Ecotonal changes and altered tree spatial patterns in lower mixed-conifer forests, Grand Canyon National Park, Arizona, U.S.A. |
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| Authors: | Joy Nystrom Mast Joy J Wolf |
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| Institution: | (1) Department of Geography, Carthage College, Kenosha, WI, 53140, U.S.A;(2) Department of Geography, University of Wisconsin-Parkside, Kenosha, WI, 53141, U.S.A |
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| Abstract: | This research analyzes patch development and determines tree spatial patterns along the lower mixed-conifer ecotone on the
North Rim of Grand Canyon National Park in Arizona (U.S.A.). Patterns of patch development were interpreted from spatial analyses,
based on tree age and size, and past records of disturbance and climate. Five plots in the ecotone between mixed conifer forests
and monospecific stands of ponderosa pine (Pinus ponderosa) were studied for patterns of patch development. The methods used include: (1) size-structure analyses, to compare species
patch development; (2) dendrochronological dating of tree establishment; (3) tree ring master chronology, to determine periods
of suppressed growth, compared to a Palmer Drought Severity Index; and (4) spatial analyses by species composition, size and
age, with univariate and bivariate analyses of spatial association and spatial autocorrelation. We found an increased density
of shade-tolerant and fire-intolerant species namely clusters of pole-sized white fir, and fewer large ponderosa pine.
This revised version was published online in May 2005 with corrections to the Cover Date.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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| Keywords: | Dendrochronology Ecotone Mixed-Conifer Patch Structure Ponderosa Pine Spatial Analysis White Fir |
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