Abstract: By using longterm climate data for dryhot valley at the upper reaches of the Min River and drywarm valley of the Yuanjiang River(the upper reaches of the Hong River), microclimate characteristics of these two valleys were analyzed and compared. In these two regions, sunshine duration was long; Annual air temperature differences were small, but monthly air temperature differences were high. Precipitation differences were greater among sites within drywarm and dryhot valleys, with obvious alternations in dry and rain seasons. Precipitation was concentrated in rain seasons. In addition, mountainvalley breeze speeds were all high, with bigger values in dry season and smaller values in rain season. However, compared to drywarm valley, higher values were observed in the sunshine duration, average air temperature and precipitation for dryhot valley. Microclimate characteristics of the two valleys were complexed and diversified. At the upside and middle part of dryhot valley, ample light and heat resource were out of harmony with insufficient water resource, which made water a primary factor to limit development. While at the upside and middle part of drywarm valley, light resource was plenty, but heat and water resource were not enough and became limiting factors. Especially at some places of middle part of drywarm valley, there was even the lack of water to influence plant growth in arid years.

Key words: drywarm valley, dryhot valley, microclimate characteristics, ecological restoration, the upper reaches of the Min River, the Yuanjiang River