The interactive effects of harvesting intensity and climatic aridity on understory plant communities and Douglas-fir seedlings
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Summers, Breanna
issued: 2024-06-26T21:29:18Z
issued: 2024
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: The impacts of overstory tree retention and climatic aridity on plant community assembly were studied in Douglas-fir dominated forests. There were observed declines in species richness, and percent cover of moss and lichens, in the low retention treatments. High overstory retention treatments conserved community composition, while clearcut and low retention treatments triggered distinct changes, with losses of shade tolerant indicator species and increases in invasive herbs. Low retention treatments reduced the presence of certain culturally important food plants. This study also examined the effects of tree retention and climatic aridity gradient on the performance of local and migrated Douglas fir genotypes and understory plant communities. Seedlings from arid climates and those under high overstory retention grew tallest, suggesting potential adaptability to increasingly arid conditions. Conversely, in humid climates, seedlings fared better in more open conditions, except where shrub cover was high. Understory plant communities played a role in sheltering seedlings from drought and frost, thus promoting their survival and growth. However, clearcutting exacerbated drought incidence due to increased plant competition for water. The retention of overstory trees mitigated the competitive effects of understory plant communities on seedlings. This study provides evidence that retention of overstory trees may protect plant species and regenerating seedlings under increasing aridity with climate change.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/88519
note: The Interactive Effects of Harvesting Intensity and Climatic Aridity on Understory Plant Communities and Douglas-fir Seedlings by Breanna Summers B.Sc., The University of Victoria, 2019 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) June 2024 © Breanna Summers, 2024 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: The interactive effects of harvesting intensity and climatic aridity on understory plant communities and Douglas-fir seedlings. submitted by Breanna Summers in partial fulfilment of the requirements for the degree of Master of Science in Forestry Examining Committee: Dr. Suzanne Simard, Professor, Forestry, UBC Supervisor Dr. Tara Martin, Professor, Forestry, UBC Supervisory Committee Member Dr. Elizabeth Wolkovich , Professor, Forestry, UBC Supervisory Committee Member iii Abstract The impacts of overstory tree retention and climatic aridity on plant community assembly were studied in Douglas-fir dominated forests. There were observed declines in species richness, and percent cover of moss and lichens, in the low retention treatments. High overstory retention treatments conserved community composition, while clearcut and low retention treatments triggered distinct changes, with losses of shade tolerant indicator species and increases in invasive herbs. Low retention treatments reduced the presence of certain culturally important food plants. This study also examined the effects of tree retention and climatic aridity gradient on the performance of local and migrated Douglas fir genotypes and understory plant communities. Seedlings from arid climates and those under high overstory retention grew tallest, suggesting potential adaptability to increasingly arid conditions. Conversely, in humi…
has type: Thesis/Dissertation
date issued: 2024-11
is shown at: 10.14288/1.0444028
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Simard, S. (Suzanne)
type: Text
identifier URI: http://hdl.handle.net/2429/88519