Sustainable Management of National Forest Trails: Structural Relationships Among Volunteer Motivation, Satisfaction, Perceived Quality of Life, and Active Participation Intention

Abstract

National Forest Trails (NFTs), a key component of forest welfare infrastructure, increasingly require a shift from government-led management to citizen-participatory governance. This study examined the structural relationships among volunteer motivation, activity satisfaction, perceived quality-of-life (QoL) change, and behavioral intention in the context of NFT volunteering. A survey was conducted with 217 adults who had participated in forest trail volunteering programs in Korea, and the data were analyzed using structural equation modeling (SEM). The results showed that volunteer motivation had significant positive effects on reward importance, activity satisfaction, and perceived QoL change. Activity satisfaction positively influenced both Future Participation Intention and Active Participation Intention, whereas perceived QoL change had a significant positive effect only on Active Participation Intention. In addition, activity satisfaction and perceived QoL change mediated the relationship between volunteer motivation and Active Participation Intention. These findings suggest that forest trail volunteers are not merely supplementary labor for trail management, but active participants in forest governance who both contribute to and benefit from the environments they help sustain. Overall, the study indicates that sustainable NFT volunteering depends not only on motivation itself, but also on the quality and personal meaning of the volunteer experience. The findings highlight the importance of experience-centered program design, appropriate recognition systems, and greater attention to participant-centered well-being outcomes in sustainable forest trail governance.

1. Introduction

The realization of public welfare through forests has attracted growing global attention, as citizen participation in natural environments generates diverse forms of social value related to health promotion, psychological restoration, community resilience, sustainable lifestyles in the context of the climate crisis, and the broader social impact of volunteerism [1,2,3,4]. Recent discussions have increasingly emphasized the need to incorporate the health and well-being benefits of nature contact into public health and welfare policy [2,5,6]. Within this broader context, forest trails serve as an important form of forest welfare infrastructure because they connect citizens directly to ecological, healing, and leisure resources in forests [7]. Owing to their high accessibility and potential for repeated, everyday use, forest trails are increasingly recognized not merely as recreational spaces but also as active sites of citizen engagement [8,9,10].

In South Korea, the Korea Forest Service (KFS) has designated major long-distance trails with significant ecological, historical, and cultural value as National Forest Trails (NFTs) in order to promote systematic national-level management, ecosystem protection, and public forest welfare [11]. As of November 2023, nine locations totaling 1465.6 km had been designated and managed as NFTs. However, as both the spatial scale of the trail network and public demand for its use continue to expand, government-led management alone faces clear physical and administrative limitations [12]. This has increased the importance of collaborative governance, in which citizens participate not only as beneficiaries of forest welfare services but also as active partners in the creation, maintenance, and operation of forest trails [8,9,12]. In this governance framework, volunteers play an increasingly central role [13,14], functioning not merely as environmental managers but also as active users who generate multilayered value through ecological conservation, support for forest healing activities, and contributions to local communities [13,14,15].

Forest trail volunteering differs in important ways from volunteering in general social welfare or education settings [16]. These activities are embedded in direct contact with the natural environment and often require physical engagement, repeated on-site participation, seasonal adaptability, and continuity over time. Volunteers who participate in forest trail programs may contribute to trail maintenance, ecological conservation, visitor support, and local community vitality while also experiencing restorative and leisure-related benefits from the forest itself [13,14,15]. In this sense, forest trail volunteers occupy a dual role as both providers and beneficiaries of the environments they help sustain. Their participation therefore cannot be understood solely through the lens of civic duty or prosocial contribution. Rather, it reflects a reciprocal form of engagement in which stewardship, personal restoration, and place-based experience are closely intertwined.

Despite this significance, existing studies on forest trails have focused primarily on visitors’ satisfaction, destination preferences, and tourism-related experiences [7,17,18], while research on forest-based health promotion has mainly examined the general therapeutic or restorative effects of forest programs [3,19]. Governance-oriented studies have also tended to emphasize institutional dimensions rather than volunteer-centered psychological processes [9,12]. As a result, relatively little is known about the psychological mechanisms through which volunteer motivation is translated into sustained engagement in the specific context of forest trail volunteering. This limitation is particularly important in Korea, where NFT volunteer programs have often been operated as event-based or one-time activities, making it difficult to build a stable institutional basis for long-term and self-sustaining participation.

Academically, volunteering has often been explained through Self-Determination Theory (SDT) and the Functional Approach [16,20]. SDT distinguishes between intrinsic motives, such as enjoyment, personal growth, and value expression, and extrinsic motives, such as social recognition, career-related benefits, and material rewards, and suggests that autonomous motivation promotes higher-quality engagement and behavioral persistence [20,21]. The Functional Approach further explains that volunteering serves multiple motivational functions, including values, understanding, social, career, protective, and enhancement motives [16]. These perspectives provide a useful foundation for understanding why people choose to volunteer. However, they do not fully capture the distinctive characteristics of forest trail volunteering, which is embedded in repeated interaction with natural environments and place-based stewardship practices. In this context, participation is shaped not only by altruistic or social motives but also by attachment to nature, restorative experiences, and emotional bonds with specific places. Perspectives such as human–nature connectedness and place attachment are therefore particularly relevant to understanding forest trail volunteers, as they help explain why participants may perceive themselves as caring for a meaningful environment rather than simply performing volunteer tasks [21,22,23,24]. In nature-based volunteering, participants often experience a reciprocal dynamic in which they contribute to trail maintenance and ecological care while simultaneously gaining leisure enjoyment, psychological restoration, and personal meaning through the forest. Thus, forest trail volunteering may be understood not merely as service provision, but as a form of healing leisure and environmental stewardship that enhances perceived quality of life (QoL) while supporting sustainable participation [21,22,23,24,25,26]. This interpretation is also consistent with prior discussions distinguishing volunteer-based nature engagement from conventional tourism consumption [27]. Recent studies on environmental volunteering and volunteer retention further suggest that continued participation is shaped not only by initial motivation, but also by post-participation evaluations such as satisfaction and perceived benefit [25,26]. A recent systematic review of environmental volunteering further indicates that motivations such as environmental concern, social interaction, and connection to nature are consistently associated with volunteer retention, while also highlighting a relative lack of retention-focused research in non-Western contexts [28].

Nevertheless, several important research gaps remain. First, most existing studies on forest trails focus on recreational visitors rather than volunteers, leaving the psychological experience of volunteer participants relatively underexplored [7,17,18]. Second, although SDT and the Functional Approach have been widely used to explain volunteer motivation [16,20], their integration with nature-specific and place-based constructs has received limited empirical attention in forest trail contexts [21,22,23,24]. Third, the motivational and behavioral mechanisms that distinguish nature-based volunteering from conventional civic volunteering remain theoretically underdeveloped. Fourth, although forest trail volunteers have often been described as “prosumers” who simultaneously produce and consume forest-related value, this dual-role structure has rarely been examined in relation to satisfaction, perceived QoL change, and continued engagement [13,14,15]. Finally, previous research has seldom distinguished between a basic intention to continue participation and a more active form of engagement involving recommendation, advocacy, or the voluntary investment of personal resources. This distinction may be particularly important in the context of NFT governance, where sustainable management depends not only on whether volunteers return, but also on whether they become more committed and active contributors over time.

To address these gaps, this study examines the structural relationships among volunteer motivation, Reward Importance, activity satisfaction, perceived QoL change, and two forms of behavioral intention—Future Participation Intention and Active Participation Intention—among participants in Korea’s National Forest Trail programs. Specifically, the study investigates whether volunteer motivation predicts Reward Importance, activity satisfaction, and perceived QoL change, whether these psychological evaluations differentially influence future and active participation intentions, and whether activity satisfaction and perceived QoL change mediate the relationship between motivation and behavioral intention. By doing so, this study seeks to clarify the psychological pathways through which forest trail volunteers become not merely temporary helpers, but active partners in sustainable forest governance, while also providing empirical evidence for the design of more effective and sustainable forest welfare policies. This objective is also consistent with recent trail stewardship research suggesting that volunteers in natural settings often assume roles that extend beyond episodic assistance and develop forms of commitment linked to long-term environmental care and governance participation [13].

2. Materials and Methods

2.1. Participants and Data Collection

This study examined adults aged 19 and older with experience in NFT volunteer programs in South Korea. Data collection occurred from 1 May to 30 September 2023, through on-site surveys targeting volunteers who participated in activities at five NFTs: Naepo Cultural Forest Path, Daegwallyeong Forest Path, Jirisan Dulle-gil, Daejeon Dulle-san-gil, and Hallasan Dulle-gil. The survey complied with the Enforcement Rules of the Bioethics and Safety Act [29]. A total of 247 responses were collected; however, this study focused on analyzing “psychological changes based on actual volunteering experience” rather than mere perceptions. A rigorous data-cleaning process was conducted, excluding insincere respondents via introductory screening questions, resulting in 217 valid samples for analysis. Although the sample size decreased due to strict selection criteria, this ensured that the analysis targeted only “Genuine Participants” who engaged in field activities and responded sincerely. Thus, the study has methodological strength in enhancing internal validity and the reliability of the results by assessing satisfaction and QoL changes derived from actual experiences. Regarding sample size adequacy, the present study included 217 cases for a model with six latent constructs and 21 observed indicators, with an estimated 48 free parameters. In addition, post hoc power analysis based on the approach of MacCallum, Browne, and Sugawara [30] indicated sufficient power for the present model. Taken together, these considerations suggest that the sample size was adequate for the analytical purposes of this study. The full questionnaire administered to participants is provided (Appendix A).

2.2. Measures

Survey items were adapted from prior studies in volunteering and leisure research to reflect the specific context of National Forest Trails (NFTs). Content validity was established through expert review and a pilot survey. All items were measured on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). Exploratory Factor Analysis (EFA) and reliability analysis were then conducted to confirm the final items used in the analysis.

Motivation: The motivation scale was developed by integrating the Volunteer Functions Inventory (VFI) [16] and the environmental volunteer motivation scale of Bruyere and Rappe [22]. Items were adapted to the NFT context by replacing generic volunteering references with trail-specific descriptors. After EFA, one item was removed, and the final scale included 14 items grouped into two sub-factors corresponding to intrinsic (9 items) and extrinsic (5 items) motivation. Internal reliability was strong for both factors (Cronbach’s α ≥ 0.84).

Reward Importance: This construct measures the extent to which volunteers consider external recognition and reward systems important in relation to their participation. It was based on prior studies of reward-related persistence factors and institutional recognition in volunteering [31,32] and included items addressing expressions of gratitude, official commendation, and public recognition. Of the eight initial items (F1-1), six were retained after EFA, and internal consistency was acceptable (Cronbach’s α = 0.80).

Satisfaction: Activity satisfaction refers to the volunteer’s overall subjective evaluation of the volunteering experience. The scale was based on the Volunteer Satisfaction Index (VSI) [33] and prior studies on volunteer motivation and satisfaction [32,34], which capture task-related benefits, satisfaction with the operational system, and interpersonal relationships. To reflect the characteristics of NFT volunteer programs, nine items were adapted using trail-specific wording. EFA retained five items loading on a single overall satisfaction factor, and internal reliability was acceptable (Cronbach’s α = 0.80).

Perceived QoL Change: This construct measures the positive subjective change in overall life quality perceived after volunteering participation. It was developed based on Diener et al.’s [35] model of subjective well-being and Thoits and Hewitt’s [36] framework linking volunteer engagement to well-being. The construct was operationalized using two dimensions: QoL impact (E2; overall life improvement and physical–mental restoration) and life satisfaction (E4; meaning in life and future outlook). This structure is consistent with prior research suggesting that nature-based volunteering can generate both hedonic and eudaimonic well-being gains [23,24]. Of the seven initial items, four were retained after EFA, and the final scale showed acceptable reliability (Cronbach’s α = 0.80). Original items were adapted to the context of outdoor forest trail volunteering and validated through expert review and pilot testing.

Behavioral Intention: This construct measures volunteers’ future behavioral plans and willingness toward continued and escalated participation. An initial pool of six items (E1) was adapted from Zeithaml et al.’s customer loyalty scale [37] and modified for the volunteering context, with conceptual support from prior studies on volunteer behavior and sustained volunteerism [38,39]. EFA identified two sub-factors—Future Participation Intention and Active Participation Intention—and, after item reduction, two items were retained for each factor in the final analysis. Future Participation Intention reflects willingness to continue participating in volunteering activities, whereas Active Participation Intention reflects more proactive engagement, such as recommending the activity to others or voluntarily investing personal resources. Reliability analysis confirmed high internal consistency for the retained items (Cronbach’s α = 0.87).

2.3. Analysis Procedure

The collected data were analyzed using R Statistical Software (ver. 4.3.1) and the lavaan package (ver. 0.6-17). The analytical procedure followed the two-step approach recommended by Anderson and Gerbing [40]: (1) a measurement model was evaluated via Confirmatory Factor Analysis (CFA) to verify construct reliability and validity prior to structural path estimation; and (2) the full structural model was estimated using maximum likelihood estimation to test the hypothesized causal paths. Model fit was evaluated using multiple complementary indices: χ²/df (<3.0), CFI (≥0.90), TLI (≥0.90), RMSEA (≤0.08), and SRMR (≤0.08) [41]. Descriptive statistics and reliability analysis (Cronbach’s α) were also conducted. Mediation effects were verified using bias-corrected bootstrapping (5000 resamples), which provides accurate confidence intervals for indirect effects under conditions of non-normality and is more statistically powerful than the Sobel test for detecting mediation [42]. The specific indirect effects are reported to provide a clear account of the mediating pathways linking volunteer motivation to Active Participation Intention.

2.4. Hypotheses

Building on Self-Determination Theory (SDT) [20], the Functional Approach [16], and prior empirical studies on nature-based volunteering [22,23,24,25,26,36], this study proposes three sets of hypotheses regarding the relationships among volunteer motivation, psychological evaluations of participation, and behavioral intention. SDT suggests that intrinsically grounded and autonomous motivation promotes positive affective and cognitive appraisals of activity experiences, thereby supporting sustained engagement [20]. Similarly, the Functional Approach explains that volunteering serves multiple motivational functions, such as values, understanding, social connection, and personal development, which shape participants’ evaluations of and commitment to volunteering [16]. Prior studies in nature-based volunteering have shown that stronger motivation is associated with higher satisfaction and greater perceived personal benefits, including improvements in quality of life (QoL) [23,24,25,26,36]. More recent studies have also reported that retention in environmental volunteer programs is strengthened when initial motivation is accompanied by positive activity evaluations and a meaningful sense of personal benefit, thereby supporting the inclusion of both satisfaction and perceived QoL change as mediating psychological variables [25,26]. Meta-analytic evidence also shows that volunteer motivations are robust predictors of satisfaction, commitment, and intention to continue, thereby supporting the theoretical plausibility of the motivation–satisfaction–behavioral intention pathway proposed in this study [43].

First, volunteer motivation is expected to positively influence key psychological evaluations of participation. In the context of forest trail volunteering, motivated individuals are more likely to perceive the activity as meaningful, satisfying, and beneficial, and may also place greater value on recognition and rewards associated with their contribution. This expectation may be particularly relevant in institutionalized volunteer settings, where recognition and reward can function as meaningful signals that one’s contribution is socially acknowledged and valued, thereby supporting continued engagement.

H1. 

Volunteer motivation will have a significant positive effect on reward importance, activity satisfaction, and perceived QoL change.

Second, post-participation psychological evaluations of volunteering are expected to influence subsequent behavioral intentions. Previous studies have consistently shown that satisfaction is a major predictor of retention and continued participation in volunteering [23,25]. In addition, perceived QoL change may serve as a distinct psychological mechanism, particularly in nature-based volunteering, where participation can generate broader restorative and life-enhancing benefits [24,36]. These benefits may be especially relevant to more proactive forms of engagement, such as recommending the activity to others or voluntarily investing personal resources.

H2a. 

Activity satisfaction will have a significant positive effect on both Future Participation Intention and Active Participation Intention.

H2b. 

Perceived QoL change will have a significant positive effect on Active Participation Intention.

Finally, the effect of volunteer motivation on active engagement is expected to operate through post-participation psychological evaluations rather than through motivation alone. Prior research suggests that satisfaction and perceived personal benefits function as important mechanisms through which initial motivation is converted into durable behavioral commitment [23,25,36].

H3. 

Activity satisfaction and perceived QoL change will mediate the relationship between volunteer motivation and Active Participation Intention.

2.5. Research Model

The hypothesized causal paths of the proposed research model are presented (Figure 1).

3. Results

3.1. Demographic Characteristics of Respondents

Examining the demographic characteristics of the final analysis subjects (n = 217), 53.9% were female, and 46.1% were male. The age distribution showed a majority in the 50 s (36.4%) and 60 s or older (36.4%), indicating that 72.8% of respondents were middle-aged or older. This suggests that forest trail volunteering is mainly conducted by the pre- and post-retirement generation, who have time availability and a strong interest in health management. Residences were distributed as follows: the Chungcheong region (27.2%), Seoul Capital Area (20.7%), and Gyeongsang region (20.3%). Regarding education level, 66.8% were currently enrolled in or had graduated from university, indicating a relatively high level of education among participants (

Table 1. Sociodemographic characteristics of the respondents.

Variable	Category	n	%
Gender	Male	100	46.1
	Female	117	53.9
Age	10–19	3	1.4
	20–29	7	3.2
	30–39	17	7.8
	40–49	32	14.8
	50–59	79	36.4
	Over 60	79	36.4
Marital Status	Single (Never married)	40	18.4
	Married	171	78.8
	Other	6	2.8
Region	Capital Area (Seoul/Gyeonggi)	45	20.7
	Gyeongsang Area	44	20.3
	Jeolla Area	26	12
	Chungcheong Area	59	27.2
	Gangwon/Jeju Area	43	19.8
Education	High school or below	42	19.4
	College (2-year)	27	12.4
	University (4-year)	109	50.2
	Graduate school or higher	36	16.6
	No response	3	1.4
Job Status	Employed	153	70.5
	Unemployed	64	29.5
Monthly Income	<1 million KRW	16	7.4
	1~2 million KRW	30	13.8
	2~3 million KRW	47	21.7
	3~4 million KRW	39	18
	4~5 million KRW	28	12.9
	5~6 million KRW	23	10.6
	6~7 million KRW	14	6.5
	7~8 million KRW	3	1.4
	≥8 million KRW	17	7.8

).

3.2. Verification of Measurement Model

Prior to the structural equation modeling analysis, Confirmatory Factor Analysis (CFA) was conducted to verify the reliability and validity of the measurement model. The model fit indices indicated an acceptable fit (χ²/df = 2.476, CFI = 0.945, TLI = 0.932, RMSEA = 0.053;

Table 2. Model fit indices for Confirmatory Factor Analysis (CFA).

Index	Value	Criteria	Evaluation
χ2/df	2.476	<3.0	Good
CFI	0.945	≥0.90	Good
TLI	0.932	≥0.90	Good
RMSEA	0.053	≤0.08	Good
SRMR	0.039	≤0.08	Good

). Standardized factor loadings for all items exceeded 0.659 (p < 0.001). The Average Variance Extracted (AVE) ranged from 0.531 to 0.711, and Composite Reliability (CR) ranged from 0.815 to 0.891, exceeding the recommended thresholds and supporting convergent validity [44] (

Table 3. Summary of CFA results.

Latent Variables	Std. Factor Loading Range	AVE	CR
Motivation	0.659~0.808	0.531	0.891
Reward Importance	0.670~0.812	0.551	0.878
Satisfaction	0.713~0.860	0.604	0.88
QoL Change	0.719~0.816	0.602	0.864
Future Participation Intention	0.836~0.850	0.711	0.831
Active Participation Intention	0.818~0.841	0.689	0.815

Note: AVE = Average Variance Extracted; CR = Composite Reliability. All loadings are significant at p < 0.001.

). Discriminant validity was also examined following the criteria proposed by Fornell and Larcker [44]. The square root of the AVE for each latent construct exceeded its highest correlation with any other construct, indicating that the latent variables were empirically distinct from one another.

Because all variables were measured using a self-reported survey administered to the same respondents at a single point in time, the possibility of common method bias (CMB) was assessed. First, Harman’s single-factor test [45] was conducted. The unrotated factor solution from the EFA showed that the first factor accounted for 32.47% of the total variance, which is below the commonly used 50% threshold. As an additional diagnostic check, inter-construct correlations were examined. None of the correlations exceeded 0.90, and the square root of the AVE for each construct was greater than its highest correlation with any other construct. Although no single statistical test can completely rule out CMB, these results suggest that severe common method bias is unlikely to have substantially affected the findings [44,45] (

Table 4. Descriptive statistics and reliability analysis.

Variables	Items	Mean	SD	Skewness	Kurtosis	Cronbach’s α
Motivation	14	3.87	0.62	−0.45	0.11	0.872
Reward Importance	6	4.02	0.55	−0.38	−0.21	0.851
Satisfaction	5	4.15	0.49	−0.53	0.35	0.879
QoL Change	4	3.91	0.57	−0.41	0.18	0.843
Future Participation Intention	2	4.22	0.48	−0.67	0.45	0.802
Active Participation Intention	2	4.11	0.51	−0.59	0.26	0.817

Note: All items were measured on a 5-point Likert scale, and Cronbach’s α showed generally good internal reliability of 0.80 or higher. Skewness and kurtosis met the ±2 criteria, indicating no significant violations of the normality assumption.

).

3.3. Structural Model Analysis and Hypothesis Verification

As a result of the SEM analysis, the structural model showed an acceptable fit (χ²/df = 2.613, CFI = 0.934, TLI = 0.920, RMSEA = 0.057, and SRMR = 0.045;

Table 5. Model fit indices for the structural model.

Index	Value	Criteria	Evaluation
χ2/df	2.613	<3.0	Good
CFI	0.934	≥0.90	Good
TLI	0.92	≥0.90	Good
RMSEA	0.057	≤0.08	Good
SRMR	0.045	≤0.08	Good

). The structural model and the standardized path coefficients are presented (Figure 2).

First, volunteer motivation had significant positive effects on Reward Importance (β = 0.512, p < 0.001), activity satisfaction (β = 0.430, p < 0.001), and Perceived QoL Change (β = 0.241, p < 0.01). This indicates that stronger motivation for volunteering was associated with greater perceived importance of rewards, higher satisfaction with the activity, and a greater likelihood of perceiving positive changes in quality of life. Second, activity satisfaction had significant positive effects on both Future Participation Intention (β = 0.364, p < 0.001) and Active Participation Intention (β = 0.317, p < 0.001), suggesting that enjoyment and a sense of accomplishment during volunteering are important factors in sustaining future engagement. Third, Perceived QoL Change also had a significant positive effect on Active Participation Intention (β = 0.215, p < 0.01). This suggests that the broader personal benefits of volunteering, including restoration and perceived life improvement, may encourage volunteers to recommend the activity to others or to invest their own resources in continued participation. The path coefficients and statistical significance of the structural model are presented (

Table 6. Path coefficients of the structural model.

Path	Std. Estimate (β)	SE	p-Value	Result
Motivation → Reward Importance	0.512	0.047	**	Sig.
Motivation → Satisfaction	0.43	0.044	**	Sig.
Motivation → QoL Change	0.241	0.061	*	Sig.
Satisfaction → Future Participation Intention	0.364	0.059	**	Sig.
Satisfaction → Active Participation Intention	0.317	0.062	**	Sig.
QoL Change → Active Participation Intention	0.215	0.07	*	Sig.

Note: ** p < 0.001, * p < 0.01.

).

3.4. Verification of Mediation Effects

Bias-corrected bootstrapping (5000 resamples) was conducted to examine the mediating roles of activity satisfaction and perceived QoL change in the relationship between participation motivation and Active Participation Intention [42]. Because no direct path from Motivation to Active Participation Intention was specified in the structural model, the reported effects represent specific indirect effects transmitted through the mediators.

The indirect effect through activity satisfaction was significant (β = 0.136, 95% CI [0.077, 0.209], Sobel z = 3.982, p < 0.001), indicating that the quality of the volunteer experience is a primary psychological pathway linking motivation to active engagement. The indirect effect through perceived QoL change was also significant (β = 0.052, 95% CI [0.017, 0.103], Sobel z = 2.540, p < 0.01), suggesting that perceived life improvement through volunteering serves as an additional mechanism promoting more proactive forms of participation. Taken together, these findings indicate that volunteer motivation influences Active Participation Intention indirectly through both experiential evaluation and perceived personal benefit (

Table 7. Mediation analysis results.

Mediation Path	Indirect Effect (β)	95% CI	Sobel z
Motivation → Satisfaction → Active Participation Intention	0.136 **	[0.077, 0.209]	3.982 **
Motivation → QoL Change → Active Participation Intention	0.052 *	[0.017, 0.103]	2.540 *

Note: ** p < 0.001, * p < 0.01. CI = confidence interval based on bias-corrected bootstrapping (5000 resamples). No direct path from Motivation to Active Participation Intention was specified in the structural model; therefore, the reported values represent specific indirect effects transmitted through the mediators.

).

3.5. Hypothesis Testing

The results of the hypothesis tests are summarized (

Table 8. Summary of hypothesis testing.

Hypotheses	Description	Result
H1	Motivation → Reward Importance, Satisfaction, QoL Change	Supported
H2a	Satisfaction → Future PI, Active PI	Supported
H2b	QoL Change → Active PI	Supported
H3	Motivation → Satisfaction/QoL Change → Active PI	Supported

). H1 was supported, indicating that volunteer motivation had significant positive effects on Reward Importance, activity satisfaction, and Perceived QoL Change. H2a was supported, showing that activity satisfaction had significant positive effects on both Future Participation Intention and Active Participation Intention. H2b was also supported, indicating that Perceived QoL Change had a significant positive effect on Active Participation Intention. H3 was supported, showing that activity satisfaction and Perceived QoL Change mediated the relationship between volunteer motivation and Active Participation Intention.

Taken together, these results suggest that volunteer motivation influences sustained engagement primarily through post-participation psychological evaluations rather than through motivation alone. In particular, activity satisfaction functioned as the strongest mediating mechanism, highlighting the importance of the quality of the volunteer experience. In addition, Perceived QoL Change contributed independently to Active Participation Intention, indicating that broader personal benefits from volunteering may play an important role in promoting more proactive and committed forms of participation.

4. Discussion

This study empirically analyzed the structural pathways through which participation motivation leads to sustained engagement via psychological mechanisms among volunteers in Korea’s National Forest Trails (NFTs). The results suggest that volunteer behavioral continuity is reinforced not through a single linear mechanism, but through two complementary psychological pathways: the quality of experience (activity satisfaction) and personal benefit (perceived QoL change). Taken together, the findings suggest three implications for the volunteering and environmental governance literature. First, they suggest that nature-related motives and restorative experiences may reflect a motivational configuration that differs from both general civic volunteering and nature-based tourism. Second, they help clarify why forest trail volunteers may be understood as value co-creators whose stewardship commitment extends beyond episodic participation. Third, by distinguishing Future Participation Intention from Active Participation Intention, the study suggests that volunteer commitment in the NFT context may be understood as a differentiated and hierarchical process rather than as a single behavioral outcome. The following discussion elaborates on these findings in relation to prior empirical and theoretical work.

4.1. Academic Implications and Comparative Analysis

First, unlike general social welfare volunteers, forest trail volunteers appear to exhibit a more complex, nature-embedded motivational pattern that combines altruistic, relational, and restorative elements. Whereas general volunteering has often been explained primarily in terms of altruism or social obligation [16,46], the present findings suggest that, in forest trail volunteering, attachment to nature and enjoyment of the activity are important alongside social contribution, which is consistent with the environmental volunteer motivation framework proposed by Bruyere and Rappe [22]. This pattern may be interpreted through human–nature connectedness, which helps explain why individuals who perceive the natural environment as meaningful may develop a more enduring relational commitment to it [47], as well as through stress recovery and attention restoration perspectives, which suggest that natural environments can replenish the cognitive and emotional resources that support continued participation [48,49]. Taken together, these perspectives suggest that forest trail volunteering involves a reciprocal dynamic in which participants care for the forest while simultaneously experiencing restoration, value, and personal growth through that engagement. This reciprocal dynamic is also consistent with scholarship conceptualizing stewardship as a relational boundary object linking people, places, and institutions [50]. These findings imply that general volunteering models centered solely on altruism or social obligation may not fully explain the motivational structure of NFT volunteers.

Second, the findings may be interpreted as suggesting that forest trail volunteers function not merely as passive users of forest services, but as participants involved in the co-creation of value [51]. In broader terms, this interpretation is consistent with a broader value co-creation perspective, in which value is not delivered unilaterally by institutions but realized through interaction and participation. From this perspective, NFT volunteers are not external helpers to a pre-existing management system, but actors who participate in producing, maintaining, and experiencing trail-related value through stewardship activities. In the NFT context, this co-creation may be understood in at least three forms. First, volunteers contribute functional value by participating in trail maintenance, environmental management, and safety-related activities that support trail operation. Second, they contribute ecological value by helping protect forest environments and sustain the quality of natural resources over time. Third, they may derive experiential value through their own participation, as volunteering provides enjoyment, restoration, accomplishment, and personal meaning [19,23,24,36]. In this sense, forest trail volunteers do not simply receive the benefits of a well-managed trail system; they also participate in sustaining the conditions through which those benefits are generated. This helps distinguish them from general visitors, who primarily experience trail environments as recreational spaces [17,18]. The strong effect of activity satisfaction on Active Participation Intention is consistent with this interpretation, suggesting that more positive evaluations of the volunteer experience may be associated with a deeper and more proactive form of commitment to forest trail governance.

Third, the distinction between Future Participation Intention and Active Participation Intention may be interpreted as reflecting different levels of behavioral commitment. Future Participation Intention refers to a relatively basic willingness to return, whereas Active Participation Intention reflects a more proactive and resource-intensive form of engagement involving recommendation, advocacy, and the voluntary investment of time, effort, or money. This distinction is broadly consistent with the serious leisure perspective, which suggests that sustained participation may develop from simple continuation toward deeper identification and increasing responsibility [52]. In the present study, activity satisfaction predicted both forms of behavioral intention, suggesting that a positive volunteer experience is an important condition for continued engagement. By contrast, perceived QoL change predicted only Active Participation Intention, indicating that broader personal benefits from volunteering may be especially relevant in motivating volunteers to move beyond passive continuation toward more committed stewardship. This pattern is also consistent with prior work on trail volunteers, including studies of PCT volunteers in the United States [13], and suggests that perceived life benefit may play a distinctive role in the transition from retention to active stewardship [23,24,36]. This interpretation is also in line with recent findings from environmental volunteer programs showing that sustained participation is more likely when volunteers experience the activity as both satisfying and personally meaningful, rather than merely duty-based [25,26].

4.2. Policy and Practical Implications

First, the findings suggest that NFT volunteer programs should shift from a manpower-centered approach to a volunteer experience-centered approach. In the present study, activity satisfaction emerged as the strongest post-participation predictor of Active Participation Intention and the most influential mediating mechanism linking motivation to active engagement. In terms of effect sizes, activity satisfaction showed a stronger path coefficient to Active Participation Intention (β = 0.317) than perceived QoL change (β = 0.215), suggesting that program quality and experiential design should be treated as the primary management priority, while well-being outcomes serve as a complementary but independently meaningful policy target. In practical terms, activities such as ecological monitoring, trail interpretation, safety stewardship, and other skill-based forms of participation may help enhance both the experiential quality and perceived significance of volunteering. From a policy perspective, long-term volunteer retention depends not only on recruiting participants but also on intentionally designing the experience of participation.

Second, the findings also indicate the importance of a more systematic recognition and feedback structure for NFT volunteers. In the Korean context, recognition appears to carry particular institutional significance, a pattern that is broadly consistent with prior discussions of civic responsibility and institutional participation in East Asian contexts [53]. The strong effect of reward importance suggests that volunteers are attentive not only to the intrinsic meaning of participation but also to how their contribution is acknowledged within the broader management system. This should not be interpreted simply as evidence of externally driven motivation. Rather, formal recognition may function as a culturally meaningful mechanism through which volunteers interpret the social value of their contribution. In this regard, non-monetary but structured feedback systems—such as certificates, participation records, or impact-based feedback on trail maintenance outcomes—may strengthen volunteers’ sense of contribution and support continued engagement. Accordingly, NFT governance in Korea may benefit from combining experience-based program design with a recognition system that is appropriate to the institutional and cultural context of volunteering.

Third, the significant role of perceived QoL change in predicting Active Participation Intention suggests that NFT volunteering may be considered not only an environmental participation activity but also a meaningful forest welfare and public health resource. Unlike activity satisfaction, which reflects evaluation of the volunteering experience itself, perceived QoL change indicates that participants experience broader personal benefits, such as restoration, vitality, and enhanced meaning in life, through their involvement [54]. Although its effect was smaller than that of activity satisfaction, its independent contribution indicates that well-being outcomes should be treated not merely as secondary by-products of participation, but as a complementary policy target in their own right. This finding suggests that NFT volunteering has policy relevance in relation to nature-based preventive welfare strategies that support health promotion and psychological well-being, which is also consistent with prior evidence on the mental health effects of forest therapy [55]. Therefore, evaluation of NFT volunteer programs should not rely solely on quantitative indicators such as the number of participants or hours contributed, but should also consider participant-centered outcomes related to well-being and restorative benefit. This broader evaluative perspective is also consistent with recent studies emphasizing the need to integrate diverse forest values, including experiential and well-being outcomes, into contemporary forest management frameworks [56]. This interpretation is also consistent with the co-benefit perspective on environmental volunteering, which emphasizes that stewardship participation can simultaneously generate individual well-being gains and environmentally meaningful action [57]. In this sense, NFT volunteering may also be discussed within the broader policy context of nature-based health promotion and green social prescribing [2,58,59].

Finally, the findings support the importance of strengthening collaborative governance for NFTs through sustained citizen participation. Because National Forest Trails are extensive linear infrastructures that are difficult to manage through centralized administrative capacity alone, long-term stewardship by volunteers and local communities is essential, particularly in the context of Korean trail management systems [60]. The present results suggest that such stewardship is more likely to be sustained when volunteers perceive their participation as satisfying, meaningful, and beneficial to their quality of life. This implies that collaborative governance in the NFT context should not be understood merely as a supplement to public management, but as a participatory system that depends on maintaining reciprocal value between institutions and citizens. Programs such as section-based volunteer stewardship, community-linked trail management, and locally embedded partnership models may therefore provide a more sustainable foundation for NFT governance than short-term, event-based participation alone, as reflected in stewardship-based trail governance approaches institutionalized in other contexts [61]. Such locally embedded partnership models are also consistent with recent discussions of social innovation in forestry [62].

5. Conclusions

This study examined the structural relationships among volunteer motivation, activity satisfaction, perceived quality-of-life (QoL) change, and behavioral intention in the context of Korea’s National Forest Trails (NFTs), which are increasingly important components of forest welfare infrastructure. The findings suggest that sustained volunteer engagement is shaped not by altruistic motivation alone, but also by psychological mechanisms related to the quality and personal meaning of the volunteer experience.

Several conclusions may be drawn from the results. First, forest trail volunteers should be understood not merely as supplementary labor for trail management, but as active participants in forest governance who both contribute to and benefit from the environments they help sustain. In this respect, forest trail volunteering reflects a reciprocal structure in which stewardship, personal restoration, and meaningful participation are closely connected. Second, activity satisfaction emerged as a central mechanism linking motivation to continued engagement, indicating that the quality of the volunteer experience is critical for sustaining participation over time. Third, perceived QoL change had an additional and independent role in predicting Active Participation Intention, suggesting that broader personal benefits from volunteering may be especially important in motivating volunteers to move beyond simple continuation toward more proactive and committed forms of engagement.

These findings have both theoretical and practical implications. Theoretically, the study suggests that general models of volunteering may not fully explain the motivational structure of nature-based volunteering, where attachment to nature, restorative experience, and stewardship are closely intertwined. Practically, the results imply that sustainable NFT governance requires more than the organization of volunteer labor. It also requires volunteer programs that provide meaningful experiences, appropriate recognition, and opportunities for continued and active involvement.

Overall, this study suggests that the long-term sustainability of NFT volunteering depends on whether participation creates reciprocal value for both the forest and the volunteer. In this sense, sustainable governance of National Forest Trails should be understood not only as a matter of maintaining physical infrastructure, but also as a process of fostering enduring relationships between people and forest environments.

Limitations and Future Research

Despite its contributions, this study has several limitations that should be acknowledged.

First, the generalizability of the findings is limited by the sample. This study focused on volunteers participating in five major National Forest Trails in Korea, and motivational patterns or participation experiences may differ across other trail types, regions, or management contexts. Future research should therefore examine a broader range of forest trail settings in order to improve external validity.

Second, caution is required in interpreting causal relationships because the study was based on a cross-sectional design. Although the field-based survey design helped capture participants’ evaluations in the context of actual volunteering experience, the temporal ordering of motivation, satisfaction, perceived QoL change, and behavioral intention cannot be fully confirmed. Longitudinal research would therefore be valuable for clarifying how volunteer motivation and stewardship develop over time, particularly from initial participation to more active and sustained engagement.

Third, the study relied on self-reported measures, especially for perceived QoL change and health-related benefit. As a result, the findings reflect participants’ subjective evaluations rather than objective indicators of psychological or physiological change. Future studies could strengthen this line of research by incorporating more objective measures, such as physiological stress indicators, wearable-device data, or repeated pre- and post-participation assessments.

Fourth, the findings should be interpreted in light of the specific institutional and cultural context of Korea. The meaning of recognition, reward, and continued participation may differ across national and organizational settings, and some findings—particularly those related to reward importance—may be shaped by Korea’s institutionalized volunteer system. Accordingly, comparisons with trail volunteer populations in other countries should be interpreted cautiously. Future cross-cultural studies directly comparing motivation structures, recognition preferences, and behavioral outcomes across different trail governance contexts would help clarify the generalizability of the findings and identify which aspects of the observed behavioral pathways are context-specific and which may be more broadly applicable.