Mediterranean Climate effects. I. Confier WATER USE ACROSS A SIERRA NEVADA ECOTONE
Title
Mediterranean Climate effects. I. Confier WATER USE ACROSS A SIERRA NEVADA ECOTONE
Abstract
Xylem water potential of the midelevation conifers Pinus jeffreyi, Pinus lambertiana, Abies concolor, and Calocedrus decurrens,the higher elevation Pinus monticola and Abies magnifica, and co-occurring evergreen angiosperm shrubs, together with soil moisture under these plants, were monitored at three sites on the Kern Plateau in the southernmost Sierra Nevada Range of California. Site locations spanned the ecotone between the mid- and upper montane forests at elevations of 2230—2820 m. Measurements were made through a low-snowfall year and a heavy-snowfall year. In the Mediterranean climate of the Sierra Nevada, the heavy winter snowpack persists into late spring, after precipitation has effectively stopped. We found the subsequent depletion of soil moisture due to plant water uptake to result in predawn xylem water potentials for conifers more negative by 0.6—1.4 MPa than those for shrubs or inferred soil potentials. Shrubs generally depleted soil moisture more rapidly and ultimately extracted a greater fraction of the available soil moisture than did the conifers. This depletion of soil moisture by shrubs, particularly Arctostaphylos patula, may limit conifer growth and regeneration by prematurely terminating growth on the shallow soils studied. The conifers all generally showed similar patterns of soil moisture use, except that A. magnifica extracted moisture more rapidly early in the season.
Purpose
The objective of this study was to identify and quantify species-specific differences in patterns of water use in response to the seasonal climate of the Sierra Nevada and to identify how these differences might influence conifer species distribution. We report measurements of the seasonal progression of soil and plant water status in the relatively unstudied southernmost Sierra, where the summer drought is most severe
Begin Date
2015-08-21
Originator Name
American Journal of Botany
Keywords
Biological sciences, Forestry
Progress
Complete
Resource Type
Document
Update Frequency
None Planned
Resource Owner
deercreekgisWebsite
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