SPIRAL GRAIN IN RELATION TO RING WIDTH AND CAMBIAL AGE IN EUROPEAN OAK (QUERCUS-PETRAEA (MATT) LIEBL AND QUERCUS-ROBUR L)

Spiral grain measurements were made across discs from ten trees of Eur opean oak (Quercus petraea/Q. robur) obtained from 16 stands spread be tween Germany, Denmark, Scotland, England and Wales. The stands were c hosen for their contrasting silvicultural management. It was found tha t spirality tended to increase with cambial age in a consistent left o r right-handed direction. In 48% of trees the grain angle remained clo se to 0 degrees not exceeding 1.5 degrees from the vertical. No signif icant relationship was found between ring width and incidence of spira l grain. There were significant differences between individual trees a nd 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.