Sedum-dominated green-roofs in a semi-arid region increase CO2 concentrations during the dry season

Har'el Agra, Tamir Klein, Amiel Vasl, Hadar Shalom, Gyongyver Kadas, Leon Blaustein

Research output: Contribution to journalArticlepeer-review


Green roofs are expected to absorb and store carbon in plants and soils and thereby reduce the high CO2 concentration levels in big cities. Sedum species, which are succulent perennials, are commonly used in extensive green roofs due to their shallow root system and ability to withstand long water deficiencies. Here we examined CO2 fixation and emission rates for Mediterranean Sedum sediforme on green-roof experimental plots. During late winter to early spring, we monitored CO2 concentrations inside transparent tents placed over 1 m2 plots and followed gas exchange at the leaf level using a portable gas-exchange system. We found high rates of CO2 emission at daytime, which is when CO2 concentration in the city is the highest. Both plot- and leaf-scale measurements showed that these CO2 emissions were not fully compensated by the nighttime uptake. We conclude that although carbon sequestration may only be a secondary benefit of green roofs, for improving this ecosystem service, other plant species than Sedum should also be considered for use in green roofs, especially in Mediterranean and other semi-arid climates.

Original languageEnglish
Pages (from-to)1147-1151
Number of pages5
JournalScience of the Total Environment
StatePublished - 15 Apr 2017

Bibliographical note

Publisher Copyright:
© 2017 Elsevier B.V.


  • CO domes
  • Carbon fixation
  • Carbon sequestration
  • Ecosystem services
  • Living roofs

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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