© 2007 Heron Publishing—Victoria, Canada
Structural characteristics of Abies mariesii saplings in a snowy subalpine parkland in central Japan
Akira Mori (1, 2, 3) and Shigeaki F. Hasegawa (1, 4)
1. Laboratory of Forest Ecology, Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University,
Oiwake-Cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan / 2. Present address: School of Resource and Environmental Management, Faculty of Applied Science, Simon Fraser University, Burnaby,
BC V5A 1S6, Canada / 3. Corresponding author (akkym@kb3.so-net.ne.jp) / 4. Present address: Laboratory of Terrestrial Ecology, Graduate School of Environmental Earth Science, Hokkaido University / Received March 29, 2006; accepted April 12, 2006; published online October 2, 2006
Summary
Structural characteristics of Abies mariesii M.T. Mast. saplings growing in sun and shade in a snowy subalpine parkland in central Japan were assessed to infer how saplings
acclimate to suppression by larger individuals in a conifer clump and to extremely snowy conditions. Sun and shade saplings
produced structurally different current-year shoots, and allocated biomass to needles and stem differently. Compared with
sun saplings, shoots of shade saplings had lower needle mass per unit shoot size, which indicates less dense needle packing
and more effective use of the limited available light by avoiding mutual shading among needles. Biomass allocation within
lateral branches also differed between sun and shade saplings. Compared with sun saplings, needle mass was a smaller proportion
of total branch mass in shade saplings although shade saplings retained needles for longer, thereby compensating, in part,
for their lower annual production of needles. Thus shade saplings incur a high mechanical cost to support their low-light
acclimated, conspicuously flattened crowns in this snowy habitat. Suppressed saplings are an important component of the persistent
conifer clumps in snowy subalpine parklands. The observed structural characteristics of A. mariesii saplings, which ensure high shade- and snow-tolerance, contribute to the dominance of the species in snowy subalpine regions
in Honshu, Japan.
Keywords:
biomass allocation, conifer clump, crown, current-year shoot, lateral branch.
