This method will work on nursery grown trees but it will take you a minimum of two years to get it right and have those trees survive.
When a tree is young, its goal is to get its head above the competition and catch as much sunlight as
possible. In the forest, where trees compete for light and space, the most efficient way to do this is with an
"ex-current" growth habit -- that is, a single, undivided stem and lateral branches. As it reaches its mature
height, the branching habit becomes "co-dominant" -- that is, its stem and branches often subdivide with
forks instead of true lateral branches.
But when we domesticate trees, we encourage them to make this transition much earlier in life... and
closer to the ground. In fact, a standard nursery practice has been to force trees into a co-dominant
branching habit. A fork near the tip of a branch has little effect on the tree's strength; but the lower the
fork occurs, the worse the problem if it fails.
A true branch is the result of a process that starts with the growth of a bud into a twig. Normally this
begins from the axillary buds found where each leaf joins the twig. The meristem (reproducing cells) at
the tip of the bud divide, and the newly formed cells become a twig. The meristem just under the bark --
the vascular cambium -- continues to divide so that the twig grows in diameter, forming a branch.
At the base of this twig is a swollen area called the branch collar. In this area the wood fibers of the trunk
(or parent branch) veer around the twig on each side and continue toward the trunk or the base of the tree;
the "plumbing system" in the branch also turns groundward -- none turns upward or goes around the trunk
or parent branch. Since growth occurs at different times in various parts of the tree, the twig and branch
fibers tend to form interwoven layers, a little like the laminations in plywood. Together, they create the
extra wood thickness of the branch collar, which continues to grow as the twig matures.
A fork is a place where a stem grew in two or more directions, instead of one. Although one side may be
larger than the other, neither side has any natural chemical protection. Most U-shaped forks, with all bark
visible, are dependable. The problem is with V-shaped forks, particularly when bark disappears down into
the fork from each side, and much of the branch junction consists of two bark faces pressed against each
other. Such forks, though graceful, have many potential problems:
First, there is no bond or strength between the two bark faces.
Second, as the two sides of the fork grow, the pressure between them tends to spread the fork,
increasing the splitting force on its the base.
Third, this pressure also crushes the living tissues under the bark, starving this area and destroying
Finally, rainwater, fungus spores and other materials seep down into the fork, rotting bark and
wood so that the weaker side is likely to split from its own weight or under wind stress.
The method takes a good set of eyes and a head that understands what creates a danger to the tree, not what looks good. Above is that information for you to use to make good pruning decisions.
You will start at the bottom most main branch and trace it up to the growing tip, use surveyors tape to mark where there is a secondary branch that doesn't have a good angle to the main branch occurs, no cutting as yet.
Work through the tree in this manner until you have inspected every main branch, this should also cover all secondary branches. Once you have marked every bad branch junction and crossing branches you can then go back and decide which to remove and which to keep.
The goal here is as strong a tree as possible no 90 degree branch angles, no super tight to the main trunk or primary branch angles, no crossing branches that can rub the bark off in windy conditions.
When you are through doing the selection work, it is easy to go back and do the cutting, just follow the same procedure as when you marked the branches with the tape.
Be sure to not cut the branch collar, that needs to remain whole so the tree can heal properly and not pick up any diseases.
William James wrote:Does anyone know the book/chapter where fukuoka talks about pruning?
I've been meaning to start looking at my young and nursery-misshapen trees with fukuoka-eyes. I have a feeling I'll have to do some adjusting because they've been monkeyed with while young.
Bryant Redhawk's post is wonderful, hopefully you got a lot out of that. Since you asked for a specific <i>reference</i>, though, I can at least provide that.
Fukuoka's book <i>The Way of Natural Farming</i> is the best primer I've found so far. Check out the third major section called "Fruit Trees." There is a fifth subsection of that chapter called "The Argument Against Pruning" and a sixth subsection called "The Natural Fruit Tree." This book can be found online in PDF form and, if you do that, these sections start on the document pages 172 and 177 respectively. I've found them to be very illuminating!
These sections have be quoted in this thread here: