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Aspen Restoration and Mortality in Southern Utah
Impact of Elk and Deer Herbivory onRegeneration of Aspen Clear-cuts
Investigators: Dr. Dale Bartos, Seth Ohms
Abstract:
Research will work to determine the (1) ability to restore decadent, non-regenerating aspen by treating mature stands, and (2) cause and extent of complete clone mortality that is occurring on Cedar Mountain.
Introduction:
It has been suggested, "No other tree in the rocky mountains is more highly valued for its amenities than aspen." These amenities include, Watershed values, Forage and Timber production, Wildlife habitat and esthetics. Local landowners have expressed a strong interest in the aspen clone mortality that is occurring on Cedar Mountain.
Methodology:
Aspen regeneration
Clones ranging from 20% to 90% decadence have been selected for treatment (clearcut). Percent decadence was obtained using random belt transects within the selected clones, measuring density and defoliation. Multiple areas within the clones were selected as possible treatment sites. Actual treatment sites (1/8 Ac.) were randomly selected for each clone. Regeneration (density and growth rate) of aspens will be measured on both treated, and untreated sites.
Cause and extent of complete clone mortality
Various techniques will be employed including (1) small temporary nested exclusion areas placed in the various treatments (These exclosures will be constructed of 7 ft tall black plastic netting and 4 ft wire fence. Regeneration will be monitored, and Wildlife/Livestock utilization measured both inside and outside of these exclosures); (2) mapping suspect clones via GIS, identifying geographic correlations; (3) application of slow release pesticide to control metallic poplar borer; (4) identify extent of fungal agents - some consultation with John Guyon (expert on aspen diseases); (5) use aerial photography to determine extent of problem; and (6) use historical and repeat photos to see magnitude of changes.
Anticipated Results:
-From the study, we hope to identify whether or not these decadent, mature aspen stands can be successfully regenerated, and if so, to what extent.
-Also, we hope to identify the probable cause(s) and extent of clone mortality, and how the process can be reversed.
IMPACT OF ELK AND DEER HERBIVORY ON REGENERATION OF ASPEN CLEAR-CUTS
Investigators: Dr. Michael Conover, and John Reichert, Jack Berryman Institute, Utah State University
Introduction:
The increasing elk population in Utah is threatening the ability of aspen stands to regenerate by overgrazing aspen shoots so severely that the shoots never outgrow the reach of an elk. Loss of aspen stands, each a separate aspen clone, is a serious problem because the aspen clones are hundreds or thousands of years old; and new clones are no longer able to survive. Yet in some areas, ungulate grazing does not threaten aspen regeneration. This study examines why some stands are threatened by elk grazing, but others are not. Such information would help us ensure that these beautiful stands of aspen will not be lost.
Objectives:
(1) To determine the impact of deer and elk herbivory on the ability of aspen to regenerate after a clear-cut.
(2) To determine if we can predict when herbivory will become so intensive as to prevent stand regeneration.
(3) To determine if we can change the characteristics of a clear-cut so that aspen can successfully regenerate the site.
Methodology:
We are studying aspen stands throughout southern Utah which were harvested within the last decade. We monitor how well the stand is regenerating, browsing intensity on aspen shoots, and characteristics of the clear-cut, such as its size, slope, elevation, age, and competing vegetation.
Results:
The study has not progressed to the point where we can draw conclusions from out data.
Partners:
Jack Berryman Institute
Dixie National Forest/Upper Sevier Watershed Project
Stoltze's Aspen Mill
