Abstract: Bareroot slash pine seedlings were subjected to undercutting and top-pruning treatments including different executing time and frequency,to evaluate the effects on seedling morphology and field performance.The results showed that undercutting treatmens reduced seedling height and diameter,and improved root fibrosity,earlier and multiple ones had more pronounced effects,undercutted seedlings displayed better growth than the control and higher survival rate on dry or severely vegetation competitive sites.Top pruned seedlings were smaller,but there were no negative effects from top-pruning on field performance,the seedling uniformity were increased due to the small seedlings free of depression,but later top-pruning was harmful to seedling bud formation timely.The application principles of the treatments as cultural practices were proposed.