Methane fluxes in mature upland conifer forests in three biogeoclimatic zones in southern British Columbia
department or school: Science, Irving K. Barber Faculty of (Okanagan)
department or school: Earth, Environmental and Geographic Sciences, Department of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Browne, Emily
issued: 2024-04-29T19:58:25Z
issued: 2024
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Upland forests typically are a sink for atmospheric methane (CH₄) because well-drained soils are inhabited by high-affinity methanotrophic bacteria. However, CH₄ commonly is generated in trees experiencing heartwood rot caused by fungal pathogens. To date, studies of CH₄ emissions associated with heartwood rot have focused primarily on deciduous trees. The objective of this study was to investigate CH₄ fluxes in upland conifer forests situated in the Montane Spruce (MS), Engelmann Spruce—Subalpine Fir (ESSF), and Coastal Western Hemlock (CWH) Biogeoclimatic zones of southern British Columbia. The study aimed to determine whether CH₄ fluxes in upland forests differ between sites, tree species, trees bearing conks, and other bark anomalies. Trees were surveyed in 10 x 10 m quadrats (n=37) for species, location, diameter at breast height, and evidence of stem fungal infection. A portable gas analyzer and sealed chambers were used to measure CH₄ flux from tree stems having a diameter >20 cm, conks resulting from fungal pathogens, stem anomalies, and the soil surface. The flux rate was determined from the change with time of the methane concentration in the chamber headspace. Methane flux was measured from 126 trees and 21 soil plots. Tree species (Picea engelmanii, Abies lasicarpa, Thuja plicata, Tsuga heterophylla, Abies amabilis, Populus balsamifera) from all three sites exhibited both emission and uptake of CH₄ with no significant differences between species. Tree stem fluxes were small (MS mean = 0.006 ± 0.059 µmol m-² h-¹, ESSF mean = -0.034 ± 0.057 µmol m-² h-¹, CWH mean = -7.0x10-⁵ ± 0.046 µmol m-² h-¹) relative to rates of soil uptake of atmospheric CH₄ (mean = -2.475 ± 0.801 µmol m-² h-). Stem fluxes from conifers at the ESSF site differed from those at the MS and CWH sites likely due to a greater prevalence of conks and fungal infection at ESSF. Bark anomalies and conks did not exhibit higher rates of CH₄ flux in contrast to the elevated emissions from similar…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/88091
note: Methane fluxes in mature upland conifer forests in three biogeoclimatic zones in southern British Columbia by Emily Browne B.Sc., University of Windsor, 2021 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Earth and Environmental Sciences) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) April 2024 © Emily Browne, 2024 ii The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis entitled: Methane fluxes in mature upland conifer forests in three biogeoclimatic zones in southern British Columbia submitted by Emily Browne in partial fulfillment of the requirements of the degree of Master of Science. Dr. Edward Hornibrook, Irving K. Barber Faculty of Science Supervisor Dr. Adam Wei, Irving K. Barber Faculty of Science Supervisory Committee Member Dr. Alyse Kiesser, School of Engineering Supervisory Committee Member Dr. Sean Smuckler, University of British Columbia-Vancouver University Examiner iii Abstract Upland forests typically are a sink for atmospheric methane (CH4) because well-drained soils are inhabited by high-affinity methanotrophic bacteria. However, CH4 commonly is generated in trees experiencing heartwood rot caused by fungal pathogens. To date, studies of CH4 emissions associated with heartwood rot have focused primarily on deciduous trees. The objective of this study was to investigate CH4 fluxes in upland conifer forests situated in the Montane Spruce (MS), Engelmann Spruce—Subalpine Fir (ESSF), and Coastal Western Hemlock (CWH) Biogeoclimatic zones of southern British Columbia. The study aimed to determine whether CH4 fluxes in upland forests differ between sites, tree species, trees bearing conks, and other bark anomalies. Trees were surveyed in 10 x 10 m quadrats (n=37) for species, location, diameter at breast height, and evidence of stem fungal infection. A portable gas analyzer and sealed chambers…
has type: Thesis/Dissertation
date issued: 2024-05
is shown at: 10.14288/1.0442044
language: eng
degree discipline: Earth and Environmental Sciences
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: Hornibrook, Edward
type: Text
identifier URI: http://hdl.handle.net/2429/88091