The contribution of particulate matter to forest decline

Bonn University scientists demonstrate that hygroscopic air pollutants decrease tree drought tolerance 

 

Air pollution is related to forest decline and also appears to attack the protecting wax on tree leaves and needles. Bonn University scientists have now discovered a responsible mechanism: particulate matter salt compounds that become deliquescent because of humidity and form a wick-like structure that removes water from leaves and promotes dehydration. These results are published in “Environmental Pollution”.

Nature conservationists call it “lingering illness”, and the latest report on the North-Rhine Westphalian forest conditions confirms ongoing damage. Bonn University scientists have now shown that salt deposits on leaves may decrease the drought tolerance of trees, thereby contributing to forest decline. “Our study reveals that so-called wax degradation on pine needles may develop from deposited particulate matter”, says Dr. Jürgen Burkhardt from the Institute of Crop Science and Resource Conservation. Wax helps to protect leaves and needles from water loss.