The Relationship between Endurance Involvement and Travel Behavior in Camping and the Moderating Effect of Place Attachment

Camping tourism is one of the fastest growing segments of the tourism industry. Global trends in camping show that this type of recreational activity has begun to emerge in Asia. Meeting the expectations of potential and current tourists in a camping destination will lead to the accomplishment of competitive advantage. The endurance involvement and place attachment play important roles in understanding camping behaviors. However, limited research identified place attachment as a moderator of the influence of endurance involvement on camping travel behavior. To fill this gap, based on place attachment theory, our study developed a conceptual model that postulates endurance involvement and place attachment as predictors of camping tourism. 216 self-administered questionnaires were retuned. Confirmatory factor analysis was used to test the psychometric properties of the measures, while regression analysis was employed to assess the research hypotheses. The study results show that endurance involvement in camping affects camping travel behavior, whereas camping place dependence, camping place identity, and camping affective attachment moderate the effect of camping endurance involvement on camping travel behavior. Camping place attachment strengthens the relationship between camping endurance involvement and camping travel behavior. To maintain the sustainable development of camping tourism, campsite authorities should attach more importance to strengthening campers’ emotional bonds and concentrate on how to encourage them to participate in tourism activities. The findings have several theoretical and managerial implications for camping tourism marketing and the development of campground.


Introduction
Sustainable tourism refers to the preservation of ecology which includes rural areas, natural resources, culture, heritage, and biodiversity [1]. The year 2020 was a difficult time for tourism, leisure, and travel activities, which faced major restrictions and losses [2]. During the COVID-19 pandemic, certain special travel types have become increasingly popular, such as camping and the use of recreational vehicles [3]. Camping is a kind of recreational activity connected with the leisure time, relaxation, and the entertainment of holiday activities. Family camping is a good way for parents, children, and friends to spend leisure time together and illustrates the value of enjoying nature [4].
Outdoor leisure activities include going on vacation, getting away from daily work or affairs, and focusing on getting involved in the content of the activity. These activities include spending vacation time in scenic areas and the natural environment, escaping from daily life, and engaging in outdoor activities [5]. Some studies have pointed out the importance of human behavior [6]. Leisure involvement is considered a crucial psychological structure [7]. This study uses enduring involvement to explain potential factors that affect Sustainability 2021, 13, 5016 2 of 16 campers' participation in camping activities. Once people participate in leisure activities physically and mentally, they will feel more satisfied [8]. Individuals expect to obtain higher benefits from participating in leisure activities [9]. Leisure involvement typically increases positive emotions and contributes to wellbeing through the process of expansion and construction [10]. Therefore, active involvement in leisure helps improve quality of life, relaxation, skills, and friendships, and increase competitiveness through participation in activities [9]. Travelers choose different destinations to meet their travel needs [11]. Travel activities can increase opportunities to view nature and provide social interaction [12].
Leisure researchers and operators have begun to use the concept of place attachment to understand leisure behavior [13,14]. Tourists who feel satisfied with the place will be more likely to interact with the environment and develop place attachment [15]. Environmental psychology researchers have used three dimensions to measure place attachment: place dependence, place identity, and affective attachment [16,17]. Tourist satisfaction will affect tourists' perceptions of tourism development [18]. People who re-stay in a certain place have a stronger attachment to that place [19,20]. Camping is an outdoor recreational activity that involves immersing oneself in nature, which can improve people's psychological wellbeing [21]. Place attachment has major implications when choosing a camping destination, which affect the travel planning behavior. However, camping studies rarely focus on place attachment [19,22]. This study attempts to identify place attachment as a moderator of the influence of endurance involvement on camping travel behavior.
In recent years, people have become more aware of the benefits of outdoor recreation and nature travel [23]. Since the 1970s, camping tourism has received little research attention [24]. Camping is accepted by the general public. Understanding camping travel behavior is a crucial research perspective. The purpose of this study is to address the gap in the tourism. It aims to investigate the following issues. First, it aims to discover how campers' enduring involvement directly affects the campers' travel behavior. Second, it aims to explore the moderating effect of campers' place attachment in relation between enduring involvement and camping travel behavior. This study is expected to lead to a better understanding of campers' behavior.

Camping Endurance Involvement
Leisure involvement is defined as engaging in enjoyable activities without obligation or responsibility [25]. Behavior involvement has been applied in tourism research [26,27]. Leisure involvement refers to the frequency and time that individuals use non-fixed working hours to participate in outdoor leisure activities [28]. Involvement in outdoor recreational activities is a kind of voluntary participation in leisure time and interaction with the natural environment [29]. Leisure involvement is widely used in various activities, such as sports, diving, paddle boarding, surfing, sailing, snorkeling, and rope rappelling [9]. Individuals gradually become involved in leisure activities based on various factors. For example, attractiveness, concentration, knowledge, and equipment [30,31]. Research has indicated that leisure involvement activities must meet personal needs, goals, values, and activity attributes [32].
McIntyre and Pigram (1992) used the Camping Endurance Involvement Scale to assess tourists in three camping areas of the Rocky Mountains [33]. The scale consists of attraction, centrality, and importance. The attraction construct contains happiness [34,35] and can connect a certain stimulus of an individual to a certain situation [30,36]. Centrality refers to the use of leisure activities as the center of personal life [33,34] and is also regarded as the deep integration of leisure activities [8]. Importance means paying attention to emotional relationships in leisure activities [33,34]. Leisure activities can meet the need to socialize and connect with family members and friends [37]. Individuals continue to be involved in specific activities and meet their life needs through activities [27,38]. Strong involvement in cruise travel improves the experience for passengers, whereas lower involvement reduces Sustainability 2021, 13, 5016 3 of 16 the enjoyability of the travel experience [39]. According to the above, leisure involvement reinforces camping participation.

Camping Travel Behavior
From leaving home to returning home, all itineraries constitute the daily activities and methods of travel [38]. The purposes of travel are vacation, business, medical treatment, shopping, and visiting family and friends [40,41]. Travel behavior was divided into three parts: travel activities, travel patterns, and travel characteristics. Travel activities include cultural, content, fixed-point vacation, passive, active, and group activities [42]. Travel patterns include place attachment, destination image, activity participation, travel attitude, subjective norms, and perceptual control behavior, which can be used to explain the connotations of travel behavior [43]. Travel characteristics include information sources, travel days, travel timing, funding sources, travel destinations, and discretionary amounts [42]. Travel environment experience can bring various benefits, including health, sports activities, entertainment opportunities, and stress relief [44]. A major debate in recent travel behavior research has been whether travel behavior is affected by objective characteristics (such as the built environment and socioeconomic factors) or subjective attitudes and lifestyles [45,46]. According to a review of the literature, travel behavior is affected by both subjective and objective factors. People choose the content of leisure travel activities according to their preferences and attitudes to meet their needs.
Camping is a form of outdoor recreational activity [19]. Nature is one of the most critical factors in the development of forest camping experiences. Camping activities and campsite facilities attract campers to engage in a series of activities in nature, including cutting wood, watching campfires, fishing, hiking, swimming, and exploring forests and creeks [24]. Through camping activities, campers can engage in short-distance trekking, and the interactions between people and the environment and among people can become closer, allowing the full integration of camping and travel. After selecting a camping destination, whether it is to enjoy and experience natural environmental attractions or travel resources in nearby areas during the day or night, travel can be enjoyed for education or entertainment [4].

The Relationship between Camping Endurance Involvement and Camping Travel Behavior
National forest parks inspire interaction between people and place and have unique environmental attributes. Therefore, national forest parks are popular tourist attractions [47,48]. Most of the time camping activities lead family members to gather together. The main reason is that forests and their surrounding environment are suitable for family leisure [49]. This explains why people increasingly like to go outdoors to engage in camping and recreational activities and enjoy the experience of nature travel. Involvement in outdoor leisure activities is considered to be the use of leisure time or vacations, voluntary participation and escape from daily work, travel in the outdoors, and enjoyment of the interaction of recreational resources and the natural environment [5,29]. Involvement also attracts attention and interest in specific activities [50]. The higher the frequency of participation in leisure activities is, the stronger the subjective wellbeing will be [51]. Involvement is a continuous concept; when people are interested in a certain leisure activity, people will often participate in that activity.
Many recreation scholars have indicated that involvement should include both behavioral and psychological aspects [52]. Behavior involvement refers to the behavior of investing energy and time in a specific activity [53]. Leisure involvement gradually strengthens behavior and participation connections [30,36]. The willingness of visitors to engage in follow-up behavior increases when they perceive something as being of high value [9].
Enduring involvement in a leisure activity means the individual has pay attention and engage in a specific activity for long time [54]. Enduring involvement directly determines tourists' judgment of tourism activities [55]. Previous studies in tourism indicate that tourists' involvement is one of the antecedents of behavior [56]. Tourists' actual behaviors are determined by their behavior when campers are involved in camping and are satisfied with the leisure activities, which in turn leads to enhanced camper behavior. This study proposed the following hypothesis: Hypothesis 1 (H1). Enduring involvement in camping exerts a significant positive effect on camping travel behavior.

The Moderating Role of Camping Place Attachment
Place attachment is derived from attachment theory [57], which originated in the early 1970s. Place attachment theory is defined as the emotional connection between the individual and the facility environment [58,59]. Place attachment is an influential psychological theory that is widely used in interdisciplinary fields to study the relationship between travel and destinations [17,60]. From the perspective of human geography and environmental psychology, many scholars believe that the development of place attachment originates from the visual landscape, from which the implicit meaning and connection of the visual landscape can be found [61]. Some researchers have used three dimensions to measure place attachment: place dependence, place identity, and affective attachment [16,17]. First, place dependence is based on environmental psychology and entertainment theory. When visitors are attracted by an activity, they have a strong sense of self-expression in the place or think that such a place is part of life. At the same time the dependence on locality is also stronger [62,63]. Place dependence shows that consumers find different resources and values in a specific place that meet the demand function, and then stay there spontaneously. As the stay time lengthens, attachment and demand are formed. Second, place identity describes the degree to which users feel they are in cognition with a particular place [61,64]. Local identity explains the relationship between people's thoughts and attitudes toward the environment, and makes participants feel a strong sense of belonging. Finally, affective attachment, which has thus far received limited attention [17,65], mainly refers to tourists' strong feelings about the destination [17] and the strong emotional attachment that people form in a specific place or environment [17,66]. The literature shows that human geography, environmental psychology, and entertainment theories all propose that place dependence, place identification, and affective attachment affect camping's endurance involvement in camping place travel, stay time, number of visits, and emotions when discussing place attachment, belonging, and the satisfaction of needs.
Past studies have confirmed a positive relationship between local attachment and recreational involvement [67]. Viden and Schreyer [68] took hikers as an example and found that place attachment and recreational involvement influence each other. Safvenbom and Samdahl (1998) studied the cognition degree of adolescents' involvement in leisure activities, and the results showed that the degree of recreation involvement exerts a major influence on the local cognition of activities [69]. Some indirect evidence has suggested that involvement in recreational activities can lead to dependence on facilities [67,70]. For example, Bricker and Kerstetter [64] proposed that rafters with experience, high technology, and high involvement are more attached to recreational places than general recreationalists. Studies have shown that local attachment affects the subsequent developmental behavior of recreational involvement.
When tourists travel to a place, they find that local functions or environmental resources increase the intensity of local attachment to meet demand [62]. Tourists develop deep emotions, connections, and strong identification with places when they travel [63,71]. For example, people who spend a lot of time at or visit a place multiple times have stronger attachment to that place [19,20]. When Lin and Chou [63] studied the influence of camping site involvement, they found the need to evaluate the effect of local attachment and tourist involvement on travel experience. Therefore, place attachment affects tourists' behavior and intention to revisit [72,73]. Subjective emotions about behavior and objective beliefs about it affect individual attitudes toward behavior [44]. Place attachment can provide the tourists' emotional bonds toward a particular environment. At this point, when campers view the environment or are attracted to it their inner self will establish emotional connection and positive behavior, and the emotional bonds will be shaped through the involvement of the campers, and between the place and campers; thus, campers are more willing to engage with the place; in other words, the place reflects emotional bonds, identification with, and dependence on the place. Place attachment provides a perspective to explain the emotional connection of the campers and camping behavior. Some scholars have considered place attachment as a moderating variable [74,75] Therefore, this study proposes the following hypotheses in accordance with the literature and theoretical basis: Hypothesis 2a (H2a). Camping place dependence exerts a moderating effect on the relationship between endurance involvement in camping and camping travel behavior.
Hypothesis 2b (H2b). Camping place identity exerts a moderating effect on the relationship between endurance involvement in camping and camping travel behavior.

Hypothesis 2c (H2c).
Camping affective attachment exerts a moderating effect on the relationship between endurance involvement in camping and camping travel behavior.
Our proposed conceptual model is illustrated in Figure 1.
stronger attachment to that place [19,20]. When Lin and Chou [63] studied the influence of camping site involvement, they found the need to evaluate the effect of local attachment and tourist involvement on travel experience. Therefore, place attachment affects tourists' behavior and intention to revisit [72,73]. Subjective emotions about behavior and objective beliefs about it affect individual attitudes toward behavior [44]. Place attachment can provide the tourists' emotional bonds toward a particular environment. At this point, when campers view the environment or are attracted to it their inner self will establish emotional connection and positive behavior, and the emotional bonds will be shaped through the involvement of the campers, and between the place and campers; thus, campers are more willing to engage with the place; in other words, the place reflects emotional bonds, identification with, and dependence on the place. Place attachment provides a perspective to explain the emotional connection of the campers and camping behavior. Some scholars have considered place attachment as a moderating variable [74,75] Therefore, this study proposes the following hypotheses in accordance with the literature and theoretical basis: Hypothesis 2a (H2a). Camping place dependence exerts a moderating effect on the relationship between endurance involvement in camping and camping travel behavior.
Hypothesis 2b (H2b). Camping place identity exerts a moderating effect on the relationship between endurance involvement in camping and camping travel behavior.

Hypothesis 2c (H2c). Camping affective attachment exerts a moderating effect on the relationship between endurance involvement in camping and camping travel behavior.
Our proposed conceptual model is illustrated in Figure 1.

Data Collection
We used a self-administered survey, designed appropriate questionnaire items based on literature, and used judgmental sampling. The samples were collected from: 1. The Wuling Farm Camping Region in the Wuling National Forest Recreation Area in Central Taiwan was used as the questionnaire field; 2. Data collection was performed via a survey on Facebook [76]. The researcher consulted with three experts with more than five years of camping experience. The optimal location at which to issue the questionnaire was the Wuling Farm Camping Site in Central Taiwan. They indicated that the campers at this site are from various regions of Taiwan, making the indicators representative. (Facebook) was used to distribute the questionnaire after consent was obtained from the moderators of the three clubs: the Camping Sharing Club, the Camping Crazy Club, and the Wild FUN Club. The members of these three clubs are all from Taiwan. The questionnaire was issued from January 2019 to April 2019. Questionnaire recovery: 1. Of the 124 questionnaires that were handed out, 9 invalid questionnaires were excluded, and 115 valid questionnaires were returned, for a recovery rate of 92.74%. 2. Of the 112 online questionnaires issued, Sustainability 2021, 13, 5016 6 of 16 11 invalid questionnaires were excluded, and 101 valid questionnaires were returned, for a recovery rate of 90.18%. In total, 236 questionnaires were issued, 20 invalid copies and wasted paper were eliminated, and 216 valid questionnaires were obtained. The overall effective recovery rate was 91.53%.

Measures
All of the items were measured using a five-point Likert scale, ranging from 1(strongly disagree) to 5 (strongly agree). We designed four sections of items to assess four aspects: demographics, place attachment, camping involvement, and travel behavior. The first section contained items to elicit respondents' demographic information, including gender, education, marriage, and camping experience. The second section consisted of 13 items measuring the three constructs of camping enduring involvement: attraction, centrality, and importance [33]. The questionnaire asked respondents to indicate their degree of agreement with statements such as 'Camping says a lot about who I am', 'I discussing camping with my friends', and 'I have interest in camping', about which visitors indicated their level of agreement, from 1 (Strongly disagree) to 5 (Strongly agree). The third section contained items to measure place attachment, the three place constructs of affective attachment, place dependence, and place identity [77]. The section listed 8 items, including statements such as 'I feel happiest when I'm at this area', 'This area is the best place for doing the things that I enjoy', and 'Everything about this area is a reflection of me'. For the fourth section, we adapted three items to measure travel behavior [78], including statements such as 'I like this destination better than any other destination', This destination is my preferred destination over any other destination', 'I have a favorable impression of this destination'.

Validity and Reliability
Before verification of the study hypothesis, three research variables (camping endurance involvement, camping place attachment, and camping travel behavior) underwent confirmatory factor analysis (CFA) to test the discriminant validity and convergent validity of the overall research construct. Bagozzi et al. [79] proposed a CFA with factor measurement model to test the fit of three-, two-, and one-factor theoretical models.
Anderson and Gerbing [80] proposed that the discriminate validity between dimensions can be assessed using the chi-square difference test. To facilitate CFA, this study first integrated the topics of camping endurance involvement, camping place attachment, and camping travel behavior into a combined score (parcel), and constructed a three-factor model of the research hypotheses, comparing the hypothesized three-factor model with the two competing models using a chi-square difference test. As shown in Table 1, χ 2 demonstrated a significant difference. According to the results of the nested structure of CFA, the chi-square test reached a statistically significant level: χ 2 = 19.13; df = 12; RMSEA = 0.05; NFI = 0.96; NNFI = 0.96; RMR = 0.02; SRMR = 0.03; GFI = 0.98; AGFI = 0.93.
In terms of the model fit test, Henry and Stone [81] indicated that the value of GFI and AGFI should be greater than 0.9. Hu and Bentler [82] stated that the RMR value should be less than 0.08. McDonald and Ho (2002) suggested an RMSEA value less than 0.08 as an acceptable threshold for model fit [83]. Hu and Bentler [82] recommended an RMSEA value lower than 0.06 for a good model. Hair et al. [84] proposed that the values of IFI, TLI, CFI, and GFI should be higher than 0.9 and the higher the better.
The statistics and reliability coefficients of each scale are shown in Table 1. Based on the criteria suggested by previous research [85,86], the value of the α reliability coefficient was between 0.867 and 0.917, indicating good reliability.

Descriptive Analysis
Among the 216 samples used in this study, approximately 51.9% were male and 48.1% were female. In terms of marriage, approximately 72.2% were married, 25.0% were unmarried, and 2.8% were widows or widowers. In terms of education, accounted for approximately 0.0%, senior high school accounted for 9.7%, college accounted for 47.7%, and graduate school or above accounted for 42.6%. In terms of camping experience, <1 year accounted for approximately 49.5%, 1-3 years accounted for 21.8%, 4-6 years accounted for 6.0%, 7-9 years accounted for 2.8%, and ≥10 years accounted for 19.9%. The demographic variables of this study are shown in Table 2.

Pearson Analysis
In this study, Pearson's product-difference correlation analysis (Table 3) was used to list the mean, standard deviation, and correlation coefficient of each variable. A positive correlation was found between camping years and camping place attachment, and the correlation coefficient was r = 0.189 (p < 0.01), which showed that the more years of camping experience, the higher the degree of attachment to the camping place. Camping experience was positively correlated with camping travel behavior, and the correlation coefficient was r = 0.168 (p < 0.05), which showed that the more years of camping experience, the greater the investment in camping travel behavior. A positive correlation was found between camping endurance involvement and camping travel behavior, and the correlation coefficient was r = 0.263 (p < 0.01), which showed that the higher the camping endurance involvement, the greater the investment in camping travel behavior. Camping place attachment was positively correlated with camping travel behavior, and the correlation coefficient was r = 0.196 (p < 0.01), which showed that the higher the camping place attachment, the greater the investment in camping travel behavior. In this study, structural equation modeling was used to verify the theoretical model and to test the adaptation of various models. The multivariate normality hypothesis can be tested with the help of Mardia's coefficients of multivariate skewness and kurtosis [87], which is a commonly used multivariate kurtosis indicator and can be used to test the multivariate normality hypothesis. When the Mardia's coefficient is less than p(p+2) (where p is the number of observation variables), the data has multivariate normal distribution [88]. In the multivariate normality analysis of the overall dimension of this study, the Mardia coefficient was 3.839, the number of observation variables was nine, and the value of p(p+2) was 99, which was significantly larger than the overall dimension Mardia's coefficient of this study (3.839), indicating multiple normality.
The three-factor theoretical model of this study has a significantly better fit than the two-and one-factor models. As shown in Table 4. The three-factor theoretical model provides the optimal degree of adaptation, demonstrating that three variable factor models independent concepts. Research has shown that the variables have good discriminative validity. The items of each scale in this study were statistically significant, and the load of Sustainability 2021, 13, 5016 9 of 16 each standardized factor (0.72-0.92) was higher than 0.5, which supports the proposal of Bagozzi and Yi [89] that the load of standardized factors must be higher than 0.5. The alpha reliability of each scale was between 0.78 and 0.85, indicating that the test items of the same factor effectively reflected the same construct [80], showing good convergence validity. Note: a three factor model (hypothetical model): camping endurance involvement, camping place attachment, and camping travel behavior; b two factor model: camping endurance involvement and camping place attachment are combined into one factor, and camping travel behavior is one factor; c one factor model: all variables are combined into a single factor; CFI = Comparative fit index; RMR = Root mean square residual; RMSEA = root mean square error of approximation; NFI = normed-fit index; NNFI = non-normed fit index.

Regression Analysis
To test the research hypothesis, this study used hierarchical regression analysis to clarify the moderating effect. Before data analysis, the variable data is converted into standard scores [90,91]. The interaction variable between camping endurance involvement and camping place attachment is then established to control the variable for camping experience.
Hierarchical regression analysis determines the first-level dependent variables (camping travel behavior) and control variables (camping years). For the second-level independent variables (camping endurance involvement) in the second model, camping endurance involvement was related to camping travel behavior. The predictive effect of travel behavior reached a significant level (β = 0.257, p < 0.01), thus supporting Hypothesis 1. The third-level moderate variable (camping place attachment) in Model 3 showed that camping place attachment had an effect on camping travel behavior and the predictive effect reached a significant level (β= 0.144, p < 0.05). The fourth-level interaction variable (camping endurance involvement × camping place attachment) in Model 4 showed the interaction between camping endurance involvement and camping place attachment. The predictive effect of the multiplication term on the interaction of camping travel behavior reached a significant level (β = 0.171, p < 0.01). As shown in Table 5. Aiken and West [90] proposed that when the multiplication term of the independent variable is in the class, the regression analysis reveals a significant effect, clearly indicating an interaction effect. Therefore, Hypothesis 1 was supported.

Moderate Analysis
For the moderating effect of place attachment, our study utilized a regression equation estimation and bootstrap test. PROCESS was used for data analysis, which can determine the effect of moderate variables with one standard deviation of the high and low conditions. The bootstrap test was used to calculate the 95% confidence interval (CI). As shown in Table 6, for the moderating effect of low camping place dependence, low camping place identity, and low camping affective attachment included a zero point and was not significant; however, the moderating effect of high camping place dependence, high camping place identity, and high camping affective attachment did not included a zero point and was significant. Thus, camping place attachment displayed a moderating effect on the relation between camping endurance involvement and camping travel behavior, which supports Hypothesis 2a, Hypothesis 2b, and Hypothesis 2c.

Discussion
This study mainly explored the relationships among place attachment, enduring involvement, and travel behavior, focusing on the moderating effect of place attachment in the context of camping tourism. The findings demonstrate relations between camping enduring involvement and camping travel behavior. Furthermore, the results also identify that camping place attachment had the moderating effect on the relation between camping enduring involvement and camping travel behavior. Our study provides important theoretical insights for researchers in camping tourism to support sustainable tourism.
First, our study incorporated the three dimensions of attractiveness, centrality, and importance to measure camping enduring involvement. The attractiveness of camping can be explained by exploring the motivations that stimulate the behavior of campers. Whether the campers choose to be in a tent or choose RV camping, it all originates from their need to escape at low-cost. Camping tourism provides individuals with an opportunity to connect with the natural environment and with themselves, family, or friends through simpler living practices. Campers use tents outdoors for the night, experience a different lifestyle in a comfortable family environment, enjoy the natural environment, mountain climbing, river tracing, eco-tourism, engage in activities, and observe nocturnal animals. These various leisure activities further contribute to pulling campers to specific locations [34,35]. The more involved in the camping experience, the more relevant the campsite attribute will be in providing the desired experience. Camping enthusiasts often interact with each other through various on-site activities, taking camping activity as the topic center. The camper's special on-site experience will evoke positive emotions such as joy, fun, happiness, and pride. Campers actively evaluated the attributes of the campsite and created a life that attracts pleasure and enjoyment [34,67]. As a result, camping has become the most important and critical thing in people's lifestyles [8,34]. Based on the above, the process of camping enduring involvement can be explained more comprehensively through these three dimensions of attractiveness, centrality, and importance.
Second, expanding our current knowledge of camping involvement, our findings confirm the important role of camping enduring involvement to stimulate camping travel behavior. During holidays or leisure time, parents and children are often seen camping at fixed or variable camping destinations. They use their time to travel to nearby areas for camping travel and to enjoy camping leisure for entertainment. Recreation can take many forms, such as outdoor activities (e.g., camping, hiking, and climbing) [92]. Travel involvement is a kind of attraction that affects the behavior of tourists [93]; that is, travel involvement affects the occurrence of subsequent behaviors. Enduring involvement in camping in this study was significantly correlated with camping travel behavior, and the predictive effect of camping enduring involvement on camping travel behavior reached a significant level. Research has revealed that leisure involvement affects satisfaction with leisure experience [94,95]. According to the expected value theory model, the motivation of human behavior is the need to be satisfied [32,96]. A critical variable that affects the decision-making process of consumer behavior is involvement [63]. In addition, despite the fundamental importance of enduring involvement as mentioned earlier, in the field of camping tourism there is no research to explore how associate enduring involvement and camping travel behaviors. In view of the lack of empirical evidence on camping enduring involvement, this study can provide a reference for future research.
Third, our study has used three dimensions to measure place attachment: place dependence, place identity, and affective attachment [16,17]. For camping, the most crucial aspect of place dependence is a favorite camping destination and satisfactory camping and leisure activities at this destination, such as engaging in camping travel in national parks. Place dependence depends on how the specific attributes or facilities of a destination meet the needs of tourists [17,97]. Place identity means that a camping destination guides campers to visit or explore the surrounding natural environment and establish good cognition and interaction behaviors with one other. Place identity refers to the connection of tourists' conscious or unconscious preferences for a certain place or environment [16,17]. Emotional attachment refers to the memories, images, and associations generated during camping, creating interesting experience activities, the desire to visit again from time to time, and a strong and friendly emotional attachment to the destination. Affective attachment means that the memories, images, and associations of visiting a specific place or environment form a strong emotional attachment [17,98]. Outdoor entertainment produces spillover benefits to fit local attachment [23,99]. Engaging in camping leads to a high degree of dependence, emotional connection, identification, and time spent in the surrounding natural environment. The greater the development involved, the greater tourists' subsequent travel behavior and intention to revisit [100]. Local attachment can affect leisure involvement [19,20,101]. As a result, place attachment also affects tourists' behavior and intention to revisit [72,73].
Finally, our study extends the camping tourism literature by exploring the moderate role of place attachment in the relation between enduring involvement and travel behavior. The implications of this study are consistent with previous research. Kim, Lee, and Lee (2017) examined that psychological or emotional attachment exerts a significant regulatory effect on the process of decision-making and evaluation [74]. Chung et al. [75] mentioned that place attachment exerts a significant moderating effect on low-level status recognition supported by spending on price fairness perception. However, it has been an underresearched topic in the camping tourism context. In light of this, our study attempts to use appropriate statistical methods [102] and incorporates place attachment as a moderator in the camping tourism literature. Furthermore, the result demonstrates that place attachment has a moderating effect and confirms that it strengthens the predictive power of enduring involvement in travel behavior. This implies that place attachment should be regarded as an essential factor to stimulate camping travel behavioral intentions. As a result, the finding helps fill this gap in camping tourism research and broaden our understanding the role of place attachment in the relation between enduring involvement and travel behavior.

Conclusions
Camping tourism has a strong attraction in actual life experience, and helps in achieving psychological happiness. Many camping enthusiasts regard camping activities as the most important thing. Using camping as a central topic center, camping involves shared camping experience content, building relationships, and obtaining happiness in leisure activities. Furthermore, campers want to further protect the local nature and culture, so camping tourism plays an important part in sustainable tourism [18].
Our study explored the travel behavior of campers and found that after being affected or stimulated by a situation campers drive the development direction of travel behavior through satisfaction. The longer people are involved, the more satisfied they are with the leisure activities in which they have participated, the higher their happiness, and the stronger their travel behavior toward subsequent participation. Leisure involvement typically increases positive emotions, triggers psychological desires, and develops emotional happiness, resulting in a good life state [10]. The research results that camping enduring involvement has a positive impact on subsequent camping travel behaviors are consistent with Sirgy, Uysal, and Kruger [37] who proposed that different forms and types of leisure participation will enrich life experience. The contribution of this research is to test the effect of camping enduring involvement on camping travel behavior. Camping place attachment has a moderating effect on the relationship between camping enduring involvement and travel behavior. Our study demonstrates that camping place attachment affects subsequent camping behaviors, forms camping place dependence and camping place identification, and that camping emotional attachment exerts a modulating effect on the enduring involvement in camping and camping travel behavior.
Camping tourism has become an extremely popular leisure activity worldwide and in Taiwan over the past decade. Our study offers important implications for sustainable camping tourism. To strengthen camping enduring involvement, it is imperative for campsite marketers to organize various fascinating activities such as camping supply carnivals to promote various on-sit recreational activities and surrounding tourism activities, hold new camping equipment sharing launches, and organize camping clubs. Such events may cause irritation to assist campers sustained involvement. To generate place attachment, campsite managers can offer luxurious eco-friendly amenities such as tents, huts, and cottages to follow this new camping trend in which campers try to mix luxury and comfort [103], create more facilities for relaxation and socializing, and try to integrate diverse natural attractions such as forests, mountain, rivers, beaches, and lakes into the camping surroundings and provide package tours of attractions near the campsite, in order to create unique camping experience.

Limitations
Although our study strived to be rigorous in the process of research design and theoretical inference to build sustainable camping tourism, it has some limitations. First, the study adopted a cross-sectional study to determine the relationships among several variables. Future research could make use of a longitudinal field study method to examine the relationship between endurance involvement and camping travel behavior. In addition, this study adopted self-report surveys for research, possibly resulting in common method variance. Future research should use multiple sources of data collection to avoid the potential problems of common method variance. Finally, this study used data collected from Wuling Farm Camping Site in Taiwan and to the extent that the findings are unique to Wuling, could limit its application elsewhere. Further research could collect data from more campsites to improve the generalizability of the findings.