Comparative Study on Growth and Transpiration of Pinus sylvestris var. Mongolica and Pinus tabulaeformis in North Shanxi Province

Pinus sylvestris var.mongolica and Pinus tabulaeformis are main reproducing tree species to defend wind and sand in north Shanxi province.Because of special physical geography and weather,the growth of these two kinds is very different.The paper studied the growing indices and the transpiration rate of these two kinds of trees.The results show that Pinus sylvestris var.mongolica is growing and developing regularly in north Shanxi province which is better than Pinus tabulaeformis,and its transpiration rate is weak,its drought-resistance is strong.So it is one of the best reproducing tree species in north Shanxi province.Pinus tabulaeformis is local tree species of north Shanxi province which have the characteristic of broad accommodation,stronger resistance,weaker transpiration rate,stronger drought-resistance,it is also one of the important reproducing tree species of north Shanxi province.Because of the obvious difference of these two kinds of trees,they have very big difference in defending wind and sand and in improving the environment.So it is very important to study the characteristics of these two kinds of trees,such as their adaptability and growing difference,this will contribute to selecting trees species according to site factors and improving the ecological environment completely in North Shanxi Province.