多功能用材林周边大气SO2和NOx的变动规律研究

树木在生长过程中,通过光合作用和树体表面,一方面能有效地吸收、阻滞和吸附大气中的SO₂、NO_x等有害气体,另一方面,由于树体的截留作用,使得其在林内及周边的浓度提高。研究表明:大气中SO₂、NO_x浓度以枝叶生长期最高,分别为高径生长期的5.2倍和6.7倍;枝叶生长期大气SO₂存在明显的上午高、下午低的日变化特点,早晨的浓度要比下午高出1倍至4倍,并以林带内最低、林带外侧次之、林带外侧最高,大气NO_x浓度则以中午较低;高径生长期大气SO₂、NO_x浓度为上午高、下午低,其中林带内和林带外侧大气SO₂、NO_x浓度早晨比下午高3倍至5倍左右;生长减缓期大气SO₂、NO_x浓度日变动幅度小,SO₂浓度从早晨开始持续上升,NO_x浓度林带外侧上升较快、林带内和林带内侧变动很小。研究认为,高径生长高峰期的下午是休息、旅游、健身等活动的最适时间。

Studies on dynamic pattern of atnospheric S02 amd NOx around muti-fimctionl timber forest

Trees can effectively absorb and block poisonous gases, such as SO2 and NOx, when they are growing. But they can also in-crease the content of poisonous gases in forest and its near area owing to interception. The contents of SO2 and NOx in and near the forest were the highest during the growth period of leaf and branch, and were 5.2 and 6.7 times respectively the content during the growth of height and diameter. In the growth period of leaf and branch, the content of SO2 was higher in the morning and lower in the afternoon, and the content in the morning was 4 times higher as much as in the afternoon. It also showed charicteristic of being highest in the forest belt and lowest outside the forest belt, but the content of NOx was lowerest at noon. In the growth period of height and diameter, contents of S02 and NO, in the atmosphere were high in the morning and were 3-5 times higher than that in the afternoon. In slowly growing period, the contents of S02 and NOx changed little. The content of SO2 increased continuously from the morning both in and outside the forest belt, the content of NOx increased more rapidly outside the forest belt, and varied litde in forest belt and inside of forest belt. The peak period of growth of height and diameter was preferred for rest, tour and bodybuilding.