Takayama et al. Progress in Earth and Planetary Science (2017) 4:17
DOI 10.1186/s40645-017-0129-6

Progress in Earth andPlanetary Science

RESEARCH ARTICLE

Open Access

The effect of slight thinning of managed
coniferous forest on landscape appreciationand psychological restoration
Norimasa Takayama1* , Haruo Saito2, Akio Fujiwara2 and Masahiro Horiuchi3

Abstract
We investigated the influence of slight thinning (percentage of woods: 16.6%, basal area: 9.3%) on landscapeappreciation and the psychological restorative effect of an on-site setting by exposing respondents to an ordinarily
managed coniferous woodland. The experiments were conducted in an experimental plot in the same coniferous
woodland in May (unthinned) and October 2013 (thinned). The respondents were the same 15 individuals for bothexperiments. Respondents were individually exposed to the enclosed plot and the forest-view plot within the sametent for 15 min. In both sessions, respondents were required to answer three questionnaires measuring their mood
(Profile of Mood States), emotion (Positive and Negative Affect Schedule), and feeling of restoration (Restorative
Outcome Scale) to investigate the psychological restorative effect before and after the experiment. They completed
two other questionnaires measuring appreciation for the environment (Semantic Differential) and the restorative
properties of the environment (Perceived Restorativeness Scale) following the experiments. We first analyzed thedifference in landscape appreciation between the unthinned and thinned conditions. We did not find any statisticaldifference in appreciation for the environment (Semantic Differential) or the restorative properties of theenvironment (Perceived Restorativeness Scale); rather, we found that weather conditions had a primary influence
on landscape appreciation. With respect to the psychological restorative effect, a two-way repeated analysis ofvaliance (ANOVA) revealed significant main effects for a selection of indices, depending on the presence or absenceof thinning. However, multiple comparison analyses revealed that these effects seemed to be due to the differencein the experimental experience rather than the presence or absence of thinning. In conclusion, the effect of theslight thinning of the managed coniferous forest was too weak to be reflected in the respondents’ landscapeappreciation or to exert a psychological restorative effect. Therefore, planners should consider stronger thinning as
it is unlikely to result in serious damage to users’ appreciation and may increase their landscape appreciation ofconiferous woodland and enhance its psychological restorative effect.
Keywords: Forest bathing, Forest management, Profile of Mood States (POMS), Restorative Outcome Scale (ROS), Positive
and Negative Affect Schedule (PANAS), Semantic Differential (SD) method, Perceived Restorativeness Scale (PRS)

Introduction
In Japan, the shortage of timber after the end of WorldWar II prompted the creation of a national policy toplant Japanese cedar (Cryptomeria japonica) and Hinoki
cypress (Chamaecyparis obtusa). Currently, forests cover
67% of the land area and approximately 40% of these
forests are artificial (Food and Agriculture Organization* Correspondence: hanri@ffpri.affrc.go.jp
1
Division of Forest Management, Forestry and Forest Products ResearchInstitute in Japan, 1 Matsuno-sato, Tsukuba City, Ibaraki 305-8687, Japan
Full list of author information is available at the end of the article2007). However, when domestic timber prices slowed
due to the total liberalization of wood imports in 1964,
the motivation of private forest owners to manage theirforests rapidly diminished.
Forests not only function to provide woodlands but
also serve as multifaceted places where biodiversity ispreserved, soil outflow is prevented, water sources arerecharged, and forest bathing areas are provided. To
manage forests that have not been profitable for forestry
enterprises, subsidies are used to encourage forest management practices such as tree thinning and weeding to© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

enhance their multifunctional functions for the benefit
of society. However, scientific evidence is required toprove the effectiveness and validity of such practices dueto the use of tax exemptions from inputting subsidies tofinancial sources (Forestry Agency of Japan 2016).
Japan is a mostly warm and humid country with a suitable climate for growing trees. Thus, to enhance the many
functions of artificial forests while responding to future
timber demands, it is necessary to artificially thin andprune dense forests. Thinning allows light to filter into theforest, which enhances the growth of the remaining trees
and increases the forest’s value and biodiversity. This leads
to the maximization of the value of the forest, including
expectations for additional functions, such as soil support
and water source recharging.
Furthermore, thinning maximizes the use of appropriately
managed forests as places of recreation and forest bathing,even in artificial forests. Therefore, to maximize the value offorests domestically, national and local governments should
require the appropriate thinning of artificial forests byproviding subsidies to forestry associations and/or forest
owners. However, we should point out that such policies
have not been progressing well and have not achieved sufficient outcomes to date (Forestry Agency of Japan 2016).
More than 30 years have passed since Ulrich’s (1984)
scientific study of the restorative effect of green andnature, during which time the primary focus has been on
psychology in relation to city life (Herzog and Chernik
2000; Hartig et al. 2003; Laumann et al. 2003; Morita et al.
2009; Velarde et al. 2007). According to Haluza et al.
(2014), since the beginning of this century, the physicaland psychological restorative effects or other immunerelated effects of forest enclosures have been investigatedprimarily in developed countries, in which aging populations and declining birth rates have become serious issues.
In Japan in particular, since the concept of forest bathing
was defined in 1982 (Morita et al. 2009), studies on thephysical and psychological restorative effects of the forest
have rapidly advanced, specifically in the second half ofthe 1990s. For example, in the areas of medicine andphysiology, Ohira et al. (1999) reported that forest bathing
was effective for immune restoration, and Li et al. (2007;2008a) found that immune cells were more active after a
3-day stay in the forest. Li et al. (2008b) also indicated thatthe benefits of forest bathing were influenced not only by
the components of air, such as phytoncide, but also by theenvironment itself, compared with staying in urban areas
for the same duration. Ochiai et al. (2015a; 2015b) showedthat 2 h of forest bathing reduced physiological parameters such as stress hormones, blood pressure, and adrenaline in middle-aged and elderly people. The Profile ofMood States (POMS; McNair et al. 1964) and the StateTrait Anxiety Inventory (STAI; Spielberger et al. 1970;
Spielberger et al. 1983) are commonly applied to analyze

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mood (Oishi et al. 2003; Park et al. 2009; Tsunetsugu et al.
2010; Park et al. 2010) and anxiety state (Takanashi 2011).
Moreover, research using newly developed indices such as
the Perceived Restorativeness Scale (PRS; Korpela andHartig 1996; Hartig et al. 1997a; Hartig et al. 1997b), theRestorative Outcome Scale (ROS; Korpela et al. 2008;
Korpela et al. 2010), and the Subjective Vitality Scale (SVS;
Ryan and Frederick 1997) has shown that forest bathing results in psychological restoration and improved vigor(Takayama and Kagawa 2013; Takayama, Korpela, Lee et al.
2014b; Tyrväinen et al. 2014). Furthermore, Kobayashi
et al. (2015) performed a large-scale field experimentthroughout Japan in 60 forests known as “therapy bases”
maintained for forest bathing. Finally, a few notable studies
have confirmed the considerable physiological and psychological effects not only of remote forests but also of urban
forests (Tsunetsugu et al. 2013; Tyrväinen et al. 2014b).
Thus, studies have shown that forest environments resultin physical and mental restorative effects and have detailed
the mechanisms behind these effects.
However, forest management planning is required toactivate the health-restorative function of a forest. Information on the arrangement of physical forest environments
and their management is needed to make forests a comfortable place to be. In the context of the effects of thephysical forest environment and forest bathing, Horiuchi
et al. (2014) reported that when individuals observed a real
forest scene, the level of cerebral oxygenated hemoglobinin the prefrontal area of the brain declined and mood
improvements were greater than in respondents who were
cut off from forest environments. Park et al. (2011) demonstrated a relationship between physical conditions, such astemperature and illumination, and impression evaluationand mood restoration. Fujisawa et al. (2012) and Takayama
et al. (2012) studied the light environment in forests andreported that in a bright environment with sunlight passing
through the trees, the blood volume in the brain decreased
and mood improvement effects were higher than in a dark
environment within the same forest. These research findings suggest that it is important to properly manage theforest’s internal environment to make forest bathing more
comfortable. However, forest management requires anunderstanding of the unique situation within each forest
depending on its intended use (Brunson and Reiter 1996;
Gobster 1999; Ribe 2006). For example, compared with remote artificial forests, forests near tourist spots or suburban forests require management to maintain biologicaldiversity while at the same time satisfying the needs of
tourists and residents of nearby neighborhoods (Brunson
and Reiter 1996; Gobster 1999; Ribe 2006). Therefore, tomanage urban forests with highly diverse uses such as forest bathing and other recreational activities, an administrator must be well informed about the level of management
required in relation to intended uses.

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

Other studies have assessed the relationship between
forest management methods and public evaluation. For
instance, Buhyoff and Leuschner (1978) reported thatfavorability ratings for forests decreased sharply after the
pinewood nematode caused damage to more than 10%;
Takahashi et al. (2006) suggested that preferences varydepending on the mix of tree types and the proportionof hardwood and softwood; and Oishi et al. (1994),
Takayama et al. (2009), and Takayama et al. (2014) investigated the relationship between tree density and the
comfortability of the forest environment. Several investigators have studied the effects of the types and numbersof trees, tree density, the presence or absence of fallentrees, and planting patterns on the evaluation oflandscape beauty, among other parameters.
The relationship between the evaluation of forest beauty
and thinning, which is a typical method of sustaining
forests, has also been investigated (Ribe 2005; Guan et al.
2010; Deng et al. 2012). Daniel (2006) highlighted that
forest users tend to prefer somewhat managed forests toentirely natural forests. However, Edwards et al. (2012)
showed that thinning was not the only task necessary topreserve forests in good condition. Even if thinning
improves the internal forest environment, the evaluation of
the forest has been shown to decrease after thinning.
Nevertheless, further studies are necessary to collect dataon the extent of users’ impact and the reduction in esthetic
evaluation by controlling the forest type, stand age, forest
compartment placement, and the degree of thinning.
Other studies have investigated the relationship between
forest landscape management and recreation. Brunson and
Sheldy (1992) found that the landscape quality of a forest andrecreational activities were closely linked. Kunisaki and Imada(1996) reported that managing the density of trees alongroads such as promenades, forest trails, and forest roads
increased users’ satisfaction, even if sufficient thinning could
not be conducted for the entire forest. The Gifu Prefectural
Research Institute for Forests (2004) reported that good
visitor ratings could be maintained by establishing a range ofapproximately 20 m from both sides of the sidewalk. Lastly,
Oku (2007) investigated the ease of carrying out various
activities in the forest, which included an analysis of the levelof management required for each type of use.
Another important aspect is how users’ evaluations offorests change depending on the degree of thinning and
its relationship to mental and physical recovery. Unfortunately, only a few previous studies have considered this
topic, such as Oishi et al. (2003), and current researchremains insufficient for specialists to form actionable conclusions. Urban forests located close to cities, or in resort
or vacation areas that have already been in service fortourism or other recreational uses, offer facilities that arereasonably maintained and managed, unlike distant forests(e.g., okuyama; forests and mountains far from urban

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areas) that are in a state of abandonment. However, healthconsciousness has recently emerged as a public issue, andforest managers must further enhance their general evaluation of forests to continually provide forest bathing experiences that bring a restorative effect to visitors. Therefore,
management criteria are required that provide guidelines
on the optimal amount and frequency of thinning, weeding, and pruning to establish appropriate goals and guideforest management. With insufficient evidence, forest administrators must decide arbitrarily on the need for anddegree of thinning using their own judgment, experience,
demand, and other plans (for example, timber production
planning), without measurable objectives. If we cannot
promote the benefits of thinning due to a lack of information on forest management and the mental and physicalrestorative effects of forest environments, both forest
administrators and users may miss a great opportunity.
In this study, we performed an experiment in which
adjusted thinning was carried out in a partially managed
urban forest located in a suburban summer resort. The purpose of the study was to investigate how thinning influenced
impressions and evaluations of the forest environment andits restorative effects on people who enjoy forest bathing.

Methods/experimental
Study design

The experiment was divided into two parts and conductedin May and October, when the average temperature andhumidity were expected to be similar (see the “Results anddiscussion” section). The study area chosen was within the
Fuji Iyashinomori Woodland Study Center, which is anexperimental forest associated with the University ofTokyo located in Yamanakako Village. This institute is
located near Lake Yamanaka, one of the five lakes around
Mt. Fuji (Fig. 1), and the experimental plot measured
2500 m2 (50 m × 50 m; Fig. 2, Table 1).
The forest chosen as the research site (approximately
40 ha) is managed by two technical staff members of the
Fuji Iyashinomori Woodland Study Center. The university
budget covers the management expenses of the forest. The
area around the Center, the buildings, gardens, forest road,and sidewalks are highly managed. However, the management status of the Larch plantation area chosen as the research site was similar to other surrounding private forests
and was not highly managed, at least at the time of theexperiment. The forest physiognomy (forest type) of theexperimental plot was a man-made (artificial) forest primarily comprising approximately 80-year-old larch trees (Larix
kaempferi); however, the amount of hardwood trees was increasing, and the forest was turning into a mixed-type forest.
In 2012, 1 year before the experiment, the shrubs and young
trees were cut and removed from the forest. Therefore, thecanopy was almost closed, but the horizontal prospect wasin quite good condition (Figs. 3 and 4 and Table 2).

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

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Fig. 1 Location of the research site

Following the completion of the first experiment in May
2013, corrective thinning of the study area was carried out
in August of the same year. Crews used two chain saws
and one portable winch during the thinning operation,with a target of approximately 15–20% thinning. Four
workers from Fuji Iyashinomori Woodland Study Center
worked for a total of 9 h for 2 days in late August. The
second experiment was conducted in October of the same
year. The period between the two experiments wasimportant because the smell of the trees, typified by phytoncide, would be stronger immediately after the thinning.
In the experimental period, we provided warm coats forthe participants so they could control the experimental
conditions in comfort. Table 2 shows the distribution ofvegetation used for the experimental stimuli, based on thebasal area at breast height in May (in October).
Respondents

Graduate students and teaching staff members from theForest Science Department of the University of Tokyo werechosen as the respondents in this experiment. Therefore,
we could assume that all respondents were favorable toward and had fundamental knowledge and experience offorests. We broadened the sample to include middle-agedteaching staff to avoid the bias that may have occurred bychoosing only students. Fifteen respondents (11 men and 4
women) with a mean age of 35.9 ± 8.19 years (Table 3)participated in this study. The respondents had no historyof cardiovascular disease or mental illness and were nottaking any medications that could affect their psychologicalresponses related to feelings, affect, and subjective restorativeness. Following a detailed description and explanationof the study procedures and the possible risks and benefitsof participation, each respondent signed an informed consent form. Respondents were randomly divided into group
A or group B and asked to abstain from consuming caffeinated beverages for 12 h and not to engage in strenuous
exercise or consume alcohol for a minimum of 24 h before
the experiment. The ethical committee of the Mt. Fuji
Research Institute approved all procedures applied in thepresent study, which were performed in accordance withthe guidelines of the Declaration of Helsinki.
We performed a statistical power analysis using the free
software G*power v. 3.1.9.2. The actual power (1-β error
probability) was 0.575 for a repeated measures, withinbetween interaction test, calculated by a post hoc achieved

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

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Fig. 3 Hemispherical photographs of the study area

the forest environment and to investigate its psychologicalrestorative effect. Because the psychological evaluations
were in the form of language information, generally it
would be easy to interpret them in comparison withphysiological data to facilitate future forest management.
Therefore, we decided to use five psychological questionnaires in the experiment. Specifically, the POMS, ROS,
and PANAS measured the psychological restorative effect,
and the SD method and PRS measured the characteristicsof the forest environment.
Fig. 2 Situation of the experimental area

power analysis with an effect size of 0.25 and α error ofprobability of 0.05. Nevertheless, previous studies haveindicated that a sample size of 12–15 respondents isenough to draw significance conclusions (Li et al. 2008a;
Li et al. 2008b; Park et al. 2009; Horiuchi et al. 2014).
Questionnaires

The study used five psychological questionnaires. Figure 5
shows the administration procedure for each questionnaire. The purpose was to evaluate the characteristics ofTable 1 Research site characteristics and weather conditions
May

October

Location

Fuji Iyashinomori Woodland Study Center,
Yamanaka Lake Town, Yamanashi Prefecture

Experimental area

2500 m2 (50 m × 50 m)

Forest status

Well-managed mixed forest(80-year-old Larch and Dogwood)

Weather
Day1

Fair

CloudyDay2

Fair

Cloudy and/or partly sunny

Day3

Fair

Cloudy and/or partly sunny

Day4

Fair

Cloudy and/or partly rainy

Monthly mean temp. (°C)

12.8

10.9

Monthly mean humidity (%) 84.6

90.9

1) Profile of Mood States (POMS)
The POMS (McNair et al. 1964) is a well-established,factor-based, analytically derived measure of
psychological distress. Its reliability and validity havebeen well documented (McNair et al. 1964). The
POMS measures six mood states: tension and anxiety(T-A), depression-dejection (D), anger and hostility(A-H), vigor (V), fatigue (F), and confusion (C). We
used the Brief Form Japanese Version of the POMS
(Yokoyama et al. 1990). Each subscale has five items
measured on a 5-point Likert scale; thus, the statisticalanalyses included the raw scores for all 30 items.
2) Positive and Negative Affect Schedule (PANAS)
The PANAS (Watson et al. 1988a; Watson et al.
1988b) measures positive affect (PA) and negative
affect (NA) using 20 items (10 items each for PA
and NA). The scales have high internal consistency,
are largely uncorrelated, and remain stable atappropriate levels over a 2-month period (Watson
et al. 1988b). Normative data, factorial elements, andexternal evidence of the scales’ convergent and discriminant validity are also available (Watson et al.
1988b). We used the Japanese version of the PANAS(16 items; 8 items each for PA and NA; measured on
a 7-point Likert scale; Sato and Yasuda 2001) andused each respondent’s total PA and NA scores inthe statistical analyses.
3) Restorative Outcome Scale (ROS)The ROS (Korpela et al. 2008) was based on
previous measures and findings regarding restorative

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

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Fig. 4 View of the study area

outcomes (Kaplan et al. 1993; Hartig et al. 1998;
Staats et al. 2003). The ROS consists of six items formeasuring restorative emotional and cognitive
outcomes in a given environment. Each item ismeasured on a 7-point Likert scale (1: “not at all”
to 7: “completely”), the reliability of which was
confirmed in previous studies (Korpela et al. 2008;
Korpela et al. 2010). In this study, we used theJapanese version, the ROS-J, and checked thereliability and validity according to Fujisawa and
Takayama (2014). The total score of the six items
was used for statistical analyses.
4) Semantic Differential (SD) method
A questionnaire using the SD method was applied to
examine the impression of the different
environments. Osgood (cited in Iwashita 1983)
Table 2 Species data for May and OctoberMay(unthinned)

October(thinned)Stand density(number/ha)

1200/ha(n = 301)

1056/ha(n = 251)

Stand basal area
(m2/ha)

48.8

44.3

Larch
(Larix kaempferi)

66.2%

66.1%

Dogwood(Cornus kousa)

10.1%

10.1%

Red pine(Pinus densiflora)

7.0%

7.3%

Fir (Abies firma)

6.4%

6.4%

Japanese-alder(Alnus japonica)

1.9%

1.8%

Veitch’s silver fir(Abies veitchii)

1.8%

1.8%

Fuji cherry(Prunus incisa)

0.8%

0.8%

Maple (Acer)

0.7%

0.7%

Species composition(basal area; %)Japanese wing nut(Pterocarya rhoifolia)

0.7%

0.7%

Others4%

4%initially developed the SD method for qualitatively
evaluating people’s impressions of the environmentand space, using adjective pairs or adjective–verb
pairs of words with opposite meanings. Park et al.
(2011) and Takayama et al. (2014) proved theeffectiveness of this scale in previous studies;
therefore, in this study, we selected 25 adjective andadjective–verb pairs that were consideredappropriate for evaluating impressions of the forest
environment. A 7-point Likert scale was used for themeasurement.
5) Perceived Restorativeness Scale (PRS)
The restorative properties of the environment were
investigated using the PRS. The questionnaire wasdeveloped by Harting (2005) based on the attention
restoration theory proposed by Kaplan and Kaplan(1989) and Shibata et al. (2008), then translated into
Japanese and subsequently revised. The Japaneseversion of the PRS comprises 26 items that measure
the extent to which a particular environment
restores mental alertness; for example, “being away,”“fascination,” “coherence,” “scope,” and“compatibility” on an 11-point Likert scale.
“Familiarity” and “preference” were also measured(Kaplan and Kaplan 1989; Shibata et al. 2008).
Procedure

All respondents were divided into either group A or group
B in May and remained in the same groups for the October experiment. There were two study conditions, andeach respondent participated in both in a certain order in
May and October (Fig. 5). One condition included viewinga real forest, whereas the other was in the same place but
respondents did not view the real forest. Cloth sheets wereTable 3 Respondents’ characteristics
Number of respondent

Mean age

S.D.

All

15

35.9

±8.19

Male

11

37.4

±7.58

Female

4

31.8

±9.53

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

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either the forest or the enclosed setting, for 15 min. The
post-measurements were then completed (i.e., POMS,
ROS, PANAS, SD, and PRS). After completing either theforest-view or enclosed condition, the other experimental
stimulus was introduced.
Carrying out the experiment according to the scheduleshown in Fig. 5 required approximately 2 h per respondent, and only three or four people could be tested eachday because of the individual experimental design.
Therefore, the 15 respondents were tested over four
consecutive days in each of May and October.
Environmental measurements

Environmental conditions (i.e., temperature and relative
humidity, wind velocity, and radiant heat) were measured
using a portable amenity meter (AM-101, Kyoto Electronic
Manufacturing, Co. Ltd, Kyoto, Japan). Illumination intensity was measured using an illuminometer (T-10, Konica
Minorta, Japan). These parameters were measured every
5 min throughout the 15 min of each experimental session.
Data analysis

Fig. 5 Experimental procedure. The same experimental procedure
was used in the May (unthinned) and October (thinned)
experiments. Only the results of the forest view session were used in
the analysis (for both May and October); the data from the enclosed
sessions were not analyzed

hung on both sides and in front of the respondent for theentire duration of the study. The cloth in front of the
respondent was opened and closed for the forest-view andenclosed conditions (with and without forest viewing,
respectively) in both May and October.
Respondents’ psychological responses were measured inboth the forest-view and enclosed conditions. Each respondent sat on a comfortable chair during both conditions. The POMS, PANAS, and ROS were administered
before and after, and the SD and PRS were administeredafter each 15-min experimental session. Respondents sat in
a comfortable chair in an upright position to complete thePOMS, ROS, and PANAS questionnaires. Respondents
were then instructed to view the landscape in front of them,

We aggregated the study index data and calculated themean and standard deviation (SD). Only the results of theforest-view sessions were used for the analysis in both May
and October. We conducted a two-way repeated measure
analysis of valiance (ANOVA) on the POMS, PANAS, andROS data to investigate the psychological restorative effectof forest thinning. The interaction and simple main effects
were calculated to investigate the relationship between the
response changes of the exposure to the stimulus (before
and after exposure) and the thinning (May–October). The
SD method and PRS, which were used as indicators oflandscape appreciation, were only administered after exposure to the stimulus. Therefore, we compared the results of
the May and October experiments using paired t-tests toinvestigate whether the evaluations changed after the forest
thinning. We calculated the average values of the environmental condition indicators over the 15 min of each experimental session, and compared the values of each indicator
between May and October using paired t-tests. Data areexpressed as mean ± SD.

Results and discussion
Physical environment

Table 4 shows the results of the physical environment measurements for the unthinned and thinned conditions. First, inthe thinned experimental environment in October, thetemperature and humidity were significantly higher (p < 0.01)
than in the unthinned environment in May, the wind wascalmer (p < 0.05) and the radiant heat was lower (p < 0.05).
Illuminance was significantly lower in the thinned condition(p < 0.01) than in the unthinned condition. The soundTakayama et al. Progress in Earth and Planetary Science (2017) 4:17

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Table 4 Results of t-test comparison between the unthinned and thinned settings (physical environment)
Item
Temperature (°C)

Unthinned
n = 50Thinned

Mean

S.D.

Mean

S.D.

17.1

±2.52

18.6

±0.92

t

p

2.90

0.006

r
**

0.383

Relative humidity (%)

37.7±20.42

92.4

±4.64

13.70

0.000

**

0.891

Wind velocity (m/s)

0.30

±0.19

0.16

±0.13

4.92

0.000

*

0.576

21.8

±2.84

18.8

±1.05

2.19

0.034

**

0.299

668.4

±236.86335.6±171.84

8.23

0.000

**

0.604

–

–

–

–

Radiant heat (°C)
Illuminance (Lux)n = 119

Sound pressure (dB)

L.O. up to 45.5

L.O. up to 46.1

L.O. shows the measurement limit (less than 40 dB) of the sound-level meter. The dB was listed from the minimum (measurement limit) to the maximum(actual number) as information of the sound pressure**p < 0.01, *p < 0.05, paired t-testpressure level for the thinned and unthinned conditions was
similar, considering 45–46 dB as the measurement limit.
To carry out the on-site comparative experiments, thestate of the forest environment should be equal in theunthinned and thinned conditions. Therefore, we choseto carry out the experiments in May and October, which
generally have similar weather conditions. However, as
shown in Table 4, we observed significant differences inthe thermal environment and illumination. More specifically, the results show that in the thinned forest environment in October, the luminance was slightly lower
and the temperature was higher than in the unthinned
environment in May.
Landscape appreciation

Table 5 compares the evaluations of the unthinned andthinned forest environments. We observed a significant
difference in the two measures (scales) of “bright-dark”(p < 0.05) and “dry-wet” (p < 0.01). In other words, thethinned forest environment was evaluated to be relatively dark and wet. We also observed different trends(p < 0.1) in three scales: “gentle lighting-too bright,”“dull-refreshing,” and “thin-thick.” Respondents used thelabels “gentle light,” but not “refreshing” or “thin” to describe the thinned forest environment.
Table 6 compares the restorative properties of the twoforest environments based on the appreciation of the respondents. The results show no significant difference between the indicators used to measure the restorative
properties (being away, fascination, coherence, scope,and compatibility) and familiarity and preference.
These results indicate that although the thinning operation physically changed the stand density and basal areaof the forest environment (Fig. 2, Table 2), the impression evaluation and restorative properties indicators
showed almost no difference between the forest environments (Tables 5 and 6). The SDs suggested that thethinned forest environment was evaluated as darker andwetter. However, this result was not because of the influence of the thinning, but rather reflected the differencein the climate and weather conditions during the experiment; for example, the luminance was lower and the humidity was higher (Table 4).
Table 4 also indicates that respondents felt the thinned
condition was relatively “dull” (dull–refreshing) and thelight in the forest “gentle” (gentle lighting–too bright),
which implies that the climate and weather conditionsin the thinned condition, when the humidity was higher
and the luminance was lower, had an influence.
Psychological restorative effectBecause both the thinning and the exposure to the forest
environment could influence the psychological restorative effect, we conducted a two-way repeated measures
ANOVA, with the presence or absence of thinning andthe observations before and after exposure to the forest
environment as factors, to analyze the interaction between the factors and the main effect (Tables 7 and 8).
The results showed no interaction effect between thepresence and absence of thinning and before and after
the experiment for the six indicators of the POMS (T-A,
D, A-H, V, F, C).
We also examined each main effect of the presence orabsence of thinning and the observations before andafter the experiment. For the former, we observed a significant effect in C (p < 0.01) and a trend in T-A (p <0.1). For the latter, we observed a significant effect in TA, D, and C (p < 0.01, respectively), and a trend in F (p <0.05) (Table 7).
Based on the results of the multiple comparison tests,
the numeric values of T-A, D, F, and C showed a significant reduction and the respondents’ mood was improved(p < 0.01) in the unthinned condition. In the thinned
condition, the numeric values of T-A, D, C, and A-H decreased significantly (p < 0.05), and F also showed a declining trend (p < 0.1) (Table 8).
The psychological restorative effect was assessed by performing a two-way repeated measures ANOVA on the
PANAS data, considering the presence or absence of thinning (unthinned–thinned) and the observations before

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

Page 9 of 15

Table 5 Results of t-test comparison between unthinned and thinned settings (Semantic Differential Method)
Unthinned
Bright (1) - Dark (7)Thinned

mean

S.D.

mean

S.D.

2.3

±0.8

3.1

±1.19

t

p

-2.48

0.027

r
*

0.552

Open (1) - Closed (7)

2.3

±1.11

2.7

±1.35

-1.03

0.320

0.266

Artificial (1) - Natural (7)

5.7

±0.82

5.4

±1.3

0.59

0.565

0.156

Smelly (1) - Odorless (7)

3.6

±1.35

3.3

±1.23

0.48

0.639

0.128

Still (1) - Animated (7)

5.0

±1

4.5

±1.13

1.37

0.192

0.345

Comfortable (1) - Uncomfortable (7)

2.5

±1.06

2.7

±1.22

-0.49

0.629

0.131

Quiet (1) - Noisy (7)

3.2

±1.35

3.3

±1.5

-0.24

0.815

0.064

Ugly (1) - Beautiful (7)

5.6

±0.74

5.3

±0.9

1.07

0.301

0.277

Pleasing sound (1) - Irritating noise (7)

2.5

±1.41

3.1

±1.25

-1.21

0.245

0.309

Friendly (1) - Unfriendly (7)

2.4

±0.74

2.3

±0.72

0.32

0.751

Dull (1) - Refreshing (7)

5.9

±0.64

5.1

±1.44

1.87

0.082

Orderly (1) - Chaotic (7)

3.7

±1.39

3.7

±1.18

0.12

0.906

0.033

Warm (1) - Cool (7)

4.9

±1.03

4.7

±1.23

0.72

0.484

0.189

Insecure (1) - Secure (7)

4.9

±1.1

4.6

±1.18

0.66

0.519

Gentle lighting (1) - Too bright (7)

2.8

±0.94

2.3

±0.7

1.88

0.081

#

0.449

Thin (1) - Thick (7)

4.0

±0.66

3.3

±0.98

1.78

0.096

#

0.431

Flat (1) - Three dimensional (7)

5.3

±1.5

5.3

±1.35

0.00

1.000

0.087
#

0.448

0.174

0.000

Awaking (1) - Soothing (7)

4.7

±1.16

4.9

±1.44

-0.39

0.700

0.105

Enchanted (1) - Disenchanted (7)

3.5

±0.74

3.2

±1.08

0.79

0.442

0.207

Fragrant (1) - Malodorous (7)

3.5

±0.74

3.3

±0.7

0.94

0.364

0.244

Non enjoyable (1) - Enjoyable (7)

5.7

±0.59

5.8

±0.78

-0.27

0.792

0.072

Restless (1) - Calm (7)

5.4

±1.18

5.3

±1.44

0.26

0.796

Dry (1) - Wet (7)

3.8

±0.86

5.3

±0.96

-3.90

0.002

Nondescript (1) - Unique (7)

3.4

±0.74

3.7

±1.03

-1.05

0.313

0.27

Healthy (1) - Unhealthy (7)

2.5

±0.52

2.4

±0.83

0.62

0.546

0.164

0.071
**

0.722

Likert scale of seven stages was used for this questionnaire**p < 0.01, *p < 0.05, #p < 0.1 paired t-test

and after the experiment (pre–post) as factors, similar to
the POMS (Tables 9 and 10).
We did not observe any interaction between the presence and absence of thinning and pre–post observations
on the two PANAS indices (negative and positive).
Table 6 Results of t-test comparison between unthinned andthinned settings (Perceived Restorativeness Scale)
Unthinned
Being away

Thinned

Mean

S.D.

34.2

±5.98 33.9

Mean

33.1

t

p

r

S.D.
±8.54 0.11

0.912 0.031±8.32 0.72

0.481 0.191

Fascination

35.1

±6.3

Coherence

20.3±4.27 21.3

±5.62 −0.45 0.657 0.121

Scope

22.7

±5.85 26.5

±5.88 −1.62 0.128 0.397

Compatibility 27.5

±4.19 28.9

±2.67 −0.84 0.413 0.221

Familiality

5.2±2.83 6.0

±2.83 −0.86 0.403 0.225

Preference

11.7±2.23 11.7

±3.37 −0.06 0.954 0.016

paired t-test

Additionally, no significant effect was found for the main
effects (Table 9). The results of the multiple comparison
tests showed no significant difference between the respondents’ negative and positive emotions before and after theexperiment in both the unthinned and thinned conditions(Table 10). To assess the psychological restorative effect,
we carried out a two-way repeated measures ANOVA on
the ROS data with the presence and absence of thinningand pre–post measures as factors, similar to the POMS
and PANAS analyses (Tables 11 and 12).
We did not find an interaction between the presenceof thinning and the pre–post measures. For the main
effects, we observed a significant effect before and after
the experiment (p < 0.05), but not between the presence
and absence of thinning (Table 11). In the unthinned
condition, there was a significant difference between preand post ROS scores (p < 0.01). However, although thepost scores also increased in the thinned condition, thedifference was not significant (Table 12).

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

Page 10 of 15

Table 7 Results of two-way repeated measures ANOVA for Profile of Mood States (mood)
POMS

Main effectInteraction

Condition
Unthinned vs. thinnedFp

Tension-Anxiety

3.51

0.072

Depression-Dejection

0.20

0.662

Time
Pre vs. post
η2#

F

Condition × time
η2

p

F

η2

p

0.032

5.02

0.033

*

0.110

0.06

0.805

0.001

0.002

4.41

0.045

*

0.115

1.06

0.312

0.006

Anger-Hostility

2.03

0.165

0.018

1.76

0.195

0.044

1.04

0.318

0.009

Vigor

1.88

0.182

0.021

1.35

0.256

0.031

0.01

0.923

0.001

Fatigue

2.15

0.153

0.013

4.12

0.052

#

0.105

1.16

0.291

0.007

Confusion

35.35

0.000

0.189

4.57

0.041

*

0.093

0.20

0.661

0.002

**

**p < 0.01, *p < 0.05, #p < 0.1 two-way repeated measures ANOVA

the experiment, the average POMS C score in the unthinned
condition was 4.07 and that in the thinned condition was
2.00. Each of these values showed a significant difference.
This indicates that the thinning did not decrease respondents’ confusion, but their experimental experience in May
helped to reduce their confusion because we carried out thesecond session in October within the same experimental
area. Comparison of the mean T-A scores showed that they
were significantly higher in the unthinned than the thinned
condition (p < 0.05), but we did not observe any significant
difference in the same comparison after the experiment.
Therefore, we conclude that the experimental experience
itself primarily influenced the respondents, rather than theinfluence of the thinned forest environment (Table 8).

We did not observe an interaction between the POMS
(mood), PANAS (emotion), and ROS (restorative feeling) indices. This implies that there was no complex effect between
the thinning of the forest environment and spending time init. As for the psychological effects on mood, emotion, andthe feeling of restoration, we did not observe any particulareffect, either in terms of thinning or of forest stay.
A main effect of thinning was observed on mood C (p <0.01) and T-A (p < 0.1) (Table 4). Based on these results, itappears that thinning effectively influenced the C and T-A
indicators of mood. However, comparing the results for eachindicator in the presence or absence of thinning in Table 8,
the average POMS C score in the unthinned condition was
5.80, whereas that in the thinned condition was 3.40. After

Table 8 Results of multiple comparison tests between before and after thinning (setting) and pre–post (exposure to the forest) for
Profile of Mood States (mood)
Unthinned

Thinned

Pre

Post

Pre

p

Mean

S.D.

Mean

S.D.

Tension-Anxiety

4.20

±3.34

2.20

±2.91

0.006

Depression-Dejection

1.47

±1.85

0.20

±0.56

0.002

Anger-Hostility

0.40

±0.74

0.20

±0.77

Vigor

5.07

±3.31

3.87

±3.54

Fatigue

2.73

±2.22

0.93

±1.16

0.002

Confusion

5.80

±2.24

4.07

±1.22

0.005

Post

p

Mean

S.D.

Mean

S.D.

**

3.07

±2.59

1.33

±1.45

0.017

*

**

1.33

±2.09

0.53

±0.62

0.043

*

0.383

0.80

±1.22

0.27

±0.57

0.023

*

0.160

4.07

±3.30

3.00

±2.63

0.211

**

2.87

±2.87

1.80

±1.76

0.061

#

**

3.40

±5.65

2.00

±1.83

0.021

*

Pre

Post

Unthinned

Thinned
S.D.

Mean

S.D.

Tension-Anxiety

4.20

±3.34

3.07

±2.59

0.043

Depression-Dejection

1.47

±1.85

1.33

±2.09

0.561

Anger-Hostility

0.40

±0.74

0.80

±1.22

0.021

Vigor

5.07

±3.31

4.07

±3.30

0.153

Fatigue

2.73

±2.22

2.87

±2.87

0.698

Confusion

5.80

±2.24

3.40

±5.65

0.000

**p < 0.01, *p < 0.05, #p < 0.1 ANOVA-Bonferroni

Unthinned

p

Mean

*

*

**

Thinned

p

Mean

S.D.

Mean

S.D.

2.20

±2.91

1.33

±1.45

0.116

0.20

±0.56

0.53

±0.62

0.152

0.20

±0.77

0.27

±0.57

0.687

3.87

±3.54

3.00

±2.63

0.214

0.93

±1.16

1.80

±1.76

0.017

*

4.07

±1.22

2.00

±1.83

0.000

**

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

Page 11 of 15

Table 9 Results of two-way repeated measures ANOVA for Positive and Negative Affect Schedule (emotion)
PANAS

Main effectInteraction

Condition
Unthinned vs. thinnedTime
Pre vs. post

Condition × time

F

p

η2

F

p

η2

F

p

η2

Negative

0.63

0.434

0.001

0.77

0.387

0.001

0.12

0.731

0.001

Positive

0.23

0.636

0.001

1.13

0.296

0.001

0.05

0.820

0.001

two-way repeated measures ANOVAof the indicators (bright–dark, dry–wet, gentle lighting–too bright, dull–refreshing, thin–thick), and as already discussed, it seems that this was because of the influence of
the weather conditions during the experiments (Table 1).
In contrast, in the analysis of appreciation for the environment, the thin–thick indicator showed a trend: thinned(3.33) was evaluated as more deserted than unthinned(4.00). Moreover, because the physical changes due to thethinning and the appreciation corresponded, as a decreasein tree density and the total basal area of the thinned condition was recognized, we suggest the possibility that thethinned forest strengthened the impression of the forest environment being deserted.
For the restorative properties of the forest environment,
there was no significant difference between the thinned andthe unthinned environment for any of the indicators related
to the restorative properties (being away, fascination, coherence, scope, and compatibility).
In general, the above results suggest that slight thinning,as executed in this study, does not affect appreciation of
the environment and its restorative properties, except for a
few indices. A few studies (e.g., Gifu Prefectural ResearchInstitute for Forests 2004 and Oku 2007) have reported anincrease in the psychological restorative effect and a general
improvement in respondents’ impressions with increased
thinning. However, our result shows that this does notalways apply to all factors. In other words, even with thinning of the somewhat managed forest, the relaxation effect(including the psychological restorative effect) will not

We also confirmed the effect of the stay in the forest on
mood (POMS; T-A, D, C) and restorative feeling (ROS).
Further, there was a tendency for the forest to restore therespondents’ exhausted mood (Table 7). The results were
supported by the multiple comparison test results shown in
Table 8; in the unthinned condition, the mean scores for
T-A, D, F, C (POMS), and ROS showed a significant decrease after compared with before the experiment (p <0.01). In the thinned condition, a similar decrease in T-A,
D, A-H, and C mean scores was observed (p < 0.05) and adecreasing trend was observed in F (p < 0.1). These results
suggest that the respondents’ mood improved and they felt
restored by being in the forest environment during the experiment, irrespective of thinning. Importantly, this finding
has not been reported in other research to date.
Regarding negative and positive emotion (PANAS), we
did not observe any significant relationship in the interaction, the main effect, or in the multiple comparison
tests, indicating that neither the thinning (unthinned–
thinned) nor the forest stay (pre–post) had a direct
effect on respondents’ emotions. This is consistent withthe results of previous studies, including that of
Takayama et al. (2014b).
In this study, we conducted slight thinning to decrease
the forest density by 16.6% and the total basal area by approximately 9.3% (Fig. 2 and Table 2). Appreciation of theforest environment did not differ significantly dependingon whether the forest was thinned or unthinned. However,
we observed a significant difference (or a trend) in some

Table 10 Results of multiple comparison tests between before and after thinning (setting) and pre–post (exposure to the forest) for
Positive and Negative Affect Scale (emotion)
Unthinned

Thinned

Pre
Mean

Post
S.D.

Mean

p
S.D.

Pre
Mean

Post
S.D.

Mean

p
S.D.

Negative

12.4

±4.82

11.0

±4.61

0.252

13.0

±5.21

12.5

±4.02

0.701

Positive

23.5

±8.58

20.5

±9.49

0.174

23.9

±7.26

21.9

±7.43

0.336

Pre

Post

Unthinned
Mean

Thinned

p

S.D.

Mean

S.D.

Unthinned

Thinned

p

Mean

S.D.

Mean

S.D.

Negative

12.4

±4.82

13.0

±5.21

0.658

11.0

±4.61

12.5

±4.02

0.263

Positive

23.5

±8.58

23.9

±7.26

0.806

20.5

±9.49

21.9

±7.43

0.484

ANOVA-Bonferroni

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

Page 12 of 15

as a trend that was probably due to a difference in the
thickness (p < 0.1) attribute and was actually rated higher inthe thinned than the unthinned condition (Table 5).
In an attempt to aggregate the above discussion, at firstsight it seems that thinning can improve respondents’appreciation of the forest environment, resulting in the
reduction of tension and anxiety (main effect; p < 0.1;
Table 7). However, looking at the results of the multiple
comparison tests (Table 8), although a significant difference was observed in the comparison of average scores
regarding the presence or absence of thinning before theexperiment, no such difference was observed after theexperiment. Thus, the forest seems to reduce tension andanxiety more than confusion, regardless of thinning.

Table 11 Results of two-way repeated measures ANOVA for Restorative Outcome Scale (subjective restorativeness)
ROS Main effectInteraction

Condition
Time
Unthinned vs. thinned Pre vs. post

Condition × time

F

p

η2

F

0.05

0.829

0.001

5.94 0.021 * 0.111 1.35 0.255 0.002

p

η2

F

p

η2

*two-way repeated measures ANOVA

necessarily increase. This is an important finding that has
not been reported in other papers on this topic (e.g., Ribe
(1989); Ryan (2005); Ribe (2009); Schroeder and Green(1985); Gundersen and Frivoid (2011); Tyrväinen et al.
(2014a)). Explanations for this observation include (1) theexperimental plot, i.e., the experimental area of this study
was a forest in which the density and undergrowth werealready moderately managed before the experiment, and (2)the slight thinning enforced in this experiment did notreach the threshold value to make a difference in theappreciation of the forest environment and its restorative
properties. To manage forests that have been only partiallymanaged previously and have already gained a certain levelof positive evaluation, it might be possible to carry out acontinuous evaluation by repeated slight thinning withminimal effort.

Thinning and psychological restorative effectFollowing thinning, the physical indicators of management in the experimental area, such as tree density andtotal basal area, were reliably reduced. However, withrespect to the psychological restorative effect, it was
directly confirmed that there was almost no indicatorinfluenced by thinning. In other words, there seemed to
be no effect on any of the mood indices (T-A, D, A-H,
V, F, C), emotion (negative and positive affect), or restorative feeling, although a restorative effect seemed tobe confirmed in some indicators after spending a certain
period of time in the forest environment. Therefore, thedifference in the psychological restorative effect may be
a result of the precondition in which the original research plot was to some extent managed already as an
artificial forest, or by the control condition in which
weaker thinning was carried out in this study.
Based on the above discussion, and assuming the
response system (stimulus → appreciation → response)
according to Lazarus’s stress model (Kosugi et al. 2002),
we could suggest that the change in the external environment influenced the environmental appreciation of“deserted-dense” (Table 5). Finally, the result of thisappraisal (greater appreciation for deserted) did not have arestorative psychological effect. In other words,

Landscape appreciation and psychological restorative effectConsidering the relationship between landscape appreciation (appreciation for and restorative properties of theenvironment) and its psychological restorative effect,
there was a main effect (or trend) for the thinned compared with the unthinned forest (Table 8).
We do not discuss confusion further here, as it wasconsidered to be influenced by the presence or absence ofthe experimental experience rather than the influence ofthinning, as discussed previously. In contrast, improving
the forest environment by thinning seemed to reduce thetension and anxiety of the respondents. However, its effecton appreciation for the forest environment was confirmed

Table 12 Results of multiple comparison tests between before and after thinning (setting) and pre–post (exposure to the forest) for
Restorative Outcome Scale (subjective restorativeness)
Unthinned

Thinned

Pre

Post

Pre

p

Mean

S.D.

Mean

S.D.

25.73

±3.22

29.53

±4.37

0.001

Pre

**

Post

p

Mean

S.D.

Mean

S.D.

26.60

±3.64

28.27

±4.50

0.110

Post

Unthinned

Thinned

p

Mean

S.D.

Mean

S.D.

25.73

±3.22

26.60

±3.64

**p < 0.01, ANOVA-Bonferroni

0.353

Unthinned

Thinned

p

Mean

S.D.

Mean

S.D.

29.53

±4.37

28.27

±4.50

0.178

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

conducting weaker thinning of a moderately managed forest for recreational use, as in this study, could enhance theappreciation of the forest by decreasing the tree density;
nevertheless, the results also imply that there may be no
psychological restorative effect of staying in a forest.

Conclusions
The results of this study indicate that when performing
thinning in a forest located in a summer resort spot near
the city used primarily for forest recreation and forest bathing, approximately half the amount (15 to 20%) of standard
thinning (30 to 40%) in forestry regions was sufficient to accomplish the management of the forest without changing
the user’s appreciation and the restorative effect.
In general, managing the density of trees, the design ofpaths, installation of facilities such as billboards andarbors, and management plans that secure all of these
aspects are potential challenges to enhancing the physicaland mental restorative effect of the forest. However,
because the forest environment itself is composed of avariety of flora and fauna, and facilities age quickly, it is essential to consider the cost of constructing these facilities(which must be new) and maintaining the diversity of animals and plants, which is the infrastructure of the forest.
For example, if we need to implement a forest management method that involves reducing the tree density by atleast 16–17% and the total basal area by 9–10%, the removal of primarily small-diameter and suppressed trees
will achieve this while maintaining the forest’s mental andphysical restorative effects and, at the same time, reducing
management costs. Thus, we can propose to develop a rational and sustainable management method that protects
large-diameter trees to ensure future management funds.
Summary

The following three points summarize the main findingsof the study:– The evaluation of the restorative effects of the forest
environment did not change after the slight thinningof the urban forest that had been maintained tosome extent, except for some impression
evaluations.
– The weak thinning of the suburban forest had less ofan effect on impression evaluations than did theeffect of the weather conditions during theexperimental period.
– The psychological restorative effects of the lightly
maintained suburban forest were not always
improved by weak thinning.
Limitations

Because the present study involved conducting two
experiments in different forest conditions (thinned andPage 13 of 15

unthinned) with the same respondents, we selected 15
people who could participate in both conditions. Similar toother psychological experiments conducted on-site (e.g.,
Oishi et al. 2003; Park et al. 2009; Tsunetsugu et al. 2010;
Park et al. 2010; Horiuchi et al. 2014), this study could beconsidered as an empirical case study conducted with a nofunction condition because the respondents were the same
in both experiments. However, the number of respondents
used to obtain the results was relatively small, and theproperties of the forest environment varied depending on
the climatic zones, biota, and management conditions ofeach region. Therefore, we must be sufficiently cautious ingeneralizing the knowledge gained through this experiment.
We strived to carry out the two experiments in May andOctober under similar conditions except for the thinning;nevertheless, strict control of some conditions, such as theweather and season-specific flora and fauna, was not possible. Moreover, the experiments were carried out while therespondents were relaxing on a chair in the forest, but wemust acknowledge that other activities, such as taking aleisurely stroll, are also common in a forest. Thus, we needto perform further experiments to understand the effects ofthinning while performing other activities such as strolling.
In addition, the respondents who participated in this research were graduate students or faculty members in forest
science, which means there is a possibility that the resultsof this experiment might not apply to general forest users.
Lastly, the difficulty of controlling weather conditions is a
critical problem for on-site experiments. For strict control,
it would be necessary to use a climate-controlled room withpre-determined weather conditions.
Future research

To generalize the results of this study, additional researchis necessary, including experiments and laboratory tests
using videos and photos as well as a greater range of respondents. Furthermore, we found that thinning improved
the impression of the forest environment, as measured by
an improvement in some indicators of mood. This aspect
can be understood through theories such as Appleton’s(1996) prospect-refuge theory, which posits that one’s fearof the natural environment can be mitigated. Thus, tomake forests comfortable spaces for recreation and mental
restorative purposes, it is important for forest managers togather additional information concerning the relationshipbetween the prospect of a forest and a sense of fear, insecurity, or nervousness of the forest environment; however,this type of empirical research is not yet common.
In this study, the psychological restorative effect of forests was not increased by thinning. However, as Appleton (1996) states in his “prospect-refuge theory,” a goodprospect environment in which one can observe whileremaining unseen by others is a necessary condition forpeace of mind; hence, higher psychological and physicalTakayama et al. Progress in Earth and Planetary Science (2017) 4:17

restorative effects may be expected when dense forests
are thinned more than they were in this study. It is
important to conduct additional experiments to assess
users of the forest and its restorative effects. For
example, an additional experiment could compare twoforest environments of the same type, one unmanaged
and natural and the other a maintained forest used forrecreation or forest bathing.
Abbreviations
PANAS: Positive and Negative Affect Schedule; POMS: Profile of Mood States;
PRS: Perceived Restorativeness Scale; ROS: Restorative Outcome Scale;
SD: Semantic Differential
Acknowledgements
The ethical committee of the Mt. Fuji Research Institute approved allprocedures applied in the present study in accordance with the guidelines of
the Declaration of Helsinki. Before the experiment, the respondents had
sufficient informed consent and agreed to participate in the experiments. We
thank all of the respondents who gave their time and effort to this study. We
gratefully appreciate the financial support (awarded to M.H.) of the Yamanashi
Institute of Environmental Sciences and Japan Society for the Promotion of
Science (No. 26400268 to M.H.) and the academic research grant (awarded to
H.S. and A.K) of the Yamaguchi Scholarship Foundation. We express our
gratitude to the following for their help in organizing the experiments andgiving us useful suggestions through their discussion: Kazutaka Murase, Norio
Nishiyama, Junko Endo, Yuko Asano, Susumu Goto, and Junko Saito.
Funding
Not applicable
Authors’ contributions
NT, MH, HS, and AF contributed to the conception and design of the study,
performed the experiments, analyzed the data, and prepared the figures andtables. NT, HS, and AF interpreted the results of the experiment; MH and HS
obtained the grants for the study. NT wrote the first draft and all authors revised
the manuscript. All authors approved the final version of the manuscript.
Competing interests
The authors declare that they have no competing interests.

Publisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims inpublished maps and institutional affiliations.
Author details
1
Division of Forest Management, Forestry and Forest Products ResearchInstitute in Japan, 1 Matsuno-sato, Tsukuba City, Ibaraki 305-8687, Japan. 2Fuji
Iyashinomoroi Woodland Study Center, The University of Tokyo, Yamanaka
341-2, Yamanakako Village, Minami-tsuru, Yamanashi 401-0501, Japan.
3
Division of Human Environmental Science, Mt. Fuji Research Institute, 5597-1
Kami-Yoshida, Fuji-Yoshida City, Yamanashi 403-0005, Japan.
Received: 30 May 2016 Accepted: 22 May 2017

References
Appleton J (1996) The experience of landscape. Wiley, New YorkBrunson MW, Reiter DK (1996) Effects of Ecological Information on Judgments
about Scenic Impacts of Timber Harvest. J Environ Manag 46:31–41. doi:10.
1006/jema.1996.0004
Brunson MW, Shelby B (1992) Assessing recreational and scenic quality. J For 90:37–41
Buhyoff GJ, Leuschner WA (1978) Estimating Psychological Disutility from
Damaged Forest Stands. For Sci 24:424–432
Daniel TC (2006) Public preferences for future conditions in disturbed andundisturbed northern forest sites. Public Wild Fire Manag Soc Sci Find Manag
53–62. https://www.nrs.fs.fed.us/pubs/gtr/gtr_nrs1.pdf#page=63

Page 14 of 15

Deng S, Yan J, Guan Q, Katoh M (2012) Short-term effects of thinning intensity
on scenic beauty values of different stands. J For Res 18:209–219. doi:10.
1007/s10310-012-0342-5
Edwards D, Jay M, Jensen FS et al (2012) Public preferences for structural
attributes of forests: Towards a pan-European perspective. Forest Policy Econ
19:12–19. doi:10.1016/j.forpol.2011.07.006
Food and Agriculture Organization (2007) Food and Agriculture Organization of
the United Nations State of the World’s Forest., http://www.fao.org/docrep/009/a0773e/a0773e00.htm. Accessed on 6 June 2014
Forestry Agency of Japan (2016) Annual Report on Trends in Forests and Forestry(in Japanese) Fiscal Year 2015
Fujisawa M, Takayama N (2014) Verification of Restorative Effect in Off-site Forest
Bathing by ROS Japanese Edition. Pap Environ Inf Sci (in Japanese) 28:316–366
Fujisawa M, Takayama N, Morikawa T (2012) Study on Physiological Response
and Subjective Appraisal Brought visually by a Light Environment of a Forest.
Pap Environ Inf Sci (in Japanese) 26:103–106
Gifu Prefectural Research Institute for Forests (2004) Methods of Thinking andManagement of the forest Landscape (in Japanese). Gifu Prefectural ResearchInstitute for Forests,Gifu
Gobster PH (1999) An ecological esthetic for forest landscape management.
Landsc J 18:54–64
Guan Q, Deng S, Yan J (2010) Effects of Thinning Intensity on the SBE in Different
Types Stand
Gundersen V, Frivoid LH (2011) Naturally dead and downed wood in Norwegianboreal forests: public preferences and the effect of information. Scand J For
Res 26:110–119
Haluza D, Schönbauer R, Cervinka R (2014) Green perspectives for public health: anarrative review on the physiological effects of experiencing outdoor nature.
Int J Environ Res Public Health 11:5445–61. doi:10.3390/ijerph110505445
Hartig T (2005) personal communication, January
Hartig T, Florian GK, and Peter AB. (1997a) Further development of a measure ofperceived environmental restorativeness. Working Paper (5), Institutet för
bostadsforskning, Gävle
Hartig T, Korpela K, Evans GW, Gärling T (1997b) A measure of restorative quality
in environments. Scand Hous Plan Res 14:175–194
Hartig T, Lindblom K, Ovefelt K (1998) The home and near-home area offer
restoration opportunities differentiated by gender. Scand Hous Plan Res 15:
283–296. doi:10.1080/02815739808730463
Hartig T, Evans GW, Jamner LD et al (2003) Tracking restoration in natural andurban field settings. J Environ Psychol 23:109–123
Herzog TR, Chernik KK (2000) Tranquility and danger in urban and natural setting.
J Environ Psychol 20:29–39
Horiuchi M, Endo J, Takayama N et al (2014) Impact of Viewing vs. Not Viewing a
Real Forest on Physiological and Psychological Responses in the Same
Setting. Int J Environ Res Public Health 11:10883–10901. doi:10.3390/
ijerph111010883
Iwashita T (1983) Guide of measurement - understanding and enforcement of
the image by the SD method (in Japanese). Kawashima shoten, Tokyo
Kaplan R, Kaplan S (1989) The Experience of Nature: A Psychological Perspective,
1st edn. Cambridge University Press, New York
Kaplan S, Bardwell LVW, Slakter DB, Kaplan S (1993) The museum as a restorativeenvironment. Environ Behav 25:725–742
Kobayashi H, Song C, Ikei H et al (2015) Analysis of Individual Variations inAutonomic Responses to Urban and Forest Environments. Evid BasedComplement Alternat Med 2015:671094. doi:10.1155/2015/671094
Korpela K, Hartig T (1996) Restorative qualities of favorite places. J Environ
Psychol 16:221–233. doi:10.1006/jevp.1996.0018
Korpela KM, Ylén M, Tyrväinen L, Silvennoinen H (2008) Determinants ofrestorative experiences in everyday favorite places. Health Place 14:636–652
Korpela KM, Ylén M, Tyrväinen L, Silvennoinen H (2010) Favorite green, waterside
and urban environments, restorative experiences and perceived health inFinland. Health Promot Int 25:200–209
Kosugi S, Shimazu A, Tanaka K et al (2002) Stress Psychology -A process andcoping of the individual difference (in Japanese). Kawashima shoten, Tokyo
Kunisaki T, Imada M (1996) Changes in visual penetration in a plantation afterthinning. Japanese J For Plan (in Japanese):26:51–58
Laumann K, Gärling T, Stormark KM (2003) Selective attention and heart rate
responses to natural and urban environments. J Environ Psychol 23:125–134
Li Q, Morimoto K, Nakadai A et al (2007) Forest bathing enhances human naturalkiller activity and expression of anti-cancer proteins. Int J Immunopathol
Pharmacol 20:1–8

Takayama et al. Progress in Earth and Planetary Science (2017) 4:17

Li Q, Morimoto K, Kobayashi M et al (2008a) A forest bathing trip increases
human natural killer activity and expression of anti-cancer proteins in female
subjects. J Biol Regul Homeost Agents 22:45–55
Li Q, Morimoto K, Kobayashi M et al (2008b) Visiting a forest, but not a city,
increases human natural killer activity and expression of anti-cancer proteins.
Int J Immunopathol Pharmacol 21:117–127
McNair DM, Lorr M, Maurice L (1964) An analysis of mood in neurotics. J Abnorm
Soc Psychol 69:620–627
Morita E, Nagano J, Fukuda S et al (2009) Relationship between forest walking(shinrin-yoku) frequency and self-rated health status: cross-sectional study ofhealthy Japanese. Jpn J Biometeorol (in Japanese) 46:99–107
Ochiai H, Ikei H, Song C et al (2015a) Physiological and Psychological Effects ofForest Therapy Program on Middle-Aged Females. Int J Environ Res Public
Health 12:2532–2542. doi:10.3390/ijerph120302532
Ochiai H, Ikei H, Song C et al (2015b) Physiological and Psychological Effects ofForest Therapy on Middle-Aged Males with High-Normal Blood Pressure. Int
J Environ Res Public Health 12:2532–2542. doi:10.3390/ijerph120302532
Ohira H, Takagi S, Masui K et al (1999) Effects on shinrin-yoku (forest-air bathing
and walking) on mental and physical health. Bull Tokai Women Univ (inJapanese) 19:217–232
Oishi Y, Hiyane A, Taguch H, Murai H (1994) Analysis for psychology in a forest
environment: Semantic differential method in the experimental forest ofrecreational function. Japanese J For Plan (in Japanese):23:33–44
Oishi Y, Kanehama S, Hiyane A, Taguchi H (2003) Comparison of Forest Imageand Wood: Psychological Examination in a Forest Environment Using Profile
of Wood States and Semantic Differential Method. J Jpn For Soc (inJapanese) 85:70–77
Oku H (2007) How does make a forest landscape? In: Oku H, Kagawa T, Tanaka N(eds) Guide for making with attractive forest Landscape (in Japanese), 1stedn. National forestry improvement Promotion Association, Tokyo, p 275
Park BJ, Tsunetsugu Y, Kasetani T et al (2009) Physiological effects of forest recreation ina young conifer forest in Hinokage town, Japan. Silva Fenn 43:291–301
Park BJ, Tsunetsugu Y, Kasetani T et al (2010) The physiological effects of Shinrinyoku (taking in the forest atmosphere or forest bathing): evidence from field
experiments in 24 forests across Japan. Environ Health Prev Med 15:18–26.
doi:10.1007/s12199-009-0086-9
Park BJ, Furuya K, Kasetani T et al (2011) Relationship between psychologicalresponses and physical environments in forest settings. Landsc Urban Plan
102:24–32. doi:10.1016/j.landurbplan.2011.03.005
Ribe RG (1989) The esthetics of forestry: What has empirical preference researchtaught us? Environ Manage 13:55–74. doi:10.1007/BF01867587
Ribe RG (2005) Comparing Changes in Scenic Beauty Produced by Green-Tree
Retention Harvests, Thinnings and Clearcuts: Evidence From Three PacificNorthwest Experiments. In: Maguire and others (eds.) Balancing Ecosystem
Values: Innovative Experiments for Sustainable Forestry. USDA Forest Service,
General Technical Report PNW-635. Portland, OR. 137–146.
Ribe RG (2006) Perceptions of forestry alternatives in the US Pacific Northwest:
Information effects and acceptability distribution analysis. J Environ Psychol
26:100–115. doi:10.1016/j.jenvp.2006.05.004
Ribe RG (2009) In-stand scenic beauty of variable retention harvests and mature
forests in the U.S. Pacific Northwest: The effects of basal area, density,
retention pattern and down wood. J Environ Manage 91:245–260. doi:10.
1016/j.jenvman.2009.08.014
Ryan RM (2005) Social science to improve fuels management: A synthesis ofresearch on esthetics and fuels management. Gen Tech Rep NC, vol 261.
USDA, Forest, St Paul
Ryan RM, Frederick CM (1997) On energy, personality and health: Subjective
vitality as a dynamic reflection of well-being. J Pers 65:529–565
Sato A, Yasuda A (2001) Development of the Japanese version of Positive and
Negative Affect Schedule (PANAS) scales. J Character Psychol (in Japanese) 9:
138–139
Schroeder HW, Green TL (1985) Public preference for tree density in municipalparks. J Arboric 11:272–277
Shibata S, Hata T, Miwa Y (2008) Perceived Restorativeness Scale (PRS) Translation
and Validation of a Japanese Version of the Perceived Restorativeness Scale(PRS). MERA J (in Japanese) 11:1–10
Spielberger CD, Gorsuch RL, Lushene RE (1970) STAI manual for the State-trait
anxiety inventory “self-evaluation questionnaire.”. Consulting Psychologist
Press, Sunnyvale
Spielberger CD, Gorsuch RL, Lushene R et al (1983) Manual for the State-Trait
Anxiety Inventory (Form Y) (“Self-Evaluation Questionnaire”)., pp 1–37

Page 15 of 15

Staats H, Kieviet A, Harting T, Hartig T (2003) Where to recover from attentional
fatigue: expectancy-value analysis of environmental preference. J Environ
Psychol 23:147–157
Takahashi N, Kanno T, Nobori Y (2006) Effects of mixture type and the ratio of
broad-leaved trees on preferences in evaluations of landscapes of mixed
forests with coniferous and broad-leaved trees. Jpn J For Plan (in Japanese)
40:191–201
Takanashi T (2011) A study on Application of Forest Landscape Management
Guidelines to the Maintenance of Non-Tending Artificial Forests of
SATOYAMA. Bulletion JSSD 58:78–86
Takayama N, Kagawa T (2013) Study on a Function of the Forest Environment as
the Restorative Environment Using the Attention Restoration Theory. J Jpn
Inst Landsc Archit (in Japanese) 76:539–542. doi:10.5632/jila.76.539
Takayama N, Kawaguchi T, Kasetani T et al (2009) The Relation between the
Measured Environmental Factors and the Evaluation Factors Extracted from Onsite Forest Environment. J Jpn Inst Landsc Archit (in Japanese) 72:669–672
Takayama N, Fujisawa M, Aramaki M, Mmorikawa T (2012) Influence of Subjective
Appraisal and Personality and Other Traits to Psychological Stress Reduction
Effect Caused by the Sunshine Filtering Through Foliage in the Forest Picture. J
Jpn Inst Landsc Archit (in Japanese) 75:565–570. doi:10.5632/jila.75.565
Takayama N, Fujiwara A, Saito H et al (2014a) Cognitive traits derived from thedifference between scenery viewing and covering in on-site forest
environment. Kanto J For Res (in Japanese) 65:157–158
Takayama N, Korpela K, Lee J et al (2014b) Emotional, restorative and vitalizing
effects of forest and urban environments at four sites in Japan. Int J Environ
Res Public Health 11:7207–7230. doi:10.3390/ijerph110707207
Tsunetsugu Y, Park BJ, Miyazaki Y (2010) Trends in research related to “Shinrinyoku” (taking in the forest atmosphere or forest bathing) in Japan. Environ
Health Prev Med 15:27–37
Tsunetsugu Y, Lee J, Park BJ et al (2013) Physiological and psychological effectsof viewing urban forest landscapes assessed by multiple measurements.
Landsc Urban Plan 113:90–93. doi:10.1016/j.landurbplan.2013.01.014
Tyrväinen L, Uusitalo M, Silvennoinen H, Hasu E (2014a) Towards sustainablegrowth in nature-based tourism destinations: Clients’ views of land use
options in Finnish Lapland. Landsc Urban Plan 122:1–15. doi:10.1016/j.
landurbplan.2013.10.003
Tyrväinen L, Ojala A, Korpela K et al (2014b) The influence of urban green
environments on stress relief measures: A field experiment. J Environ Psychol
38:1–9. doi:10.1016/j.jenvp.2013.12.005
Ulrich RS (1984) View through a window may influence recovery from surgery.
Science 224:420–421
Velarde MD, Fry G, Tveit M (2007) Health effects of viewing landscape-Landscapetypes in environmental psychology. Urban For Urban Green 6:199–211
Watson D, Clark LA, Carey G (1988a) Positive and negative affectivity and theirrelation to anxiety and depressive disorders. J Abnorm Psychol 97:346–353
Watson D, Clark LA, Tellegen A (1988b) Development and validation of brief
measures of positive and negative affect: The PANAS Scales. J Pers Soc
Psychol 47:1063–1070. doi:10.1037/0022-3514.54.6.1063
Yokoyama K, Araki S, Kawakami N, Takeshita T (1990) Production of the Japaneseedition of profile of mood states (POMS): Assessment of reliability andvalidity. Jpn J Public Health (in Japanese) 37:913–918