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Distribution and regeneration strategies of major canopy dominants in species‐rich subtropical/warm temperate rainforests in south‐western Japan
Author(s) -
Takyu Masaaki,
Ohsawa Masahiko
Publication year - 1997
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/bf02523779
Subject(s) - canopy , rainforest , ecology , temperate rainforest , dominance (genetics) , habitat , biology , subtropics , temperate climate , altitude (triangle) , ecosystem , biochemistry , gene , geometry , mathematics
The distribution and regeneration strategy of the major canopy dominants in species‐rich subtropical/warm temperate rainforests in south‐western Japan was studied in a hilly zone below 1100 m a.s.l. Using the patch sampling method, four dominance‐community types were numerically identified and they corresponded to four habitats which represented a combination of topography and altitude (i.e. ridges vs slopes, and below vs above 500 m a.s.l.) Seven major canopy dominants had their respective distributional core in one of these topo‐altitudinal habitats. The seven canopy dominants could be classified into three species groups according to their size structure and growth habits. Group A ( Tsuga sieboldii and Quercus gilva ) and group B ( Quercus acuta, Quercus salicina, Machilus thunbergii ) were restricted to the emergent and canopy layer, respectively. These two groups had only a few subcanopy trees and saplings. Saplings of group B showed a rapid growth rate in canopy gaps. Group C ( Distylium racemosum ) was characterized by many subcanopy trees and saplings that grew steadily under the closed canopy. Castanopsis sieboldii showed intermediate characteristics between group B and C in the size structure and growth habit of its saplings. The density of D. racemosum canopy trees was markedly reduced on ridges and slopes above 500 m and on slopes below 500 m. In these marginal habitats, the three species groups coexisted by sharing different strata within a community. This situation was possible due to the differences in regeneration strategies among the canopy species.