The Impacts of Clearcutting on Understory Plants and Culturally Significant Species In Coastal Western Hemlock Forests of Vancouver Island

Lambert, Emily

The Impacts of Clearcutting on Understory Plants and Culturally Significant Species In Coastal Western Hemlock Forests of Vancouver Island

dc.contributor.advisor	Goldblum, David
dc.contributor.advisor	McDermid, Greg
dc.contributor.author	Lambert, Emily
dc.contributor.committeemember	Bender, Darren
dc.contributor.committeemember	Rogers, Sean
dc.date	2024-05
dc.date.accessioned	2024-01-30T17:55:18Z
dc.date.available	2024-01-30T17:55:18Z
dc.date.issued	2024-01-25
dc.description.abstract	The goal of the study is to understand successional changes in an understory plant community after clear-cut timber harvesting. The forest ecosystem is within the Southern Very Wet Hypermaritime biogeoclimatic subzone in the broader Coastal Western Hemlock zone along the west coast of Vancouver Island. The ecosystem is located in Huu-ay-aht First Nations traditional territory, and the subzone falls within various Nuu-chah-nulth First Nations traditional territories. A chronosequence was used to categorize various stages of forest growth in five successional stages: Regeneration, Immature, Thinning, Mature, and Old-growth. Forests censused ranged in age from 1 to 354 years old with old-growth stages described as stands over 250 years. The leaf cover and stem density of understory plant species were recorded within 83 subplots. These metrics were evaluated with regard to environmental variables (slope aspect, elevation, canopy openness, soil pH, A horizon depth, soil profile depth, tree basal area, tree stem density, ground moss cover, and bare ground cover) to determine which, if any, factors influenced understory species composition and structure. Out of 45 species identified, 19 are culturally significant plant species to the Nuu-chah-nulth First Nations. The species restricted to one successional stage were identified, with emphasis on opportunistic species in early stages and rare species in the Old-growth stage. There was a large decrease in many culturally significant species immediately after clearcutting. There was a large decrease in species (stem density, leaf cover, species richness, species diversity) from the Regeneration stage to the Thinning stage (1 to 80 years); however, these values steadily increased thereafter. Plant leaf cover and stem density were influenced by the amount of light reaching the understory. The natural disturbance regime that shade-tolerant plants are adapted to in these old-growth forests is small-scale gap formations, which clearcutting does not mimic. Timber harvesting options are recommended to better mimic the natural disturbance regime in this region, which is optimal for the understory species in this region. Many rare and culturally significant plant species were negatively impacted by clearcutting. Protecting rare plant species in old-growth forests is important for maintaining forest biodiversity and indigenous cultural practices in the future.
dc.identifier.citation	Lambert, E. (2024). The impacts of clearcutting on understory plants and culturally significant species in coastal western hemlock forests of Vancouver Island (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/118107
dc.identifier.uri	https://doi.org/10.11575/PRISM/42951
dc.language.iso	en
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	ethnobotany
dc.subject	forest science
dc.subject	chronosequence
dc.subject	succession
dc.subject	plant ecology
dc.subject	understory
dc.subject	forestry
dc.subject	biogeoclimatic
dc.subject	old-growth
dc.subject.classification	Education--Sciences
dc.subject.classification	Literature--Canadian (English)
dc.subject.classification	Physical Geography
dc.subject.classification	Geography
dc.subject.classification	Ecology
dc.subject.classification	Forestry and Wildlife
dc.subject.classification	Native American Studies
dc.title	The Impacts of Clearcutting on Understory Plants and Culturally Significant Species In Coastal Western Hemlock Forests of Vancouver Island
dc.type	master thesis
thesis.degree.discipline	Geography
thesis.degree.grantor	University of Calgary
thesis.degree.name	Master of Science (MSc)
ucalgary.thesis.accesssetbystudent	I do not require a thesis withhold – my thesis will have open access and can be viewed and downloaded publicly as soon as possible.