Pre-Commercial Thinning Increases Merchantability and Reduces Western Gall Rust Infections in Lodgepole Pine

  • Author / Creator
    Scaria, Francis
  • Alberta’s forest industry is predicted to be impacted by a short to medium-term decline in timber supply. Intensive silviculture tools, such as pre-commercial thinning, have been shown to increase individual tree growth, shorten rotation lengths and improve stand merchantability in important commercial species such as lodgepole pine. However, lodgepole pine stands are susceptible to western gall rust infections and thinning at an early stage may increase infection rates. But again, concrete information on these issues are missing from an operational scale. This study collected tree and stand level data from 33 operational harvest origin lodgepole pine stands consisting of 11 earlier thinned (PCT18; 17-19 years), 11 later thinned (PCT24; 23-25 years) and 11 unthinned stands. Pre-commercially thinned stands, regardless of timing, had greater individual tree size (~15% higher) compared to unthinned stands approximately 40 years after thinning. Pre-commercially thinned stands also have a higher potential for commercial thinning since they have lower variability in tree size and longer live crown lengths. In addition, the timing of thinning did have an impact on western gall rust infections, with PCT24 stands having lower infection rates and infection severity compared to both PCT18 and unthinned. In conclusion, pre-commercial thinning should be considered for lodgepole pine stands in order to address timber supply issues in Alberta.

  • Subjects / Keywords
  • Graduation date
    Fall 2023
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.