华盛顿州昆西地区的果农泼雷波格创造出一种新型的苹果树高产密植树形——M型。这种树形无中心干,以两大侧枝为领导干,夹角为30°,树形完成后,其叶幕剖面形似英文字母M。 1981年5月,泼雷波格定植了112亩苹果,所用品种是他个人培育的一种红元帅短枝型“Ace”。株行距1.2×5.6米,平均每亩100株,每株二个主干。定植后,对枝条进行刻伤处理,刻伤的位置在第1芽以上的部位。重施肥水促进幼树生长。第一年枝条平均长度近152厘米。然后立一固定支柱,并在树的两侧拉两条铁线。第三年春天,在树体距地面1 Apple Tree, Quincy, Washington, USA, created a new type of high-density, tree-shaped apple tree. This tree has no central stem, with two side branches as the leader, with an included angle of 30 °. When the tree is completed, its leaf profile resembles the English letter M. In May 1981, Predlegrave planted 112 acres of apples, the variety he cultivated a red Marshal spur type “Ace ”. Plant spacing 1.2 × 5.6 meters, an average of 100 plants per acre, two plants per plant. After planting, the branches were inscribed, the location of inscriptions in the first bud above the site. Reusing fertilizing water to promote young tree growth. The first year the average length of branches nearly 152 cm. Then stand a fixed pillar and pull two wires across the tree. The third spring, at the tree body from the ground