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－ 1 － （Accepted 31st of July 2024）
A case study of treating on an abandoned coppice of a local hospital
to rehabilitate and recreation purposes
Iwao UEHARA1
1Tokyo University of Agriculture
Abstract: This paper shows a case where a hospital-owned secondary forest of broad-leaved trees, which had been abandoned for
more than 30 years, was developed for patients’ rehabilitation and recreation at a regional hospital in Tokyo. The survey site is
Ongata Hospital and its forest (approximately 6 ha) located in suburb of Hachioji City. The owned forest is mainly a secondary
forest of broad-leaved trees. The tree layer consists of trees such as Quercus serrata, Q. acutissima, and Castanea crenata, as well
as Zelkova serrata, Celtis sinensis, and Magnolia ovobata. The forest floor is thriving with Sasamorpha borealis. As of September
2020, the tree density before maintenance was around 4,000 to 6,000 trees per a ha, and the average relative light intensity in the
forest was around 5 %.Clearing and thinning work on this forest block began in October 2020 and continued until September 2022.
The tree density decreases to 1,500 trees/ha in 2021 and to 300 to 500 trees per a ha in 2022. The average relative illuminance
improved to around 15 to 30 %. The number of confirmed tree species on the forest floor was around 40. The thinned wood was
used to create rest benches, walking paths and occupational therapy of patients.
Key-words: secondary forest, thinning, Sasamorpha borealis, forest therapy, Hachioji City
地域病院所有の広葉樹二次林を保健休養目的に整備した事例
上原 巌1
１ 東京農業大学
要旨：本研究は，約 30 年放置されてきた病院所有の広葉樹二次林に数回の間伐を実施した結果，どのようにその森林
環境が変化し，保健休養の環境として提供できるかを調べることを目的におこなった．調査地は，東京都八王子市に
位置する恩方病院とその所有林（面積約 6ha）である．同林は，広葉樹二次林が主体であり，高木層はコナラ，クヌ
ギ，クリ，ケヤキ，エノキ，ホオノキなどで，林床にはスズタケが多く繁茂していた．2020 年9月時点での整備前の
立木密度は 4000～6000 本/ha 前後，林内の平均相対照度は 5％前後であった．同林において除伐および間伐作業を
2020 年10 月より開始し，2022 年9月まで行った．立木密度 300～500 本/ha 程度まで除・間伐をおこなった結果，平
均相対照度は，15～30％前後となり，林内では約 40 種の樹種が確認された．間伐された材は，休養ベンチ，散策路，
作業療法の資材に活用された．
キーワード：広葉樹二次林，間伐，スズタケ，森林療法，八王子市
Ⅰ Introduction
Currently, so-called "abandoned forests", which are not
properly cared for, are increasing in various parts of Japan. This
applies not only to artificial coniferous forests such as cedar and
cypress, but also to secondary broad-leaved forests that used to
be central to Satoyama (1). However, on the other hand, the
need for health and recreation utilizing forests has been
increasing. This is more noticeable in medical, welfare, and
educational settings, and has taken on even more concrete
meaning in recent years due to the outbreak of pandemics on a
global scale (2, 3). Therefore, this research focused on a
secondary forest of broad-leaved trees owned by a regional
hospital in the suburbs of the city, and aimed to develop it for
rehabilitation and recreation, and to present an example of
abandoned forest maintenance. The location is the Ongata
Hospital of Eijukai Medical Corporation in Hachioji, Tokyo.
Figure 1 shows the forest stand condition in September of 2020,
before thinning cutting. There were some fell down and
hanging trees, shrubs and bush covered the floor.
The forest maintenance that was the subject of the research
was carried out at the request of the hospital. The forest area is
about 6 hectors. When the hospital first opened in 1965, the area
Original Article
Journal of Forest and Human Health Promotion Research 5 (2024)
－ 4 －
around the hospital was surrounded by thickets, mainly
woodlands and coppice forests. However, the forest stand has
been abandoned for more than 30 years without appropriate
treatment. The hospital and forest now are surrounded by
residential area. In these circumstances, the hospital has made
three requests: consideration of fallen leaves and shadows on
nearby houses, reduction of fallen tree damage caused by
typhoons, and improvement of the scenery from the ward. . In
September 2020, I reconfirmed the hospital's request before
starting forest maintenance. To summarize their requests, it
needs to maintain forests to prevent landslides and flood
damage during heavy rains. This abandoned forest had a
possibility to create a space that can be used not only by patients
but also by hospital staff. However, they didn’t know what it
would be like, so the first three points were to create a trial space
that would make patients and hospital staff understand what is
forest therapy.
Figure 1 The condition of forest stand in September 2020
図1． 2020 年9月の調査地の状況
First of all, I did a reconnaissance in the same forest. The
reconnaissance was conducted together with Tokyo Chainsaws
Co., Ltd. (Representative: Mr. Ryosuke Aoki), which is in
charge of forest maintenance. Based on the reconnaissance,
through this development, I reported on the current state of the
forest at Ongata Hospital and the trees and plants in the forest.
The hospital should first create a space that can be used as a
place for medical treatment and health and rest for patients, a
space that can be used as a place for rehabilitation and rest for
medical staff and a trial space for them. In addition, the
guideline for the forest maintenance method is to start by
clearing fallen down trees, hanging trees, and dead trees, to
open up the space in the forest to form a space for health and
recreation, and to clean up shrubs and vines to significantly
lower the forest density,
As a guideline, I decided to set a target value of 30% or more
relative illumination in the leafing period, and to retain useful
broad-leaved trees and medicinal plants used for health and
recreation.
Forest maintenance was started in September 2020 and was
almost completed in October 2022. The maintenance work was
commissioned to Tokyo Chainsaws Co., Ltd. with subsidies
from the Tokyo Metropolitan Government's afforestation
subsidized project. The contents of the maintenance are
cleaning, thinning, and construction of walking paths.
Ⅱ Methodology
This research surveyed the changes in the tree density, relative
illuminance, tree height, trees stories, stand condition, and
vegetation in the forest. I set 4 surveying plots (10 meters ×10
meters) in the forest.
Before clearing and thinning, the tree density was around
4,000 to 6,000 trees per hectare and the average illuminance
was around 5 %.
Forest maintenance started in September 2020 and it was
almost completed in October 2022. The maintenance work was
commissioned to Tokyo Chainsaws Co., Ltd. with subsidies
from the Tokyo Metropolitan Government's afforestation
subsidized project. The contents of the maintenance are
cleaning, thinning, and construction of walking paths.
Ⅲ Results and discussion
1. Changes in tree density and relative illuminance After
the first clearing and thinning in October 2021, the tree density
was 1,500 to 2,000 trees / ha, and at the end of the work in
September 2022, it was 300 to 500 / ha. The average relative
illuminance in the forest improved to 15 to 30 %, about twice
as much as before the thinning cutting. Figure 2 shows the
changes of landscape of the stand.
2. Investigation of vegetation in the forest Already
abandoned for more than 30 years, the forest was in a chaotic
state, but there were many places where the Sasamorpha
borealis were particularly luxuriant. They had a density of 50 to
70 stocks per a square meter (Figure 3).
The tallest trees in the forest were Quercus serrata and
Zelkova serrata, both of which were around 20m in height.
Next, Quercus acutissima and Castanea crenata, the average
tree height was around 18 m. Many straight individuals were
－ 5 －
Journal of Forest and Human Health Promotion Research 5 (2024)
seen, and as of September 2020, there was almost no damage
from the Platypus quercivorus. Next was a mixture of Celtis
sinensis and Magnolia ovobata at a height of 12 to 14 m. In
addition, about 60 % of Quercus serrata were sprouted.
Figure 2 Changes of forest landscape before and after
thinning at same site.
(Top) September 2020 (Bottom) October 2022
図2． 同一地点における間伐前後の森林景観の変化
（上）2020 年9月 （下）2022 年10 月
Figure 3. Sasamorpha borealis were seen on the forest floor
(September 2020).They were growing at a density of 50-70
plants per square meter.
図３．林床にみられるスズタケ（2020 年9月）．
50～70 本／㎡の密度で繁茂していた．
It suggested that it was once used as a coppice forest and as a
satoyama. On the forest floor, there were mainly Quercus nuts,
but also acorns and seedlings of Fagaceae trees. More than 40
species of tree species have been confirmed on the forest floor
every year since thinning in 2020. Several types of medicinal
trees such as Smilax china, Lindera umbellata have also been
identified. Table 1 summarizes the tree species in the tall tree
layer, sub-tree layer, shrub layer, and forest floor. From the
vegetation of the shrub layer and the forest floor, it can see the
tree species ranging from pioneer tree species to shade trees (Fig
4). It suggested that the forest was in the process of succession
from deciduous broad-leaved trees to evergreen broad-leaved
trees.
Sasamorpha borealis had grown thick in various places were
cut down all at once. After clean-cutting, along with the
reduction in the density of standing trees, new seedlings, mainly
intolerant and pioneer species such as Wisteria floribunda,
Alaria elata, Rhus javanica, and Morus australis, have sprung
up on the forest floor due to buried seeds and natural scattering
by wind and animals. can be seen. Also, due to neglect for more
than 30 years, lignified Wisteria floribunda can be seen at many
places in the forest. Also, many individuals have reached the
tree canopy and are growing in hypertrophy. In addition, the
number of Platypus quercivorus damaged trees such as Quercus
serrata and Q. myrsinifolia which could not be confirmed
visually at first, increased significantly from the spring of 2022,
and by September of the same year, more than 60 damaged trees
were confirmed in the entire forest. The damaged trees are
felled and placed on the side of the walking path (Figure 5).
Figure 4. The tree layer is composed of zelkova serrata and
Quercus serrata. Other species mixed in include Magnolia
obovata, Carpinus tschonoskii, and Castanea crenata.
図４．ケヤキ，コナラなどで構成される高木層．
そのほか，ホオノキ，イヌシデ，クリなども混交してい
る．
－ 4 －
Table 1 Tree species of forest stand of this research
表1． 調査対象地の樹種
< High story >
Quercus serrata, Q. acutissima, Castanea crenata,
Zelkoba serrata, Celtis sinensis, Magnolia obovata
< Sub-High story >
Carpinus tschonoskii, Cerasus jamasakura, Cornus kousa,
Quercus myrsinifolia, Q. glauca
< Lower story >
Stylax japonicus, Morus australis, Eurya japonica,
Aralia elata, Ilex macropoda, Clethra barbinervis,
Aucuba japonica, Carpinus laxiflora
< Floor vegetation >
Mallotus japonicus, Callicarpa japonica, Albizia julibrissin,
Neillia incisa, Smilax china, Dendropanax trifidus
Symplocos sawafutagi, Toxicodendron vernicifluum,
Viburnum dilatatum, Kalopanax septemlobus,
Euonymus sieboldinus, Hydrangea hirta, Thus javanica,
Acer crataegifolium, Zanthoxylum piperitum,
Lindera obtsusiloba, Fatsia japonica, Lindera umbellata,
Elaeagnus umbellata, Ilex crenata, Ardisia crenata,
Viburnum phlebotrichum, Acer palmatum, Abies firma,
Nandina domestica, Pieris japonica, Euonymus oxyphyllus,
Osmanthus heterophyllus, Aralia elata, Castanopsis sieboldii
Figure 5 Damaged trees and set on the side of path
図5． 被害木と歩道脇に置かれた伐採木
3. The other features of the forest Soil of the forest stand
was brown forest soil, the A layer was about 20 cm thick, and
the B layer underneath was clayey soil (Figure 6). The average
pH of the soil was around 5.2.
Figure 6. Soil profile of the survey area. The A layer was about
20 cm deep, and below that was clay soil.
図６．調査地の土壌断面．A層は 20 ㎝ほどで，その下は
埴土であった．
In the wild, several species of mammals inhabit or use the site,
and more than 10 badger （Meles anakuma）nests were found
in the colony（Figure 7）. In addition, the footprints of deer and
wild boars can be seen even after the maintenance.
Figure 7. Badger （Meles anakuma）nests found in multiple
locations in the forest
図７．林内で複数個所みられたアナグマの巣
4. Proposing ways to create and utilize a resting space and
use of felled trees In November 2020, the first year of work,
I set up a trial space for forest therapy for patients and medical
staff (Figure 8). Locations were selected that were close to the
ward and visible from each other. Dead trees and hanging trees
were used to create the benches in this space.
－ 5 －
Journal of Forest and Human Health Promotion Research 5 (2024)
Figure 8 Trial space for forest therapy
図8． 森林療法のための空間
Logs of oak trees damaged by Platypus quercivorus were used
for earth retaining of walking paths, fragrant felled trees such as
cherry trees are used as wood chips, and vines of Wisteria
floribunda are used as materials for occupational therapy for
patients, such as making Christmas wreaths. The walking path
was created with a width of 2.0 to 3.0 m and the gradients was
lower than 5 % (4). This width was requested by the hospital so
that two wheelchairs could pass each other (Figure 9). Totally
more than 400 meters long path was constructed. Patients are
expected to enter the forest in both wheelchairs and motorcars.
Figure 9 Walking path of width 2.0 to 3.0 meters
図9．幅 2.0～3.0 メートルの散策路
Ⅳ. Conclusion
This research worked to create a space for health and
recreation by maintaining a secondary broad-leaved forest that
had been abandoned for more than 30 years. Results showed it
could change the abandoned forest condition to rehabilitate and
recreational environment with keeping diversity of tree species
by thinning cut (Figure 10). After treatment, hospital staff
planned that occupational therapy using the trees in the forest
(making Christmas wreaths, and so forth.), and walking and
counseling using the recreation space in the forest. The main
target participants will be dementia patients and mental disabled
patients such as depression.
Figure 10. The rehabilitation course was built in a hospital forest
that had been abandoned for over 30 years. This is what it
looked like after thinning.
図10．30 年以上放置されていた病院林の中に作られた
リハビリテーションコース．間伐後の姿である．
References
(1) Japan Forest Agency (2022) Forest Forestry White Paper.
(2) Forest Recreation Association (2022) Handbook of Forest
Recreation for Elder People and People with
Disabilities.(in Japanese). 74p.
(3) Uehara I., Takayama, N., Takeuchi, H. (2022) Forest
amenities with case studies. Our forest and our health.
Forestry Improvement and Extension Association 300p.
(4) Ohta T. (2001) Forest Universal Design. Japan Forestry
Research.