北京市三种道路防护林滞尘格局及其影响机制研究

发布时间：2019-01-12 14:07

【摘要】：城市森林能够通过其复杂的叶面结构和冠层结构吸附、阻滞空气颗粒物。道路防护林是城市森林的重要组成部分,对主要由道路交通引起的颗粒物污染有较好的防护作用。本文以北京市3种具有代表性的道路防护林为研究对象,对林内叶面滞尘量、地表降尘量、空气颗粒物浓度进行了全年同步观测,对3种道路防护林滞尘的时空变化规律及影响机制进行了全面系统的研究,主要结论如下:1、3种道路防护林滞尘能力的差异。(1)叶面尺度滞尘能力表现为圆柏林银杏林油松林,不同季节油松林和圆柏林表现为为冬季春季秋季夏季,银杏林表现为春季和秋季接近,夏季最低;单株和林地尺度滞尘能力均为油松林圆柏林银杏林。(2)地表降尘能力3种道路防护林差异不大,不同季节表现为春季冬季夏季秋季。(3)TSP和PM10浓度均为春季冬季夏季秋季,PM2.5和PM1浓度均表现为冬季最高,春、夏、秋季差异不大。(4)3种道路防护林叶面滞尘能力、地表降尘能力的季节变化与TSP、PM10浓度的季节变化具有较高一致性,与PM2.5和PM1关联性差。(5)同面积林地全年及各季节地表降尘总量均明显高于冠层滞留总量。2、3种道路防护林滞尘的时间变化特征。(1)圆柏林叶面滞尘的稳定性最高;银杏林叶面滞尘增长速度和降低速度均远高于油松林和圆柏林。(2)叶面滞尘不同季节的时间变化特征表现为冬季变化幅度最低,春季、夏季、秋季变化幅度均较高,不同道路防护林时间变化特征也有差异。(3)3种道路防护林内地表降尘量时间变化趋势基本一致;不同季节地表降尘量的变化特征表现为冬季变化幅度最大,春季次之,夏秋季较低。(4)3种道路防护林内叶面滞尘与地表降尘均呈现出正相关关系,冬季、春季相关性较低,夏季、秋季较高。3、3种道路防护林滞尘的空间变化特征。(1)3种道路防护林叶面滞尘、地表降尘及TSP、PM10浓度空间变化特征相似,表现出明显的关联性,油松林和圆柏林内均表现为单谷型分布,银杏林内均表现为双谷型分布,与PM2.5、PM1的空间分布特征关联性微弱。(2)不同季节3种道路防护林叶面滞尘、地表降尘及TSP、PM10浓度空间变化特征均表现为冬季香山路侧滞尘量高,春季则为五环路侧较高,夏、秋季两侧无明显差异。(3)3种道路防护林内不同位置树体南北两侧的滞尘量有较大差异,总体表现为迎路面明显高于背路面,从林缘到林内,南北方向滞尘量的差距逐步缩小。4、气象条件对3种道路防护林滞尘作用的影响。(1)降雨对3种道路防护林叶面滞尘的影响表现为低雨量促进,高雨量减弱,对叶面滞尘的减弱作用表现为为银杏林油松林圆柏林。(2)不同风力等级对3种道路防护林的叶面滞尘均有促进,对银杏林促进作用最明显;地表降尘量随着风力等级的增大呈增长趋势。(3)重度污染天气及桑拿天对3种道路防护林叶面滞尘均有不同程度促进;对地表降尘均表现为减弱作用。
[Abstract]:Urban forest can block air particles by its complex leaf structure and canopy structure. Road shelter forest is an important part of urban forest, which has a good protective effect on particulate pollution caused mainly by road traffic. In this paper, three kinds of representative road shelterbelts in Beijing were used as the research objects. The dust retention on the leaf surface, dust fall on the surface and the concentration of air particles in the forest were observed synchronously throughout the year. The temporal and spatial variation law and influence mechanism of dust retention in three kinds of road shelterbelts were studied comprehensively and systematically. The main conclusions are as follows: (1) the dust retention ability of the three kinds of road shelterbelts is different. (1) the dust retention ability of the leaf surface scale is shown as the Pinus tabulaeformis forest in the Ginkgo biloba forest, the Pinus tabulaeformis forest and the round Berlin forest in winter, spring, autumn and summer in different seasons. Ginkgo biloba forest showed that the spring and autumn were close to each other, and the summer was the lowest. The dust retention capacity of individual plant and woodland was the same as that of Pinus tabulaeformis forest and Ginkgo biloba forest. (2) there was no significant difference among the three kinds of road protection forests. (3) the concentrations of TSP and PM10 are both spring, winter, summer and autumn, and PM2.5 and PM1 are the highest in winter, spring and summer, respectively. There was no significant difference in autumn. (4) there was a high consistency between the seasonal variation of surface dust lowering ability and the seasonal variation of TSP,PM10 concentration in three kinds of road shelterbelts. The correlation with PM2.5 and PM1 was not good. (5) the total dust fall on the surface of the same area woodland was significantly higher than that on the canopy in the whole year and in each season. 2. The time variation characteristics of dust retention in the three kinds of road shelterbelts were observed. (1) the stability of dust stagnation on the leaf surface of Berlin was the highest; The increasing rate and decreasing speed of dust retention in leaf surface of Ginkgo biloba forest were much higher than those in Pinus tabulaeformis forest and round Berlin. (2) the time variation characteristics of leaf surface dust retention in different seasons were the lowest in winter, and higher in spring, summer and autumn. The time variation characteristics of different road shelterbelts are also different. (3) the time variation trend of dust fall on the interior surface of three kinds of road shelterbelts is basically the same; The variation of surface dust fall in different seasons was the biggest in winter, followed by spring, and lower in summer and autumn. (4) there was a positive correlation between surface dust retention and surface dust fall in three kinds of road shelterbelts, and it was found that there was a positive correlation between leaf surface dust retention and surface dust fall in winter. The spatial variation characteristics of dust retention in three kinds of road shelterbelts were lower in spring and higher in summer and autumn. (1) the spatial variation characteristics of dust retention, surface dust fall and TSP,PM10 concentration in three kinds of road shelterbelts were similar, showing obvious correlation. In Pinus tabulaeformis forest and round Berlin, there were single valley distribution and double valley distribution in ginkgo biloba forest, which had a weak correlation with the spatial distribution characteristics of PM2.5,PM1. (2) three kinds of road shelterbelts in different seasons had a weak correlation with leaf dust, surface dust and TSP,. The spatial variation characteristics of PM10 concentration showed that the dust content in the road side of Xiangshan was high in winter, and that in spring was higher on the side of five-ring road, and higher in summer. There was no significant difference between the two sides in autumn. (3) there were great differences in dust retention between the north and south sides of the tree at different positions in the three kinds of road shelterbelts. The overall performance of the dust retention was that the road surface was obviously higher than the back road surface, from the forest edge to the forest. 4. The influence of meteorological conditions on the dust retention of three kinds of road shelterbelts. (1) the effects of rainfall on the dust retention on the leaf surface of three kinds of road shelterbelts are promoted by low rainfall and weakened by high rainfall. The dedusting effect on leaf surface was shown as follows: round Berlin of Pinus tabulaeformis forest in Ginkgo biloba forest. (2) different wind levels promoted dust retention on leaf surface of three kinds of road shelterbelts, and the most obvious effect was on ginkgo forest. (3) severe polluted weather and sauna can promote the dust retention of the three kinds of road shelterbelts to some extent, and weaken the dust fall on the surface of the three kinds of road shelterbelts.
【学位授予单位】：中国林业科学研究院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X513;X173

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