Comparative Rates of Western Juniper Afforestation in South-Central Oregon and the Role of Anthropogenic Disturbance*
نویسندگان
چکیده
We examine changes in canopy cover for adult western juniper from the 1960s to 1994 in central Oregon using repeat aerial photography. We compare changes at four sites with a land-use history of minimal anthropogenic disturbance to changes on adjacent sites that have a disturbance history more typical of central Oregon rangelands. Canopy cover increased at all sites, but afforestation on sites with domestic livestock grazing was greater. The potential driving forces common to all sites include a long fire-free interval, early twentiethcentury favorable climatic conditions, biological inertia, and atmospheric CO2 enrichment.
منابع مشابه
Updated Findings in the Determination of the Mechanical Properties of the Wood of Western Juniper ( Juniperus occidentalis Hook . ) Report of 3 September 2008
As previously reported, wood of western juniper, Juniperus occidentalis Hook, was collected from nine locations throughout its range in northern California, south-central and central Oregon. Trees for testing were selected, in part, by their stem form and ability to provide useable test material. Trees of unusual size and form were not, however, selected for test trees, but were bypassed in fav...
متن کاملClimatic Regionalization and the Spatio-Temporal Occurrence of Extreme Single-Year Drought Events
Tree-ring records from western juniper (Juniperus occidentalis var. occidentalis Hook.) growing throughout the interior Pacific Northwest identify extreme climatic pointer years (CPYs) (i.e., severe single-year droughts) from 1500–1998. Widespread and extreme CPYs were concentrated in the 16th and early part of the 17th centuries and did not occur again until the early 20th century. The 217-yr ...
متن کاملClimatic Regionalization and the Spatio-Temporal Occurrence of ExtremeSingle-Year Drought Events (1500–1998) in the Interior PacificNorthwest, USA
Tree-ring records from western juniper (Juniperus occidentalis var. occidentalis Hook.) growing throughout the interior Pacific Northwest identify extreme climatic pointer years (CPYs) (i.e., severe single-year droughts) from 1500–1998. Widespread and extreme CPYs were concentrated in the 16th and early part of the 17th centuries and did not occur again until the early 20th century. The 217-yr ...
متن کاملNew Findings in the Determination of the Mechanical Properties of the Wood of Western Juniper ( Juniperus occidentalis Hook . ) Report of 13 September 2007 Edwin
As previously reported wood of western juniper, Juniperus occidentalis Hook, was collected from nine locations throughout its range in northern California, south-central and central Oregon. Trees for testing were selected, in part, by their stem form and ability to provide useable test material. Trees of unusual size and form were not, however, selected for test trees, but were bypassed in favo...
متن کاملData set on the effects of conifer control and slash burning on soil carbon, total N, organic matter and extractable micro-nutrients
Conifer control in sagebrush steppe of the western United States causes various levels of site disturbance influencing vegetation recovery and resource availability. The data set presented in this article include growing season availability of soil micronutrients and levels of total soil carbon, organic matter, and N spanning a six year period following western juniper (Juniperus occidentalis s...
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