Proper Pruning Diagrams?

[CreakyGardener]

Hey all! About 4 yrs ago, there were these baby Japanese Green Maple seedlings at work looking pitiful for yrs. The landscapers would hit it with a string trimmer and/or wack them back like small bushes. The parent tree it came from was very old and outrageously impressive to look at. The biggest I've ever seen! I knew it was hardy because it was in an asphalt parking lot, up against a concrete building with no irrigation system a top of a hill with only shade in early morning. I always thought I'd like to have one if it was that durable. The Maintenance Manager told me they were going to get rid of them. The next day I came to work with a shovel. It only took one scoop and one of them made it's way home with me. 3 yrs later it grew from 16 inches to 15 ft. Maple trees love it here. I pruned it back to avoid breakage from winter snow. It shoots out 3-4ft branches, very vigorous.

Okay, enough history. I air-layered one of the limbs below as an experiment becasue I wanted to start thinning it out and getting rid of problem limbs but hated to waste it. It's time to start training it to get the shape I'm after and allow things under it to get some light and grow. I did it last minute at the end of August and it had a huge root ball in 3 weeks! This limb had been trimmed before, so it has areas I'm in question about keeping. Like on one side where it was cut, the limbs sprouted two. Now it has several 'U' shaped split leads - not a 'V' or 'Y'. I like the looks, but it is going to be weak as it becomes heavier with age?

I've looked around, reading talk about pruning, etc. But I can't find any place that talks in 'detail' about the do's and don'ts. What to avoid, what to look for and what's best when choosing a good structure or framework for a Green Japanese Maple Tree. Illustrations would sure be best for my brain, but all I find is Bonsai type stuff - small. I have so many questions like, can I have a multi trunk and if so at what level is best for each lead or trunk - how far apart? Will it always need to be pruned or will there be a day when I can just watch it grow? Seems like if I stopped pruning, they'll get too heavy at the rate they grow and break. I use to be a tree trimmer and landscaper. But this is different than what I did back then. Those were already established and I let the tree show me what to do. These are small and needing guidance. I need to plan ahead and know what to avoid to get to that point with these,... don't I? Most of all I want to know the rule of thumb for what's weak and what's strongest. We've had a lot of tree problems with our property. I'd like to give these a good shot at longevity. Kind of like what they do for the Japanese gardens. (pic below - not mine.)

Does anybody have any links or ideas to share. Or where to look for info like this? Not general pruning so much, but the planning and structure part. Thanks as always!! Most of mine will be more natural than below - pic. Though, I would like to do one or two like that.

 

[Marck]

The same structural and aesthetic concepts apply for both pruning an established tree and training/pruning a young tree, except when you work with a young tree, you can do a better job.

Whenever possible you will want to avoid large cuts. As a general rule, if you have to use a saw instead of loppers or secateurs, you've waited too long. Still, even most smaller saw cuts usually end up alright.

You do want to remove unwanted branches when they are small, but it is also good to err on the side of less pruning rather than more.
Remember that many trees do their own self-pruning an end up looking great with no human intervention. Still, it is good to be able to knowledgeably observe, plan, and intervene when it will be beneficial.

Pick a day in December or January and mark it on your calendar. That will be the day you will survey your trees and decide what should be done. If you have a lot of trees it will take more than a day, but do it every year and keep notes of what you have pruned and what want the future result to be.

Both wide U-shaped forks and wide V-shaped forks are usually acceptable. It is the narrow V-shaped forks and completely parallel-sided U-shaped forks that should be avoided when possible.

If possible post pics of your tree, even particular branch junctions. It could be interesting to discuss the possible results of a particular branching arrangement or pruning cut.

 

[DirtMechanic]

To extended one idea @Marck gave on the angles, it is limbs extending out at 90⁰ from a trunk that are often the strongest though wood types have a say. A vee or parallel branch can peel easier in the wind because the roundness of the union is not there to dissipate stress. It has long been observed that stress spreads itself through materials in ovoid fields of energy. The resulting cracks are not of course, as a material shears apart.

Many trees, like oak, know this but bradford pears do not.

 

[CreakyGardener]

The same structural and aesthetic concepts apply for both pruning an established tree and training/pruning a young tree, except when you work with a young tree, you can do a better job.

Whenever possible you will want to avoid large cuts. As a general rule, if you have to use a saw instead of loppers or secateurs, you've waited too long. Still, even most smaller saw cuts usually end up alright.

You do want to remove unwanted branches when they are small, but it is also good to err on the side of less pruning rather than more.
Remember that many trees do their own self-pruning an end up looking great with no human intervention. Still, it is good to be able to knowledgeably observe, plan, and intervene when it will be beneficial.

Pick a day in December or January and mark it on your calendar. That will be the day you will survey your trees and decide what should be done. If you have a lot of trees it will take more than a day, but do it every year and keep notes of what you have pruned and what want the future result to be.

Both wide U-shaped forks and wide V-shaped forks are usually acceptable. It is the narrow V-shaped forks and completely parallel-sided U-shaped forks that should be avoided when possible.

If possible post pics of your tree, even particular branch junctions. It could be interesting to discuss the possible results of a particular branching arrangement or pruning cut.

Thanks for the replies! Trimming existing trees, it was easier becasue most decisions were made already. Most weren't ones I would have chosen but previous gardeners or landscapers likely didn't know or care. And you couldn't cut too much and risk damage to the tree. So, to me it was easier working with what was given and it did make for some interesting choices I wouldn't necessarily have made otherwise. I agree with what you said about the tree deciding,.. neat.

One thing that always enters my mind is how close a branch is to another on the same lead - when it's a vital lead or branch I'd lie to keep. Some of them a V, like I think you were talking about. When the tree becomes larger, will it be pushed outward somewhat and away? How do I cut it? Remove the weaker side?

I know the weight of the tree as it grows will have an effect too. But I've had trees that grew against itself and held moisture between. A lot of the breakage I've witnesses in landscaping maintenance from winter damage was at the point where it was trimmed once apron a time. The new branch grew out and was weaker at the joint. I 'm hoping to avoid that kind of stuff by figuring out why.

Marck, can you define the difference between a parallel U shape and a wide U shape for me? When I think 'U' shape I think of two branches sprouting across from each other from the same branch. Wouldn't that make them parallel? What I have is a U with a stick at the bottom,... like a Y but a U on a stick. haha! I'll try and get some pics today.

I was thinkin' I might take pic of it 4 times a yr and show it's progress down the road somehow like in a video just for kicks.

DirtMechanic,... wow! Your brain is awesome, I love it. If I had a parallel V or branches lacking that roundness and strength, what's the best way to remedy that? Trim one side? Both and start over? These are the kinds of questions I have. Normally I wouldn't worry so much, but we've had a lot of snow breakage so I'm trying to give them the best chances of survival down the road.

 

[DirtMechanic]

Thanks for the replies! Trimming existing trees, it was easier becasue most decisions were made already. Most weren't ones I would have chosen but previous gardeners or landscapers likely didn't know or care. And you couldn't cut too much and risk damage to the tree. So, to me it was easier working with what was given and it did make for some interesting choices I wouldn't necessarily have made otherwise. I agree with what you said about the tree deciding,.. neat.

One thing that always enters my mind is how close a branch is to another on the same lead - when it's a vital lead or branch I'd lie to keep. Some of them a V, like I think you were talking about. When the tree becomes larger, will it be pushed outward somewhat and away? How do I cut it? Remove the weaker side?

I know the weight of the tree as it grows will have an effect too. But I've had trees that grew against itself and held moisture between. A lot of the breakage I've witnesses in landscaping maintenance from winter damage was at the point where it was trimmed once apron a time. The new branch grew out and was weaker at the joint. I 'm hoping to avoid that kind of stuff by figuring out why.

Marck, can you define the difference between a parallel U shape and a wide U shape for me? When I think 'U' shape I think of two branches sprouting across from each other from the same branch. Wouldn't that make them parallel? What I have is a U with a stick at the bottom,... like a Y but a U on a stick. haha! I'll try and get some pics today.

I was thinkin' I might take pic of it 4 times a yr and show it's progress down the road somehow like in a video just for kicks.

DirtMechanic,... wow! Your brain is awesome, I love it. If I had a parallel V or branches lacking that roundness and strength, what's the best way to remedy that? Trim one side? Both and start over? These are the kinds of questions I have. Normally I wouldn't worry so much, but we've had a lot of snow breakage so I'm trying to give them the best chances of survival down the road.

So limbs breaking can be different places. The worst to me are when they break off the trunk. The Golden Raintrees and the Bradfords I have left are my worst culprits. They can easily break at the trunk. I learned some time ago about an idea called cabling. A tv show called "Treehouse Masters" was also educational. Those guys punch holes through the tree without compromising it. The Bradford Pear to which I have fastened big branches with all-thread rod are the biggest Bradfords in the yard. Call me crazy but I think they like a little zinc and iron.

I use threaded rod and about 4 big washers, and a nut on the end and cinch it tight. The bark grows over the wound.

I will probably want a metal detector on it before I use my chainsaw though. I think that rod was 1\2 or 5\8" steel. It comes smaller though to your point. The biggest problem is drilling through. Coming from 2 directions to meet in the middle is a real challenge.

 

[Marck]

You will encounter a full range of angles and branch curvatures, so the distinction between a U-shaped and V-shaped will intergrade. The important thing is that the angle of the fork be wide enough to not form included bark. Included bark is bark that literally gets trapped within the fork of a tree as the branches grow. This included bark prevents the two branches of a fork from joining properly and eventually you have two large branches connected by a very small amount of wood. This, even more than the angle itself is why weak crotches are so weak.

Three or more branches coming off at the same point will further compound this problem. That is what often happens with Bradford Pears (Pyrus calleryana 'Bradford'), a cultivar that was selected for it silhouette with an amazing disregard for the reason for this and consequences down the road.

 

[DirtMechanic]

You will encounter a full range of angles and branch curvatures, so the distinction between a U-shaped and V-shaped will intergrade. The important thing is that the angle of the fork be wide enough to not form included bark. Included bark is bark that literally gets trapped within the fork of a tree as the branches grow. This included bark prevents the two branches of a fork from joining properly and eventually you have two large branches connected by a very small amount of wood. This, even more than the angle itself is why weak crotches are so weak.

Three or more branches coming off at the same point will further compound this problem. That is what often happens with Bradford Pears (Pyrus calleryana 'Bradford'), a cultivar that was selected for it silhouette with an amazing disregard for the reason for this and consequences down the road.

And the cherry like timing of their dense shade coming far too early in the year. This disallows proper sun to so many plants that need to grow then because they suffer later in the heat here. I will be glad when they are all gone. Down to 3 of 6 at this point