THE INFLUENCE OF RAYS ON THE SHRINKAGE OF WOOD

Abstract
Dissections from solid blocks and from microtome sections have shown that the broad rays of Quercus ilex, Cardwellia sublimis , and Helicia terminalis shrink less radially and more longitudinally (axially) than the intervening tissues. Dried cross-sections show the broad rays projecting from the top and bottom edges, with the other tissues curving inwards. Strips cut with one side composed of a ray and the other of the intervening tissues curve on drying, the strip becoming convex on the side of the ray. The shrinkage rates of sections vary considerably from those of solid wood, but the comparison of one tissue with another gave similar results whichever method was adopted.