Changes in water distribution in heartwood along stem axes in Cryptomeria japonica

Abstract

Three-dimensional distribution of water in the heartwood of Cryptomeria japonica D. Don was observed by soft X-ray photography. The within-tree variation in the distribution of "wet areas" (water-accumulated areas in heartwood) was enormous, as was the variation among trees. Although we found no universal pattern of changes in wet area distributions along the stem axes of all trees, similarities among individual trees within each cultivar and clone were observed. The difference between the two kinds of wetwood in C, japonica - genetically defined wetwood and secondarily induced wetwood - is discussed, as is the use of soft X-ray photography in Japanese tree breeding programs.