September 9, 2024
Further Measures to Preserve Trees and New Measures to Create Greeneryin the Jingu Gaien District Urban Redevelopment Project(Supplementary Materials)
This document provides supplementary materials to the following release dated on the same day.
Further Measures to Preserve Trees and New Measures to Create Greenery in the Jingu Gaien District Urban Redevelopment Project
URL：https://www.jingugaienmachidukuri.jp/pdf/en-jingugaienmachidukuri_news_2024090901.pdf

1. Increase in the number of trees after redevelopment(1) Reduction in the number of trees to be removed due to facility design adaptions, etc(i) New rugby facility site
The number of trees to be removed in the new rugby facility site will decrease by 27 (including 6 dead or ailingtrees*1).
a. Facility design adaptions
By setting back part of the northern section of the new rugby facility, 9 trees for removal at the Kenkoku Kinen Bunko
site will be preserved (Figure 1).
b. Revisions etc. based on the 2023 tree research
Based on the results of the 2023 tree research, 12 trees for removal will be transplanted, including trees judged to be
recovering as the project progresses and trees judged to be viable for transplant due to sufficient preparation.
*1 “Dead or ailing trees” refers to withered or decaying trees that need to be removed for safety management reasons.

To improve the growing environment for trees around the new rugby facility, the height of the building will be
reduced from approximately 55.0 meters in the original plan to around 48.0 meters.

Figure 1 New rugby facility site - Location of reclassified trees and facility design changes<Key>

Preserved trees
Transplanted
trees
Newly planted
trees

Trees reclassified from removal topreservation

Original plan

Location of the above trees in the originalplan

Entire rugby facility site

Revised plan

Removed → Preserved：11* The number of trees to be removed is 9, as
2o trees originally planned for preservation
will be removed due to changes to thefacility design.

*2 Existing trees shown in the figure for the original plan are based on data from the 2019 tree research, while existing trees shown in the figure for therevised plan are based on data from the 2023 tree research; tree canopy (shown by size of circle) may differ between the figures due to tree growth,etc.
*3 Preserved trees shown in the figure for the revised plan include trees that have been reclassified from transplant to preservation due to the facility
design adaptions.
*4 Only trees 3.0 meters or taller are shown.
*5 Specific details on the location of transplanted and newly planted trees are yet to be determined and may be subject to change.

(ii) Project plan for the area in front of the Meiji Memorial Picture Gallery (hereinafter, “the area in front of the picture
gallery”)
The number of trees to be removed from the area in front of the picture gallery will decrease by 79 (including 18 deador ailing trees).
a. Facility design adaptions, etc.
Due to changes to the layout and a reduction in the scale of buildings and other structures, 55 trees for removalfrom the road around the gallery will be preserved (Figure 2).。
b. Design changes to the Maruike area
Due to design changes to the Maruike area, 2 trees for removal will be preserved (Figure 2).
c. Revisions based on the 2023 tree research
Based on the results of the 2023 tree research, 4 trees for removal will be transplanted, as they are judged to be
recovering.

Figure 2 Area in front of the picture gallery - Location of reclassified trees and facility design changes<Key>
Preserved trees

Transplanted
trees
Newly
planted trees

Trees reclassified from removal topreservation
Location of the above trees in the originalplan

Original plan

Entire area in front of the picture gallery

Revised plan

Removed → Preserved：58* The number of trees to be removed is 57, as 1 tree originallyplanned for preservation will be removed due to changes to thefacility design.

Large ginkgo tree

*6 Existing trees shown in the figure for the original plan are based on data from the 2019 tree research, while existing trees shown in the figure for therevised plan are based on data from the 2023 tree research; tree canopy (shown by size of circle) may differ between the figures due to tree growth,etc.
*7 Preserved trees shown in the figure for the revised plan include trees that have been reclassified from transplant to preservation due to the facility
design adaptions.
*8 Only trees 3.0 meters or taller are shown.
*9 Specific details on the location of transplanted and newly planted trees are yet to be determined and may be subject to change.。

(iii) Reasons for tree removal
Under the project, each and every tree will be handled with care, and the layout and distribution of buildings will beconsidered to preserve as many trees as possible. Trees that are judged to be difficult to preserve in their current state
will be transplanted.
However, trees that are not deemed to be viable for transplantation and trees that are not expected to be able to maintainhealthy tree growth and shape after replantation because of unavoidable reasons such as “designation as a priority control
invasive alien species*10,” “proximity to existing facilities preventing necessary preparation for transplantation,” or“weak tree vitality,” will be removed and reutilized, including within the Gaien land where possible.

*10 Priority control invasive alien species: Species such as the Glossy Privet (ligustrum lucidum), which is designated as a “priority control invasive alien
species” in the “List of Invasive Alien Species That May Cause Damage to the Ecosystem in Japan (List of Invasive Alien Species for the Preventionof Ecosystem Damage)” prepared by the Ministry of the Environment and the Ministry of Agriculture, Forestry and Fisheries in 2015.

Of the 619 trees to be removed, 474 trees will be removed from the Scenic District for the following reasons.
Table 1: Reasons for removal of trees in the Scenic District
Reasons
for removal
伐採理由

No.本数
of trees(i)
Priority control invasive alien species①重点対策外来種

28(ii) Close proximity to existing facilities②既存施設に近接している樹木

270

(iii)
Weak tree vitality③樹勢が弱っている樹木

164(iv) Soil contamination
④土壌汚染

2

(v) Other*11⑤その他（※）

10

Total
合計

474

*11 The 2023 tree research determined that these trees can be transplanted due to a recovery in vitality or the progress of the project, butthey are outside the scope of the redesigned new rugby facility site and the area in front of the picture gallery, so they remainclassified as trees to be removed, in line with the original plan based on the 2019 tree research. As the facility designs progress, theclassification of these trees will be updated to reflect the latest research results.

Figure 3: Examples of trees not deemed to be transplantable
Examples of trees in close proximity to existing facilities (to be
removed as preparation for transplantation cannot be carried out)

Example of a tree with weak vitality

Roots dig into therestroom step

Close to restrooms, making
it difficult to secure asufficient root ball

Decay on major branch(large)Open cavity (large)
Roots pushing up curb
Decay on trunk (large)
Abnormal tree sounding

Baseball field first base side, Y02-172 trident maple

Baseball field first base side, Y02-086 Japanese stone oak

Examples of trees in close proximity to existing facilities(to be removed as preparation for transplantation cannot be carried out)

Row of trees next to the indoor tennis court

Row of trees next to the indoor ballgame facility

(2) Increase in the number of newly planted trees(i) New rugby facility
Regarding the greening plan for the new rugby facility site, (1) new trees to be planted on the east side of the site will
be planted in counterpoint to the existing trees in the plaza in front of the picture gallery, giving further consideration tocontinuity along the green walkway that runs north-south through the Jingu Gaien District. (2) In addition, under theplan for the south side of the site, a new, more lively open space for resting and walking with a large volume of mediumheight shrubbery and a light thicket of trees will be created, improving integration with the Jingu Gaien District Central
Plaza and new woodland areas.
As a result, the number of new trees to be planted will increase from 81 under the original plan to 212, an increase of
131 trees, resulting in a green environment with more trees than on the current site.
(ii) Area in front of the picture gallery
Regarding the greening plan for the area in front of the picture gallery, the distribution of new trees has been revised
based on an approach of naturally distributing trees of various species and heights, referencing how the plaza looked
when it was built. As a result, the number of newly planted trees will increase from 398 under the original plan to 528,
an increase of 130 trees.
As a result of the above, changes in the number of trees from the original plan are as follows.
(The increase of 400 trees is the total of: a reduction in the number of trees to be removed (124); an increase in the number of trees to beplanted (261); an increase in new trees to be planted under the original plan (94); minus dead or ailing trees (79))

Figure 4: Comparison of number of trees between original plan and revised plan

Original plan
Before development: 1,904
Preserved trees
886

Transplanted
trees

Removed trees
743

Transplanted
trees

Newly planted trees
837

275

After redevelopment: 1,998
Preserved trees
886

275

＋94 compared
to before
development

Revised plan
Preserved

886
Dead or ailing trees -32
Transplanted → Preserved +44
Removed → Preserved +66

Preserved 964
Preserved +78
Transplanted 275

Dead or ailing trees -5
Transplanted → Preserved -44
Removed → Transplanted +16
Transplanted 242

Transplanted -33
Removed743

Dead or ailing trees -42
Removed → Preserved -66
Removed → Transplanted -16

Removed 619
Removed -124
Newly planted

837

Newly planted

1,098

Newly planted +261

+400 compared tobefore development

After redevelopment: 2,304
Preserved trees
964

Transplanted
trees

242

Newly planted trees
1,098*12 The number of trees described in this release and the Supplementary Materials only covers trees 3.0 meters or taller.
*13 Transplanted trees include 19 trees under consideration for transplantation.

2. Wider setback for the new baseball stadium(1) Results of root system research
The objective of the root system research is to confirm the positioning of the roots and their growth condition(circumference, number of roots, etc.) with respect to the westernmost row of the Four Rows of Ginkgo Trees uponassessing effects that construction of the new baseball stadium situated adjacent to the trees would have. The first rootsystem research surveyed the circumference and the number of roots. The second root system research then added tothis by confirming the length of some of the roots.
The environmental impact assessment report has set the distance from the sidewalk curb on the west side of the rows of
ginkgo trees to the underground framework of the new baseball stadium (hereinafter, “the setback width”) as 8.0 meters.
It also sets following criteria for determining how to deal with roots: “If root system research results in fewer than fourlarge roots (diameter of at least 30 millimeters) in the surveyed section (1.0 meter x 1.0 meter), the roots may be cut,
and if the research finds four or more roots, girdling shall be carried out on the roots. In cases where a tree doctor has
judged that there are multiple roots that have an influence on the growth of a tree, then efforts will be made to preserve
said tree, including adjustments to facility design, based on the opinion of the tree doctor.” (Figure 5)
Figure 5: Survey cross section criteria in root system research

1.0 m

10 cm
1.0 m

10 cm

■ Root distribution checked within each 10 centimeter mesh square of the survey cross section (1.0 meter x
1.0 meter)■ The criteria for making judgements in the environmental impact assessment report are as follows.
・Fewer than four roots with a diameter of at least 30 millimeters: Roots will be sharply cut off
・Four or more roots with a diameter of at least 30 millimeters: Roots will be girdled
・If a tree doctor judges that there are multiple roots that have an influence on the healthy growth of the tree:
Efforts will be made to preserve said tree, including adjustments to facility design, based on the opinion of
the tree doctor.

For an overview of the research, including methodology and locations studied, please refer to the following release.
“The Root System Research at the Four Rows of Ginkgo Trees,” January 11, 2023 (in Japanese)
URL：https://www.jingugaienmachidukuri.jp/pdf/jingugaienmachidukuri_news_20230111.pdf“The Second Root System Research at the Four Rows of Ginkgo Trees,” January 9, 2024
URL：https://www.jingugaienmachidukuri.jp/pdf/en-jingugaienmachidukuri_news_2024010901.pdf(2) Results of root system research
Results of the first and second root system research are as follows (See Table 2 and Figure 6)
Table 2: Results of root system researchFirst root第1回根系調査
system research
2023年1月
January2023

実施時期
PeriodLocation
調査位置

Second 第2回根系調査
root system research
2024年1月
January2024

Approx. 6.5いちょう並木（歩道縁石）から約6.5m
meters from the row of ginkgo trees (sidewalk curb)

Numberof sites
調査箇所数

10箇所
10
・一部の根が障害物により調査できなかったため、2回目の- Some of the roots could not be surveyed due to obstructions,

・1つの調査断面に直径30㎜以上の根は4本未満しか確認され- All survey sections were confirmed to have fewer than four rootswitha diameter of at least 30 millimeters and based on the criteria
ず、環境影響評価書記載の判断基準に基づけば、約10.5m地
for making judgements in the environmental impact assessment
点で根を切断可能と判断できることがわかった。
report,it can be judged as acceptable to cut the roots at a distance of
10.5
meters.
・なお、全12箇所の調査地点で確認された概ね直径30㎜以上の- Also, at all 12 locations where roots with a diameter of at least
根5本はたぐり掘りによる伸長範囲の確認を実施した。5本のapproximately
30 millimeters were confirmed, the progress of the
内、2本は約17m未満で根の伸長が止まっており、2本は根がroots
was checked through lateral digging. Out of five roots, two
ended
within about 17.0 meters, two were assumed not to progress
西側には伸長していないと想定され、1本は約22m地点まで
in a westerly direction, and one extended for about 22.0 meters, but
it伸長していたものの約17m地点で直径30㎜未満となることが
was confirmed that these roots did not have a circumference of atleast
30 millimeters at the 17.0-meter point.
確認された。

調査を実施することとした。
so
it was decided that a second survey will be conducted.
- Also, there were no areas where more than four roots with a・なお、調査を実施できた範囲内では、1つの調査断面に直径
diameterof at least 30 millimeters were identified in a single
30㎜以上の根は4本未満しか確認されなかった。
survey section.

Results
結果

いちょう並木（歩道縁石）から約10.5m
Approx. 10.5
meters from the row of ginkgo trees (sidewalk curb)
12
12箇所

Figure 6: Locations where roots with a diameter of at least approximately 30 millimeters were confirmed in the second root system
research
Locations where roots with a diameter of at least approximately
30 millimeters were confirmed and lateral digging was conducted

1 root2 roots
Location 1

1 rootLocation 2

Location 3

Location 5
Location 4

West
Location 7
Location 6

1 rootLocation 10
Location 8 Location 9

Location 11
Location 12

North

South
East
Based on the results of the above research, we have formulated the following additional preservation measures tocreate a better growing environment for the roots while also minimizing any negative impact.
(3) Extended setback width for the new baseball stadium and additional root preservation measures

The results of the second root system research judged that there were no areas where more than four large roots with adiameter of at least approximately 30 millimeters were identified in a single survey section and that it was acceptableto cut the roots at a distance of around 10.5 meters. However, a total of five large roots with diameters exceedingapproximately 30 millimeters were identified at four* of the 12 survey sites. The five roots were identified to their tips
using lateral digging*14. This confirmed that two had stopped growing at a distance of less than approximately 17.0
meters, two were assumed to not be growing to the west, and one had grown to approximately 22.0 meters but was lessthan 30 millimeters in diameter at approximately 17.0 meters. Under the criteria for making judgements in theenvironmental impact assessment report, it would be acceptable to cut these roots at a distance of around 10.5 meters.
However, after conducting lateral digging and obtaining the opinions of tree doctors and other experts, we decided to
set the root system protection area at approximately 17.0 meters from the sidewalk curb. Also, to secure an additional
1.3 meters of space during construction and to provide additional space for root system growth, the setback width has
been extended from approximately 8.0 meters in the original plan to approximately 18.3 meters (Figure 7).
*14 A method of carefully digging to the root tips while taking care not to cut the roots*

September 11, 2024 postscript: The description of “three” has been corrected since the correct number of location is “four” as shown in
Figure 6.

Figure 7: Simplified diagram of the root system protection area and the setback width to the underground framework
for the baseball stadium*The shape of the underground framework and structure, the above-ground buildings
and the ball-stop net are still under consideration.

Original Plan

Curb
Sidewalk(approx. 4.5 meters)

Road

Approx. 8.0 meters*The shape of the underground framework and structure, the above-ground buildings
and the ball-stop net are still under consideration.

After change

Curb
Sidewalk(approx. 4.5 meters)

Approx. 18.3 meters
In addition, the following actions will be taken as specific measures to preserve the roots.

Road(i) Management of roots identified outside the root system protection area (approximately 17.0 meters)
Roughly one year before the start of construction of the new baseball stadium, all root growth will be checked at
approximately 17.0 meters. If roots are identified at approximately 17.0 meters, tree doctors and other experts will be
consulted to determine if the roots are bendable. If so, these roots will be bent to change the growth direction. Of
roots judged to be unbendable, those with a diameter of at least 30 millimeters will be girdled*15 and then cut off one
year later. Roots with diameters of less than 30 millimeters will be sharply cut off to encourage feeder roots to sprout.
After girdling or cutting the roots, a root accelerator or similar agent will then be applied and a root system protection
area secured.
*15 Method of removing the epidermis of roots of a certain thickness down to the formation layer to promote root growth from thestripped area and reduce the burden on the tree from root removal.
Figure 8: Management of roots identified at approx. 17.0 meters

Bendable

Bend

Roots identified at
approx. 17.0 meters

Diameter of at least
30 millimeters

Cut after
girdling

Diameter of lessthan 30 millimeters

Cut sharply

Not bendable(ii) Soil improvement
Soil improvement will be performed on an area roughly 10.5 meters to 18.3 meters from the rows of ginkgo trees(sidewalk curb) to create an environment conducive to root growth.
(iii) Measures to remediate the vitality
For ginkgo trees with declining vitality, irrigation, application of liquid fertilizer, removal of hedera, etc., andcontinued tree care based on the level of vitality, will create a better environment for the ginkgo trees to remediate
their vitality.
The following measures to remediate the vitality of some of the ginkgo trees were implemented from April to June
2024. These measures are explained in a release published on July 26, 2024*16.
・Removal of hedera and undergrowth・Soil improvement through hydraulic injection
・Laying of rice straw mulch・Installation of an irrigation system
・Removal of roadbed of former road・Installation of wood decking in the shops lining the road passing through the ginkgo tree rows
*16 “Measures to Remediate the Vitality of Ginkgo Trees (Implemented April-June 2024),” July 26, 2024
https://www.jingugaienmachidukuri.jp/pdf/en-jingugaienmachidukuri_news_2024072601.pdf

(4) Input from tree doctors and other experts
Root system research is being conducted by IBIDEN Greentec Co., Ltd. Based on the opinions of several tree doctors
and other experts, research methods were reviewed and the results were analyzed before reaching our decision on thispolicy. Individuals who provided technical advice regarding root system research and tree monitoring and research,
and advice and opinions on the setback width for the new baseball stadium, setting the scope of the root system
protection area, and root protection policy, are listed below.
Satoshi Naoki
Naoki Technical Office, Director of the Society for Tree Ecology Research (NPO), engineer and tree doctor
Taisai Hori
Tree Application Research Center, Chief Advisor of the Society for Tree Ecology Research (NPO)Kumiko Mito
Tree Cultivation Laboratory, part-time lecturer at Tokyo University of Agriculture and Hosei University, tree doctor
The following individuals provided guidance on ginkgo tree vitality research conducted in 2023.
Satoshi Naoki
Naoki Technical Office, Director of the Society for Tree Ecology Research (NPO), engineer and tree doctor
Hiroyuki Wada
Director and Vice Chairperson of the Japan Tree Doctors Association, Director and Vice Chairperson of the Tree
Health Research Society, Japan, tree doctor
Nana Adachi
Auditor of the Society for Tree Ecology Research (NPO), tree doctor
Tadashi Touchi, Director of the International Society of Arboriculture and Director and the Urban Tree Diagnosis
General Incorporated Association, provided a second opinion on these measures (full text is available at the following
URL), based on the reports of the first and second root system research and on ginkgo tree vitality research conducted
in 2023 and other reports.
Tadashi Touchi
Director of the International Society of Arboriculture and the Urban Tree Diagnosis General Incorporated
Association, tree doctor
Second Opinion on the Survey of the Westernmost Row of the Four Rows of Ginkgo Trees and Preservation Measures
Related to the Jingu Gaien District Type-1 Urban Redevelopment Project (in Japanese)
URL：https://www.jingugaienmachidukuri.jp/pdf/jingugaienmachidukuri_news_2024090903.pdf

■Survey reports
Jingu Gaien District Urban Redevelopment Project (Tentative Name): Root System Research Work – North-South on West Side ofGingko Trees (in Japanese)
URL：https://www.jingugaienmachidukuri.jp/pdf/jingugaienmachidukuri_news_2024090904.pdf
Jingu Gaien District Urban Redevelopment Project: Report on Ginkgo Tree Vitality Research – Annual Survey (in Japanese)
URL：https://www.jingugaienmachidukuri.jp/pdf/jingugaienmachidukuri_news_2024090905.pdf
Jingu Gaien District Urban Redevelopment Project: Second Root System Research Work – North-South on West Side of Gingko Trees (inJapanese)
URL：https://www.jingugaienmachidukuri.jp/pdf/jingugaienmachidukuri_news_2024090906.pdf

For inquiries regarding this release, please use the contact details below.
You can also submit questions about this project via the Q&A page on the project website using the URL below.
Responses to questions are posted on the website within about three weeks to one month.
URL：https://www.jingugaienmachidukuri.jp/en/faq/

Please direct inquiries to:
Jingu Gaien District Redevelopment Project Planning Office (Japanese language only)
Telephone: 03-6695-0539
Reception hours: Monday to Friday (excluding national holidays) 9am to 6pm
Jingu Gaien District Urban Redevelopment Project website: https://www.jingugaienmachidukuri.jp/en/
Please refrain from contacting or interviewing the companies, organizations, or individuals mentioned in this releaseand supplementary materials.