INTERACTION BETWEEN OZONE AND COLD SENSITIVITY IN NORWAY SPRUCE: A FACTOR CONTRIBUTING TO THE FOREST DECLINE IN CENTRAL EUROPE?

Abstract

S ummary Three‐year‐old clonal saplings of Picea abies L. Karst. were fumigated for 60 d during the summer of 1985 with four different levels of O 3 . Visible injury (in the form of severe, uniform brown necrosis and shedding of affected needles) occurred after a frost in November on the older needles of three of the clones which had received over 200 μg m −3 of O 3 during the summer, 47 d previously. No visible injury occurred during the fumigation period or on the current (1985) year needles. It is suggested that the results provide preliminary evidence for an enhancement of frost sensitivity by O 3 which may be significant in the current wave of forest decline affecting high‐altitude forests in central Europe.