Trunk Chopping Nursery trees

[Scrogdor]

Been posting a lot lately, appreciate everyone’s guidance on here! But alas I have a new question!

I saw this awesome trident maple about 8-10 feet tall, had a terrific trunk taper and it is wayyy cheaper than buying a pre bonsai trident of that caliper. 125$

My question is, what is the process for trunk chopping nursery trees in fairly big pots?

1) is it too late to trunk chop tridents in September in Northern California?
2) Would I have to trim 1/2 to 2/3’a the root mass? Or would I leave it in the huge pot it’s in?
3). What kind of timeline am I looking at from first chop to finish?

 

[caffeinated]

The end of summer / beginning of fall is a great time to do a trunk chop. You don't trim the root mass (now), they're filling full of starches and you want that to start rebuilding your tree in the spring. Leave it in it's huge pot until repotting time. A photo would really help, but you might be looking at several years just to redevelop the main trunk and primary branches, leaving alone ramification / refinement time.

 

[leatherback]

I would let the tree just sit how it is. Maybe in winter reduce somewhat. In late spring, after the first flush, chop. I find the growth when chopping after early spring to be better (Short internodes). As the tree is fully awake and active, wound healing starts right away and is fast. Repot the year after.

 

[Shibui]

I'm not sure it matters what time of year tridents are chopped if the winter is not too cold. I do most of mine from mid- winter through to spring in conjunction with root pruning and seem to get good response but later spring is also OK (chop, not root prune)
Trunk chops can be done without any root reduction. You will probably find a more vigorous regrowth if the roots are left intact but roots are important and will need to be addressed at some point. i find it more comfortable to do the hard root chop when there is minimum growth on top ie at the time of trunk chop. Alternative is to develop new top growth then make root reduction when the tree has more branches to support. Both will probably work but I'm happier to do maximum root reduction when there's minimum top to support.

Timeline is very variable after the first chop. I'd consider several years very optimistic but it depends very much on how big the cuts are and how well the tree can be grown afterwards. With limited growth in a pot a 1" diam cut can take up to 10 years to heal over completely. The initial cut will probably be around first branch high meaning the rest of the tree needs to be grown in sections with further cuts to develop better taper and more shape in the upper trunk. Allow a year or 2 for each section of the trunk as you go through the grow and chop cycles.
Most of my trident rebuilds after large chops have taken 5-10 years but maybe if you are satisfied with less taper and less ramification in branches the lower end would be realistic?

 

[63pmp]

I trunk chopped a dozen tridents while in the ground once at beginning of autumn and they all died back to the lowest node, as they were cuttings that was at or near ground level. Made for some ugly bonsai, been challenging to make anything of them. I trunk chop when repotting as I trim roots savagely at same time.

 

[63pmp]

Here's a recent picture of one of them, only kept a couple for playing.

 

[sorce]

I'm not a fan of chopping to nothing, better to chop to a branch already prepared to be the next segment.

Something about layering it yearly from the top down to have less waste and get those low branches started.

Sorce

 

[63pmp]

I'm not a fan of chopping to nothing, better to chop to a branch already prepared to be the next segment.

Something about layering it yearly from the top down to have less waste and get those low branches started.

Sorce

Yes, I usually chop to prepared branch. These were field grown trees ready for first chop, about one to two inches thick, in the ground for two or three years, no lower branches. I usually lift the trees and chop with a severe root prune, but was impatient and someone on Bnut said "chop in autumn". Each chop was about 5 inches above soil level and each tree died back to first node at ground level.