Date of Award:

5-2003

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Department name when degree awarded

Forest, Range, and Wildlife Sciences

Committee Chair(s)

Dale L. Bartos

Committee

Dale L. Bartos

Committee

John C. Malechek

Committee

Michael R. Kuhns

Abstract

Aspen clones of an aspen-dominated community in Southwestern Utah are declining, some having experienced high mortality coupled with in sufficient regeneration. The objectives of this study were to (I) determine if decadent, non-regenerating mature aspen stands could be regenerated through disturbance of the 111 auxin/cytokinin hormone relationship by clearcutting; (2) determine the extent of ungulate use of regenerating aspen ramets. Clearcuts were made in late summer of 2001 in 10 different clones that exhibited various levels of decline on a continuum from relatively healthy to extremely deteriorated. Nested wildlife/livestock exclosures were constructed in each clearcut plot, as well as in a corresponding uncut control plot. In the fall of 2002, regenerating suckers were counted. In addition, vigor and ungulate utilization of these suckers were measured in the wildlife and livestock exclosures, as well as in an unprotected portion of the clearcut and control plots.

Regeneration of the clearcut plots ranged from none in the most decadent clones, to 75,000 stems/ha in the least decadent clone, and was significantly greater than the control plots. Vigor, as measured by height of the suckers, was 1.5 to 2.1 times greater in the clearcut plots than in the control plots. Seventy-three percent of the suckers in the unprotected portion of the plots were heavily browsed, while only 12% were not browsed. Successful regeneration of aspen clones is heavily dependent upon clone decadence. Unregulated browsing pressure may limit the clone’s ability to successfully restock and remain on the landscape.

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