Defoliation for ramification?

I just read a recent post where Jonas mentioned ramification as one of the benefits of defoliation. I have read this on other bonsai websites also. But I have also read on other bonsai websites that this is unfounded and that defoliation does nothing to help with ramification. How can it? Merely cutting leaves off of a branch would not make the branch ramify with new branches, only new, smaller leaves.

So, I am wondering if this is just a ‘wives tale’, or is there some science behind defoliation helping ramification.

PS: if this topic has already been discussed in the archives, please forgive the repeat.

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I think the theory behind it is that, when you defoliate the bigger leaves on the outside it pushes the growth that was once going to the bigger leaves and branch tips back into the interior buds and branches stimulating growth evenly and not so much energy towards the leader branch. And probably slows the tree down a little, resulting in smaller leaves. I could be wrong maybe someone else knows for sure?

Very good question Les! I didn’t fully explain at the related post. Here’s how I understand it.

When the aim is to develop primary branches, you can defoliate everything to slow down the overall growth and keep the internodes short.

Because full defoliation is so stressful, you can expect some interior branches to die. This doesn’t matter when developing primary branches as typically only a small section of primary branch will be added during each growing season. The secondary branches will come later.

Short internodes is what matters when building primary branches and fully defoliating a tree is a great way to apply the brakes and produce shorter internodes. That’s the “science” behind it: more stress = shorter internodes which is a good thing when developing primary branches.

Partial defoliation is used when you want to preserve weaker, interior branches. This is generally the case on more developed trees where balancing vigor is important.

Here’s a case study for when not to fully defoliate:

And here’s the same tree partially defoliated a few years later:

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