Nature reserves are facing a very challenging conflict between conservation and development today. The protection
effect of Jiuzhaigou Nature Reserve has received considerable attention, especially in view of its stimulating tourism
after the 1990s. Remote sensing data from 1974, 1994 and 2002 were chosen for the analysis of this reserve, since they
closely represented the vegetation situation before and after felling, as well as the disturbance from the flush of tourism.
We find that the quality and quantity of the forest in Jiuzhaigou Nature Reserve continues to decline, owing to the
conifer area and whole forest area constantly shrinking, as well as the landscape fragmentation increasing. The rate of
loss of forest in the second period (1994-2002) had showed down much than that in the first period (1974-1994), due to
nature protection. Shrubland area continued to increase throughout the two periods, with an increased speed in the
second period which was about 3.5 times that in the first period. The treeline was consistently retreating, contributing a
total of 467.96 ha of conifer forest lost. However, the causes involved in tree mortality and the resulting regression of the
treeline are not clear. In any case, under the general background of global warming, human impact undoubtedly should
have direct or indirect cause dramatic consequences for the forest in this very sensitive zone, while there are many
uncertainties in the behaviour of high mountain ecosystems.
Keywords: Jiuzhaigou Nature Reserve, Vegetation, Habitats fragment,