Pine Questions: Removing the Leader

This is a very typical case, especially for a grafted Japanese black pine. A customer L. asks:

"I suppose that you may recognize this.  I cut the top out of it this summer. I wasn't sure if it was the right thing to do, and I almost e-mailed you before I did. I removed 50% of the tree, which was my biggest concern at the time.... Am I headed in the right direction? (I couldn't find a 'before' pic)"

The answer is that this is the correct thing to do, but the timing may have been wrong. Let's analyze this. There is no 'before' photo, but we really don't need one. The leader was cut out of this tree. Just imagine a stem running up through the #1 arrow. This was the unpruned main stem of the grafted tree. This stem, or leader, was removed at the first node leaving the two branches that you see. The right stem will be the new leader, the left one will be the first branch. This is a very good beginning. You now have a low turn in the trunk and the beginning of a very small shohin Nishiki Kuromatsu.

Well grafted trees should offer opportunities like this. Whereas seedling trees will very often have no lower branches with which to work, grafted trees are propagated with selected scions. This means that you can select a scion with buds that will be very close to the graft union, and thus will be low on the tree. The central bud of the scion is left to grow and forms the leader that was removed in this case. The question now is: When do you remove the leader and direct the new trunkline into one of these low branches?

The longer you leave the leader in place, the faster the caliper increases at the first node (between the arrows at #2). So the leader should stay on until you reach, or nearly reach,  the desired caliper of the finished tree. In some cases, where you leave the leader on for a long time, the branches at the first node will become weakened and you may risk losing them if you don't invigorate them. If this is the case, you would reduce the leader to direct some growth into the first node, and then continue with the leader growth until the desired caliper is obtained.

If you remove the leader too soon, as I fear was done here, you still get the low movement of the trunk, but by the time the trunk is finished, you will lose much of the taper ratio between the base and the second trunk section. By removing the leader at this point, you have committed yourself to a smaller tree. Nothing wrong with this, but if you wanted a larger tree, the leader should have remained. I generally keep the leader growing on containerized grafted pines for about ten years. It gets pretty silly after awhile, because I will end up removing about 90% of the tree, but this is what is necessary to create really good pines.

Comments

[Jeff]

If you leave the leader for greater girth, do you let the lower branches grow in a whorl, or do you remove all except two,assuming one will be the new apex and one will be the first branch?

[Brent]

Jeff

You can leave the branches as a whorl as long as a bulge doesn't form. When you start to get reverse taper, you have to remove some of the branches in the whorl. Also consider the role of each branch as you are thinking about above. So, if some of these are potential final branches, you will have to treat them as such and not let them grow wild. If one is to be a new leader, you can wire it or tie it up into a more vertical position if you desire. If one can be used as a sacrifice, that one can grow freely.

Brent