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Patterns of Instream Wood Recruitment and Transport at the Watershed Scale
Author(s) -
Martin Douglas J.,
Benda Lee E.
Publication year - 2001
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(2001)130<0940:poiwra>2.0.co;2
Subject(s) - large woody debris , hydrology (agriculture) , fluvial , environmental science , watershed , channel (broadcasting) , streams , erosion , drainage basin , debris , abundance (ecology) , drainage , bank erosion , habitat , ecology , structural basin , geology , geography , riparian zone , geomorphology , oceanography , biology , geotechnical engineering , cartography , engineering , machine learning , computer science , electrical engineering , computer network
A wood budget was constructed for the Game Creek basin (132 km 2 ) in southeast Alaska to identify spatial and temporal controls on the abundance and distribution of large woody debris (LWD). Field measurements of wood storage, size, and age were used to estimate volumetric rates of LWD recruitment and transport. Mortality recruitment did not follow a spatial pattern and ranged from 0.1 to 8.1 m 3 ·km −1 ·year −1 (recruitment corresponded to forest mortality rates of 0.1–2.6% per year). Wood recruitment by bank erosion increased with increasing drainage area and ranged from 1 m 3 ·km −1 ·year −1 at the smallest drainage areas to about 16 m 3 ·km −1 ·year −1 at 60 km 2 . Bank erosion recruitment exceeded the maximum mortality recruitment at a drainage area of approximately 20 km 2 (about 10‐m‐wide channel). Recruitment from land‐sliding was only locally significant. The contribution of fluvial transport (flux) to total LWD storage increased with drainage area to an asymptotic maximum of 50% at about 50 km 2 (about 20‐m‐wide channel). Mean predicted transport distances for mobile LWD over the lifetime of individual pieces ranged from about 200 m in small, jam‐rich streams to about 2,500 m in larger channels with fewer jams. Fluvial transport of LWD increased interjam spacing and jam size and decreased jam age with increasing distance downstream. Constructing LWD budgets at the watershed scale has numerous geomorphic and ecological implications, including identifying spatial controls on the abundance and diversity of aquatic habitats. In addition, information on LWD budgets may be useful for determining how and where to protect LWD sources to streams.