18-05-2025
Cork's 'robot trees' removed after years of criticism and high costs
Cork City's much-criticised 'robot trees' have been removed, bringing an end to a four-year saga of controversy, mounting maintenance costs, and persistent questions over their effectiveness.
The CityTrees, moss-filled, high-tech air purifiers installed in 2021 – were taken down early this morning from their locations outside Dubray Books on Patrick Street and the City Library on Grand Parade. While the devices are gone, their hexagonal wooden bases remain, continuing to serve as public benches, which many locals have long joked was their most useful function.
Billed as sustainable 'moss walls' designed to filter fine dust from the air, the five CityTrees were installed by Cork City Council at a cost of €355,000, funded through a €55 million National Transport Authority scheme aimed at promoting cleaner air and greener transport. The German-designed units were said to clean the equivalent of air breathed by up to 7,000 people per hour. Cork City's much-criticised 'robot trees' have been removed, bringing an end to a four-year saga of controversy, mounting maintenance costs, and persistent questions over their effectiveness. Pic: Cork City Council
However, from the outset, the structures were dogged by controversy.
In 2023, a University College Cork (UCC) report, commissioned at a cost of €2,500, failed to find conclusive evidence that the devices meaningfully improved air quality, in part due to readings being taken on low-pollution days.
Atmospheric scientist Dr. Dean Venables of UCC had previously warned that while the CityTrees might have a limited localised effect, they were unlikely to have any real impact on citywide air quality. Pic: Cork City Council
Labour councillor Peter Horgan went further, calling the devices 'the most expensive benches ever purchased by a local authority' and slamming the lack of transparency around their purchase. 'We'd have been far better off planting real trees,' he said, describing the moss machines as 'monstrosities with LED screens.'
The annual upkeep of the units added fuel to the fire, costing the council over €17,000 each year. Frustration grew among elected members, who said they were kept in the dark about the decision to purchase the devices, with some resorting to Freedom of Information requests to uncover cost and maintenance details.
For now, what's left behind in Cork is not cleaner air, but five pricey wooden platforms, reminders of an ambitious project that never quite took root.
