Study On Carbon Fixation And Oxygen Release, Cooling And Humidification, And Landscape Evaluation Of12Magnoliaceae Trees

With rapid rise and development of urbanization all around the world, plants, as an important soft landscape material for gardening and environment improvement, its development and utilization are becoming hotspots. As the most basic part in the development and utilization of garden plants, study on landscape evaluation of plants is getting more attentions of scholars from various countries. Magnoliaceae plants are a class of species which have high value in gardening, this paper studies Magnoliaceae plants’ landscape and ecological benefits, integrated both sides, selecting12Magnoliaceae trees of Michelia chapensis, Michelia cavaleriei, Michelia crassipes, Tsoongiodendron odorum, Manglietia for di ana, Manglietia moto, Magnolia soulangeana, Magnolia denudate var. flava, Magnolia officinalis, Magnolia officinalis var. biloba. Magnolia cylindrical and Liriodendron chinense×tulipifera to discuss their landscape evaluation and development ranking, it provides reliable theoretical bases and scientific guidances for development of Magnoliaceae plants and breeding of superior ornamental species in Changsha.The specific studies are as follows:(1) The test proved that the green biomass of individual plant’s are closely linked with its leaf area index, canopy, canopy structure, and other factors.6deciduous species have higher average leaf area index than6evergreen kinds, which shows that deciduous plants are better than evergreen plants on effective absorption and utilization of light energy. Green amount per unit land area is the key factor to determine the species’ ecological performance. During growth period,6deciduous are1.50times higher to6evergreen trees in average carbon fixation and oxygen release per unit land area, while1.84times higher in cooling and humidification. Obviously, deciduous trees have a distinct advantage to evergreen species in capacities of average carbon fixation and oxygen release, cooling and humidification during growth period.(2) Through study on landscape effects of12Magnoliaceae trees, we find that Liriodendron chinense×tulipifera has the most special ornamental characteristics, which has mandarin jacket-shaped leaves and spindle-shaped fruits, and its leaf color become golden yellow in autumn. Seasonal changes of evergreen species focuse on leaf color, while deciduous species show their beauty of branches in winter and spring. (3)Using methods for evaluation of environmental benefits, we conclude that total average annual economic benefits of6evergreen trees is164.08yuan per square meters, while plus of6deciduous plants is149.75yuan per square meters. Though deciduous plants have much shorter growing season than than evergreens, economic value created by deciduous plants is in no way inferior to evergreen plants.(4)In this paper, we establish AHP model combined qualitative and quantitative indicators, which takes plants’ landscape evaluation as target layer, with criteria layer include landscape effects and ecological benefits. Using difference method to analyze the results of landscape evaluation, we can get grade1whose landscape evaluation index are greater than2.43and have higher landscape value, they are Manglietiu fordian. Liriodendron chinense×tulipifera and Tsoongiodendron odorum: Grade Ⅱ’s composite index are between2.21and2.43which have high landscape value, there are Michelia cavulerici and Magnolia soulangeana; Grade Ⅲ’s composite idex are between1.99and2.21, which have medium value, they arc Michelia crassipes, Manglietia molo. Magnolia denudate var. flava. Magnolia officinalis and Magnolia qffichialis var. biloba; Grade Ⅳ’s compositive undex are between1.77and1.99, which have general value, there is only Magnolia cylindrical: Grade V*s compositive index are equal or less than1.77, which have poor value, there is only Michelia chapensis.In the future process of plant landscape in cities, Magnoliaceae trees should be paid attention for their select and development, taking advantage of deciduous and evergreen plants’ scientific configuration, to achieve landscape effects and ecological benfits’ optimization.