Study On Contrast The Growth Rule Of Introduction Pinus Flexilis James. In The Different Experimental Terra

The northern regions of our country, especially in northwest and North China, exist many problems, such as the climatic drought, lack of appropriate tree species, scarce vegetation, it has great significance to introduce alien fitness trees to enrich urban tree resources of those areas. Pinus flexilis James. are also widely distributed in North America, which have nice view and strong adaptability, the ecological environment and climatic conditions of their natural distribution area are similar to North China and northwestern regions of our country, so it is feasible to introduce Pinus flexilis James. into northern cities of our country. Through the mensuration and comparison on the preservation rate, the growth status of Pinus flexilis James., for different provenance in different pilot areas (Hebei Dongling, Beijing Miaofeng, Jiufeng Luobodi, Bainijing Forest Farm and pilot terra in Hohhot), we drew the following preliminary conclusions:Firstly, by the comprehensive analysis of the survival rate , the preservation rate, the height, diameter, root and biomass of three different seedling source of Pinus flexilis James., which were Stockton California (seedling sourceâ‘ ), San Diego California (seedling sourceâ‘¡), Lincoln New Mexico (seedling sourceâ‘¢), showed that: In the Hebei Dongling, the ecology compatibility of seedling sourceâ‘¢was strongest, next was seedling sourceâ‘¡, the compatibility of seedling sourceâ‘ was worst; But in Beijing Miaofeng, Jiufeng Luobodi, Bainijing Forest Farm and pilot terra in Hohhot, the best adaptability of Pinus flexilis James. for introducing was from seedling sourceâ‘¡, the compatibility of seedling sourceâ‘ was worst. Obviously, seedling sourceâ‘ was worst suitable in the five experimental fields, so it could be eliminated in practice. Furthermore, by the analysis of annual growth rule of Pinus flexilis James., found that the seedlings had two fast-growing period every year, which were July and September, so at the breeding time, it was necessary to take full advantage of the fast-growing period of Pinus flexilis James., in order to improve the quality of breeding.Secondly, through the generalized analysis of germination percentages, the survival rate, preservation rate and the growth condition of three seedling source's, include Stockton California (seedling sourceâ‘ ), San Diego California (seedling sourceâ‘¡), Lincoln New Mexico (seedling sourceâ‘¢) which were respectively in Hebei Dongling, Miaofeng, Jiufeng Luobodi, Huhhot experimental field and Bainijing experimental field, such a conclusion could be drawn that the growth condition of Pinus flexilis James. was best in Hebei Dongling. Meanwhile, the growth condition did not have the obvious difference in radish and Miaofeng, the survival rate and the preservation rate in the Huhhot sample plot to be lower than Bainijing experimental field, simultaneously the growth condition in the Huhhot sample plot also slightly worse than in Bainijing experimental field. Therefore the environment of these five sample plot, Hebei Dongling was most fit for introduction.Finally, Pinus flexilis James. seedlings had a ability of drought-resistant and cold resistance, which were able to adapt to the arid and cold climate in northwestern regions of our country.