Author
Tang Jingming, Song Congwen, Dai Junhua, et al
Abstract
The frozen snow damage of main afforestation tree species in southeastern and southwestern Hubei from February to March in 2008 was investigated with a sampling method in typical plots , that was set up 20 m ×20 m square .The results showed :1)Damage rate , damage grade and damage index of forest trees in southwest Hubei was respectively 2.0%, 12.0 %, 12.1 %higher than that of forest trees in southeast Hubei .2)Damage rate , damage grade and damage index of evergreen tree species was respectively 177.0%, 260.0%, 117.2% higher than that of deciduous tree species in southeast Hubei , whereas that of evergreen tree species was respectively 23.4 %, 33.0 %, 33.0 %lower than that of deciduous tree species in southwest Hubei .3)Damage rate , damage grade and damage index of coniferous tree species was respectively 14.7 %, 46.7%, 48.2 % higher than that of broadleaved tree species in Hubei .4)Damage rate , damage grade and damage index of introduced tree species was respectively 54.4 %, 95.5 %, 92.6 %higher than that of native tree species in Hubei .5)Stand structure had an important effect on the frozen snow damage of forest trees .Both too high and too low stand densities could make the frozen snow damage of the trees more serious , and damage extent of pure forests was more serious than that of mixed forests.6)Topographic factors had directly influence on damage extent of the frozen snow damage of forest trees , and their damage extent showed :high altitude>low altitude , north facing slope >south facing slope , upper slope >lower slope , steep slope >gentle slope .7) Scientificmanagement , for example timely tending thinning and applying fertilizer , was beneficial to lighten the frozen snow damage of forest trees .Therefore , we suggest to take the following measures :further study mechanism and evaluate risk of the frozn snow damage of main afforestation tree species ;pay more attention to superior native tree species , prudently introduce exotic tree species , but do not easily abandon the exotic Larix kaempferi and Cryptomeria fortunei ;carry out the principle of`proper trees on proper sites' , and accomplish scientific afforestation ;emphasize the near-natural mixed forest cultivation ; implement necessary silvicultural thinning for natural forest .
