|Shields Jr, Fletcher|
Submitted to: Journal of the American Water Resources Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2005
Publication Date: 2/1/2006
Citation: Pezeshki, S., Shields Jr, F.D. 2006. Black willow cutting survival in streambank plantings, Southeastern United States.. Journal of the American Water Resources Association. 42(1):191-200.
Interpretive Summary: Planting of dormant willow posts (cuttings 8 to 10 ft long and 1 to 3 in. diameter) has been used to address problems associated with streambank erosion, but survival rates and success have been disappointing for plantings along incised, rapidly eroding channels. A series of field studies at three streambank restoration projects in northern Mississippi were conducted to monitor willow performance and environmental conditions for 1-2 years. Although conditions were harsh for plant growth, willows planted about 0.5 to 1 m above base flow elevation exhibited rapid growth and high survival rates. Sandy, moist soils were superior to droughty soils and those with more than about 20% silt-clay content. These findings will allow preplanting evaluation of streambanks and reduce the risk of planting failure.
Technical Abstract: Field studies were conducted on black willow (Salix nigra) cuttings planted for riparian zone restoration along Harland Creek (HC), Twentymile Creek (TC), and Little Topashaw Creek (LTC) in Mississippi, USA. Planted posts were 2.5-3 m long and had base diameters of 2.5-7.5 cm. Streams were unstable, deeply incised sand-bed channels with eroding banks 1 to 6 m high. Soil texture, redox potential (Eh), depth to water table and willow survival were monitored for 2-3 years after planting. While many factors influence willow cuttings at restoration sites, soil texture and moisture are key to plant success. In these studies, plant survival and growth were best for cuttings planted in soils with less than 40% silt-clay content, and a water table 0.5 m to 1.0 m below the soil surface during the growing season. These conditions produced soil Eh > ~200 mV, and were most often observed 1 to 2 m higher than the bank toe. These findings suggest criteria useful for pre-planting site evaluations. Additional evidence suggests that pre-planting soaking enhances performance of black willow cuttings. Additional factors (channel erosion, herbivory by beaver, and competition from exotics) may control performance over periods longer than 2-3 years.