Abstract: Xiaolong Mountain woodland,located in the west of the Qinling Mountains and the southeast of Gansu Province,provides an important role as "blue barrier" for the Loess Plateau.This area is also a crucial forest ecosystem that conserves water sources to the middle and lower reaches of the Yellow River and the Changjiang River and guarantees ecological safety of these two large river watersheds in China.Based on the accumulated and collected data of this area,service function of the forest ecosystem was evaluated using the market valuation method and substitute cost method.Results show that the annual average value of the service function of the Xiaolong Mountain forest ecosystem was estimated at around 40.236×108 yuan RMB,among which direct economical value amounted to around 2.204×108 yuan RMB and ecological value around 38.032×108 yuan RMB,forming a ratio of 1∶17.26.Obviously the latter is much larger and more important than the former.Based on these estimations and conclusions,it is suggested that in developing local economy,first priority attention be given to understanding ecological value of the local forest ecosystem,so as to protect and exploit forest resources reasonably and scientifically.

Key words: Xiaolong Mountain, ecosystem service, economical value, ecological value