Developing Dwarf Maples

[Johnnyd]

Hi,
I thought most dwarf JM cultivars are basal dominant which means you have to keep the bottom branches in check to keep the top half of the tree alive. Most dwarfs have very short internodes which is great for bonsai but slow to create.
Am I on the right track? Others agree or can correct me please.
Charles

I think it depends on the cultivar. Koto is apicaly dominant kyohime is basal dominant. Pygmies are apical. Growing out a dwarf cultivar can be slow. I've had some decent results removing the 1st set of leaves on a shoot with 6 leaves and then removing one of every two pair out to the tip. About a foot of extension per year is decent for a true dwarf. This is probably why they are recommended for smaller bonsai.

 

[AndyJ]

I think it depends on the cultivar. Koto is apicaly dominant kyohime is basal dominant. Pygmies are apical. Growing out a dwarf cultivar can be slow. I've had some decent results removing the 1st set of leaves on a shoot with 6 leaves and then removing one of every two pair out to the tip. About a foot of extension per year is decent for a true dwarf. This is probably why they are recommended for smaller bonsai.

Thanks Johnny - that might be worth a try. I’m happy to give anything a go!

 

[leatherback]

Maybe you can get @MACH5 to chime in. He has a thread on this variety which he rebuilt, so he knows how to develop these.

KASHIMA MAPLE

Starting a new thread on this tree. There is an older one but due a reshuffling of photos on my image hosting site Photobucket, many of the images were deleted. You can find the old thread here: http://www.bonsainut.com/threads/kashima-maple-redux.9465/. Here is a little backstory. In the...

www.bonsainut.com

 

[PA_Penjing]

Everyone here is just trying to help, we mean nothign aggressive by it. My sentiment has been echoed a few times now, you want low branching to build taper, height will obviously come with time. Not sure what part of my comment makes you think I have no clue what's going on. But I will leave you alone if you like

 

[JonW]

One thing everyone is agreeing on is that foliage produces energy for growth and thickening (when that energy is stored).

One thing people are disagreeing about is encouraging vertical growth in trees that have a dwarf or horizontal habit. Nothing is going to completely change that growth habit, but I think you can influence it - it is analogous to, but maybe opposite of, trimming apically dominant trees. You need to trim the top of apically dominant trees 2x as much as lateral branches (gross generalization) because their habit is to grow tall and kill off the low branches when shaded out / no longer needed. We see the opposite in some dwarf cultivars such as Kiyohime, in which the top can die off.

However, keep in mind the difference between dwarf and basally/laterally dominant. Dwarfism is caused by:

• Lack of gibberellin
• Few gibberellin receptors
• Gibberellin antagonist hormones

Apical dominance is caused by high levels of auxin, while my understanding is laterally dominant plants have less auxin. For example ShiShi and Kotohime seem to be very apically dominant despite being dwarf - they have strong upright growth and root easily (auxin encourages root growth). Kiyohime is dwarf and has very horizontal growth. I'd trim these very differently.

Cytokinin (growth hormone that causes cell division and differentiation) "sinks" (moves towards and stays in) areas with higher concentrations of auxins, such as apical buds. Removing the apical bud removes the high concentration of auxin, allowing cytokinin to "sink" in lateral, adventitious buds, causing lateral growth/ramification. In apically dominant trees, we cut the apical buds stop upright growth and cause branching. During fall, leaves convert chlorophyll to energy and send nutrients back into the tree for storage - once the leaves turn/fall, it is a good time to remove apical buds on an apically dominant tree: it stops cytokinin from "sinking" in those buds and give the tree the whole fall/early spring to re-allocated the cytokinin to lateral buds (why fall pruning can be more effective at activating adventitious buds than pruning during the growth season, which typically just release a couple buds right behind the cut point unless really hard pruning). I'm not completely certain of the physiology of horizontally growing dwarf maples, but I assume the opposite pruning method: pruning the side branches allows for reallocation of resources to upper areas.

Taking this a step further, in terms of sources and sinks of resources, mature leaves are the main "source," as well as starch storage from winter dormancy during the spring (ie., the roots would be the source), of energy (photsynthates). And energy / nutrients tend to be able to move throughout the tree to areas that need them (sinks), such as new growth / immature leaves at the tips, or if pruned, adventitious buds, as well as downward to roots.

While some people who are trying to rapidly grow trees don't prune even during fall, others recognize it isn't the length of branches that contribute to trunk growth, but rather the foliage mass. And in spring, the tree won't activate all the dormant buds on an untrimmed tree. So pruning in the fall shouldn't necessarily slow growth too much - it reallocates resources from tips to the inside.

 

[0soyoung]

I'm so glad to have another tree physiology nerd here (BNut).

But, ...

I disagree with this portion of your post

Taking this a step further, in terms of sources and sinks of resources, mature leaves are the main "source," as well as starch storage from winter dormancy during the spring (ie., the roots would be the source), of energy (photsynthates). And energy / nutrients tend to be able to move throughout the tree to areas that need them (sinks), such as new growth / immature leaves at the tips, or if pruned, adventitious buds, as well as downward to roots.

Specifically, I think it a scientifically established fact that energy storage in trees is as starch grains in the vacuoles of living cells that are distributed throughout the tree. Further, I think it can be said that all energy storage is local and its use is local. In other words, carbohydrates stored in the roots stay in the roots and are utilized in the roots = trees are not potatoes (as I like to say).

On the other hand, it seems that too many roots does indeed lead to explosive top growth. It is mostly a hormonal thing I do believe. I find it interesting that some species of deciduous trees leaf out from the bottom up (lower branches toward the apex) and others from the top down. It is also puzzling to me how this hormonal signaling must occur, because there is no significant transpiration to be drawing nutrients or hormone signals from the roots.


Anyway, lets nerd on dude!

 

[JonW]

I'm so glad to have another tree physiology nerd here (BNut).

But, ...

I disagree with this portion of your post

Specifically, I think it a scientifically established fact that energy storage in trees is as starch grains in the vacuoles of living cells that are distributed throughout the tree. Further, I think it can be said that all energy storage is local and its use is local. In other words, carbohydrates stored in the roots stay in the roots and are utilized in the roots = trees are not potatoes (as I like to say).

On the other hand, it seems that too many roots does indeed lead to explosive top growth. It is mostly a hormonal thing I do believe. I find it interesting that some species of deciduous trees leaf out from the bottom up (lower branches toward the apex) and others from the top down. It is also puzzling to me how this hormonal signaling must occur, because there is no significant transpiration to be drawing nutrients or hormone signals from the roots.


Anyway, lets nerd on dude!

Cheers!

Hmm, now that I think about it, I haven't read about starch coming out of dormancy in an actual plant physiology textbook or article, so you may very well be right. I always try to separate the "green thumber" (my term of endearment for conclusions people make about plant physiology from growing plants rather than science) info from physiology. I'm about 95% sure that Ryan Neil and some bonsai books I own talk about energy being stored in roots during winter for summer. You're definitely right it gets stored in vacuoles, and I would assume energy - starch or sugars - "prefers" to stay local. I suppose if this is true about starches, that would explain why trees grown more rapidly when repotted (and moderately root pruned) than when they are closer to being rootbound. Not at all that I doubt you, just interested in learning - if you have any sources on this topic (no need to go searching if you don't know off the top of your head). I also think I recall that buds have enough energy stored in them over winter to open on their own without additional energy resources, which is why some winter hardwood cuttings leaf out and die (if they don't grow roots in time to support the leaves).

However, I'm not sure that this applies to less complex energy like sugars. At least insofar as providing energy for roots, it does have to travel from shoots to roots since the roots can't make their own energy. The other thing is transport of nutrients, which I'm also not fully confident in my knowledge especially since transport varies significantly between some different nutrients, but it typically follows the opposite pathway of energy (from roots to shoots), of course, except for fall when some excess nutrients in leaves might move back into the stems.

Interesting stuff - in my opinion - I know its not everyone's cup of tea, but beyond curiosity, it also helps me make decisions about the work I do on plants. I've only started reading actual scientific sources on physiology over the last year or so. I recently found a textbook in PDF format online, which reads at a graduate level (the math was beyond what I was interested in interpreting). I'm nearly through reading it - got bogged down on the ethylene chapter.

 

[SeanS]

Wire a sideways shoot to be an upwards shoot and let it grow, then chop it back and repeat the process with another sideways shoot that appears. That’s how you’ll produce a tapered upward trunk.

 

[leatherback]

Hmm, now that I think about it, I haven't read about starch coming out of dormancy in an actual plant physiology textbook or article

energy being stored in roots during winter for summer.

I think you are trying to make something which is very complex,too simplistic. It varies from species to species and location to location what is happening and many things happen at the same time. This is a domain with substantial academic interest, and understanding of the NSC mobility in woody tissues is only slowly getting clearer.

https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.13955

Active summer carbon storage for winter persistence in trees at the cold alpine treeline

Abstract. The low-temperature limited alpine treeline is one of the most obvious boundaries in mountain landscapes. The question of whether resource limita

academic.oup.com

Diurnal Variation in Nonstructural Carbohydrate Storage in Trees: Remobilization and Vertical Mixing

NSC storage is highly dynamic at the diurnal timescale, exhibiting vertical mixing and a potential role for the xylem as a secondary pathway for sugar redistrib

www.plantphysiol.org

 

[JonW]

I think you are trying to make something which is very complex,too simplistic. It varies from species to species and location to location what is happening and many things happen at the same time. This is a domain with substantial academic interest, and understanding of the NSC mobility in woody tissues is only slowly getting clearer.

https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.13955

Active summer carbon storage for winter persistence in trees at the cold alpine treeline

Abstract. The low-temperature limited alpine treeline is one of the most obvious boundaries in mountain landscapes. The question of whether resource limita

academic.oup.com

Diurnal Variation in Nonstructural Carbohydrate Storage in Trees: Remobilization and Vertical Mixing

NSC storage is highly dynamic at the diurnal timescale, exhibiting vertical mixing and a potential role for the xylem as a secondary pathway for sugar redistrib

www.plantphysiol.org

Thanks for the articles - I will read them over the next few days. I'm not trying to make it simple, I just don't have a reasonably good understanding of it yet.

 

[leatherback]

I will read them over the next few days

A search on gogle scholar you will find dozens of papers on the subject of non-structural carbohydrate storage / relocation / winter protection

 

[leatherback]

Energy is stored throughout the tree. Trimming wood = removing energy stores.
What is in however also happening.. In many species variation in sugar stores is not per se linked to growing cycle.

 

[AndyJ]

Thanks Oso, JonW, Leather. Some very interesting points raised - I really appreciate you taking the time to put your thoughts down.

Do you know what? I think I’m going to try pruning out all of the twigginess in the side branches and on the leader and just leave top shoots that (hopefully) will be full of auxin and will grow up. It will be an interesting experiment. Let me know if you would like me to create a thread with pictures to document the journey.

Thanks again everyone.

 

[clem]

Let me know if you would like me to create a thread with pictures to document the journey.

Yes, i'd like to see it, and you could put your pics on this topic, to show your tree actually, and what is your goal (virtual)... this way, skilled people in Kashima cultivation will give you proper advises to reach your goal, imo

 

[0soyoung]

Let me know if you would like me to create a thread with pictures to document the journey.

mais oui