森林立地学会誌 森林立地37(2), 1995, pp, 94～99
Data
A survey on the canopy gaps and
gap phase replacement
in an old-growth beech-dwarf
bamboo forest,
Wakasugi Forest Reserve,
southwestern Japan
Shin-Ichi YAMAMOTO・ Naoyuki NISHIMURA
Shin-Ichi
YAMAMOTO, Naoyuki NISHIMURA: A survey on
the canopy gaps and gap phase replacement in an old-grouth beech-dwarf bamboo
forest, Wakasugi Forest Reserve, southwestern Japan: Jpn. J. For. Environment
37. 94-99, 1995
Canopy gaps and gap phase replacement
in an old-growth beech forest with dwarf bamboo understory, Wakasugi Forest
Reserve, southwestern Japan, were surveyed to clarify the regeneration and to
predict the future status of the beech forest. Percentage gap area (percentage
of total gap area to the area surveyed) was 15.2%. Gap density was 13.7gaps ha-1
and mean gap size was 110.6m2 ranging from 9.1m2 to
285.0m2. Gaps smaller than 160m2 were much more abundant
than larger ones (73.7% of total 19gaps). About 68% of all gaps were those
formed by single gapmakers and the remainder were by multiple gapmakers.
Dominant mode for the death of canopy trees was by broken trunks; 42.9% of
canopy trees died by broken trunks. Death of canopy trees by leaving
standing-dead was 10.7% and that by uprooting was 7.1% of all gapmakers (28trees).
Density and size traits of canopy trees
in this forest were not different with those of other old-growth beech forests.
Of important canopy tree species, Fogus
crenata and cryptomeria jaonica might regenerate in gaps from
saplings recruited before gap formation, although Betula grossa and Quercus
mongolica had no regenerations. Thirty-nine percent of the area under
crowns of canopy trees sampled and 58% of the understory of all gaps surveyed
were occupied by a dwarf bamboo, Sasamorpha
borealis, and were without regenerations of any tree species. If this
situation continues, it seems that density and number of species of canopy
trees in this forest will clearly decrease.