring these characteristics and their homogeneities are discussed. Their annual distribution and their long-term changes (fluctuations, trends) are studied. The main forest disasters of the 20th century attributable to the identified meteorological extremes are described. The analysis does not, however, permit reliable conclusions about the future behaviour of those extremes and their impact on forests under conditions of global warming.