Study On The Ecological Function Of Urban Greenery Tree

Study on the eco1ogica1 benefit, such as green quantity, nitrogen fixationand oxygen re1ease, transpired water vo1ume and absorbed caloric of leaf, dustdetention, and 1ight uti1ization of common trees in Harbin was carried throughon the basis of ensured consistent conditions with the method of infraredgas--exchange.The capacity of nitrogen fixation and oxygen re1ease for 8 tree speciesthrough whole growth period 1ines up from more to 1ess as follows: Ubotw1a,and that of high forest is more than 1ow tree and low tree is more than shrubin Ju1y. So different tree species can be arrang6d according to their capacitiesof nitrogen fixation and oxygen re1ease.The transpired nter vo1coe and absorbed ca1oric of 1eaves e8ch day for 8tree species through whole gro'th period lines up fron more to less as fo11ows:Acer W' In July, birch is the most in transpired water vo1ume and absorbedca1oric of leaves in high tree and Pjnus Sy1vesdri L is the 1east. IanthOcmesOrbjfO11A M is the most and Pgus uSSUrtenS1s and ~ racas as1ib arethe 1east in low tree. The transpired water vo1ume and allsOrbed ca1oric of leaveseach day varied great1y in shrub and the more are FOrerthia SuSPensa yAn1.P1cea MienS1s and Junwt hada are excellent tree species for dustdetention in evergreen tree in Harbin. bods the are good in dustdetention in broad1eaf and their average quantities for dust detention in 7d arerespective1y l. 9215g. mo, 2. 4504g. m-' and 2. 0284g. mo. The difference in thecapacity of dust detention is determined by the con formation of leaf in treespecies, that is, the coarseness and the hair shape and quantity tPp or underepidermis of leaf. l,Plant can be classified into three groups according to their characteristicsof 1ight utilization, that is, higher light compensation point and higher lightsafuration point, 1ower 1ight compensation point and higher 1ight safurationpoint, higher light compensation point and 1ower light safuration point.