Recent advances in cause-effect research on oak decline in Europe.

• DOI: 10.1079/pavsnnr20083037
• Publication Date: 2009-01-07T06:47:50Z
• Authors: F. M. Thomas
• Keywords: Frost (temperature)

Abstract This review attempts to assess the causal factors and their interrelations that cause decline of widespread European oak ( Quercus ) species. In particular, it provides an overview recent advances in cause-effect research since 2000. The first recorded outbreak took place 1739-1748, was followed by several other episodes, most them occurring twentieth century. mortality rates differ substantially among regions episodes; however, entire stands is a rare event. principal causes are following site-unspecific factors: severe (in repeated) defoliation insect larvae, especially combination with infection powdery mildew weather extremes (summer drought, winter frost spring frost); site-specific root pathogen Phytophthora quercina (which virulent soils pH[CaCl 2 ] value ≥3.5 certain fractions exchangeable calcium), distinct decrease groundwater level. At hydromorphic sites, intermittent soil moisture can intensify impact drought. least temperate regions, two or more these have act major outbreaks decline. Other biotic such as Collybia fusipes borers Agrilus biguttatus Platypus cylindrus contribute damage later stages Mediterranean region, aggressive cinnamomi well prolonged periods intense drought probably capable causing without any contribution additional factors. possible factors, whose importance still has be corroborated, chemical defence compounds against leaf herbivores due eutrophication nitrogen, increased ozone concentrations.