| In the current process of rapid global urbanization,with the rapid development of modern economy and society and the gradual fierce social competition that the young people are under increasing pressure from life and work,the mental diseases such as depression and anxiety are increasing and chronic diseases such as hypertension and heart disease tend to be younger.In recent years,research related to the improvement of human physical and mental health in urban forest environments has been gaining attention.Resting and walking in the forest environment were regarded as important ways to improve happiness.Usually,the process in which visitors get the health benefits of body and mind while walking,watching or exercising in the forest environment is called "forest bathing".Contemporary youth groups are the core driving force of national development and their physical and mental health is related to the future of the whole society and the country.Therefore,it is of great significance to study the recreational benefits of urban forest bathing and its mechanism to improve the physical and mental health of youth.In this study,three typical urban forest environments in Changchun City,namely Beihu National Wetland Park,Jingyuetan National Forest Park and Nanhu Park,were used as the research sites,and the urban street environments were used as a reference.The psychological and physical changes of 72 young visitors(college students aged 19～29)were studied when they stayed in the urban forest environment in three different seasons of spring,summer and autumn for 4.0 hours.To compare self-evaluated of 12 questions on a questionnaire reflecting psychological status before and after the trial to quantify the effect of urban forest bathing in different seasons on the relief of inner anxiety in the subjects.The physiological parameters of the subjects in the urban forest environment in different seasons were studied according to the changes of blood pressure and heart rate every 30 minutes to determine the length of the forest bathing experience to maximize the health benefits in the urban forest environment.At the same time,compared the effects of forest bathing in different seasons to select the best season for urban forest bathing which further studied the effects of factors(including temperature,humidity,wind speed,noise,photosynthetic photon flux density and the ratio of red,green and blue spectra)on physiological parameters in the urban forest environment.The spatial and temporal variation and correlation of the indicators are studied by repeated measures ANOVA and multiple stepwise regression analysis.The main findings are as follows:1.Compared to the urban street environment,the psychological effects of urban forest bathing in different seasons are the best in spring.The proportion of urban forest bathing in spring to alleviate anxiety is 50%～67%>summer 25%～42%>autumn 25 %～33%.The spring urban forest bathing can promote positive emotion and relieve negative emotion of subjects.Compared to the urban street environment,Nanhu Park’s urban forest bathing has better psychological effects on subjects than Jingyue Park and Beihu Park.2.In different seasons,compared to the urban street environment,the effects of urban forest bathing in the three parks are the best in spring.In the spring urban forest bathing,the blood pressure and heart rate of the subjects reached their lowest values at 2.0 h or 2.5 h.Therefore,the optimal length of stay in the forest environment is 2.0～2.5 h,at which time the regulation effect on the autonomic nervous system and cardiovascular system of the subjects is the best.Compared to the urban street environment,the urban forest bathing in Jingyue Park in spring has better physiological effects on subjects than Beihu Park and Nanhu Park.3.The environmental factors of the urban forest environment had a greater effect on subjects’ blood pressure and heart rate than the urban street environment.In the urban forest environment,the ratio of green light to blue light in the solar spectrum was the main factor influencing the changes in blood pressure and heart rate of subjects.Blood pressure was mainly affected negatively by the ratio of green light,and an increase in the ratio of green light was the main cause of the decrease in blood pressure.Heart rate was mainly positively correlated with the proportion of blue light,and a decrease in the ratio of blue light was the main reason that affects the decrease in heart rate.Combining the correlation analysis between the structural characteristics of the arbor layer and the environmental factors in different parks.It is suggested that the proportion of green light in the environment can be increased by increasing the canopy density of the forest environment and the proportion of blue light can be reduced.In downtown parks or parks with high noise levels,planting high trees to reduce noise levels,thereby improving blood pressure and heart rate.This study provide scientific research methods and data results for the scientific exploitation of urban forest health benefits.Providing a scientific and theoretical basis for urban forest base planning and construction in terms of correlation studies between physiological indicators and environmental factors.It also provides a reference to further research on the mechanism of the effect of forest bathing on human psychological and physiological health. |
