Spiral grain in relation to ring width and cambial age in European oak (Quercus petraea (Matt) Liebl and Q-robur L)

Spiral grain measurements were made across discs from ten trees of European oak (Quercus petraea/Q. robur) obtained from 16 stands spread between Germany, Denmark, Scotland, England and Wales. The stands were chosen for their contrasting silvicultural management. It was found that spirality tended to increase with cambial age in a consistent left or right-handed direction. In 48% of trees the grain angle remained close to 0 degrees not exceeding 1.5 degrees from the vertical. No significant relationship was found between ring width and incidence of spiral grain. There were significant differences between individual trees and between stands, but not between types of silvicultural management. Variation between and within stands indicated scope for selection and breeding for the reduction of spiral grain.