湖北林业科技

By conducting on-site measurements of environmental factors in several major forest types in Jiufeng National Forest park,a comprehensive evaluation system for summer forest environmental effects was constructed to provide scien- tific reference for the development of forest health industry. Multiple ecological factors of five representative forest types and control points (Ck) in the park were selected to monitor, including air temperature and humidity, atmospheric particle concentration and negative air ion concentration . The diurnal variation of each factor was analyzed and the differences a- mong different forest types were compared. The environmental effects in different forest types were comprehensively e- valuated by principal component analysis . The results showed that ①the daily air temperature of each forest type showed a single peak type curve, and the relative air humidity showed a single valley type curve, with the temperature decreasing 2. 63℃ and relative humidity increasing 10. 38% on average compared to the control point , and the characteristic of hu- man comfort index showed relatively more comfortable in the morning and evening. ②the daily variation of the atmos- pheric particle concentration was gradually decreasing, with the daily average purification rate of TSP, PM1. 0 , PM2. 5 and PM10reaching 64. 13% ,35. 26% ,44. 49% and 57. 69% respectively. ③the daily variation of negative air ion concentration showed a double-peak change, and the daily average value was 899. 21ion per square centimeter,2. 65times of the control point. ④the concentration of negative air ions was negatively correlated with air humidity, PM2. 5 , PM10 and DIFN, while positively correlated with LAI. The PM2. 5 mass concentration was positively correlated with PM10 mass concentration, hu- midity, and DIFN, while negatively correlated with temperature and LAI. The ranking of the comprehensive evaluation results of environmental effects was coniferous and evergreen broad-leaved mixed forest>evergreen broad-leaved forest> deciduous broad-leaved forest>coniferous and deciduous broad-leaved mixed forest>evergreen deciduous broad-leaved mixed forest. The comprehensive environmental effect of coniferous and evergreen broad-leaved mixed forest was the highest , mainly composed of pinus elliottii and castanopsis sclerophylla . For different forest types , due to the different tree species composition, density, age structure and individual tree distribution in forest land, the effects of forest on the environment are different.