Canadian Forest Service Publications

How do trees grow? Response from the graphical and quantitative analyses of computed tomography scanning data collected on stem sections. 2014. Dutilleul, P.; Han, L.W.; Beaulieu, J. Comptes Rendus Biol. 337:391-398.

Year: 2014

Issued by: Laurentian Forestry Centre

Catalog ID: 35581

Language: English

CFS Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1016/j.crvi.2014.05.002

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Tree growth, as measured via the width of annual rings, is used for environmental impact assessment and climate back-forecasting. This fascinating natural process has been studied at various scales in the stem (from cell and fiber within a growth ring, to ring and entire stem) in one, two, and three dimensions. A new approach is presented to study tree growth in 3D from stem sections, at a scale sufficiently small to allow the delineation of reliable limits for annual rings and large enough to capture directional variation in growth rates. The technology applied is computed tomography scanning, which provides – for one stem section – millions of data (indirect measures of wood density) that can be mapped, together with a companion measure of dispersion and growth ring limits in filigree. Graphical and quantitative analyses are reported for white spruce trees with circular vs non-circular growth. Implications for dendroclimatological research are discussed.

Plain Language Summary

The annual growth rings of a tree are concentric circles in the trunk that are visible when the tree is felled or when wood cores are extracted from the trunk. These rings vary in width, depending on the tree’s growth rate. Several factors such as climate and insect attacks have an impact on these growth rates. Researchers measure growth rings to assess, among other things, the environmental impacts affecting trees and determine what the climate was like in the past.

This article describes a new three dimensional method for studying tree growth based on stem sections at a scale small enough to attribute reliable boundaries to the growth rings.

The technology used is computerized axial tomography, which produces millions of data for a stem section that can be mapped. This new method makes it possible to study tree growth in fine detail and obtain data such as wood density at various stem heights. Because of its greater accuracy, it makes researchers’ work easier.