---
OA_place: publisher
OA_type: hybrid
_id: '22472'
abstract:
- lang: eng
  text: "Increasing urban tree cover is an often proposed mitigation strategy against
    urban heat as trees are expected to cool cities through evapotranspiration and
    shade provision. However, trees also modify wind flow and urban aerodynamic roughness,
    which can potentially limit heat dissipation. Existing studies show a varying
    cooling potential of urban trees in different climates and times of the day. These
    differences are so far not systematically explained as partitioning the individual
    tree effects is challenging and impossible through observations alone. Here, we
    conduct numerical experiments removing and adding radiation, evapotranspiration,
    and aerodynamic roughness effects caused by urban trees using a mechanistic urban
    ecohydrological model. Simulations are presented for four cities in different
    climates (Phoenix, Singapore, Melbourne, Zurich) considering the seasonal and
    diurnal cycles of air and surface temperatures.\r\nResults show that evapotranspiration
    of well-watered trees alone can decrease local 2 m air temperature at maximum
    by 3.1– 5.8 °C in the four climates during summer. Further cooling is prevented
    by stomatal closure at peak temperatures as high vapour pressure deficits limit
    transpiration. While shading reduces surface temperatures, the interaction of
    a non-transpiring tree with radiation can increase 2 m air temperature by up to
    1.6 – 2.1 °C in certain hours of the day at local scale, thus partially counteracting
    the evapotranspirative cooling effect. Furthermore, in the analysed scenarios,
    which do not account for tree wind blockage effects, trees lead to a decrease
    in urban roughness, which inhibits turbulent energy exchange and increases air
    temperature during daytime. At night, single tree effects are variable likely
    due to differences in atmospheric stability within the urban canyon. These results
    explain reported diurnal, seasonal and climatic differences in the cooling effects
    of urban trees, and can guide future field campaigns, planning strategies, and
    species selection aimed at improving local microclimate using urban greenery."
article_number: '126970'
article_processing_charge: Yes (in subscription journal)
article_type: original
author:
- first_name: Naika
  full_name: Meili, Naika
  last_name: Meili
- first_name: Gabriele
  full_name: Manoli, Gabriele
  last_name: Manoli
- first_name: Paolo
  full_name: Burlando, Paolo
  last_name: Burlando
- first_name: Jan
  full_name: Carmeliet, Jan
  last_name: Carmeliet
- first_name: Winston T.L.
  full_name: Chow, Winston T.L.
  last_name: Chow
- first_name: Andrew M.
  full_name: Coutts, Andrew M.
  last_name: Coutts
- first_name: Matthias
  full_name: Roth, Matthias
  last_name: Roth
- first_name: Erik
  full_name: Velasco, Erik
  last_name: Velasco
- first_name: Enrique R.
  full_name: Vivoni, Enrique R.
  last_name: Vivoni
- first_name: Simone
  full_name: Fatichi, Simone
  id: cf8e546b-a9b0-11f0-a43b-aa89ed1b56d6
  last_name: Fatichi
citation:
  ama: 'Meili N, Manoli G, Burlando P, et al. Tree effects on urban microclimate:
    Diurnal, seasonal, and climatic temperature differences explained by separating
    radiation, evapotranspiration, and roughness effects. <i>Urban Forestry &#38;
    Urban Greening</i>. 2021;58(3). doi:<a href="https://doi.org/10.1016/j.ufug.2020.126970">10.1016/j.ufug.2020.126970</a>'
  apa: 'Meili, N., Manoli, G., Burlando, P., Carmeliet, J., Chow, W. T. L., Coutts,
    A. M., … Fatichi, S. (2021). Tree effects on urban microclimate: Diurnal, seasonal,
    and climatic temperature differences explained by separating radiation, evapotranspiration,
    and roughness effects. <i>Urban Forestry &#38; Urban Greening</i>. Elsevier. <a
    href="https://doi.org/10.1016/j.ufug.2020.126970">https://doi.org/10.1016/j.ufug.2020.126970</a>'
  chicago: 'Meili, Naika, Gabriele Manoli, Paolo Burlando, Jan Carmeliet, Winston
    T.L. Chow, Andrew M. Coutts, Matthias Roth, Erik Velasco, Enrique R. Vivoni, and
    Simone Fatichi. “Tree Effects on Urban Microclimate: Diurnal, Seasonal, and Climatic
    Temperature Differences Explained by Separating Radiation, Evapotranspiration,
    and Roughness Effects.” <i>Urban Forestry &#38; Urban Greening</i>. Elsevier,
    2021. <a href="https://doi.org/10.1016/j.ufug.2020.126970">https://doi.org/10.1016/j.ufug.2020.126970</a>.'
  ieee: 'N. Meili <i>et al.</i>, “Tree effects on urban microclimate: Diurnal, seasonal,
    and climatic temperature differences explained by separating radiation, evapotranspiration,
    and roughness effects,” <i>Urban Forestry &#38; Urban Greening</i>, vol. 58, no.
    3. Elsevier, 2021.'
  ista: 'Meili N, Manoli G, Burlando P, Carmeliet J, Chow WTL, Coutts AM, Roth M,
    Velasco E, Vivoni ER, Fatichi S. 2021. Tree effects on urban microclimate: Diurnal,
    seasonal, and climatic temperature differences explained by separating radiation,
    evapotranspiration, and roughness effects. Urban Forestry &#38; Urban Greening.
    58(3), 126970.'
  mla: 'Meili, Naika, et al. “Tree Effects on Urban Microclimate: Diurnal, Seasonal,
    and Climatic Temperature Differences Explained by Separating Radiation, Evapotranspiration,
    and Roughness Effects.” <i>Urban Forestry &#38; Urban Greening</i>, vol. 58, no.
    3, 126970, Elsevier, 2021, doi:<a href="https://doi.org/10.1016/j.ufug.2020.126970">10.1016/j.ufug.2020.126970</a>.'
  short: N. Meili, G. Manoli, P. Burlando, J. Carmeliet, W.T.L. Chow, A.M. Coutts,
    M. Roth, E. Velasco, E.R. Vivoni, S. Fatichi, Urban Forestry &#38; Urban Greening
    58 (2021).
das_tickbox: '1'
date_created: 2026-07-27T12:30:23Z
date_published: 2021-03-01T00:00:00Z
date_updated: 2026-07-30T08:40:12Z
day: '01'
ddc:
- '550'
doi: 10.1016/j.ufug.2020.126970
extern: '1'
has_accepted_license: '1'
intvolume: '        58'
issue: '3'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1016/j.ufug.2020.126970
month: '03'
oa: 1
oa_version: Published Version
publication: Urban Forestry & Urban Greening
publication_identifier:
  eissn:
  - 1610-8167
  issn:
  - 1618-8667
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Tree effects on urban microclimate: Diurnal, seasonal, and climatic temperature
  differences explained by separating radiation, evapotranspiration, and roughness
  effects'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 58
year: '2021'
...