Research in Context
Greenhouse experiments
At some projects, monitoring in the field is complemented with tests in the greenhouses/glasshouses at the University campuses or Research Center premises.Such facilities and infrastructure when available allows for the modification of conditions to simulate extreme hot summer conditions. At the same time, the comparison of a broad array of species and measurement of their reactions becomes feasible. In Australia and the project "Which Plant Where", young potted plants (4 months old) are submitted to heatwave or drought conditions. Damage to tissues is assessed visually and with instruments. Analysis leads to the ranking of species regarding their thermal tolerance. (Tabassum et al., 2023).
Image credit: Wix Studio Database
In the Netherlands a series of advanced equipment are employed, such as camera systems, measuring tables and sensors in order to physiological responses. At the greenhouse facility of the Netherlands Plant Eco-phenotyping Centre (NPEC) plant properties are recorded accurately and analyzed quickly to provide essential data related to drought like water use efficiency and critical wilting point. A partnership has been developed with the Hebrew University of Jerusalem which specializes in the use of latest technology for measuring plant characteristics and crop drought tolerance. (Wageningen University 2023, De Groene Stad 2023, Groen Kennisnet 2023).
Image source: Wix Studio Database
In Switzerland a partnership of many universities has led to a project with a more targeted scope. A number of forest tree species, considered do be adapted to future climate conditions, have been chosen for further studies. Young seedlings are grown in plastic greenhouses. In the context of natural forest regeneration the effect of young trees' growth on soil and its functions will also be monitored. The species that have been chosen for the greenhouses in three different locations are :
Indigenous group Fagus sylvatica, Quercus petraea, Abies alba
Exotics group Pseudotsuga menziesii, Cedrus atlantica, Quercus cerris (WSL 2021)
Image source: Fuchs, Michael Derrer. 2023.Construction of greenhouse at farm at City of Zürich on a sunny late summer afternoon. [Online image] Shutterstock https://www.shutterstock.com/image-photo/construction-greenhouse-farm-city-on-sunny-2362785737
In Japan, a series of studies focus on the effects of increased temperatures to leaves and photosynthesis. The selection of urban tree species for the future is based on their ability to tolerate or acclimate to warmer growing conditions. Young saplings of selected tree species are planted inside the greenhouse and are subjected to warming, passive or not. (Hara, Inoue, Ishii et al. 2021, Okubo, Inoue & Ishii 2023)
Their results show that warm-temperate evergreen species are not necessarily more tolerant than cool-temperate deciduous species. (Okubo, Inoue & Ishii 2023).
NOTES Some the species included in the studies are present in Athens, rarely or not. 1) Gingko biloba. In a few sites in parks and gardens in the city. 2) Cinnamomum camphora syn. Camphora officinarum, images and occurrences on page "Indian subcontinent to SE Asia". 3) Euonymus japonicus. It is quite common as a shrub in the urban spaces and occasionally can be found as a small tree. 4) Ligustrum japonicum. It is quite often used as a small street tree in Athens and other boroughs.
Image source: mirmam 2025. Front yard of Kobe University Campus, look over the downtown of Kobe city and the sea [Online image] Shutterstock. https://www.shutterstock.com/image-photo/front-yard-kobe-university-campus-look-2588529819
View of Kobe city taken form the University Campus. Professor Roaki Ishii (Kobe University) and Sumihiro Inoue (Tsukuba Research Institute) participated in studies on the selection of urban tree species based on experiments in a greenhouse in Tsukuba.
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REFERENCES
​PAPERS
Hara, C., Inoue, S., Ishii, H.R. et al. 2021
Tolerance and acclimation of photosynthesis of nine urban tree species to warmer growing conditions.
Trees 35, 1793–1806 (2021).
https://doi.org/10.1007/s00468-021-02119-6
Okubo, N.; Inoue, S.; Ishii, H.R. 2023
Tolerance and Acclimation of the Leaves of Nine Urban Tree Species to High Temperatures.
Forests 2023, 14, 1639.
https://doi.org/10.3390/f14081639
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Tabassum, S., Beaumont, L. J., Shabani, F., Staas, L., Griffiths, G., Ossola, A., & Leishman, M. R. 2023.
Which Plant Where: A Plant Selection Tool for Changing Urban Climates.
Arboriculture and Urban Forestry, 49(4), 190–210.
https://doi.org/10.48044/jauf.2023.014
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UNIVERSITY RESEARCH WEBSITE ARTICLES
Wageningen University and Research Website. Kennis online Magazine. 2023.
The quest for climate-resilient urban trees.
https://subsites.wur.nl/en/article/the-quest-for-climate-resilient-urban-trees.htm
https://www.wur.nl/en/show-longread/the-quest-for-climate-resilient-urban-trees.htm
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Swiss Federal Institute for Forest, Snow and Landscape Research WSL (Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft). 2021.
Arbres sous serre.
https://www.wsl.ch/fr/projets/arbres-sous-serre/​
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NEWSMEDIA ARTICLES
De Groene Stad. 2023.
Klimaatbomen met toekomst
https://degroenestad.nl/onderzoek/klimaatbomen-met-toekomst/
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WEBINARS AND SEMINARS
Groen Kennisnet. (2023, April 24). Baten van groen in de stedelijke omgeving. https://www.youtube.com/watch?v=8WVg_7K7aV4
https://www.youtube.com/watch?v=8WVg_7K7aV4&t=1303s
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Swiss Federal Institute for Forest, Snow and Landscape Research WSL (Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft).
WSL Workshops & Seminars. (2022, May 17).
Arbres sous serre: Effets des essences d'avenir sur les fonctions forestières et pédologiques