| Due to its various ecological health functions,the forest in has become an important place for urban residents to relax.People pay more and more attention to the health care factors such as air quality environment and microclimate comfort in the forest.Forest tourism has gradually become an important part of China’s forestry industry.It is of great significance to study the dynamic law of air negative ions in forest healthy environment and the factors causing the change of air negative ions in forest environment.Then,at present,the research objects of urban forest mainly focus on urban park green space and residential green space,the research on suburban mountain forest is relatively lack,and the dynamic change law of health care factors in forest environment is still unclear.Therefore,taking the urban forest in the suburbs of Guangzhou Maofeng Mountain Forest Park as the research object,this paper monitored the healthy environmental factors in the forest environment,such as microclimate factors,air anion concentration,air particulate matter mass concentration and ozone concentration,and analyzed their temporal and spatial variation rules.The main conclusions are as follows1.During the observation period of Maofeng mountain forest environment,the annual average temperature is 20.5℃,the average relative humidity is 82%,the total precipitation is 2277.2mm,Water surface evaporation is 744.6mm,the average temperature in dry season is 16.5℃,the average temperature in rainy season is 24.6℃,the average humidity in dry season is 77%,and the average humidity in rainy season is 87%.The change of relative humidity in each month of the whole year is relatively stable,and the number of days with annual average temperature>18.5℃exceeds 80%,reaching the peak of 29℃in July;339days with"very comfortable"comfort index;The best period of human comfort is from April to may in the rainy season and from October to November in the dry season.The index is less than 4.Maofeng mountain is the most comfortable at 7:00 in the evening.At night,the comfort index reaches the maximum due to the decrease of temperature and the increase of wind speed,;The dynamic change curves of temperature and humidity are inversely consistent,and the change characteristics of gas particulate matter and ozone mass concentration are roughly opposite to that of air negative oxygen ions,mainly concentrated in December～March of dry season(100～140mg·m-3);The dynamic change law of temperature is inversely consistent and related to solar radiation.2.The average concentration of negative oxygen ions in Maofeng mountain forest environment is 1360 ion·cm-3,which basically meets the needs of health care.The annual concentration level in dry season(1500～1700 ion·cm-3)is higher than that in rainy season(800～1200 ion·cm-3),the lowest in April(750 ion·cm-3)and the highest in December(2000ion·cm-3);The change law of monthly mean value shows a double peak curve,which decreases first and then increases.There are two peaks in October and December;In the dynamic change of one day,the maximum value appears at 10:00 a.m.(1900 ion·cm-3),the minimum value appears at 20:00 p.m.(1200 ion·cm-3),and the concentration level in other periods(1500 ion·cm-3).The change of the whole day shows a single peak curve of first rising and then falling.The concentration level of negative oxygen ions in forest environment is from high to low:Coniferous and broad-leaved mixed forest land(1400～1500ion·cm-3)>Natural Evergreen broad-leaved forest land(1200～1400ion·cm-3)>artificially restored forest land(1000～1200ion·cm-3)>suitable forest land（400～850ion·cm-3）.The diurnal dynamics of negative oxygen ions in the air suitable for forestry showed an upward trend from morning to night;The daily environmental dynamics of coniferous and broad-leaved mixed forest and natural evergreen broad-leaved forest decreased first and then increased.3.The negative oxygen ions in the ambient air of Maofeng mountain forest were negatively correlated with ambient air temperature,soil temperature,relative humidity,wind speed and wind direction（P<0.01）,and positively correlated with total radiation,photosynthetic effective radiation and atmospheric pressure（P<0.01）.There was a very significant negative correlation between air negative oxygen ions and atmospheric particulate matter in natural evergreen broad-leaved forest（P<0.01）,there was no significant correlation between air negative oxygen ions and gaseous particulate matter in suitable forest land and artificial restoration forest,and there was a negative correlation between environmental ozone and air negative oxygen ions,and the degree was not uniform.To sum up,Maofeng Mountain Forest Park in Guangzhou has a beautiful environment and a suitable microclimate.The pollutants in the environment(TSP,PM10,PM2.5,PM1,O3)are far less than the limits of environmental Air Quality Standard（GB 3095-2012）.The average concentration of negative oxygen ions in air(1400 ion·cm-3)was much higher than the critical value(700 ion·cm-3),and the content of negative oxygen ions was higher in dry season.There is a significant negative correlation between air negative oxygen ions and environmental factors.It shows that Maofeng Mountain is exerting a good ecological effect and playing an irreplaceable role in improving the ecological environment in the suburbs of the city.The study of forest health factors is of great significance to the planning and construction of urban green space and forest park and the improvement of urban residents’life quality. |
