Are the faster growing trees resistant enough to air pollution and pests?

Abstract

The growth differences of trees judged to be sensitive to air pollution and Phytophthora sp. fungi have been investigated. Three experimental pine stands were selected in the vicinity of a nitrogen fertilizer plant ‘Achema’, approximately 35 kms from Kaunas. The plant was founded in 1965; the composition of aerial emissions in the 1980s was following: carbon monoxide – 26.5%, sulphur dioxide – 12.4%, nitrogen oxides – 10.3%, ammonia – 10.1%, and mineral dust – 37.3%. The first signs of forest damage at the local level were observed in 1972, and the forest damage increased until 1979. The recovery of the severely damaged pine stands located within a 5 km distance from the plant began in the transition from the 1980’s to the 1990’s when emissions were dramatically reduced (Fig. 1, left). Samples were taken from 202 mature pines of dominant, codominant, and emergent crown classes. The strongest growth depression period was noticed in 1979-1987. The average tree-ring widths in this period were reduced to less than 0.50 mm per annum. The average decrease in the radial growth of sensitive trees during the 1979-1987 period was 1.6 mm, while the growth of resistant trees decreased by only 0.2 mm. [...]