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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects of environmental variables and grazing on planted willow (Salix boothii Dorn) cuttings

Lowson, Katherine L. 13 January 2004 (has links)
The influence of streambank location and timing of herbivory on success of planted Booth's willow (Salix boothii Dorn) cuttings along a Rosgen C5-type stream in an eastern Oregon meadow was determined. Willow cuttings were planted on two morphological locations (i.e. point bar and floodplain) in May of 2002 and 2003. Gravimetric soil moisture and depth to water table data were collected periodically on each planting location during the growing season, May through September, in both years. Three grazing treatments, early season, late season, and none (control) were conducted. Percent survival, leader density, and number of browsed leaders of willows were recorded prior to and after each grazing treatment, as well as stubble height of forage species. Simple linear regression was used to determine if a relationship between residual stubble height and percent willow browse existed. Multiple linear regression was used in an attempt to develop a predictive equation for percent browse based on pre-grazing stubble and willow heights. It was hypothesized that depth to water table and percent soil moisture throughout the growing season would significantly influence willow survival and growth; that survival would be higher on point bar locations; and that willows would be browsed at different intensities according to season of grazing. Soil moisture content at point bar locations was greater than that of floodplain locations for the majority of the growing season in both years. In 2003, groundwater levels were higher on point bar than floodplain locations from May through September. Willow survival was higher for point bar locations than floodplain locations, in both years, regardless of grazing treatment. Willows were browsed more intensively later in the growing season. Results from the simple linear regression suggest that percent browse of willows was related to the residual stubble height, but did not explain the variability observed. An attempt to develop a predictive equation, i.e., expected browse based on pre-grazing stubble height, was made, however no apparent relationship between the willow height, stubble height, and percent browse was found. Grazing treatment did influence willow survival; survival on floodplain locations within the late grazing treatment was less than that of the ungrazed floodplain locations. Our results suggest that planting willows in locations where the planting depth remains within 40 cm of the groundwater depth will increase planting success. Protection from grazing for at least the first year of growth is recommended for optimum planting survival; grazing early in the season is more favorable to survival than grazing later in the season. / Graduation date: 2004

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