4.1. Qualitative Assessment of AEFES
The current study aims to describe a new method of assessing the preferred pleasantness induced by urban and forest environments and to validate the instrument developed for this purpose: the AEFES. It is worth noting that preferred pleasantness is a construct that consists of many dimensions and the AEFES scale captures only some of them. The four-factor structure of the questionnaire was confirmed in an exploratory factor analysis using excluded factors that suggest the vulnerability of self-boundaries of subjects for contact with plants and litter in the forest, animals in the forest, disgust in the forest and insects in the forest. The subscales used have high reliability (αs = 0.783 to 0.859). This relevance was confirmed in two independent online studies.
As theoretically expected, the instrument showed that four subscales were positively correlated to the Amoebic Self Scale’s spatial–symbolic domain (concurrent validity) and negatively correlated with the CNS (discriminant validity), and three of the four subscales were correlated negatively with preferred pleasantness (predictive validity). This suggests that AEFES might have the potential to measure real phenomena, as it is connected with the preferred pleasantness induced by forest environments. To sum up, the AEFES is a reliable and valid instrument with practical use for measuring an anti-environmental forest experience, which might be useful for the prediction of the preferred pleasantness of subjects towards forest environments.
4.2. Theoretical Integration
It is worth mentioning that there is probably some psychological mechanism which, by inducing fear or disgust, divides the body of a subject from the natural environment in the forest. Contact in these other situations might be harmful or dangerous to the health of a subject’s body, so fear or disgust responses protect the body before it comes into contact with a potentially dangerous environment. The “Plants or litter” subscale of AEFES provides information about the vulnerability of a subject’s hypothetical self for contact with trees, other plants and litter in the forest environment. The mean values of this scale in both analyzed studies were moderate, which indicates that this environmental feature might have a moderate level in the analyzed samples. The subscale “Animals” had the lowest mean values in both samples (in comparison to other subscales); thus, components of the forest environment like large herbivores or small mammals, which are not dangerous, are not seen as harmful from the perspective of self-boundaries. This subscale is also slightly correlated with AmSS-SS, the slightest values from all subscales of AEFES, but this subscale has good predictive validity and might also be used for prediction of the level of preferred pleasantness of subject. The subscale “Disgust” had moderate values and was significantly correlated with AmSS-SS. This subscale measures self-boundaries which are vulnerable for interaction with disgust or undesirable items, which might be seen, touched or smelled in the forest. This subscale has good predictive validity. The last subscale, “Insects”, contains items which describe the interaction with insects in the forest and also concerns other organisms like ticks or spiders (from other groups of animals). This scale had the highest mean values but has the least predictive validity. This means that subjects observing photographs of forest environments have the worst ability to predict the occurrence of lower values of preferred pleasantness but can have some negative attitude against “Insects”.
This finding supports both theories included in the introduction: if the object is far from a subject’s skin, it is probably far from the self-boundaries, so it is connected with Amoebic Self Theory; if the object is far from a subject’s skin, there is some prospect (distance between subject and object), showing that the Prospect and Refuge Theory may be relevant. That these two theories address and allow measurement of the same things was only possible to ascertain after this research and discussion.
As mentioned in the introduction, other questionnaires cannot be used in these studies for various reasons. The Subiza-Pérez [47
] study used the Natural Environment Scoring Tool and the Place Attachment and Place Identification Scale [48
] questionnaire to predict the restorative quality of the environment. However, these questionnaires were not used in relation to the forest environment of the temperate zone and they did not mention an important aspect—the proximity to the body of the examined objects. Therefore, the analyzed AEFES scale is much more comprehensive in this respect. The aforementioned research also does not address issues related to the different perceptions of forest landscapes resulting from the density of vegetation and therefore the possibility of hiding insects and potential predators. In the current research, it was proven that dense forest is less pleasant for the respondents, which explains, among other things, the observed correlation between preferred pleasantness and the values of the “Insects” subscale.
Presumably, AEFES can also be used to predict psychological relaxation. This prediction can be made by qualified personnel who would like to determine whether a hypothetical participant of forest recreation can benefit from this activity in the form of psychological relaxation, i.e., improved mood, an increased level of positive emotions, a decreased level of negative emotions and regeneration of mental strength (increased restorativeness). Other studies have predicted the level of psychological relaxation of the natural environment using scales measuring place attachment and place identification [47
], so the AEFES scale will also probably be a scale that can be used for this purpose, but this requires further research.
Since preferred pleasure is correlated with restorativeness [19
] and restorativeness is related to the positive properties caused by the forest, among other things, in the examined patients of a psychiatric hospital [48
], it can be concluded that the subjects experiencing the pleasure of viewing pleasant pictures of the forest landscape will experience beneficial effects on their health. However, confirmation of this fact requires future studies in order to verify whether the AEFES scale may be useful in predicting the therapeutic effect for patients. The AEFES questionnaire can also be used to predict the benefits that participants of forest therapy may derive in various areas that may be affected by the forest: psychological effects, physiological effects and effects on social wellbeing. In addition, different features of the forest may have a different impact on the respondents (different forms of forest use, different species or different types of forests, including those resulting from geographic diversity), which can be predicted using the AEFES scale [49
The limitation of this study may be the use of virtual examples of the forest environment in the form of photos, instead of landscape in a natural environment. However, looking at a virtual forest landscape is also associated with many benefits that can be derived by the respondents. A good example is a study in which people looking at films from forest areas experienced relaxation, but this also decreased their willingness to procrastinate [51
]. In other studies, looking at a virtual forest reduced stress in adults [52
], and the respondents’ relationships to the virtual forest environment were varied [53
It is also worth noting that different environments will not necessarily be suitable for forest therapy, which is an implication of the Prospects and Refuges Theory [22
]. On the other hand, the diversity of the environments in which the participants of forest therapy stay is of great importance for the therapy, where the diversity of the environment and the presence of open space is also important [54
The AEFES questionnaires are not the only tool to predict the expected benefits that contact with nature may bring to its participants. Subjects with acute depressive symptoms preferred dark and dense forest landscapes [56
]; experts and laypeople might have different perceptions of tree features [10
]. In addition, individual preferences were important in the mental and physical reactions of the respondents to the forest environment [9
Future research should be carried out to check whether, for example, the statement “feel one with nature” included in the CNS scale will be related to receiving psychological benefits related to nature. The analysis of the available literature shows that this relationship has not yet been studied.
It is possible that not all of the statements in the AEFES scale will always reflect real fear in the forest. For example, a person who claims to experience discomfort in the forest as a result of contact with a snake may not feel this discomfort in the real environment, and vice versa. This requires empirical testing in future research. In these studies, however, an image of the situation in the forest was presented, and it is highly likely that this image of discomfort is real, as evidenced by different responses to different landscapes viewed.
On this scale, items about discomfort that could be caused by deadwood were not included. Neither of the items concerned this. It is planned in future studies to supplement the AEFES scale with statements regarding possible discomfort resulting from the perception of deadwood in the forest.
In these studies, half of the respondents were people using forest areas regularly and half of the respondents did not use forest areas (in both groups). Therefore, some of the respondents are representative people using the forest and some are not. This diversification was intended to ensure that all groups are considered equally, which makes the results plausible—as they show the distribution of actual use of the forest environment by social media society. Additionally, the respondents presented different levels of education, which was also intended to reflect the society using social media, which could potentially benefit from computer-mediated forest therapy in the future.
4.4. Implications and Future Research
The ability to predict the restorativeness of the environment (which is correlated with pleasantness [57
]) is used in a small number of scientific articles regarding the possibility to predict pleasantness or restorativeness [19
]. This study is innovative in the creation of a novel instrument designed exactly for the prediction of benefits taken from natural forest environment. The study showed that it was possible to predict social media users’ possibility to like or evaluate positively each forest environment. The AEFES also has potential to be used by physicians or therapists working with depression or anxiety because forest environments might be an additional remedy for those patients with psychological problems [48
], and prediction of pleasantness felt by each patient from described contact with forest environment is possible with the use of this instrument.
Future research is needed concerning AEFES. In the current study, only the prediction of preferred pleasantness was tested. Because other measurements of the impact of forest or natural environments are also possible, it is worth considering the verification of the predictive potential of AEFES for this measure. Restorativeness is one possible measure of effects. The current study also only verified the photographic illustration of the forest environment influence in relation to AEFES vs. preferred pleasantness. In future studies, it will be very important to use the proposed instrument to predict effects in real forest environments.
Moreover, in future research, the usage of confirmatory factor analysis (CFA) for analysis should be considered. This research planned and performed comparisons of two samples for EFA, but because CFA cannot be done on the same sample as EFA, CFA could not be done in this research.
The current problems with the COVID-19 pandemic [59
] also bring new possibilities for environmental studies on the influence of virtual forest environments on humans. Many people are living in isolation during the pandemic, sometimes with no contact with the outside environment. Some form of replacement of interaction with these outside environments, such as photographs of a forest environment, might be needed because of the natural need of people to be in contact with nature [60
]. Thus, the instrument is needed to personalize these photographs or films to increase the pleasantness experienced by the subjects. It can be imagined that a tree stand (landscape) with different characteristics may be better suited to the needs of the person who would benefit from viewing it. For example, a given person gains the benefits of viewing both the stand and the dense stand (which was predicted by the AEFES scale); therefore, for such a person, there are no contraindications for practicing forest therapy in both stands.