Study On The Ecological Benefit Of Beijing City About Common Greenery Tree

The urban greening is an important part of the urban construction. The trees' ecologybenefits of the urban beautification directly affect the urban environment quality. Thedomestic and foreign cities all have the certain researches on the green space system, butthe foreign countries have done earlier than China to this aspect. Their quantitative degreeis higher and systematic. The domestic researches started late to the urban green spacesystem's ecology benefits, mainly emphasizing particularly on the qualitative researches.The research scope is also limited in some certain sides and has not formed thesystem.This article took the main beautified trees of Beijing as the study object,guaranteeing the environmental consistent condition, made use of the scientificquantitative test and analysis as the research methods, the influence of the urbanbeautification on the human living environment as the main theory meaning, the effectiveactions and the countermeasures to improve the urban beautification as the goal, to studythe ecology effects of the common beautification trees in Beijing (Carbon fixation,oxygenreleasing,transpired water release,absorbed caloric,dust absorption,absorbing SO₂). Thefindings of the article could provide the scientific basis for the urban construction. Thisstudy had been conducted from the May to September of 2006,and the study area locates inthe major streets, which are lying in Beijing city.The findings showed that in the entire growth season and in 10 kinds of the commontrees, the average Carbon fixation and oxygen releasing ability's order of the unit leaf areafrom high to low is:Prunus persica,Prunus triloba Lindl,Fraxinus chinensisRoxb, Forsythia suspense Vahl, Wisteria sinensis (Sims)Sweet,Eucommia ulmoidesOliv,Euonymus japonicus Thunb,Acer truncatum Bunge,Magnolia liliflora Desr, Robiniapseudoacacia; Various trees' average transpiration's heat absorption and the releasing watervolume order from high to low is: Prunus persica,Prunus triloba Lindl,Fraxinus chinensisRoxb,Forsythia suspense(Thunb.)Vahl,Eucommia ulmoides Oliv, Wisteria sinensis(Sims)Sweet, Euonymus japonicus Thunb.,Acer truncatum Bunge,Robinia pseudoacacia,Magnolia liliflora Desr.Among 20 testing beautified trees, according to the blocking dusts ability to classify,Syzygium aromaticum (L.)Merr.Et Perry, Lagerstroemia indica, Weigela florida (Bunge)A.DC, Viburnum sargentii in the colored shrub are stronger, Prunus trilobaLindl,Kerria japoniea,Rosa chinensis,Lonicera maackii,Cercis chinensis Bunee are generaland Buxus microphylla,Berberisthun bergiicv.atropurpurea are weak;In the arbors,S.chinensis (L.)Ant.,Populus tomentosa Carr, Aeer truncatum Bunge, Ginkgo Liloba L,Robinia pseudoacacia are stronger, Ailanthus altissima Swingle,Koelreuteria paniculataLaxm are general and Fraxinus chinensis Roxb,Pinus tabulaeformis Carr, Salix babylonicaLinn are weak. The paper also discussed the blocking dusts ability from the leaf structure.In order to eliminate the environmental pollution and achieve the environmental qualitystandard of people, this paper had studied the trees beautification ration of Beijingaccording to the trees ability of purifying SO₂. The results indicated that, Is by thebroad-leaf arbor had the strongest SO₂ purification ability. Under the pollution condition ofdischarging SO₂ approximately 175,500 t per year, depending upon the broad-leaf trees topurify completely, Beijing need increase the broad-leaf trees about 94.355 million trees.