Restorative effects of different forest environments in spring, summer, and autumn
方法 实验时间为2017年4月（春）、6月（夏）、10月（秋）。三季分别招募40、18、20人。春季采用被试间设计，研究对象随机分配到北京某城郊开发区域森林公园和某半原始区域森林公园进行体验，每名被试只体验一种森林环境。夏、秋两季采用被试内设计，每名被试对两种森林环境都进行体验，第一天在城郊开发区域森林公园，第二天在半原始区域森林公园。森林体验前完成简明心境量表（BPOMS）问卷，监测心率10 min；进行30min的静坐实验，监测心率10 min，完成BPOMS问卷，并完成中文版复愈性环境量表。在进行森林体验时同步监测客观物理环境指标，分析不同季节森林体验前后各指标变化。
Background It has been proved by many studies that forest environment has good restorative effects. Some researchers have attempted to identify natural factors affecting restorativeness. However, current studies have not focused on the effect of seasonal variation of forest environments on its restorative strength.
Objective To evaluate the restorative effect changes of two types of forest environments across different seasons.
Methods The experiments were conducted in April (spring), June (summer), and October (autumn) of 2017. Forty subjects were recruited in spring, 18 in summer, and 20 in autumn. In spring, the subjects were randomly assigned to a forest park in suburban area and one in semi-pristine area in Beijing where each subject only experienced one kind of forest environment. In summer and autumn, each subject experienced two kinds of forest environments. They spent the first day in the suburban area forest park, and the second day in the semi-pristine area forest park. First the subjects completed the Brief Profile of Mood States (BPOMS) and had their heart rate been monitored for 10 min before test followed by a 30 min forest experience with sedentary sitting. At the end of each experience, the subjects completed the BPOMS again, and also the Restoration Environment Scale-Chinese version. Objective physical environment indicators were monitored simultaneously during forest experience. The changes of each indicator were analyzed before and after forest experience in selected three seasons.
Results In the objective physical environment indicators, the concentrations of anion in selected three seasons in the semi-pristine area forest were higher than the values in the suburban development area forest; the concentration of anion in autumn was much higher than those in the other two seasons. In the assessment of the Restorative Environment Scale, the total scores of restorativeness of the semi-pristine area forest were generally higher than the scores in the suburban development area forest, but significant differences were found only in spring and summer (P< 0.001 in spring,P=0.022 in summer, and P=0.083 in autumn). In terms of physiological indicators, the average heart rate was decreased, while short-term R-R interval standard deviation (SD1) and root mean square of difference of successive intervals (RMSSD) were increased after the designed forest experience sessions in the three seasons, and there was statistical difference between forest types. In terms of psychological indicators, a decrease in the score of total mood disorder was presented after the experience session. In spring, there was a trend that the forest park in suburban development area had a better regulation effect on total mood disorder (P=0.07). In summer and autumn, there was a trend that the semi-pristine area forest park had a better regulation effect on total mood disorder (P=0.062 in summer and P=0.001 in autumn).
Conclusion Generally, forest environments can improve the psychological and physiological indicators of human, and the improvement varies with frosts types and seasons. The restorative effects of forests in semi-pristine areas is better than those in suburban development area.