earticle

영어

The ebb and flow of Northern limit of Citrus cultivation, represented by ‘the Citrus Change the Trifoliate Orange,’ reflects the history of climatic variation in China. Climate has been changing constantly in the last 5,000 years. The change made the Northern limit of Citrus cultivation go up and down repeatedly. Huai-River was lying on the border of the limitation during the Chunchou-Period. In the second century B. C. the temperature was milder than today, even though the line moved to the southern area, Chang-River area. After the Nanbeichao-Period consisted of cold current, the warm climate during the Xiu·Tang-Period let the line of limit go northward until the Huai-River. The climate warming contributed to make Dongting-Mountain into the largest production region of mandarins. The Song-Period was also warm, because ‘Medieval Warm Period’ maintained until this period. The twelfth century was very cold, in particular, so that the arable boundary of citrus fruits moved back to the south until the Chang-River. In the thirteenth century, it went up and reached Huai-River again. As the Little Ice Age started, the belt of citrus cultivation came south back again. Especially, the seventeenth century was cold, so the changed current became a cause of freezing to death of citrus fruits in areas which located southern parts of Jiangnan - Jiagnxi, Hunan, Anhui, Zhejang. During the Little Ice Age the latitude of the northern limit of citrus cultivation had moved two to three degrees southwards. This demonstrates how much the areas were cold. This also suggests that there was a huge conversion of eco-system at that time. It should be remembered that the human history makes its progress in the context of the overwhelming change.