Windstorms and forest disturbances in the Czech Lands: 1801–2015

• Published in: Agricultural and forest meteorology 2018-03, Vol.250-251 (C), p.47-63
• Main Authors: Brázdil, Rudolf, Stucki, Peter, Szabó, Péter, Řezníčková, Ladislava, Dolák, Lukáš, Dobrovolný, Petr, Tolasz, Radim, Kotyza, Oldřich, Chromá, Kateřina, Suchánková, Silvie
• Format: Article
• Language: English
• Subjects: Agriculture; Czech Lands; Documentary data; Forest damage; Forest disturbance; Forestry; Meteorology & Atmospheric Sciences; Windstorm
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/j.agrformet.2017.11.036

•Creating 215-year long windstorm and forest damage series from documentary data.•Outstanding windstorms show large meridional pressure gradients in W Europe.•The frequency of outstanding windstorms shows increased forest damage after 1950.•Bark-beetle effects and mismanagement intensify wind-related damage. The long-term relationship between windstorms and forest disturbances in the Czech Lands is analysed in this paper, covering a very long period of 215 years (1801–2015). Based on documentary evidence and instrumental records, long-term series of severe windstorms in the summer half-year (April–September) and in the winter half-year (October–March) are compiled. Severe windstorms were more frequent in the 1820s–1840s, 1900s–1930s, and 1960s–2000s, less so in the latter half of the 19th century and in the 1940s–1950s. Their long-term variability is revealed with three differently-created series of forest damage for the periods of 1801–1900, 1900–1980 and 1963–2015. Based on these comparisons, 14 windstorms that did outstanding damage to forests are selected: 12 occurred in the winter half-year and two in July. They are further investigated with respect to their meteorological character and the damage done. In this sample, the high-impact winter half-year windstorms are typically related to very distinct (>45 hPa) pressure gradients between low pressure systems over the North/Norwegian Sea and high pressure systems south-west of the Iberian Peninsula, which exhibits an eastward-shifted and tilted NAO pattern, inducing the passage of frontal waves across the Czech Lands. High temperatures arising from south-westerly airflow and wet ground before windstorms provided conditions conducive to extensive windthrow in forests, sometimes with damage exacerbated by subsequent bark-beetle calamities. The increase in windstorms with outstanding forest damage after 1950 may be attributed in part to the negative consequences of forest management that prioritises high, short-term profits over ecological well-being.