Shade for the City | Tomohiro Ichinose, Dean of the Faculty of Environment and Information Studies

Before I knew it, it was already July, and the spring semester is drawing to a close. This year, we’ve been hit by two typhoons as early as June, earlier than usual, but aside from that, it feels like we’re finally experiencing a rainy season that actually feels like a rainy season for the first time in a while. Since the end of the rainy season has been coming earlier each year, I was dreading the possibility that the intense heat would start as early as June, but fortunately, the rainy season hasn’t ended yet in Kanagawa Prefecture. That said, the arrival of midsummer is surely just around the corner. When I was a child, I used to look forward to summer with excitement, but considering how hot it’s been in recent years, it just makes me feel gloomy.

Across Europe, heat waves struck from late June through the end of the month, reportedly claiming numerous lives. In countries such as France, the United Kingdom, and Germany, where air conditioning isn’t widely used, temperatures exceeding 40 degrees would be a strain even for healthy adults. Paris is moving ahead with a plan to significantly increase greenery across the city by 2030, and one of the goals of this initiative is to combat summer heat. Trees not only provide shade but also help cool the air through plant transpiration. In some areas, this cooling effect is said to be as much as 4 degrees.

On May 24, the Nikkei Shimbun published an article titled “Japan’s ‘Green Parasols’ Disappearing: 500,000 Street Trees Lost—Going Against Global Urban Development Trends.” In Tokyo’s 23 wards, the tree canopy cover—the proportion of the ground covered by tree branches and leaves—decreased from 9.2% to 7.3% between 2013 and 2022, resulting in the loss of 12 square kilometers of tree shade. Cities abroad, by contrast, are increasing their canopy cover: Paris stood at 17.6% in 2025, Sydney at 19.8% as of 2022, and New York—famous for its skyscrapers—at 23.4% as of 2021.

This is not limited to Tokyo’s 23 wards—street trees and park trees have been felled across Japan in recent years. This is largely due to the frequent occurrence of accidents caused by falling trees. Recently, at Kinuta Park in Setagaya Ward, there were four incidents of falling trees between early March and April, resulting in injuries and vehicle damage, which received considerable media coverage. In Japanese cities, street trees and other greenery have been actively planted since the era of rapid economic growth, and these trees are now reaching maturity all at once. Since maintaining large trees involves significant costs, species that do not grow to enormous sizes—such as dogwood—are often chosen when trees are replaced. On private property, too, trees are cut down, and the land is sold off at the time of inheritance. As a result, Japan appears to be moving in the opposite direction from global trends.

Last year, I began a collaborative research project to explore the future of street trees in Japanese cities. Of course, the national government and local municipalities are not sitting idly by; they are considering various measures. At least here at SFC, with its abundance of greenery, it feels much cooler than in the city center. I hope to keep exploring how we might bring more green shade to Japan’s cities as well.