9:00 am - 10:00 am
South Academic Building (SAB) 150, University of Alberta, Edmonton AB
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree. This is an ALES MSc Final Exam Seminar by Andrew Sperling. This seminar is open to the general public to attend.
MSc with Dr. Brad Pinno.
Thesis Topic: Pre-Commercial Thinning in the Boreal Mixedwood: Change in Site Resource Availability & Modelled Growth
Abstract:
Pre-commercial thinning is a silvicultural treatment that can increase stand merchantable timber production and
resistance to drought.
Processes driving growth response to density management are poorly understood but important when applying thinning to
stands that will grow under future warmer and drier conditions. Consequently, we evaluated microclimate and resource
availability in operational-scale pre-commercial thinning trials of young (19-year old) boreal trembling aspen/white
spruce/paper birch mixedwoods in northern Alberta, Canada. Thinning created an improved but also more extreme tree
growing environment, highlighting a need to evaluate the treatment from a risk perspective.
Available tools to evaluate growth response to pre-commercial thinning include two growth models, MGM and GYPSY.
We evaluated the consistency of projected thinning effects within and between estimates by both models to gauge their
reliability. GYPSY’s projected thinning effect was greater than MGM’s projected effect, and significant differences between
models were found in both the magnitude and direction of projected thinning effects. While these results cannot be used
to determine model accuracy, their variability highlights the limitations of interpreting any single model projection.
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