1. Institute of Wood Technology; Akita Prefectural University; 11-1 Kaieizaka 016-0876 Noshiro Japan
2. Ecological Chemistry Group; Department of Chemistry; Royal Institute of Technology; Teknikringen 30 SE-100 44 Stockholm Sweden
3. The Forestry Research Institute of Sweden; Ekebo 2250 SE-26890 Svalöv Sweden
4. Faculty of Agriculture; Yamagata University; 1-23 Wakaba-machi 997-8555 Tsuruoka Japan