Theoretical and Applied Climatology

, Volume 117, Issue 3–4, pp 363–376 | Cite as

Transmissivity of solar radiation through crowns of single urban trees—application for outdoor thermal comfort modelling

  • Janina KonarskaEmail author
  • Fredrik Lindberg
  • Annika Larsson
  • Sofia Thorsson
  • Björn Holmer
Original Paper


Trees play an important role in mitigating heat stress on hot summer days, mainly due to their ability to provide shade. However, an important issue is also the reduction of solar radiation caused by trees in winter, in particular at high latitudes. In this study, we examine the transmissivity of total and direct solar radiation through crowns of single street trees in Göteborg, Sweden. One coniferous and four deciduous trees of species common in northern European cities were selected for case study. Radiation measurements were conducted on nine clear days in 2011–2012 in foliated and leafless tree conditions using two sunshine pyranometers—one located in shade of a tree and the other one on the roof of an adjacent building. The measurements showed a significant reduction of total and direct shortwave radiation in the shade of the studied trees, both foliated and leafless. Average transmissivity of direct solar radiation through the foliated and defoliated tree crowns ranged from 1.3 to 5.3 % and from 40.2 to 51.9 %, respectively. The results confirm the potential of a single urban tree to reduce heat stress in urban environment. However, the relatively low transmissivity through defoliated trees should be considered while planning street trees in high latitude cities, where the solar access in winter is limited. The results were used for parameterisation of SOLWEIG model for a better estimation of the mean radiant temperature (Tmrt). Measured values of transmissivity of solar radiation through both foliated and leafless trees were found to improve the model performance.


Thermal Comfort Shortwave Radiation Direct Component Direct Solar Radiation Urban Tree 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The project is being funded by the Swedish Research Council Formas, the Swedish Energy Agency, the Swedish Environmental Protection Agency, the Swedish National Heritage Board and the Swedish Transport Administration.


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Copyright information

© Springer-Verlag Wien 2013

Authors and Affiliations

  • Janina Konarska
    • 1
    Email author
  • Fredrik Lindberg
    • 1
  • Annika Larsson
    • 2
  • Sofia Thorsson
    • 1
  • Björn Holmer
    • 1
  1. 1.Department of Earth SciencesUniversity of GothenburgGothenburgSweden
  2. 2.Faculty of Landscape Planning, Horticulture and Agricultural ScienceSwedish University of Agricultural ScienceAlnarpSweden

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