There has been recent concern regarding the regeneration and recruitment of aspen (Populus tremuloides) in the western United States. Forest management techniques have been employed in order to promote the regeneration and recruitment of aspen. We quantified aspen regeneration treatments in southern Utah, USA to better understand the factors driving aspen recruitment. Driving factors were identified by addressing two major research themes: (1) identify the primary ecological controls on aspen regeneration success; (2) assess the relative importance and influence of these controls on successful regeneration. Our definition of successful aspen regeneration requires the satisfaction of two criteria relating to height and density, respectively: (1) regeneration that has attained heights above the ungulate browsing threshold (e.g. >2m); and (2) regeneration that is occurring at a density that represents desired conditions for future stocking (e.g. ≥10,000 stems ha⁻¹). The primary ecological controls on regeneration success were identified using nonmetric multidimensional scaling, and Random Forests analysis was used to assess the relative importance and influence of regeneration controls. These analyses identified three primary factors that are responsible for regeneration success. These factors were (1) contemporary herbivory pressure, (2) site preparation technique, and (3) advance reproduction. Herbivory is the leading predictor of regeneration success, and has integral impacts on other primary regeneration drivers. We suggest considerations that can be made regarding regeneration drivers in order to enhance the effectiveness of aspen management in the future.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-5173 |
| Date | 01 May 2014 |
| Creators | Britton, Justin M. |
| Publisher | DigitalCommons@USU |
| Source Sets | Utah State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | All Graduate Theses and Dissertations |
| Rights | Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact Andrew Wesolek (andrew.wesolek@usu.edu). |
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