Natural propagation in a forest garden - blending techniques.

This is a theoretical solution to a problem I had previously discussed in this thread here regarding apple propagation and a lack of genetic diversity. The idea is to balance the dependency on cloning by blending the practice of grafting with the natural process of seed propagation. Essentially, it is a controlled natural selection to promote good genetics in the food forest and maintain a diverse gene pool. In addition, unlike transplants the taproot is not affected adversely increasing hardiness. This methodology can be applied to other tree crops.

Establishing the forest.
This is the typical creative process described in many design text books. In selecting the trees, I would blend transplants and propagate by seed. The transplanted trees will naturally have a head start however the seeded plants will have the advantage of undisturbed root development. Fruit will develop faster from the transplants and the quality of the fruit will be more consistent. The seeded trees will provide the genetic lottery and building on this analogy, not every specimen will produce a winner.

Evaluation of desirable traits.
This process leads up to the selective proliferation. During this time, the plants have matured and fruited so characteristics such as hardiness, appearance and fruit quality are noted. Special consideration should be taken for seed propagated specimens given that fruit quality is variable until the 3rd or 4th fruiting. In other words, for the seeded population the fruit quality cannot be properly evaluated up until a few fruiting seasons.

Spread seed.
Once the desirable specimens are determined, disperse seed from these trees by any preferred means. Animals can automatically perform this task, even by passing through the digestive tract.



Culling the trees.
With the desirable specimens known, the less desirable specimens will be reduced to rootstock. This will be best done during the dormancy period before spring. The advantage of this is that the undesirable specimens will produce more hardy rootstock than the transplanted counterparts can provide with the taproot fully intact and unhindered. Additionally, little resource in time and space is wasted as the investment builds into a productive investment. The desirable specimens naturally will provide the graft samples. Holistically, grafted specimens standardize the quality and seeds provide the evolutionary innovation.

we're in the early stages of trying this with lots of stuff, but mostly focused on hazels, pawpaws, aronia, elderberry, and mulberry.

Another strategy to add to the mix is cutting scions from young seedlings and top working them onto established rootstocks, this will produce fruit much quicker than on it's own roots. This is how Luther Burbank was able to do selections on whatever ridiculous number of species it was on only 1/4 acre.

I've been doing something similar. I have brought in some local plum and pear varieties that were grafted on to cuttings, so the roots are pretty weak.

Luckily I have wild pear trees around here with much better root systems so I transplant them next to my purchased pear trees. I am grafting the purchased pears on to the wild pear rootstock and I am expecting the wild pear root stock will do better.

For the plums, I grab baby plum trees that have seeded in the shade of larger plum trees and I will use those as rootstock for my purchased plum varieties.

To a large extent, I think this is largely a waste of time, and a misguided use of valuable resources (mostly time and space), especially if you are working with apple. It was established centuries ago that the genetics of apple are hopelessly complex, so I am really surprised that you can state something like a lack of diversity in apple. Plus, the big horticultural departments of state universities have done a pretty good job of supplying relatively new varieties through selective breeding. Honeycrisp is a good example. That's what can be accomplished when you have the ability to screen tens of thousands of offspring.

Since Osker mentioned Luther Burbank, I thought I'd mention that my local library has a copy of his original 6 volume manuscripts, which I feel very privileged to have available to me. I'd suggest trying to get ahold of your own copies and learn from the experience of a real tree breeder, with experience gained over a lifetime.

That's not to say that your process will not work on any tree species. If you look back at Burbank's early work, he obtained a randomly collected bag of Japanese plum pits. After sprouting a dozen seedlings from them, he managed to select such a superior variety (Satsuma) that it is still a commercial variety more than a century later. Not bad out of 12 chances. Peaches are another worthy choice that will definately give you more reliable results than apple.

I could suggest an alternative stratage that I myself am applying. I do sprout my own apple, pear, peach seedlings, but use them all as grafting rootstock. I graft onto branchlets, a lot like Luther Burbank did a century ago. What I do differently though is I always try to leave one single branch on the tree as the wildtype (not grafted), so the tree can express it's natural genetics. So, I think I have the best of two worlds. I get grafted apples of known quality, that I can rely on for production, but I still leave room for random change to supply me with a good apple. At the very least, the wildtype branch will serve as a pollunator for the other grafts. This way you are not wasting massive amounts of space on trees that are likely never to amount to anything.

BTW, don't imagine that just because a tree has seedling roots, it automatically has a taproot. Some trees, such as Oak, do have taproots, but apples, peaches, pears, ect do not. Perhaps what you are thinking of is the severly pruned roots you commonly see on bare-root commercial trees. Yes, their roots are damaged, and cut short, but there was never a tap root to start with, so stop worrying about it. The single most important factor that will promote robust root development is loose, friable soil that rootlets can penetrate through. When you are ready to plant any tree, always plant a round tree in a square hole. What I mean is I usually remove about 4 cubic feet of soil from the spot the tree goes, more or less in the shape of a cube. Tree roots spread out radially, so if you plant in a round hole, all of the newly spreading roots hit dense, undisturbed soil all at the same time. This can stunt, and even kill some trees. In a square hole, some roots may be hitting the hard wall, while in other radii, they are still expanding through soft soil. This gives the newly estblished tree more time to adapt to changing soil density. Right angles also tend to direct root growth downwards, whereas a curved surface tends to encourage spiralling of the roots (Very bad).

Michael Qulek wrote:To a large extent, I think this is largely a waste of time, and a misguided use of valuable resources (mostly time and space), especially if you are working with apple. It was established centuries ago that the genetics of apple are hopelessly complex, so I am really surprised that you can state something like a lack of diversity in apple.

I would not go as far as calling it a waste of time. I should have articulated myself better, but my argument was that avoiding natural propagation is unsustainable. Sure, apples do have genetic variation but I would not call it hopelessly complex. That sounds like a flawed argument to make given the trend of habitat loss. There is a great deal of work done by researchers in Kazakhstan that counter that mindset. Not fully following the motivation of discouraging a practice to breed your own varieties contributing to the genetic diversity of a species. The risk mitigation is there when you essentially cull the less desirable specimens and graft to the root stock.

Michael Qulek wrote:Plus, the big horticultural departments of state universities have done a pretty good job of supplying relatively new varieties through selective breeding. Honeycrisp is a good example. That's what can be accomplished when you have the ability to screen tens of thousands of offspring.

Very true. Why not work with the universities essentially doing the same thing?

Michael Qulek wrote:Since Osker mentioned Luther Burbank, I thought I'd mention that my local library has a copy of his original 6 volume manuscripts, which I feel very privileged to have available to me. I'd suggest trying to get a hold of your own copies and learn from the experience of a real tree breeder, with experience gained over a lifetime.

Did you say original manuscripts? Impressive.

Michael Qulek wrote:That's not to say that your process will not work on any tree species. If you look back at Burbank's early work, he obtained a randomly collected bag of Japanese plum pits. After sprouting a dozen seedlings from them, he managed to select such a superior variety (Satsuma) that it is still a commercial variety more than a century later. Not bad out of 12 chances. Peaches are another worthy choice that will definately give you more reliable results than apple.

Alright, this is where I will make a good point. Assuming Burbank is your idol, I can safely say that he values the contribution of seed propagation.

Michael Qulek wrote:I could suggest an alternative stratage that I myself am applying. I do sprout my own apple, pear, peach seedlings, but use them all as grafting rootstock. I graft onto branchlets, a lot like Luther Burbank did a century ago. What I do differently though is I always try to leave one single branch on the tree as the wildtype (not grafted), so the tree can express it's natural genetics.

I think that is a very clever and sustainable approach compatible with my own principles.

Michael Qulek wrote:BTW, don't imagine that just because a tree has seedling roots, it automatically has a taproot. Some trees, such as Oak, do have taproots, but apples, peaches, pears, ect do not. Perhaps what you are thinking of is the severly pruned roots you commonly see on bare-root commercial trees. Yes, their roots are damaged, and cut short, but there was never a tap root to start with, so stop worrying about it.

Good point. I think we can agree however that the root structure is unimpeded and generally more healthy when left undisturbed.

Michael Qulek wrote:The single most important factor that will promote robust root development is loose, friable soil that rootlets can penetrate through.

I think that kind of observation is a little antiquated, by what I mean it is limited to the macroscopic (eyesight) level. I imagine Luther Burbank may not have had the advantage of modern biology to expand on such theories.

When you are ready to plant any tree, always plant a round tree in a square hole. What I mean is I usually remove about 4 cubic feet of soil from the spot the tree goes, more or less in the shape of a cube. Tree roots spread out radially, so if you plant in a round hole, all of the newly spreading roots hit dense, undisturbed soil all at the same time. This can stunt, and even kill some trees. In a square hole, some roots may be hitting the hard wall, while in other radii, they are still expanding through soft soil. This gives the newly estblished tree more time to adapt to changing soil density. Right angles also tend to direct root growth downwards, whereas a curved surface tends to encourage spiralling of the roots (Very bad).

Very interesting, can you provide a reference to this information?

When you are ready to plant any tree, always plant a round tree in a square hole. What I mean is I usually remove about 4 cubic feet of soil from the spot the tree goes, more or less in the shape of a cube. Tree roots spread out radially, so if you plant in a round hole, all of the newly spreading roots hit dense, undisturbed soil all at the same time. This can stunt, and even kill some trees. In a square hole, some roots may be hitting the hard wall, while in other radii, they are still expanding through soft soil. This gives the newly estblished tree more time to adapt to changing soil density.

THIS makes total sense to me and its so simple. I love it. This is one of those ideas that other people need to hear about. I can see of no drawback except that digging the extra soil would be a little bit more work.

*As for the rest of that post it was a bit negative, didnt like the tone. Its hard to tell what the intent was, though, since text is such a limited form of communication.

The idea of the square hole got me thinking about how this might be used for transplanting smaller plants. I dont think you would need to be really strict with the shape. Just generally dig the hole with some elongated area so that (assuming the roots grow roughly the same in all directions) they will not all hit the sides of the hole at the same time, i.e. anything but a circle would work. Of course ensuring that the backfill is the exact same as the surrounding soil is also really important so that the roots do not have shock growing through the transition, it is also important for water drainage.

I wonder if the way you dig your hole could be used to exercise some control over where the plants roots grow , but maybe its best to leave that decision to the plant.

(sorry to change the topic of the thread, but I think that is part of the magic of forums)