Spelling suggestions: "subject:"willows -- cology -- oregon, eastern"" "subject:"willows -- cology -- oregon, astern""
1 |
Effects of environmental variables and grazing on planted willow (Salix boothii Dorn) cuttingsLowson, 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
|
Page generated in 0.3219 seconds