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Duration: 2007 - 2013

Querco – Macro and micro-morphological reactions in foliage

Querco – Macro and micro-morphological reactions in foliage
Fig. 1: Oaks in Querco showing specific drought stress symptoms in foliage. Photo: Pierre Vollenweider

Oaks belong to the tree species tolerant to drought stress in central Europe. As a consequence of global warming and more frequent droughts, they are expected to extend their present range. The Querco experiment has been designed to evaluate and compare the drought tolerance of Swiss provenances belonging to the three main Swiss oak species. During three years, saplings were exposed to 1-2°C passive air warming, irrigation reduction by -43% to -60% and their combination on two forest soils and within an ecosystem facility reproducing the growth conditions in a young afforestation in a semi-controlled way. Within the present sub-project, the principal objectives are to 1) survey the visible symptoms in foliage and diagnose the causing stress factors, 2) analyze the structural reactions at cell, tissue and leaf level causing the drought stress symptoms and 3) identify the stress, defense and tolerance responses within oak foliage. The development of symptoms within the tree crown and the onset of intolerant drought reactions has been monitored during the three experimental years. The structural change.


Pierre Vollenweider (project leader)

Terry Menard





Keywords climate change, oak, drought stress symptoms, functional plant anatomy