FOLIAR INJURY IN YOUNG BETULA-PENDULA ROTH, SALIX-PURPUREA L AND ILEX-AQUIFOLIUM L TREES AND IN PROPAGATED TAXUS-BACCATA L SHOOTS EXPOSED TO INTERMITTENT FOG AT A RANGE OF ACIDITIES

The occurrence of various visible symptoms of foliar injury was assessed on a 5-point scale for each of the species. There was a distinct increase in the incidence of most types of injury in plant material which has been exposed to pH 2.5 acid fog. No clear pH-related trend in foliar injury occurred in plants exposed to acid fog at pH 3.5, pH 4.5 and pH 5.6, indicating that a threshold for a range of different types of visible injury may exist between pH 2.5 and pH 3.5 for all four species.