India, 1st November, 2025: As cities become denser and hotter, finding space for greenery has become increasingly difficult. To tackle this challenge, researchers from Chiba University have developed a data-driven framework that integrates artificial intelligence (AI) and spatial analysis to map and evaluate vertical greenery across Tokyo’s 23 wards.
By analyzing over 80,000 Google Street View images, the team identified uneven patterns of vertical vegetation such as green walls and balcony plants and proposed a new Vertical Greening Demand Index (VGDI) to guide future urban greening initiatives and climate-resilient city planning.
AI-Powered Urban Greening
In compact cities like Tokyo, where space for trees or parks is limited, vertical greening offers a creative way to reintroduce nature into urban environments. However, there has been no clear method to assess where such greenery is most needed or effective until now.
Led by Professor Katsunori Furuya, along with Ruochen Ma, Yunchen Xu, Yan Tang, Sihan Zhang, and Yuhui Liao from Chiba University’s Graduate School of Horticulture, the team used a YOLOv8 deep-learning model to detect vegetation on building façades. Their study—published in Sustainable Cities and Society (Volume 132, September 2025) provides Tokyo’s first citywide vertical greenery map.
“We wanted to show how vertical greenery is distributed across dense urban areas and where it aligns or fails to align with environmental needs,” explains Prof. Furuya. “By combining AI image analysis with spatial data, we can pinpoint where greening would make the greatest difference.”
The Vertical Greening Demand Index (VGDI)
The VGDI combines factors such as land use, building density, surface temperature, and pedestrian heat exposure to identify “priority greening zones.” These are areas where adding vertical vegetation could reduce surface temperatures and enhance thermal comfort for residents.
Findings revealed that while central commercial and residential zones had some greenery, heat-prone and lower-income neighborhoods were underserved—highlighting the need for equitable greening initiatives.
“Vertical greening isn’t just an architectural choice it’s an environmental necessity,” says Prof. Furuya. “Our framework helps city authorities target areas where greening can most improve cooling, biodiversity, and resilience.”
Global Implications
The implications extend beyond Tokyo. As cities worldwide face rising temperatures and shrinking open spaces, this AI-based framework can guide policymakers and urban planners to strategically integrate vertical greenery for maximum environmental benefit.
Indices like the VGDI could also inform building codes, urban renewal projects, and incentive programs to promote equitable greening. By visualizing where greenery is lacking, the framework enables transparent, fair, and sustainable urban planning.
Toward Greener, Cooler Cities
Looking ahead, the researchers aim to refine the model by including additional parameters such as air quality and energy efficiency, and to extend it to other megacities facing similar climate challenges.
“Expanding greenery within existing urban environments is one of today’s most urgent challenges,” concludes Prof. Furuya. “Combining AI and spatial analysis will be key to designing greener, cooler, and more livable cities in the decades ahead.”
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