关键词: 巨尾桉, 巨尾桉, 大叶栎, 混交林

Abstract: The winter temperature of 2016 to 2017 is the warmest since 1961 in China. The effect of warm winter on winter wheat is different from freezing injury of cold winter and cold spell in later spring, it can cause withering seedlings and vegetative organs. An investigation at Gucheng Station showed that green leaf withering rate varied with planting periods, the withering rate was 92.95% to 41.95% with the delay of planting date, the withering of green leaf and vegetation organs had irreversible harm to wheat plants and great effects on vegetation organs’recovery after green-up. Under the global climate warming, semi-winter wheat varieties and weak-spring winter wheat varieties have replaced strong-winter wheat varieties and winter wheat varieties in north China, and the suitable sowing temperature (15-18℃) for winter varieties should be revised. Based on the temperature increase of 1.5-2℃, the suitable sowing temperature for semi-winter wheat varieties in north China should be revised to 13-16℃, and it is estimated that the suitable sowing period of semi-winter wheat varieties in Gucheng Station is October 2-14.