© 1997 Heron Publishing—Victoria, Canada
Effect of heat on cambial reactivation during winter dormancy in evergreen and deciduous conifers
Yuichiro Oribe and Takafumi Kubo
Wood Technology Division, Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba City, Norin Kenkyu Danchi-nai,
Ibaraki 305, Japan / Received July 14, 1995
Summary
Responses of cambium to warming were recorded three times (December 14–27, 1990, January 18–February 3 and February 27–March
13, 1991) on 14-year-old Cryptomeria japonica D. Don and four times (December 12–26, 1990, January 18–February 2, February 26–March 12 and March 28–April 13, 1991) on
27-year-old Larix leptolepis Gord., during a period of winter cambial dormancy. Stem surfaces at breast height, mid-tree height and the crown base were
warmed to 25–30 °C for 2 weeks. After heat treatment, cambia in the treated regions and in untreated regions 1 m above each
treated area were examined by optical and transmission electron microscopy (TEM). In C. japonica, heat treatment often resulted in cambial reactivation in the treated regions, and this response to heat gradually increased
as the dormant season passed from winter to spring. Conversely, in L. leptolepis, no cell division was observed in the cambial region of warmed stems until natural resumption of cambial activity, which
occurred after bud break.
Keywords:
Cryptomeria japonica, heat treatment, Larix leptolepis, winter cambial dormancy.
