Fine root adaptive strategy of main afforestation tree species in Horqin sandy land

To understand fine root adaptive strategy of main afforsetation tree species in Horqin sandy land,the vertical distribution characters of fine root specific root length and specific root surface area of Populus simonii,Ulmus pumila,Pinus tabulaeformis,and different aged Pinus sylvestris var. mongolica were analyzed. The results showed that there were different vertical distribution rules in fine root specific root length and specific root surface area for different forests. The values of P. simonii,U. pumila,P. tabulaeformis,and 22 years old P.sylvestris var. mongolica were high in the both sides and low in the middle of soil layer,but those of 10 and 32 years old P. sylvestris var. mongolica gradually increased from surface to bottom soil layer,The fine root specific root length and specific root surface area were significantly greater in P. simonii and U. pumila than P. sylvestris var. mongolica and P. tabulaeformis( P 0. 05). With the increasing of age of P. sylvestris var. mongolica,the fine root specific root length gradually reduced,and the fine root specific root surface area gradually rose except the 42 years old. These results indicated that P. simonii and U. pumila adapt the habitat by increasing the unit biomass investment in the fine root length and surface area,and they had higher resources utilization efficiency than P. sylvestris var. mongolica and P. tabulaeformis. P. sylvestris var. mongolica adapt the habitat by gradually declining the biomass investment in fine root length,while increasing the biomass investment in fine root surface area with the increasing of age.