The Xitou long-term ecosystem research site (XT, 23°39’N, 120°47’E) was established in 1950 for comparison of spacing on growth of Cryptomeria japonica and build flux tower in 2009 for observation of carbon flux by the Experimental Forest, National Taiwan University (EXFO, NTU), Taiwan. This evergreen coniferous forest site is located in central Taiwan at an altitude of 800 to 2000 m a.s.l.. The dominant species, Cryptomeria japonica, was planted over 60 years in Taiwan. The soil belongs to Inceptisol with over 50% of coarse material of lithic sandstone. The soil pH is below 5.0 and contains low base cations above O horizon because of high precipitation. Mean annual temperature is 16.6 ℃, varied from mean maximum of 20.8 ℃ in July to mean minimum of 12 ℃ in January. Mean annual precipitation is 2635 mm. The precipitation is divided two patterns: dray season (October to April) and wet season (May to September). The topography of XT site is relative homogeneous, with an average slope of 15°.

The wind character analysis showed significant pattern of mountain/valley breeze and slower wind speed of valley breeze during daytimes. The preliminary CO2 flux result of the Xitou Cryptomeria japonica plantation showed the annual net ecosystem exchange (NEE) is approximately 12.97 ton C/ha/yr.