Abstract:

The anion released by the forest and wetland has important ecological functions and is a significant evaluation index.The article focused on several eco-factors which have notable influence on the anion thickness.A qualitative,quantitative and visual study on the forest and wetland in Qingdao was for the first time conducted in large scale to guide the construction and ecological benefit assessment of anion bathing Forests.The study was based on the survey data,block plan and ALOS image,combining with the spatial statistics and 3S technique.The main results were as following:1) The longest influence external distance is 10 m at the early growth stage of vegetation and the longest influence external distance is 40 m at the middle growth stage of vegetation.2) At the early growth stage,the capacity of anion release from forests and wetlands varied as following,mixed forest>coniferous forest>broadleaf forest>wetlands>economic forest.At the middle growth stage,the released capacity of anion was:economic forest>wetlands>mixed forest>broadleaf forest>coniferous forest.3) The first and second grade scattered in the urban,Jiaozhou and Laoshan regions of the city at the early growth period.At that time,the mean concentration of anion was 1 651 unit·cm^-3 ,average humidity 35.38% RH，mean temperature 16.05 ℃.The covered area was 77.01 km² ，among which forests took 40.85 km² ，wetland area was 0.37 km² ,and forest coverage was 53%.The first and second grade scattered in the south Laixi,Jimo,Chengyang,urban，Jiaozhou gulf，Laoshan Pingdu and Jiaonan region of the city at the middle growth stage.Just as above,mean concentration of anion was 3 550 unit·cm^-3 ,average humidity 67.43% RH，mean temperature 26.77℃.The area covered 5 687.58 km² ，with forest 2 380.25 km² ，wetland 472.07 km² .The forest with the mean concentration of anion more than 3 550 unit·cm^-3 accounted for 53% of land area of the Qingdao city,the forest coverage was 42%，the concentration of anion at middle growth period was 4 times of that at early stage.4) This study confirmed the ecological value of economic forest.

Key words: Anion spatial distribution, semi-variant analysis, spatial interpolation, overlay analysis