Knot Measurement & Modelling Using CT Scanning


Using X-ray computed tomography, or CT scanning, coupled with image analysis, this project aims to model knot size and shape within a tree stem based on the tree’s external profile.

CT scanning moving image

Research objectives

Knots are a critical factor in timber strength and value. Being able to estimate the effect of forest management decisions on the volume of shape of knots within the tree stems would be highly advantageous. Following in the footsteps of French and Canadian studies we are using scanning techniques for Scottish-grown Sitka spruce. By linking knot internal geometry to the associated branches characteristics we hope to quantify the volume, shape and location of knots within trees.

Results so far

Using the Scottish Rural University College’s CT Scanning Service (more conventionally used on sheep!) we have imaged knots within a number of trees and (using the Gourmands plugin for Image J software) we are able to create full 3-D stem reconstructions in a visualisation program developed by LERFoB (France).

CT scanning


Current (2015-2017)


Adam Ash

Funders and partners

The project is co-funded by FC Scotland, FC England and Natural Resources Wales, via the Forest Products Research Programme (Wood and Timber Properties).

Forestry Commission policy

FC Scotland policy: The Scottish timber industry and Scotland's timber resources, particularly via The timber development programme
FC England policy: Protecting, improving and expanding England's woodland resource
Welsh Government policy: Woodlands for Wales