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Soaking Willow Cuttings Helps Them Protect StreambanksBy Hank Becker
September 27, 2000
Soaking willow cuttings gives them a head start in protecting eroding stream banks.
Channel erosion is a serious problem in many areas. For years, researchers have tried to stabilize streambanks with planted vegetation. This technique is usually cheaper, better for the environment and more aesthetically pleasing than artificial structures made from concrete and stone.
For four years, Agricultural Research Service hydraulic engineer Doug Shields at the National Sedimentation Laboratory, Oxford, Miss., and University of Memphis wetland plant physiologist Reza Pezeshki investigated willow cuttings survival or effectiveness when planted along streambanks to control erosion.
Planting willow cuttings 3 to 8 inches in diameter and 4 to 8 feet long in winter when they are dormant is an attractive option for rapidly eroding sites. The posts hold and stabilize the bank until the young trees become established. Then the willows create conditions favorable for natural establishment of native vegetation. However, in many cases, willow posts planted in streambanks have died within a year.
To find ways to enhance willow survival and growth, the scientists conducted a series of field and greenhouse studies that showed that cuttings are very sensitive to moisture and soil type. Theyre currently developing a simple site evaluation protocol to assist streambank restoration planners in deciding where to plant willow posts. Site characteristics used in the protocol will include typical groundwater elevations and soil type.
Recent greenhouse studies have shown that survival rates can be doubled by soaking cuttings for 10 days before planting. Soaked cuttings outperformed those planted immediately after they were cut, growing higher and producing more biomass and greater numbers of roots.
This finding will be of great interest to all who are working to create forested riparian buffer strips, control streambank erosion and restore the nations 3.5 million miles of rivers currently considered degraded by erosion, sedimentation and excess nutrients.
ARS is the chief research agency of the U.S. Department of Agriculture.