Advanced search
2 files | 4.63 MB Add to list

Urban tree canopies drive human heat stress mitigation

Loïc Gillerot (UGent) , Dries Landuyt (UGent) , Pieter De Frenne (UGent) , Bart Muys (UGent) and Kris Verheyen (UGent)
Author
Organization
Project
Abstract
Climate warming and urbanisation compound the public health risk posed by heat. Heat can be mitigated at local scales through urban greening, which provides shade and reduces surface and air temperatures. Yet, the relative effectiveness of different greening options on human thermal comfort based on physiology-based indices is understudied. We installed microclimate stations at 17 locations covering a gradient of tree canopy cover and perviousness in the city of Ghent, Belgium, and monitored the modified Physiologically Equivalent Temperature (mPET) during 195 days over Spring and Summer. We assessed the canopy cover, pervious surface fraction and building sky fraction based on field measures and hemispherical pictures. Unpaved locations with trees experienced a 2.4-fold reduction in the number of days with strong heat stress (mPET > 35 C-degrees) compared to paved, treeless locations. Based on mixed models and our selected environmental variables, cooling effects were predominantly driven by tree canopy cover, where locations with 100% canopy cover had temperature maxima 5.5 C-degrees mPET lower than treeless locations throughout the monitoring period. When air temperatures rose to 40 C-degrees, cooling by tree canopies increased to 8.8 C-degrees mPET. The pervious surface fraction and building view factor were less influential, generating variation of at most 1.7 C-degrees and 1.1 C-degrees mPET, respectively. In contrast, night-time temperatures were rather determined by the regional-scale urban heat island effect than by aforementioned local factors. Still, tree canopies slightly cooled the warmest nights only, whereas the vicinity of buildings led up to 1.2 C-degrees mPET warming on average. Expanding the urban tree cover may therefore be the best solution for improving local thermal comfort levels when daytime heat peaks, but will provide little relief at night.
Keywords
Soil Science, Ecology, Forestry, Dr.FOREST, Forest Microclimate, Heat Stress, Nature-Based Solution, Thermal Comfort, Urban Microclimate, SKY VIEW FACTOR, THERMAL COMFORT, CLIMATE-CHANGE, TEMPERATURE, ISLAND, CITY, MICROCLIMATES, ENVIRONMENT, DENSITY, WEATHER

Downloads

  • Accepted Author Manuscript.pdf
    • full text (Accepted manuscript)
    • |
    • open access
    • |
    • PDF
    • |
    • 1.57 MB
  • (...).pdf
    • full text (Published version)
    • |
    • UGent only
    • |
    • PDF
    • |
    • 3.06 MB

Citation

Please use this url to cite or link to this publication:

MLA
Gillerot, Loïc, et al. “Urban Tree Canopies Drive Human Heat Stress Mitigation.” URBAN FORESTRY & URBAN GREENING, vol. 92, 2024, doi:10.1016/j.ufug.2023.128192.
APA
Gillerot, L., Landuyt, D., De Frenne, P., Muys, B., & Verheyen, K. (2024). Urban tree canopies drive human heat stress mitigation. URBAN FORESTRY & URBAN GREENING, 92. https://doi.org/10.1016/j.ufug.2023.128192
Chicago author-date
Gillerot, Loïc, Dries Landuyt, Pieter De Frenne, Bart Muys, and Kris Verheyen. 2024. “Urban Tree Canopies Drive Human Heat Stress Mitigation.” URBAN FORESTRY & URBAN GREENING 92. https://doi.org/10.1016/j.ufug.2023.128192.
Chicago author-date (all authors)
Gillerot, Loïc, Dries Landuyt, Pieter De Frenne, Bart Muys, and Kris Verheyen. 2024. “Urban Tree Canopies Drive Human Heat Stress Mitigation.” URBAN FORESTRY & URBAN GREENING 92. doi:10.1016/j.ufug.2023.128192.
Vancouver
1.
Gillerot L, Landuyt D, De Frenne P, Muys B, Verheyen K. Urban tree canopies drive human heat stress mitigation. URBAN FORESTRY & URBAN GREENING. 2024;92.
IEEE
[1]
L. Gillerot, D. Landuyt, P. De Frenne, B. Muys, and K. Verheyen, “Urban tree canopies drive human heat stress mitigation,” URBAN FORESTRY & URBAN GREENING, vol. 92, 2024.
@article{01HNA8FGEPX75WZ42KN2T9STK3,
  abstract     = {{Climate warming and urbanisation compound the public health risk posed by heat. Heat can be mitigated at local scales through urban greening, which provides shade and reduces surface and air temperatures. Yet, the relative effectiveness of different greening options on human thermal comfort based on physiology-based indices is understudied. We installed microclimate stations at 17 locations covering a gradient of tree canopy cover and perviousness in the city of Ghent, Belgium, and monitored the modified Physiologically Equivalent Temperature (mPET) during 195 days over Spring and Summer. We assessed the canopy cover, pervious surface fraction and building sky fraction based on field measures and hemispherical pictures. Unpaved locations with trees experienced a 2.4-fold reduction in the number of days with strong heat stress (mPET > 35 C-degrees) compared to paved, treeless locations. Based on mixed models and our selected environmental variables, cooling effects were predominantly driven by tree canopy cover, where locations with 100% canopy cover had temperature maxima 5.5 C-degrees mPET lower than treeless locations throughout the monitoring period. When air temperatures rose to 40 C-degrees, cooling by tree canopies increased to 8.8 C-degrees mPET. The pervious surface fraction and building view factor were less influential, generating variation of at most 1.7 C-degrees and 1.1 C-degrees mPET, respectively. In contrast, night-time temperatures were rather determined by the regional-scale urban heat island effect than by aforementioned local factors. Still, tree canopies slightly cooled the warmest nights only, whereas the vicinity of buildings led up to 1.2 C-degrees mPET warming on average. Expanding the urban tree cover may therefore be the best solution for improving local thermal comfort levels when daytime heat peaks, but will provide little relief at night.}},
  articleno    = {{128192}},
  author       = {{Gillerot, Loïc and Landuyt, Dries and De Frenne, Pieter and Muys, Bart and Verheyen, Kris}},
  issn         = {{1618-8667}},
  journal      = {{URBAN FORESTRY & URBAN GREENING}},
  keywords     = {{Soil Science,Ecology,Forestry,Dr.FOREST,Forest Microclimate,Heat Stress,Nature-Based Solution,Thermal Comfort,Urban Microclimate,SKY VIEW FACTOR,THERMAL COMFORT,CLIMATE-CHANGE,TEMPERATURE,ISLAND,CITY,MICROCLIMATES,ENVIRONMENT,DENSITY,WEATHER}},
  language     = {{eng}},
  pages        = {{10}},
  title        = {{Urban tree canopies drive human heat stress mitigation}},
  url          = {{http://doi.org/10.1016/j.ufug.2023.128192}},
  volume       = {{92}},
  year         = {{2024}},
}

Altmetric
View in Altmetric
Web of Science
Times cited: