Oak Shake research project on Ruskin Land

Joe Beesley, Spatial Scientist at Forest Research, explains the current project using Ruskin Land to look at Oak Shake.

Oak is one of the UK’s most important broadleaved tree species, supporting high biodiversity and producing excellent timber. However, it can be affected by a condition known as shake, where cracks form within the wood of a growing tree. Shake is often only detected when the tree is felled, and the cracks can greatly reduce the value and utility of harvested timber. Stems that could have been milled into long-lasting beams for construction are downgraded to firewood. With the UK undergoing a wave of woodland creation, oak is one of the most commonly planted species. As a result, shake poses a significant economic risk for future oak woodlands established for timber production and carbon net zero goals.

A new project, funded by Defra through the Centre for Forest Protection, is bringing together researchers from Forest Research, the Royal Botanic Gardens, Kew, and Edinburgh Napier University. Our aim is to better understand how shake develops and whether it can be detected before a tree is felled. To do this, we are working with the Guild of St George and Wyre Community Land Trust to intensively study an oak woodland at Ruskin Land in the Wyre Forest.

Several biological factors and environmental triggers are known to contribute to shake, but its exact causes remain unclear. Previous research has linked certain external features, such as stem curve, spiral grain, and late leaf flushing, to a higher risk of shake. Environmental conditions such as drought or periodic waterlogging have also been shown to increase shake risk in certain areas, and soil type and geology play a role. We are investigating these links by assessing the external features of oak trees and measuring environmental factors within the woodland. Understanding these environmental drivers is especially important as climate change is expected to worsen the conditions that contribute to shake, including drier summers, wetter winters, and more frequent storms.

As well as improving our understanding of how shake occurs, we are also testing whether shake can be detected in standing trees. Acoustic tomography is a non-destructive technique that uses sound waves to measure wood properties and is often used to identify areas of internal rot or decay (see photograph above). In this project we will assess whether it can also detect the cracks characteristic of shake.

In the coming months, a number of study trees will be felled at Ruskin Land. This will allow us to assess the severity of shake in each stem and determine which external indicators were most strongly associated with the defects. We will also be able to see whether the acoustic tomography correctly identified cracks in the trees before they were felled. If successful, this technology could become a powerful tool for oak woodland managers. Knowing which trees are more likely to contain shake allows them to be thinned earlier and those with sound stems grown on to produce high-quality long-lasting wood products that lock up carbon.

In later stages of the project, Royal Botanic Gardens, Kew will carry out genomic research to discover whether particular genes or mutations are linked to a higher likelihood of shake. This not only deepens understanding of the genetic traits behind the condition but could also guide future oak breeding programmes to select seedlings less likely to develop shake.

For more information on this work, please visit the project website.

With thanks to Joe Beesley for authoring this on behalf of the project.