Discomfort Over Tokyo’s Greenery Increase Amid Jingu Gaien and Hibiya Park Redevelopment

Tree Trimming Proceeding in Various Places in Tokyo Due to Major Developers’ Redevelopment

Due to redevelopment by major developers, “tree felling” is progressing rapidly in various parts of Tokyo such as Jingu Gaien, Hibiya Park, Kasai Rinkai Aquarium, Tamagawa Josui Green Road in Shibuya Ward, and street trees in Chiyoda Ward.

Whenever such tree felling becomes a topic of discussion, the following counterargument inevitably arises:

“But Tokyo’s greenery is increasing.”

One of these grounds is that Governor Yuriko Koike has been repeating the following explanation as part of “Tokyo Green Biz”:

“Looking ahead 100 years, promoting city development that lives with greenery,” “Realizing a city that harmonizes with nature,” “In recent years, through skillful land creation and harmonization with nature, greenery in the central parts of Tokyo where development is progressing has actually increased.” (’23, September 19, Tokyo Metropolitan Assembly 3rd Regular Session Policy Address)

Is this really true?

Pointing out the falsehood of “Tokyo’s greenery is increasing” is Eijiro Fujii, honorary professor at Chiba University and former president of the Japan Garden Association.

“When they say greenery in Tokyo is increasing, they’re often referring to publicly accessible open spaces left when tall buildings are constructed (typically, land where pedestrians can freely pass or use on a daily basis without being covered by buildings).

For developers, these open spaces are highly valuable because they allow for relaxed building density regulations. In reality, this indicates that tall buildings are increasing within Tokyo.” (Eijiro Fujii)

The basis for publicly accessible open spaces is the “Comprehensive Design System” under Article 59-2 of the Building Standards Act, which allows for exemptions in building volume and other height restrictions by providing open spaces within the site, recognized to “contribute to the improvement of urban environmental conditions.”

The additional floor area ratio (FAR) made possible by providing open spaces can be up to 1.5 times the standard and within a 200% increase. Furthermore, systems like the “Urban Housing Comprehensive Design System,” “Central City Residential Comprehensive Design System,” and “Site Size Comprehensive Design System” have been successively created, allowing combined techniques to permit up to a maximum of 2.0 times the standard FAR and within a 400% increase.

Additionally, the “Revised Condominium Reconstruction Law” enacted in December ’14 has also incorporated relaxation of FAR restrictions. In essence, these are all convenient systems that enable the construction of high-rise buildings and tower apartments in urban areas.

“Since there are no standards or evaluations for managing green spaces after construction, publicly accessible open spaces often end up being neglected. The more high-rise buildings you construct, the more advantageous it becomes—whether for selling them or for asset management purposes.”

Furthermore, one of the bases Tokyo Metropolitan Government cites for “greenery increasing” is the “Green Coverage Ratio” (“みどり率”). This ratio represents the proportion of green areas, including parks and water surfaces like ponds, relative to the total area of a region. On Tokyo Metropolitan Government’s website under “Current Status of Greenery in Tokyo,” they display data on “Green Coverage Ratio Trends” for Tama Area, Entire Tokyo, and Ward Areas for the years ’03, ’08, ’13, and ’18, noting recent years have shown a stable trend in green coverage ratio.

Additionally, regarding the “Green Coverage Rate” (“緑被率”), which measures the proportion of land covered by greenery such as vegetation over buildings and roads, data is provided for Chiyoda Ward (’10, ’18), Chuo Ward (’04, ’17), and Minato Ward (’16, ’21), indicating changes over different years—spanning eight, thirteen, and five years—raising questions about the methodology of comparing such disparate periods side by side. Nonetheless, it is noted that the “Green Coverage Rate” has increased in these three wards.

The global standard is “canopy cover ratio” rather than “green coverage ratio.”

However, explaining using these two criteria is unique to Japan, according to Professor Fujii.

“Green coverage ratio (みどり率) is not commonly used within academic circles. The term green coverage rate (緑被率) is more widely used, but it strictly measures the area covered by vegetation, whether it’s grass, squares, fields, promenades, or green roofs on buildings.

Moreover, considering the shift from a ground-based perspective, where rooftop greening has advanced, I believe this interpretation has expanded to facilitate the construction of high-rise buildings.”

On the other hand, from the perspective of impact on global warming and the urban heat island effect, what is currently globally emphasized is canopy cover ratio. Canopy cover ratio measures the proportion of land area covered by the branches and leaves of tall trees. It involves taking aerial photographs to calculate the percentage of land area covered by tree canopy.

“In English, this canopy cover ratio is referred to as ‘canopy cover.’ For example, in the United States, there’s a smartphone app called ‘i-Tree,’ provided by the USDA Forest Service, which allows users to look up the canopy cover rates of major U.S. cities.

In New York City, there’s a goal to increase canopy cover to 30% by ’35. In Melbourne, Australia, which had about 22% canopy cover until recently, they aim to reach 30% by ’30 and 40% by ’40.

Even in France, where temperatures exceed 40°C, efforts are being made to rapidly increase canopy cover to reduce heat accumulation. In Lyon, they’ve implemented a Tree Charter, reducing car lanes and increasing street trees.

Thus, Western countries are pushing forward with efforts to curb global warming at a rapid pace because they recognize the urgency of the situation.”

In Japan, trees are counted only by “number”!?

Globally prevalent canopy cover data, however, does not exist in Japan. Simply calculating the area covered by the canopy of tall trees within a certain land area is the approach, but in Japan, trees are counted only by number. Therefore, no matter how many mature trees are cut down, the excuse that trees are increasing can be made by planting numerous young trees.

“The criteria for canopy cover involving tall trees are ambiguous, but especially when considering the effectiveness in mitigating global warming, trees taller than about 10 meters are generally necessary in areas lined with high-rise buildings.

Unfortunately, Japan’s street trees are constrained in height and canopy spread. For instance, when a tree taller than 10 meters is cut down and replaced with smaller trees, they are counted as the same single tree. However, the canopy cover significantly differs between tall trees and small ones.

In terms of street trees, those around 4 to 5 meters tall typically have a canopy size of about 1 to 3 square meters. Newly planted trees have canopies of around 1 square meter. In contrast, a tree taller than 10 meters can have a canopy covering 10 to 20 square meters or more per tree. The canopy size of the same tree varies significantly over years, resulting in varying degrees of heat island mitigation.

Currently, trees being felled in places like Hibiya Park are over 100 years old. Tokyo, rapidly cutting down these centennial tall trees, is becoming an incredibly concerning city.”

By the way, while surfaces directly exposed to sunlight typically rise to nearly 60°C, shaded areas under tree canopies reach around 40°C, a significant 20°C cooler. The difference between sitting under tree shade on a scorching summer day compared to being on bare grass needs no further explanation.

Japan’s focus on green coverage rate or number of trees instead of “canopy cover ratio,” and the ongoing felling of currently growing trees under the assumption of creating public open spaces raises other concerns.

“Hibiya Park and Meiji Jingu Gaien are fundamentally places accessible to the general public at any time. However, in recent years, there has been a growing trend where private companies seek to profit through development under the guise of introducing private capital.

For example, places like Yamashita Park in Yokohama and Ueno Park have seen the introduction of private capital ventures like Starbucks, where parts of the parks are utilized as profit-generating spaces.

Following this trend, there are plans to connect Hibiya Park with Mitsui Fudosan’s ‘Tokyo Midtown Hibiya’ via decks, effectively integrating Hibiya Park into Mitsui Fudosan’s building complex as usable space.

Even more concerning is the situation at Meiji Jingu Gaien. What was once freely accessible space for everyone is now being enclosed by private entities like membership-based tennis clubs. This not only reduces green spaces but also privatizes public areas for the profit of a few private corporations, which is a significant issue.”

Insufficiently Discussed on Top-Down Approach to Reconstruction and Redevelopment.

When asked whether the privatization of public spaces by certain major corporations could occur overseas, Professor Fujii responds:

“I believe the fundamental issue in Japan lies in the lack of adequate consultation. In France, consultations are frequently repeated, and consensus on what the plan demands is reached before any concrete actions are taken.

However, in Japan, for instance, Hibiya Park is managed by the Tokyo Metropolitan Government. While officials should have a thorough understanding of the plans, there has been insufficient questioning and explanation with users and local residents from the planning stages onwards. These matters are not adequately discussed even in the Tokyo Metropolitan Assembly.

There is a norm where no consultations or explanations are provided, and citizens simply accept whatever decisions are made. The national parliament and metropolitan assembly, which should ideally oversee these processes, are also not functioning effectively enough to check these developments.”

Furthermore, the dysfunction of public officials who should act as stoppers is also a significant issue.

“Due to past issues of collusion among public officials, measures have been implemented to prevent such collusion, such as regular transfers every three years or so. 

As a result, a drawback is that specialists are not being nurtured. For example, concerning plans to heavily cut down trees in parks, technical staff in the park division may no longer be able to point out issues and advocate from a technical perspective. This leads to situations where decisions are made according to the wishes of governors, district mayors, and other leaders.

In other countries, even if large corporations attempt privatization, officials in charge within the public sector act as stoppers, and the public itself monitors such actions, preventing them from doing as they please.

Recently, I interviewed tree officials in France. Some have been in their positions for 20 years. In contrast, in Japan, most tree officials are amateurs, and similar issues are occurring in parks as well.”

For example, in civil engineering projects like roads, the reality is that construction companies often wield more influence than public officials. Due to the lack of expertise among public servants who are tasked with public projects, they often yield to corporate logic and prioritize profit.

“Due to the regular transfers of public officials and, during the time of Chief Cabinet Secretary Kan, meddling in the personnel affairs of national civil servants, we have lost seasoned bureaucrats. 

Additionally, universities have been corporatized and pressured to become profitable universities, which has hindered diligent research.

When the quality of graduates declines due to these factors, it affects not only universities but also the quality of education in elementary, middle, and high schools, thereby impacting society as a whole. This is a structural issue in Japan. Correcting this requires political action—it’s a true political reform.”

Professor Fujii is urging local governments and others to adopt the global standard “canopy cover rate,” but there has been no progress in Japan so far. However, he also mentions a faint hope.

“Recently, about ten Tokyo Metropolitan Assembly members from the Communist Party expressed interest in learning about street trees, so we toured the city together in a microbus. It seems they are considering setting goals for canopy cover rate.

Rather than standards like public open space, which are convenient for companies constructing high-rise buildings, or green cover rate seen in places like Hibiya Park, where trees are heavily cut down and replaced with all lawn areas, we should adopt the globally recognized canopy cover rate as a response to global warming and the heat island effect, following the world’s lead.”