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Perched Water Table Responses to Forest Clearing in Northern Idaho
Author(s) -
Rockefeller S. L.,
McDaniel P. A.,
Falen A. L.
Publication year - 2004
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2004.1680
Subject(s) - clearance , canopy , water table , soil water , hydrology (agriculture) , environmental science , tree canopy , seasonality , precipitation , table (database) , geology , ecology , soil science , groundwater , geography , biology , medicine , geotechnical engineering , meteorology , urology , computer science , data mining
Many forested soils of northern Idaho containing fragipans and seasonal perched water tables (PWTs) have been cleared for agricultural use. However, little information exists on the direct effect of canopy removal on PWTs in these soils. We compared PWTs in soils where forest canopy had been removed with those in adjacent soils with intact canopy. Study sites were selected such that both cleared and forested treatments occurred within the same soil map unit. Perched water table levels in shallow wells were monitored weekly or biweekly from November to June or July for 3 yr. Results indicate that canopy removal substantially affects both average height and duration of seasonal PWTs. Average PWT levels were 6 to 107% higher under cleared treatments, with greatest increases observed when seasonal precipitation was close to long‐term averages. Seasonal PWTs developed 2 to 8 wk sooner under cleared treatments compared with forested treatments. Additionally, it took as much as four months before PWTs in the forested treatments reached an equivalent height as those in the cleared treatments. At one study site, the average volume of perched water in the cleared treatment was 7.5 cm greater than that in the forested treatment over the period of episaturation. Results suggest that land‐use interpretations based on duration and proximity of a seasonal PWT to the soil surface may need to be adjusted when vegetation cover is altered. It may also be appropriate to distinguish between cleared and forested phases of fragipan‐containing soil series when developing hydrologic interpretations.