After the walnut enters the aging period, peripheral branches grow weaker, droop, and large and middle branches die. At this time, if the rejuvenation is updated in time, the result can be extended. Update the big update, medium update, and small update. The big update is also called the trunk update, which means that the tree trunk with a taller trunk and a weaker tree is sawn from the appropriate part of the trunk; the medium update is also called the trunk update, which means that the appropriate part of the main branch is sawn off; the small update is also Call the collateral update, that is, retract the collateral. The rejuvenation should be based on the tree potential, and there should be more post-updates. Shanghai J.Shine Co.,Ltd , https://www.jshinechem.com