杭州市城市森林生态保健功能动态变化监测

选择杭州市具有代表性的郊野森林、森林公园、社区绿地3种类型的城市森林样地及城市中心对照点共4个监测点，建立定位监测站对气温、相对空气湿度、风速、CO₂浓度、空气负氧离子浓度、噪声值等6项指标进行全天24 h不间断连续监测，并对周边的植被状况设置样地进行调查。综合监测数据和调查资料分析了城市森林生态保健功能的动态变化规律及群落结构对其影响。结果表明:1）城市森林具有良好的调节户外舒适度、降低CO₂浓度、增加空气负氧离子浓度、降低噪声等生态保健功能；2）除噪声外，城市森林的其他多项生态保健功能的日变化曲线呈现出明显的单峰式。舒适度指数的最高值出现在5:00-6:00，最低值出现在12:00-14:00。CO₂浓度的最高值出现在5:00-8:00，最低值出现在13:00-14:00。空气负氧离子浓度的最高值出现在15:00-16:00，最低值出现在21:00-22:00。郊野森林和森林公园噪声日变化波动性不大，均处于较低值；3）城市森林调节户外舒适度的功能在3种类型的城市森林均表现为冬季最低，而其他季节的次序并不一致。降低CO₂浓度和增加空气负氧离子浓度的功能均为夏季最高，冬季最低，春、秋两季次之。降低噪声的生态保健功受季节的影响不明显。本研究还探讨了城市森林群落结构对所体现出来的城市森林生态保健功能的差异性的影响。

Monitoring of Dynamic Changes of Ecological Health Functions of Urban Forests in Hangzhou

In this study, three sites which represent typical types of urban forests (suburban forest, forest park, residential green space) and one control site (central city area) were chosen for long-term monitoring in the views of ecological healthcare function. At each site, a monitoring platform was set up to monitor air temperature, relative humidity, wind speed, the concentration of carbon dioxide, the concentration of negative air ions, and noise level continuously. Conditions of surrounding vegetation were investigated by using sample plots. The results showed that (1) urban forests could regulate the outdoor comfort level, lower the concentration of CO₂ and noise levels, and increase the concentration of negative air ions; 2) except for noise level, the daily variations of other ecological healthcare functions appeared as uni-modal curves. The comprehensive comfort index peaked around 5:00～6:00 AM and dropped to the lowest point around 12:00～14:00 PM. The concentration of CO₂ was the highest around 5:00～8:00 AM and the lowest point appeared around 13:00～14:00 PM. The highest and lowest concentrations of air negative oxygen ions appeared around 15:00～16:00 PM and 21:00～22:00 PM, respectively; and 3) the capacity of the three types of urban forests in regulating the outdoor comfort level was the lowest in the winter but did not show a uniform pattern in other seasons. The functions of lowering the concentration of CO₂ and increasing the concentration of negative air ions were both the highest in the summer and the lowest in the winter, with those of spring and fall falling in between. The function of lowering the noise level was not significantly affected by seasonality. The effects of community structures of urban forests on the variations of ecological health functions of these forests were also discussed.