Distribution of Aggregate Rays in Red Alder


  • Arthur F. Noskowiak


Alnus rubra, aggregate rays, wood figure, juvenile wood, adult wood, rays


The distribution of aggregate rays in 23 trees of red alder was examined. Three patterns of distribution were determined for the relationship between the number of aggregate rays counted at the cambium on the cross section and height in the tree. Aggregate rays are virtually absent in a coneshaped zone of juvenile wood in the lower half of the tree bole but present in varying numbers in the sheath of adult wood surrounding the juvenile core in the lower half of the bole and in both juvenile and adult wood in the upper half of the bole. That pattern explains their sporadic distribution in alder lumber. The number of aggregate rays observed at the cambium on cross sections from ground line to tree tip is not related to tree diameter, geographic location, or quadrant sectors within trees. Clusters of closely spaced aggregate rays are frequently associated with frost injuries, indentures, or undulating annual rings and branch traces.


Panshin, A. J. and Carl de Zeeuw. 1970. Textbook of wood technology, Volume 1, 3rd edition. McGraw-Hill Book Company, New York, N.Y.n






Research Contributions