Helsinki identifies five new street tree species from ongoing trial in Vartiokylä

Helsinki has identified five new potential street tree species through an ongoing tree trial initiated in 2012. In Vartiokylä, city arborists planted 44 saplings representing 13 new tree species to monitor their growth and adaptability under climate change conditions and to assess how species that thrive in other Northern European cities might fare in Helsinki’s climate.

Juha Raisio, a tree expert in Helsinki, noted that if someone had suggested planting these species 25 years ago, they might have been dismissed as overly ambitious. The trial results are now visible along Vartioharjuntie in East Helsinki.

Among the 12-year-old trial subjects, five species are thriving: the sweet cherry (Prunus avium), the bald cypress (Taxodium distichum), the silver hawthorn (Crataegus prunifolia), the European hornbeam (Carpinus betulus), and the blunt hawthorn (Crataegus viridis). According to Raisio, these trees are expected to be more commonly planted along the city streets and in parks over the next decade. Although they may not dominate as principal species, their use as street trees is likely to grow if they adapt well to the changing climate.

Other species tested are still under evaluation to determine their suitability for Helsinki’s conditions. Each species has unique characteristics that could shape the urban landscape, such as the sweet cherry, which produces small, sweet fruit and is valued among woodworkers.

Raisio emphasizes the importance of experimenting with these new species across Finland, urging local leaders to take bold steps in tree experimentation to ensure a resilient urban canopy for the future.