我区属大陆性气候,在这种自然条件下,当年生的幼树越冬后其枝梢常常出现由上而下抽缩干枯,群众把这种现象叫“抽条”。“抽条”是什么原因引起的呢?原来冬春期间土壤冻结,幼树的根系浅,分布在土壤冻土层内的根系吸收水分困难,而幼树地上部分尽管在气 My district belongs to the continental climate. Under this kind of natural conditions, the shoots of the current year’s young trees often shrink from the top to the bottom after they wintering. The masses called this phenomenon “drawing strips.” What is the reason of “pumping”? The original soil freezing during winter and spring, young root system shallow, distributed in the soil in the soil layer of the root absorption of water difficult, while saplings of aerial parts despite the gas