AusBonsai

It is said that when hard pruning Pines it must be done gradually other wise the tree will suffer.

From Bonsai4me https://www.bonsai4me.com/AdvTech/ATPine%20Pruning.html
It is better to be conservative when hard-pruning and reducing Pines. Severe reduction without allowing for recovery time can be fatal particularly with old or large trees. Reduce large trunks and/or branches gradually over a number of seasons so that the tree is able to adjust.

This is something I considered when hard pruning my JBP entry although I did push it very hard to try to get the results I was after in the one year time frame.
viewtopic.php?f=122&t=2623
So far so good. Infact the tree still looks vibrant. I figure the health and juvenility of the tree has worked in my favour.

I am in no way trying to debunk what seems to be sound advice but I do want to try and understand what reason there is that reducing a pine severely in one go is detrimental.
is it the possible sap loss? Does it have some detrimental affect on how the tree is able to function?
Any ideas?

G,day Bretts. I have had that unfortunate experience. The black pines are a little tougher, as is the mugo, mostly 2 needle pines are tougher. Try it with a J.w.p and it will be gone in a month. I have had the experience of styling and pruning the 5 needle pine in one sitting and took of to much foliage, as i said, gone. I have tried the same with older j.b.p. and they pulled through no worries.

Any idea why they have this issue?

Brett JWP just aint as hardy when it comes to hard pruning, Also the timing for JWP plays a vital role on how the tree will cope where as JBP can be done is less than optimun times of the year and still respond. I hard pruned most of my JBP last winter and have experianced the shortest needles yet in my bonsai journey. This year they are around the inch mark with two dwarfs pushing 1/2 inch. Since i have no experiance with jwp or mugos for that im going off what a good bonsai artist south has said to me. Also most white pines in this country are grafted to make them stronger. I only know of 2 mature ones (25yearsplus ) on there own roots. In general you just have to leave more needles on, watch how far you cut back, watch what season you do this. Most artists also cut white pine needles instead of plucking for loss of dormant bud.
Having said all this thers something about there pine sap that is completey diffent to JBP so when i get south im getting one or two.........

Brett I remember well a lesson taught me by a JBP early in my Bonsai journey. I like all styled my tree at this stage 1986 cut of branches as it said in the book.
Then about 4 years or so later Dot Koreshoff was here in the West.
Dot relates to her first experience with a JBP. Dot had Vita for advice.I had no one, he told her do not cut off flush and do not cut off too much.
Dot being a typical wife ( her words not mine ) took no notice 5 years down the track that tree above the branch died.
Mine also died, but mine was the whole top.
The reason was sap withdrawal. Not evident straight away but inevitable old older trees. Not so much with younger ones.

I persevered with mine turned it into a nice Bunjingi. Then we had a holiday over East in 2000.
The sitter then was not as reliable as my last one. The JBP and my first ever tree kept as a reminder and two Azaleas died, along with some Minis .
I was devastated, as I had had his whole collection on my benches for 4 months while he was away.
Needless to say not very friendly now.
Cheers Pup

Thanks guys for the effort. But what I am really after is why! Why is it that you can chop a deciduous trees back as hard as you like and it shows little sign of stress but a Pine has a sissy fit and carks it?

What physical disposition of how the tree works causes the trouble. Do the cells explode becasue they have no where to go. Does it stop drawing water into the trunk. What does the tree actually die from?


Edit Thanks Pup. So I figure what you are saying is that the tree panics and withdraws the sap too far thus killing itself?

They have answered as best as i possibly could have. One thing that i did notice was the loss of sap on the white Pine, it was extreme. I suppose you could say it slowly bled to death.

Thanks Bodi I figured it was a hard question I tend to get these questions and find them interesting.
When I consider your answer I wonder if this is so as doing the prunning in winter should reduce the sap flow and allow the harder prunning!
Hence the advice would be Don't do major reduction in summer but teh advice is don't do major reduction full stop
This was something I considered when drastically reducing my Pine out of season. I experimented a little beforehand removing small branches and needles to asses sap loss.
I figured that if I just stripped the tree of needles which did not seem to encourage much sap loss then it might direct the growth where I wanted without killing the tree.
Lets pose the question this way. If you had a mature pine and without doing any hard pruning that induced loss of sap removed 3/4 of the foliage is this also cause the tree extreem stress?
Hence is it the open wounds that is the issue or the loss of foilage?

in my experience with jbp, i only do any major choping in the winter months, when the sap is not flowing
as much as in the spring/ summer months. i lost a nice tree early on that was hard pruned in the spring.
i sort of look at it like a human, u cut off your finger,u lose a small amount of blood, cut off your arm/leg
u can lose alot. the blood keeps flowing as does the sap.
jmo
strawbs

Bretts wrote:Thanks guys for the effort. But what I am really after is why! Why is it that you can chop a deciduous trees back as hard as you like and it shows little sign of stress but a Pine has a sissy fit and carks it?

What physical disposition of how the tree works causes the trouble. Do the cells explode becasue they have no where to go. Does it stop drawing water into the trunk. What does the tree actually die from?


Edit Thanks Pup. So I figure what you are saying is that the tree panics and withdraws the sap too far thus killing itself?

That is my none scientific take on it by observation. With older trees when you leave a stub, as it is now widely told, you do not get sap withdrawal.
The fact that deciduous regenerate every year so to speak, helps with the pruning process better.

Cheers Pup

Its the absence of foliage which causes Pines to withdraw support. Therefore, always leave some foliage on any branch which you wish to keep. Complete removal of branches sometimes gives the tree the message that things are not well up there and it withdraws support to everything above the operation. Gradual removal seems to allow the tree to adjust gradually.
When reducing a branch to use for jin, leave it at least half as long again to the size that you are aiming for and reduce when dry.

I think most things have been said. The other thing to consider is how strong the bud your cutting back to is. If it is not strong enough it will not draw the sap. If it doesn't draw sap, I dies!

I agree with strawbs, so now I'm gonna wait 'til winter to cut my leg off

MM

Jarrod wrote:I think most things have been said. The other thing to consider is how strong the bud your cutting back to is. If it is not strong enough it will not draw the sap. If it doesn't draw sap, I dies!

Not really? If I don't want half the tree then I want that part to die and all the foliage on that part is removed, what I want to know is what causes the rest of the tree to die? Yes remove all the foliage on a branch and that branch dies (although I have seen some one show me otherwise that is not what I am questioning here).

What I am trying to work out is if you reduce the foliage on a mature pine back by a large amount why does it kill the whole tree, even past where healthy foliage has been left. It seems Radiata is an exception as may other pines but lets concentrate on the ones that do have this issue.
Leong does show a major reduction of a kotobuki pine same as mine, except much more mature, that seems to have been done in September of this year!
http://www.bonsaisouth.com.au/cms3/inde ... &Itemid=75
If you take a look at my entry that is linked above. I have left foliage on the branches I want to survive what I am trying to understand is why this treatment can kill a tree. Obviously by Leong's video and the apparent survival of mine it is possible in some instances but I would like to gtry to understand this some more.
Is it just a matter of trying to stop sap loss or is there something else that happens when this is done that can kill a pine?

I appreciate the effort but I would say Pup is the only one that has actually addressed the question as it was put.

I believe he has suggested that the tree panics and withdraws the sap too far (to stop bleeding) and this results in a dead tree.

The roots and the foliage are part of the food producing factory of the tree . The tree has to collect the sunshine for the roots to produce the sugars to feed the needles. It is a symbiotic relationship. reducing too much foliage too quickly is the same as taking off too many roots. The tree cant feed properly and dies. unlike most species pines wont bud on bare wood particularly if there is no foliage to pull the food up through the branch.