广州机场路景观防护林的环境效应特征

Characteristics of Environmental Effects in the Landscape Shelter Forest along the Aerodrome Road in Guangzhou

为了计量城市路网景观防护林的环境效应,采用群落生态学及水平多点定位同步观测方法,对机场路景观防护林群落结构及消减路面热岛、污染气体浓度效应进行了观测研究;结果显示:防护林群落呈4层垂直结构(上层乔木平均高(珚H)=12.6 m、中层乔木珚H=6.3 m、灌木层珚H=3.2 m、草本层珚H=0.6 m),水平30 50 m沿机场路侧带状分布;防护林群落的Shannon(H)达2.39,均匀度达0.76,而森林群落郁闭度达0.68。相对路面空气SO2、NO2(0.150、0.083 mg·m-3)的日均浓度,防护林林内20 m则减小到0.05 mg·m-3以下,空气温度则减小2.0℃,空气湿度增加2.4%,风速减小0.7 m.s-1;雨季晴天日,13:00-15:00、林内20 30 m空间相对路面的气温减小值大于2.0℃,而林内10 30 m空间相对路面的空气湿度增加5.0%7.1%;林内20 30 m空间空气SO2浓度≤0.05 mg·m-3的白昼持续时间达8.3 9.0 h,而林内30 40 m空间空气NO2浓度≤0.05 mg·m-3的白昼持续时间达8.3 h;机场路景观防护林群落对路面热岛强度、空气SO2、NO2浓度消减效应极其显著。采用趋势面回归方法,获得的机场路面至林内水平尺度空气SO2、NO2浓度时空分布拟合方程适宜于估算应用。

The function on reducing the heat island effect and contaminated gases on road surface was studied by means of multiCpoint synchronous observation method on horizontal scale of the landscape protection forest along an aerodrome road in Guangzhou.The results showed that the forest stand had a vertically 4-storey community structure by 2.39 of Shannon（H）,and 0.76 of uniformity index and its canopy density attained to 0.68.Its vertical structure incarnates the multi-hierarchy collocation with the upper-storey of 12.6 m（Eucalyptus species）,the middle storey of 6.3 m（hardwood species）,the shrub storey of 3.2 m and herbage storey of 0.6 m.The shelterbelt stretches along the road with the width 30 m to 50 m.The results of a six-day observation in September 2006 showed that the daily mean concentration of SO2 and NO2 was 0.150 mg·m^-3 and 0.083 mg·m^-3 on road surface while that of in the forest belt with 20 m in width was reduced to lesser than 0.05 mg·m^-3.At the same time,the air temperature of the road surface decreased by 2.0 ℃ and the air humidity of road surface increased 2.4 % by the forest belt with 20 m in width.In fine weather,the air temperature in the area 20 m and 30 m inside forest belt was 2.0 ℃ lower compared with that on the road surface from 13：00 to 15：00.Concurrently,the air humidity in the area 10 m to 30 m inside forest belt increased from 5.0% to 7.1%.The results of a observation of September 11-16,2008 showed the SO2 concentration in the air was ≤0.05 mg·m^-3 for 8.3-9.0 hours in the forest with a width of 20 m to 30 m,and the NO2 concentration in the air was ≤0.05 mg·m^-3 and could last for 8.3 hours in the forest with a width of 30 m to 40 m.The shelter communities along the aerodrome road have marked ecological function on reducing the heat island effect and contaminated gases of road surface.Using trend surface regression method,the temporal and spatial distribution fitting equation of SO2 and NO2 concentrations from the road to forest obtained a good fitting result.