1976年底到1977年初,上海等地柑桔遇到严寒危害,本院20亩桔树,地上部分几乎全部冻死,损失甚重。但位于长江入海口的长兴和横沙两个小岛上的桔园几乎没受危害,甚至连不抗寒的碰柑和日本夏橙也安全无恙,77年仍获得好收成。如长兴岛上的前卫农场,24亩温州蜜柑亩产38担;3.6亩黄皮桔亩产42担。这引起了不少生产和科研单位的兴趣。本文对此作初步分析,以便为柑桔生产合理利用有利的局地气候提供参考。(一)上海地区冬季柑桔受冻机率上海是我国柑桔栽培北缘地区,影响本地柑桔安全越冬的主要气象因子是低温。如:温州蜜柑,一般在-7℃叶片有冻害;-9℃ From the end of 1976 to the beginning of 1977, the oranges in Shanghai and other places encountered the severe cold damage. There were 20 mu of orange trees in the hospital, and almost all the ground parts were frozen to death with heavy losses. However, the orange orchards on the two islets of Changxing and Hengsha at the mouth of the Yangtze River were scarcely harmed. Even the non-salty oranges and Japanese summer oranges were safe and secure, and a good harvest was achieved in 1977. Such as Changxing Island avant-garde farm, 24 acres of Wenzhou Satsuma 38 per mu; 3.6 acres of yellow peel per mu 42 Tam. This has caused a lot of interest in production and research institutes. This paper make a preliminary analysis of this in order to provide a reference for the rational use of citrus production favorable local climate. (A) the rate of winter citrus freezing in Shanghai Shanghai is the northern margin of citrus cultivation in our country. The main meteorological factors that affect the safety of local citrus overwintering are low temperature. Such as: Wenzhou Satsuma, generally freezing leaves at -7 ℃; -9 ℃