Study On Carbon-fixing, Oxygen-releasing,Temperature-reducing, And Humidity-increasing Effects Of Green Tree Species In Coal Mine Reclaimed Soil

The paper tested photosynthetic rate and transpiration rate of17common green trees on the spot in Datong wetland park, used the CI-340photosynthesis system in spring, summer and autumn. The testing period was divided into six periods, and measured every two hours(8:00-18:00), meanwhile CI-340recording data automatically in the process of testing. Used CI-110plant canopy analyzer to determine leaf area index of every trees. Analyzed the test datas, then study the variation formula of diurnal photosynthetic rate and transpiration rate about each species respectively, meanwhile calculated the net amounts of carbon fixation and oxygen release and the ability of cooling and humidification on the basis of calculation formulas. The amount of cooling and humidification studied in summer only. The main conclusions of this paper are as follows:(1) Most of the diurnal course of photosynthesis rate in three seasons were double-peak and exited obvious photosynthetic midday-depress phenomenon. The double peak roughly appeared at10:00and14:00, the diurnal photosynthesis rate will be reduced at12:00. In summer, the daily variation transpiration rate is most similar to the diurnal course of photosynthesis rate, the double peak roughly appeared at10:00and14:00.(2) The trends of seasonal change for the ability of carbon fixation are:Amorpha fruticosa, Black Locust, Paulownia and Cunninghamia Lanceolata are spring> summer> autumn; Liriope, Wild jujube, Weigela florida, Firmiana simplex and Prunus persica are summer> spring> autumn; Sweet viburnum, Osmanthus fragrans, Ligustrum lucidum, Pittosporum tobira, Ailanthus altissima, Cinnamomum camphor a and Photinia serrulata are spring> autumn> summer; Magnolia grandiflora is autumn> summer> spring.(3) In17species, the arranging order of carbon fixation and oxygen release for per unit leaf area of different trees about the average of three seasons are Prunus persica> Amorpha fruticosa> Paulownia> Ailanthus altissima> Cunninghamia lanceolata> Black locust> Photinia serrulata> Ligustrum lucidum> Firmiana simplex> Weigela florida> Sweet viburnum> Pittosporum tobira> Wild jujube> Cinnamomum camphora> Osmanthus fragrans> Liriope> Magnolia Grandiflora. The arranging order of carbon fixation and oxygen release for per unit land area of different trees about the average of three seasons are Cunninghamia lanceolata> Pholinia serrulata> Ligustrum lucidum> Black locust> Amorpha fruticosa> Pittosporum tobira> Osmanthus fragrans> Weigela florida> Prunus persica> Ailanthus altissima> Firmiana simplex> Sweet viburnum> Cinnamomum camphora> Paulownia> Liriope> Wild jujube> Magnolia Grandiflora.(4) The ability of cooling and humidification for per unit leaf area of different trees in research area are Prunus persica> Amorpha fruticosa> Black locust> Ligustrum lucidum> Pittosporum tobira> Firmiana simplex> Paulownia> Photinia serrulata> Cunninghamia lanceolata> Osmanthus fragrans> Sweet viburnum> Ailanthus altissima> Magnolia Grandiflora> Wild jujube> Liriope> Cinnamomum camphora> Weigela florida. The ability of cooling and humidification for per unit land area of different trees in research area are Ligustrum lucidum> Amorpha fruticosa> Black locust> Photinia serrulata> Pittosporum tobira> Cunninghamia lanceolata> Prunus persica> Osmanthus fragrans> Firmiana simplex> Magnolia Grandiflora> Sweet viburnum> Oinnamomum camphora> Paulownia> Weigela florida> Ailanthus altissima> Liriope> Wild jujube.(5) Considering the amount of carbon fixation and oxygen release for per unit leaf area and per unit land area, the greening tree species were divided into three grades by using clustering analysis of SPSS:the first grade includes Photinia serrulata, Cunninghamia lanceolata, Black locust, Ligustrum lucidum and Amorpha fruticosa; the second grade includes Weigela florida, Osmanthus fragrans, Pittosporum tobira, Prunus persica, Ailanthus altissima, Cinnamomum camphora, Sweet viburnum, Firmiana simplex and Paulownia; the third grade includes Wild jujube, Liriope and Magnolia Grandiflora. Comprehensively, Photinia serrulata, Cunninghamia lanceolat, Black locust, Ligustrum lucidum, and Amorpha fruticosa are advantage species for carbon fixation.(6) Considering the factor of carbon fixation and oxygen release and cooling and humidification, the greening tree species were divided into four groups by using clustering analysis of DPS:the first group includes Liriope and Pittosporum tobira; the second group includes Prunus persica, Firmiana simplex, Wild jujube and Ailanthus altissima; the third group includes Photinia serrulata, Magnolia Grandiflora, Weigela florida, Sweet viburnum, Amorpha fruticosa, Paulownia, Osmanthus fragrans, Black locust and Ligustrum lucidum; the fourth group includes Cinnamomum camphora and Cunninghamia lanceolata. The species which were in the same group have ecological similarities to some degree, they can be replaced each other according to the landscape and other requirements when selecting species.