The assessment of health in three native UK tree species/ Fagus sylvatica, Quercus robur/ petraea, Taxus baccata/ in southern England : Ecological Monitoring in Forestry

1989

S. 1-11

1 Abb., 3 Tab., 11 Tab.

Unselbständiges Werk

200060212

The health of three native tree species, Fagus sylvatica /beech/, Quercus robur/petraea/oak/ and Taxus baccata/yew/ was assessed in southern England using parameters such as crown density, leaf discoloration, needle retention and the presence of abnormal growth patterns. The survey results show that nearly 40% of beech, over 50% of oak and nearly 75% of yew were found to be moderately or severely damaged, on the basis of crown density. Only 5·% of beech, 10% oak and 4% of yew were found to retain the full crowns indicative of entirely healthy trees. These results give cause for concern as the species examined in this survey were all found within their natural range in the UK. In addition, a large number of the trees surveyed were on sites of conservationally valuable woodland. Although clear, causal proof that air pollution is damaging these trees is lacking, the balance of current evidence seems to suggest that the widespread and severe damage reported in this survey cannot be explained by the influence of other abiotic or biotic stresses alone.