Factors affecting shake defects in timber (primarily in native oaks)

rings of napoleaninc Oak This project updates the Forestry Commission Research Information 218 ‘Shake in Oak’ (1992) with a new research report Shake in oak: an evidence review, which describes the various factors influencing shake in sessile and pedunculate oaks.

Research objectives:

  • Research and summarise current knowledge regarding factors causing shake.
  • Investigate whether an extension to the Ecological Site Classification (ESC) decision support system could be developed to predict shake-prone sites.
  • Determine whether acoustic devices can be used to predict the presence of shake in standing trees.

Results so far:

  • Considerable evidence-based knowledge exists concerning shake risks governed by vessel diameter, cambial injury, and abrupt transitions in growth rate. The research report collates and summarises, these findings in a more easily disseminated format. Useful recommendations can be are made for the management of existing crops to help prevent the planting of higher-risk sites where timber production is an objective and to identify risky individuals trees that might be at risk of shake.
  • Preliminary analysis of acoustic velocity data also indicates that it may be possible to predict the likelihood of shake using acoustic devices, although the influences other factors (particularly slope, aspect and exposure) need further quantification at this stage.


Current (2011-2016).

Related Resources:

The Ecological Site Classification Decision Support System enables identification of suitable site types for species, including oak. Only optimal sites should be considered for higher quality timber production. The current project will enable site selection to be further refined in terms of identifying sites that, although ecologically optimal for oak, may be of higher risk of shake.


Andrew Price

Funders and partners

Forestry Commission Forest Products Research Programme, ( Wood and Timber Properties: Assessing Quality of Broadleaves).

Forestry Commission policy :