Causes of decline in United Kingdom broadleaved stands

Decline of broadleaved trees has been recognised in the UK for over a century. No single causal agent has been determined; all work suggests a complex of interacting factors involving climate, particularly drought, and insects and pathogens. Tree species most affected include oaks and ash, although alder, beech and chestnut also sometimes display symptoms. In a limited number of instances pathogens have been demonstrated to cause symptoms similar to general dieback: initial symptoms of Alnus decline resulting from infection by Phytophthora alni, being an example. This presentation focuses on declines of oak and ash, their possible causes and their impacts on the landscape and aesthetic values of these species.