I was going to post this tomorrow but since today is the last consecutive date that will ever be seen by all people now alive on Earth, I decided to post it today. 12-13-14
Today I wish to talk about the maple myth of defoliation. When I think of the term defoliation I am reminded of a fortune I received in a cookie many years ago. It reads; Before you wonder “Am I doing things right,” ask “Am I doing the right things?”
So the question has to be asked, “What is it you expect from defoliation?” The myth says two things will happen after defoliation.
1. leaves will be smaller.
2. increase in ramification.
While it is partially true that the leaves will become smaller after defoliation, the reason why they are smaller is decreased health in the tree. Defoliation in and of itself weakens the tree, thereby making smaller leaves. There is no significant ramification increase by the technique of defoliation alone. To engage in the task of defoliation, light or heavy pruning is done in conjunction with the defoliation. It is the light or heavy pruning that increases the twigs on the branches and not the defoliation.
A good strong growing maple tree will fight with itself for apical dominance. A few branches will emerge victorious and will begin to elongate. These runners will continue to elongate, growing in girth and length until stopped by pruning. The runner will continue because of a terminal bud. This bud has the genetic predisposition to continue growing straight ahead without lateral branching. Along with this running on top, the same will be going on below the soil with fast increase of girth and length of roots. These long shoots are what cause roots to wrap around the walls of a container.
Plants grow leaves proportionate to the quantity contained by its branches. A tree with a few large branches will have few leaves but of a very large size. The trees health needs are met by a certain amount of real estate tied up in leaves. The tree is much healthier making 25 large leaves the size of your hand, and much weaker making 250 leaves the size of a dime. If a person has a tree with the 25 leaves and wants the 250 small leaves, then a support structure for so many leaves must be built. Defoliating a tree with 25 leaves to get smaller leaves is not only hard on the tree from a defolaition stand point but also hard on the tree from a nutrition (photosynthesis) stand point. While defoliating the tree with 25 leaves may get you some smaller leaves in the beginning, unless more grow in a hurry, they will get larger in a few weeks. Thats just the nature of the beast.
How can I get a tree to have smaller leaves and more twigs?
There is nothing more simple than pruning a maple to increase ramification and make smaller leaves. If you have more twigs the tree will make more leaves. If the tree has more leaves they don’t have to be as large to get the same amount of photosynthesis. The tree will make small leaves all by itself without ever removing one leaf for the rest of its life. In this case a heavily ramified tree will always have small leaves and will never have to be defoliated to decrease the size. If the tree has proper structure and twigs it needs no defoliation for that either. So a properly prepared maple has absolutely no need for defoliation.
I read on many forums people recommending to defoliate to build ramification and defoliating to make smaller leaves, and then a picture of the tree is shown and it has a trunk, five branches the thickness of your finger and one or two tertiaries. Defoliating is going to do absolutely nothing for this tree. The only thing that is needed to help the tree is selective pruning. People recommend defoliating because the myth has been perpetuated on the net and people keep spreading it like gospel and have never even worked with a maple with a properly ramified crown. People throw the word around and have no idea what the technique does and does not do. I think they think it makes them sound important or that they know what they are doing.
When is defoliating be necessary?
When a person has a properly ramified maple and the tree may have some insect damaged leaves or burnt edges and the tree is ready to be exhibited. At that time a tree can be defoliated about 60 days before the event and the tree should have a whole new change of clothes. (Koromo ga e) This tree can be exhibited now and all the leaves will be fresh and green. This is not necessary with the spring growth and is usually reserved for showing in late summer when leaves have burned thru the summer.
Tell me more about pruning
Maples respond well to pruning. pruning a maple is akin to mowing the grass, they just keep pruducing divisions. What is a division? Its when the terminal bud is removed the tip of a branch. All living plants have a terminal bud. It is the bud that is wired to move ahead in a straight line. When a branch has its terminal innterupted by removal, the two apical lateral buds will shoot away in opposite directions, a division. Some may know this as a forked branch. If the two lateral buds are not allowed to elongate, meaning to let go the new terminal bud that emerges at the tip of the new lateral shoots, then two new shoots will emerge from those two lateral. So now one branch was pruned and made two, then pruned again and made four, etc, etc. Now this steady pruning will not go on forever. One may get about three good prunings on a healthy tree. More than that and the trees health is severely diminshed and the tree may respond by not opening any more buds till fall. Pruning in early spring and early summer should be held to March thru June. Rest thru summer and then cut back in late August to middle Sept.
I have a few pictures to share. First is a couple seedling trident maples from two years ago. They have been allowed to grow unchecked and are about 7 feet tall this year. The trunks are about 3/8 inch across at the soil and are grown on a tile. There is no branching on these shoots. The terminal bud has not been touched and for all intents and purposes, these plants will continue to gorm untill interrupted by a storm, snail, insect anything that would interrupt the growth.
If I bend on of the shoots over to take a picture we can see all the buds for next year already set on the shoot. The terminal is almost twice as large as the laterals. This is becuase the terminal contains two sets of leaves instead of only one leaf. Maples grow in offset pairs of leaves offset by 90 degrees. This is to insure that a large proportion of the leaves will be in contact with the sun.
Even palmatums that grow in my yard exhibit the same growth habit by elongated shoots growing to the sky unhindered. They will not ramify untill interrupted by pruning. Why should they? this is easy growing like this.
At the base of each leaf stock is an adventitious bud. A adventitious bud is a bud that in the “advent” the leaf gets eaten or burned off in the sun, and new leaf is ready to take its place. Now here is the part one has to think about. If a person comes in and defoliates this branch, artificially makes it believe the leaves were eaten off by a moth larve, the branch is not going to make more branches. It is just going to make new leaves. The terminal bud is still there, all the latent advetitious buds are there and now they are all stimulated into action to make new leaves. There has been no division of branch or twig, just new leaves in exactly the same place they were before.
See how much larger the terminal is than the lateral. One leaf compared to two.
In the picture below, one can see the stub in the middle od the branch that was cut. This was a pruning. This picture makes this look large but in reality the stub is half the size of a BB, about 3 mm.
If the shoot is pruned to the red line, the two buds at the end of the shoot will become branches and the buds below that will become leaves. They are marked T for terminal and L for leaf.
If one were to prune out even further on the branch the effect would be the same except there would be two more buds below and two more leaves. The problem with leaving two sets of nodes behind the cut is that the neck of the branch segments are two large and on smaller trees this can make the tree look disproportionate. If you look behind my first scar and go down a little more, you can see the scar of the branch cut before. So what you see here is a small, less than 1/2 inch segment of a branch cut back to split once and then split again, and now I will cut again and have three branch divisions in 1/2 an inch. This is how you build ramification and attain smaller leaves, by making more of them. More than the tree actually needs.
In the case of this branch below I would be better to make the cut at the first node and make a directional change in the ramification. This area is in the top of this tree and I don’t need the branches horizontal but rather upward and full. Keep in mind that one does not have to keep both buds. The downward growing one in this case can be rubbed off and only the upward growing bud can be kept. This shoot will elongate and another pair can be kept that may be in a better position after some growth.
Just so you know the tree in these pictures looks just like what yu see. Still has all its green unburned leaves on 12-13-14. I hope this tip can help some of those out there with what defoliation really is. It can be used with great effect of heavily ramified trees , but does not build raminfication on its own. Do it if you must but know that all you are doing is weakening the tree and losing precious weeks in the growing season to growing back leaves. That is such a waste of time. I say; prune to get twigs..Justin case.