Abstract: In Asia, Tsuga is mainly distributed in the Asian Monsoon region , and intermittently distributed in Mainland China, Taiwan Central Ranges and Japanese Archipelago ( except Hokkaido) . InMainland China, it is discontinuously distributed in the southwestern mountains ( the Hengduan Mountains and a part of the Eastern Himalayas), the central mountains
( the Qinling Mountains and the Daba Mountains) and the southeastern mountains ( the East China mountains). In its modern geographical distribution, Tsuga growth requires following climatic conditions : annual precipitation (AP) range of 720 - 2 103mm, growing season precipitation (GP) range of 635 - 1 489 mm, annual mean temperature (AMT) range of 5 . 8 - 18 .2℃ , winter mean temperature (WMT) range of - 2 . 7 - 11 .5℃ , mean temperature for the coldest month (MTC) range of - 3 . 7 - 10 . 9℃ , mean temperature for the warmest month (MTW) range of 13 .0 - 28 . 2℃ , and the annual range of monthly mean temperature (ART) range of 9 . 7 - 25 . 4℃ . In the AsianMonsoon region , AP in Korean Peninsula and its adjacent northeast China mountainous region , and the Shangdong mountainous region is more than 700 mm and generally meet the moisture requirements of Tsuga growth. But ART of these two Tsuga-free regions are apparently higher than that of Tsuga regions, and WMT and MTC are lower than those for Tsuga regions . It indicates that temperature conditions, particularly WMT, MTC and ART are constraints for the growth of Tsuga in these Asian Monsoon region . In conclusion, moisture conditions can generally meet Tsuga living requirements in these monsoon mountainous regions, but winter temperature ( including WMT and MTC) and ART become limited factors of Tsuga in these regions .

Key words: Tsuga