果树冻害是指果树因遭受0℃以下低温，使细胞和组织发生冰冻而受伤或死亡，进而造成树体的一部分或全株死亡的现象。果树冻害根据冻害程度划分为5级：无冻害的为0级；形成层稍有变色或呈水浸状的为1级；形成层浅褐色的为2级；形成层红褐色的为3级；形成层黑报色的为4级。新疆北 Frozen fruit trees refers to fruit trees suffer from 0 ℃ following low temperature, so that cells and tissues frozen and injured or died, resulting in part of the tree or whole plant death phenomenon. Fruit tree frost damage according to the degree of frost damage is divided into five levels: no frost damage to 0; formation layer slightly discolored or was immersed in water for the level 1; formation layer light brown for 2; formation layer reddish brown for 3; Black formed a layer of color 4. Xinjiang North