The common basis of wood grain figures is the systematically changing orientation of cambial fusiform cells

Abstract

Various types of wavy grain, the striped figures on radial surfaces of wood with interlocked grain, and even moire or checkered figures, are all interpreted as resulting from systematically changing orientation of cambial cells. Such changing orientations are manifestations of morphogenic wave phenomena that affect the orientation (rightward or leftward) of anticlinal and pseudotransverse divisions of fusiform initial cells and of subsequent intrusive growth. The accumulated effects of such nonrandomly oriented events determine local grain inclination. Morphogenic waves move slowly along the cambium, about one wavelength in 10 to 15 years. Grain waves and other figures in wood are automatic, permanent recordings of the existence and movements of morphogenic waves in the cambium. These may still be several orders removed from more fundamental and more rapidly moving phenomena associated with timing and spacing in tree development.