The purpose of this report is to collate evidence on the factors whch contribute to shake development, assess its relative strength and provide, where possible, recommendations for managers.

Shake is the phenomenon of internal, longitudinal splitting of the wood in a growing tree. It occurs in either an annular pattern as ring shake or radially as star shake and is only possible to detect definitively once a tree is felled. Oaks can be affected by either or by both types, although star shakes occur more frequently than ring shakes.

Logs that may otherwise be suitable for higher value decorative or structural use may be so degraded by shake that they are fit only for fencing or even firewood. Logs may be devalued by up to 80% of their full potential value. Shake therefore represents a very major economic defect to the UK growing and processing sectors, especially since there is a persistent shortage of larger, better quality domestic hardwood sawlogs.