园林树木偏冠和窄冠是两种常见树冠异常的表现。偏冠是因为树木长期遭受外力或受临近物体的影响,树冠不能自然成形,出现畸形的现象。窄冠则是由于管理不当,一些原本冠幅开张的树木,树冠窄小而出现的异常现象。偏冠和窄冠不仅会使遮阴面积减小,而且影响树冠的观赏效果。偏冠大风吹袭有些树木栽植于风口,树种本身抗风能力不强,加之栽植密度较小,在长期遭受大风吹袭的情况下,极易出现偏冠。如雪松、桧柏等抗风能 Crown tree crown and narrow crown is the crown of two common abnormalities. Partial crowns because trees suffer long-term external forces or by the impact of nearby objects, the canopy can not be formed naturally, the phenomenon of deformity. Narrow crown is due to improper management, some of the original opening of the crown of the tree, the narrow crown and the emergence of anomalies. Partial crown and narrow crown will not only reduce the shade area, but also affect the ornamental crown effect. Partial crown of wind struck some trees planted in the tuyere, the tree itself is not strong wind resistance, combined with planting density smaller, long-term exposure to strong winds hit the situation, prone to partial crown. Such as cedar, cypress and other wind energy