自北方兴建果园以来，人们就开始筛选围国的树种。榆柳虽生长迅速，但无刺不够安全，榆树还能使葡萄质次晚熟；沙棘虽有利刺，但枝条太软，防效不佳,刺槐虽然枝挺又有尖刺，可惜又与仁果类病害共感，是害虫的中间寄主；山丁子、山梨虽应用渐多，终未能尽如人意。经观察在北纬45 Since the establishment of the orchard in the north, people have begun to screen the trees in the surrounding countries. Although the rapid growth of Ulmus, but no puncture is not safe enough, Elm can make the late grapes quality; seabuckthorn spines, but the benefits are too soft, poor control effect, although the acacia branches have sharp spines, but unfortunately with the pomes Common sense of disease, is the intermediate host of pests; Hill Dingzi, Yamanashi, although more and more, eventually failed to satisfactory results. Observed at latitude 45