DNA analysis of clonal structure of an old growth, isolated forest of Cryptomeria japonica in a snowy region

The regeneration system and clonal structure of Cryptomeria japonica D. Don were investigated in an old growth forest at an altitude of 1420 m, by examining root connections and DNA analysis. The C. japonica at this site was found to regenerate mostly by layering, and we found no clear evidence of regeneration through seedlings. Determining the clonal structure of this stand is much simpler by DNA analysis than by tracing root interconnections. The results of the DNA analysis suggest that all the C. japonica individuals present have close kinship. The study also supported earlier suggestions that the stand is becoming increasingly dominated by a few C. japonica clones with high levels of cold tolerance and good rooting ability. The formation of this type of stand appears to be strongly related to environmental factors such as the mean temperature and snow depth in winter.