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dc.creatorPeterson, D.L.
dc.creatorHammer, R.D.
dc.description.abstractDuring the past century, forest structure on south-facing slopes of Mount Constitution, Orcas Island, Washington, USA, has changed from open-grown Douglas fir (Pseudotsuga menziesii) mixed with prairie to primarily closed canopy forest. Density of open-grown Douglas fir was approximately 7 stems/ha in the 19th century, while the current density of trees in closed-canopy mature forest is 426 stems/ha. Trees occur at intermediate densities in areas of transition from savanna-like stands to closed canopy. Analysis of fire scars indicates that at least seven fires have occurred on Mount Constitution since 1736, but only one fire has occurred since 1893, which suggests that the recent increase in stem density has been caused primarily by fire exclusion. The high stem densities currently found in this landscape put the relict (120-350+ years old) Douglas fir at risk from contemporary fires, which would likely be high-intensity crown fires. Given the transition of forests on Orcas Island during the 20th century to closed canopy structure, undisturbed open-grown coniferous forest is now extremely rare in the San Juan Islands.en_US
dc.publisherWSU Press
dc.rightsIn copyright
dc.subjectconiferous forests
dc.subjectforest fires
dc.subjectsavanna woodlands
dc.subjectstand density
dc.subjectstand development
dc.subjectstand structure
dc.titleFrom open to closed canopy: a century of change in a Douglas-fir forest, Orcas Island, Washington
dc.description.citationPeterson and Hammer "From open to closed canopy: a century of change in a Douglas-fir forest, Orcas Island, Washington." Northwest Science. 2001; 75(3): 262-269

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  • Northwest Science
    Northwest Science features original research in the basic and applied sciences, with emphasis on the Pacific Northwest region of the United States and Canada.

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