Studies On Characteristics Of Trees And Grass Ulmus Pumila L.var.sabulosa Woodland Of Sanggendalai In Hunshandake Sandy Land

Ulmus pumila L.var.sabulosa J.H.Guo Y.S.Li et J.H.Li woodland was divided into 4 site types to study in the grazing areas of Sanggendalai in Sandy Land. The result showed :⑴The 4 site types included lands between dunes, the top of dunes,leeward slope and windward slope. The result showed that with the wider middle part and the relatively narrow top and bottom part, the age structure graphs of Ulmus pumila L.var.sabulosa population in 4 site types showed kettle shape. All the 4 site types belong to the typical declining type. The age structure of the individual Ulmus pumila L.var.sabulosa of elm population close to each other and showed no significantly different in the 4 site types. Almost all the Ulmus pumila L.var.sabulosas in the Ulmus pumila L.var.sabulosa population were in young or mature stage with the shortage of seedling and adverse renewal.⑵The average plant height of Ulmus pumila L.var.sabulosa was 6.17 to 6.77m, The average basal diameter of Ulmus pumila L.var.sabulosa was 22.75 to 29.88 centimeters, The average crown of Ulmus pumila L.var.sabulosa was 40 to 44 square meter .The growth of Ulmus pumila L.var.sabulosa was best in the lands between dunes and the average basal diameter of Ulmus pumila L.var.sabulosa. reached 29.88 centimeters.⑶The result showed that 62 herbs grew in the grazing areas, among Compositae were the most, quantity of single genus of family,single species of family and single species was more. Quantity of single genus of family,single species of family and single species was more than 70% in 4 site types. Species composition were complicated. Flora was a high degree of fragmentation, Composition was fragile in all the grazing areas.⑷Types of herbaceous plants were more in leeward slope than other 3 site types. There were 49 grass plants which was contained 22 family or 40 genus.⑸Perennial herb was more than 50% in 4 site types. Mesophyte was more in leeward slope, but xerophil was more for the water ecological types in other 3 site types.⑹Production capability of lands between dunes was the best because biomass of lands between dunes was the best in 4 site types. Therophyte was the constructive species in windward slope, which indicated the windward slope was destroyed or severly damage and flowage.⑺Because the habitat was destroyed, the variance of 4 plant diversities was different in 4 site types.