Changes in water distribution in heartwood along stem axes in <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

 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. Received: December 21, 2001 / Accepted: May 1, 2002 Part of this paper was presented at the 46th Annual Meeting of the Japan Wood Research Society, Kumamoto, Japan, April 1996 Correspondence to:R. Nakada