Isa Pruning Techniques For The Uc

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desertsquirrel

desertsquirrel

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ISA pruning techniques

Proper as well as improper pruning can drastically affect your plants health in areas such as vigor, structure, yield, natural resistance to pests and pathogens, reproduction, ability to uptake water and solution, its production of plant growth regulators and plant health in general. Because of the importance of proper pruning practices as well as the general lack of them within the community i decided to post some of the International Society of Arboriculture's pruning techniques that i have been loosely adapting to Cannabis since my arboriculture class a few years ago...


Methodology:

As with anything in growing, no methodology can be viewed as optimal without clearly defined goals or objectives. Only within the context of an objective can optimization become clear. That being said, only prune to achieve specific goals, ie; change plant structure, provide more bud sites, prune-for-clones, etc.

Pruning objectives:

Because each cut made has the potential to change the entire structure and growth pattern of the plant, no cuts should be made without clearly established goals. Removal of specific branches and foliage as well as how they are removed is as important to your plants health as any other aspect of its care.

Branches:

The first thing to keep in mind when pruning is basic plant biology. Branches can usually be placed in one of two categories; dominate and co-dominate. They are most easily identified by they way in which they protrude from the trunk, in that dominate tend to extend at a 90 degree angle while co-dominate are at a 45 degree angle (more or less). However this is more difficult to discern with Cannabis.

Beyond their shape, the two kinds of branches have very significant differences in terms of plant structure and stability. Dominate branch's rings flow down the branch and one by one wrap around and into the rings of the trunk creating incredibly strong bonds (similar to the braids of a rope). co-dominate on the other hand, do not connect to the trunk in this fashion and are easily split (this is why you see so many Y shaped cannabis plants split down the center.)

Furthermore, dominate branches are protected by the branch bark ridge and branch bark collar which when pruned correctly create a branch bark protection zone. What this means is that if the branches are pruned outside of the branch bark collar a cube of protective tissue (physically and chemically) forms at the edge of the cut sealing it off from decay and pests.

It is important to point out that branch hight is set. Whether your cultivar be Cannabis or Christmas tress, branch height on all trees and plants does not change once it starts to grow.
 
desertsquirrel

desertsquirrel

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Topping:

Topping has become a serious problem both with trees as well as cannabis on a global scale. Trends in the tree market demand small lollie-pop structured trees, which usually result in the death of the tree prior to it actually achieving tree-ness at all. (Never can these trees become large, shady, productive, specimens of their species.) Without digressing, what this means for cannabis is that IF you're forced to top in order to achieve a certain goal (ie yield/plant count) you understand the long term implications of doing so, and provide proper support for the unnatural and unsustainable plant structure.

When topping it is important to remember that though your going to see an explosion in lateral and canopy growth, the majority of that growth will consist of co-dominate stems and watersprouts. This means weak connections to the plant as a whole (co-dominates) and growth shoots incapable of supporting the weight of the flowers intended for them to produce. That being said, I do think there are times when topping is advantageous. However to do so without properly pruning and supporting the topped plant is a serious mistake.

Topping for mothers is far more important then plants which will be flowered and dead in 2-3 months time. The long term nature of their existence necessarily changes what acceptable and manageable mean in terms of the plants structures. The earlier the mother is topped, the sooner you will see implications of instability. However, if it is topped it can be retrained through pruning in order to reestablish a dominate leader and progress toward proper structure again.

For example, with my mothers I wait as long as I can before the first top. After the canopy fills out again, I remove most of the top branches save one last dominate leader. For the next set of cuts, I move to the bottom of the plant and remove proper pruning cuts (see Maintenance for more info) for that round of clones. I then re-top the plant and begin the process all over again. (6-8 weeks total for all 3 rounds of cuts).


The ISA provides 8 reasons not to top trees:

1) Starvation: Good pruning practices rarely remove more then 25% of the crown, which does not interfere with the trees ability to manufacture food in the leafy crown. Topping removes so much of the crown that it interferes with the root-to-crown ratio and temporarily cuts off food production.

2) Shock: A tree’s crown is like an umbrella that shields much of the tree from direct sunlight. sudden removal of this protection can result in scalding on the the trees leaves, bark and branches.

3) Insects and Disease: The large stubs of a topped tree have a difficult time forming callus. The terminal location of these cuts, as well as their large diameter, prevent the tree’s chemically based natural defense system from doing its job. The stubs become highly vulnerable to invasion of insects, spores, and decease.

4) Weak limbs: At best, the wood of a new limb that sprouts after a larger limb is truncated is more weakly attached than a limb that develops more normally. If rot exists or develops at the severed end of the limb the weight of the sprout makes a bad situation even worse.

5) Rapid New Growth: The goal of topping is usually to control the height and spread of a tree. Actually it has the opposite effect. The resulting sprouts (often called watersprouts) are far more numerous than normal new growth, and they elongate so rapidly that the tree returns to its normal hight in no time.

6) Tree Death: Some older trees are more tolerant of topping than others. Beeches, for, example do not sprout rapidly after severe pruning, and the reduced foliage most surely will lead to the death of the tree.

7) Ugliness: A topped tree is a disfigured tree. Even with its regrowth, it never regains the grace and character of its species. The landscape and the community are robbed of a valuable asset.

8) Cost: To a worker with a saw, topping a tree is much easier than applying the skill and judgement of good pruning. Therefore, topping may cost less in the short run. However, the true costs of topping are hidden. These costs include reduced property value, expense of removal of dead trees, loss of surrounding trees/shrubs, liability of weak branches, increased future maintenance, etc.

Bark/Trunk:

Flow of water/solution from the roots to the foliage takes place in a very small space between the outer and inner bark called the phloem. It is of primary importance that this layer never be breached or broken in any way. For this reason scissors should always be used, for every cut made, on every plant.

This flow of water and solution also must be channeled into each branch along the stem and it is for this reason that branches forming too closely together should be pruned. They will be in competition with each other for the nutrients and solution flowing from roots to shoots.
 
desertsquirrel

desertsquirrel

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Foliage:

Defoliation can be an effective practice when trying to shorten node length, increase flower size or provide more light penetration to lower bud sites. “As a rule, growth is maximized if pruning is done just before the buds swell.” It is a viable alternative to more stressful cultural controls such as lst, hst, super cropping etc (all of which are significantly stressful to the plant).

It is important to note that ISA recommendations for defoliation are to never exceed 20-25% of viable healthy foliage.

I love to use minor defoliation in conjunction with single topping in RDWC. You can see the results here:



Wound dressing:

Once thought to both help protect as well as increase recovery; wound dressings actually have the opposite effect and are used far more for cosmetic purposes. Would dressings are “neither required nor recommended.”

Maintenance:

All pruning begins with plant structure maintenance. Always begin with:

Removal of dead and dying leaves.
Removal of dead and dying branches.
Removal of sucker/ codominate branches (when possible).
Removal of any branches which originate too closely together.
Reduction of weight on heavy branches should be done by pruning along the branch, not by “topping” it. (which will result in increased weight).
 
UCMENOW

UCMENOW

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Very informative an relevant, you stated the best time to prune would be before the buds swell, can you elaborate on the correct times to prune (to improve structure/vigor during veg and for the best fruit/ flower set).
 
P

phup

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DS, I've been lurking on this forum for the last year (although I've been growing for a long time) and am thoroughly impressed with the breadth and depth of the knowledge you are dropping. Great to see somebody who is taking cultivation to the next level and is willing to share it with the rest of us. Keep it up!
 
E

E.T.

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been a certified arborist for years and i can't tell you how nice it is to see the community starting to embrace proper pruning techniques. living in california, i'm fortunate enough to get to spend time amongst some of the largest trees in the world. nothing like walking through the woods of giants that are thousands of years old....makes you feel very small. i do some recreational climbing of these giants as well...just amazing. i digress, great info to see up here squirrel. thank you. +rep
 
S

southern

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nice. Going to reevaluate my pruning and topping methods. Thanks for the good stuff DS
 
desertsquirrel

desertsquirrel

1,177
83
Very informative an relevant, you stated the best time to prune would be before the buds swell, can you elaborate on the correct times to prune (to improve structure/vigor during veg and for the best fruit/ flower set).

Sure. I will add that section to the thread and continue to add pics of my mother pruning as well as the single top/defoliation/pruining of the new 24 site UC. (should take about a week). It will be this room here:



DS, I've been lurking on this forum for the last year (although I've been growing for a long time) and am thoroughly impressed with the breadth and depth of the knowledge you are dropping. Great to see somebody who is taking cultivation to the next level and is willing to share it with the rest of us. Keep it up!

Wow. Thank you so much man. I hope your finding it helpful.
 
M

medicine21

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Thanks for this post. Interesting stuff. It sounds like a technique for maintaining healthy, robust and high producing plants that are TALL.

My impression is that this technique is being positioned as an alternative to LST, supercropping and to a smaller degree topping.

How can this technique be used to achieve shorter, bushy plants with an even canopy?
 
E

E.T.

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you can use structural pruning to attain a small even canopy and create a plant that has not only an even canopy, but even scafolding branches that are radially placed around the trunk. using this proper pruning technique along with lst will give you a plant that will require less bracing when fruit develops.


Thanks for this post. Interesting stuff. It sounds like a technique for maintaining healthy, robust and high producing plants that are TALL.

My impression is that this technique is being positioned as an alternative to LST, supercropping and to a smaller degree topping.

How can this technique be used to achieve shorter, bushy plants with an even canopy?
 
M

medicine21

37
6
you can use structural pruning to attain a small even canopy and create a plant that has not only an even canopy, but even scafolding branches that are radially placed around the trunk. using this proper pruning technique along with lst will give you a plant that will require less bracing when fruit develops.

Ok. So in a nutshell to achieve this:
156154d1309468199-isa-pruning-techniques-uc-isa7.jpg.att


We should prune like this?
156158d1309469018-isa-pruning-techniques-uc-isa10.jpg.att


Very informative an relevant, you stated the best time to prune would be before the buds swell, can you elaborate on the correct times to prune (to improve structure/vigor during veg and for the best fruit/ flower set).

I also have the same question, when is the proper time to prune?
 
E

E.T.

1,322
113
Bud swell does not happen on cannabis plants. Best time to prune is when the plant is healthy and in a vegatative state.
 
E

E.T.

1,322
113
Ok. So in a nutshell to achieve this:
156154d1309468199-isa-pruning-techniques-uc-isa7.jpg.att


We should prune like this?
156158d1309469018-isa-pruning-techniques-uc-isa10.jpg.att




I also have the same question, when is the proper time to prune?

It appears to be a drawing of how to prune for apical dominance...and a bad example at that. Too many issues with that image...codominant stems, crossing branches to name a few
 
desertsquirrel

desertsquirrel

1,177
83
thanks for fielding the questions while i am so busy ET. Your right those diagrams are poor at best but i figured they were better then nothing and all i could find at the time.

Over the next week ill include pics of several large scale pruning projects that i hope will make this information more clear.
 
desertsquirrel

desertsquirrel

1,177
83
Bud swell does not happen on cannabis plants. Best time to prune is when the plant is healthy and in a vegatative state.

I dont know that i agree with this. I find that defoliation at the right times forces the plant to create more vegetative matter in the bud site, spurring the swell. I will cover it in more detail when i can post pics.

Though i do agree it doesn't happen in the same way as tree budding.
 
A

antimatter

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I love topping, and then topping some more after I have topped again.
 
desertsquirrel

desertsquirrel

1,177
83
I love topping, and then topping some more after I have topped again.

I find that multiple topping makes not only for poor plant structure but also poor flowers.

I tried to find pics of your grows antimatter, but i couldn't. Can you post some pics and or data on your technique
 
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