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Population Dynamics of a Montane Conifer Forest, Western Cascade Range, Oregon, USA
Author(s) -
Stewart Glenn H.
Publication year - 1986
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1938596
Subject(s) - tsuga , ecology , dominance (genetics) , canopy , range (aeronautics) , biology , population , regeneration (biology) , montane ecology , forest dynamics , geography , demography , biochemistry , materials science , sociology , composite material , gene , microbiology and biotechnology
Size and age structure were used to reconstruct the population dynamics of two forested stands in the western Cascade Range, Oregon, USA. Trees with different growth rates and size—age relationships occurred in the same stand. The relationships between diameter and age of 939 aged trees of four species, although statistically significant, were often weak. Data on both age and spatial dispersion added critical information on stand dynamics not available from size alone. The population structures and regeneration patterns described were strongly influenced by natural disturbances and species' life history characteristics. Periodic fires of variable intensity and extent have produced a mosaic of relatively even—aged patches of different conifer species. The early establishment and dominance by a species on a site was a determinant of subsequent forest regeneration. If Pseudotsuga menziesii dominated early, regeneration of Tsuga heterophylla, and often Abies amabilis, was rapid. If, however, Tsuga heterophylla established first, further regeneration of other species was absent or minimal until canopy openings formed.