The why of fruit thinning

I noticed one of the apples in the food forest had finished blooming and now had tons of tiny apples clustered on its branches. I took the situation in hand and started to pick them off.

13217562 - close up of bee pollinating apple blossom
photo by Jenella

Five flowers form on each spur, leaving five small fruits after pollination. They naturally fall off, one by one, until a single fruit is left to make seed. Contrary to what we might think, an apple has grown to its maximum potential within thirty days after the flower drops its petals. From this point, any ‘growth’ is just cells filling up with sap like balloons. The number of balloons to be filled with juice resulting from cell division is already decided.

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I was pulling off all but one fruit on each spur. From this, I expected each apple left on the tree would have more nourishment from the tree, be larger, and better shaped. If I had waited for the tree to pair down the fruits itself, it would have divided that nourishment between all those extra apples that would never stay on the tree anyway.

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Is there a drawback to this unnatural thinning? Perhaps.

When plucking off the fruits I noticed a few had codling moth damage. I have gotten fine harvests of apples from my trees, with very little, if any, codling moth damaged in years past. Whether this is an especially good year for codling moth population or not might explain this damage. Or perhaps the tree had dropped much of the fruit with codling moth damage so I never noticed? It quickly occurred to me the tree grows the extra fruit in part to increase the chances at least one will make seed -as codling moths eat the seeds of the apples they infest.

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Codling moths have several generations through a season, so we will see if the moths come back for more later.

Another effect of thinning apples is more regular fruiting. The seeds in each fruit create a hormone that blocks fruiting the next year. Some varieties of apple are notorious for their violent fruiting cycles -one year not a fruit on the tree, the next (or year after that) the branches break for the myriad fruit clogging the works. By thinning, a moderate amount of hormone is produced every year, allowing a moderate amount of fruit every year.

Perhaps such staggered fruit production in un-thinned apples is a tactic for cutting down on codling moth population?

As is, thinning delivers better results for me. But my trees are also quite small -just barely above my head. Thinning falls into what I call pleasurable interaction with the food forest, or work I enjoy, and usually only takes five minutes or so to complete.

I may quit it in years to come, and just trade thinning time and larger fruit for hacking out the good hunks from myriad smaller fruits. Masanobu Fukuoka, when his students asked how they could grow good apples without equipment and sprays, said to simply feed the poor quality fruit the students thought eminent to pigs. I’m not so skeptical as Fukuoka’s students; I have seen my trees produce quite healthy fruit already, so we’ll see what they give as the system builds. Below are some of my Fuji apples last year.

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You may wonder how the heck massive orchards ever thin their fruit one by one. By machine? No, by chemicals. Hormones in trees largely dictate the quality and growth of the fruit. We have developed an array of synthetic hormones, of which there are no counterparts in nature, that cause apple trees to drop their fruit. Run some experiments to properly calibrate the dosage, and you have thinned trees by simply spraying. Some of the hormones they have developed even increase the cell proliferation process beyond what the fruit tree offers, resulting in abnormally large fruit. I’ll let you research the health effects of these synthetic hormones.

When I first came across this information years ago, I went on a long search for an equivalent that could be derived from plants. I didn’t come across one, or any information on a hormone pathway that could cause the fruit to drop, accept for stressing a tree, or simply reducing pollination. I am suspicious there is an even more elegant answer:

I find that increasing the health of trees and their ecology in general can can at times truly transform their character. Mortal Tree is still a long ways from being notably fertile. But Fruiting factors are building on their own in some places. So perhaps the good effects will get out of hand, and produce some good results I never would have expected. 

 

The rules of spacing

I was at a Christmas party in conversation with a local Timken engineer who, hearing I design food forests, wanted to pick my brain on apple trees. He had six trees in two rows of three, well spaced in his backyard. He was throwing out terms about the mainstream organic sprays he was using, and framed his questions expecting me to know some super organic spray, or spray regimen, that would fix his problems of pests and low vigor in general. I don’t think he expected the answer I gave: ‘What’s planted around the trees?’

We often think of the rules of spacing as rules for keeping other plants away from each other. In practice I find the lines blur between species, and enters a much more broad science: it’s what should be included near the plant, as well as what shouldn’t. Between these two aspects, you make or break the majority of fruit tree problems.

The lines often blur between species because, let’s face it, plants don’t grow in a vacuum and always have something growing up against them. In this guy’s case, his trees were planted right into his lawn. They were in competition with the grass.

Looking at their history, grass and trees are in most cases nemesis of one another. Trees make forest; but grass needs open space. The setting in most yards of trees with grass between is quite artificial, and only exists because we keep the grass mowed. In any other situation, trees would take over.

The prairies are the kingdom of grass, and these occured because of rain shadows, or areas where circumstances such as the Rocky Mountain range messed with the winds that carry rain, creating droughts in one part of the year, and near flooding in another. Trees don’t like that, because most have relatively shallow roots, as much as 80 percent residing in the top three feet of soil depending on the kind and its conditions; but prairie plants, such as the grasses, and N fixers like senna hebecarpa, put roots down unusually deep, so reach the water table whether rain comes or not.

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An experiment showing the root growth of Red Delicious apple tree two years after planting.
Have you ever wondered as you pass woods how the trees survive so close? If you were planting an oak tree in your yard that would someday reach a hundred foot tall, can you imagine the spacing recommendations? They would be over fifty feet apart. Most yards couldn’t fit more than one tree. But in the woods they stand on top of each other, growing for hundreds of years, happy, and healthy.

Studies have shown that trees can grow their roots deep into the ground, but prefer to keep their roots higher in the soil if possible. There is more organic matter, hence nutrients and water, in this layer. If there isn’t, trees will try to put in the work to grow deeper. This is a lot more work, and certainly isn’t their first choice.

What trees really prefer is building networks in which they share and preserve resources. For instance, trees have what is called hydraulic redistibution, which is a fancy term for moving water not only up for their own use, but back down into the soil for storage, and horizontally to other plants. Peter Wholleben, in his book The Hidden Life of Trees recalls his surprise when he found a ring of roots from a beech tree that must have been cut down well over a century beforehand, but still had green, living roots showing above ground. It had no leaves, and the stump was gone. As he explained, citing various studies, the living trees around this ancient (should be dead) tree were feeding it sugars made in their leaves, keeping it alive. Likely, they got some kind of kickback from the extended root system because it allowed them access to more resources.

This is in ancient, established forests, so conditions aren’t quite the same for our young transplants. We can get some similar effects by growing fruit trees in more open settings, or riparian zones. These are zones similar to fencerows and overgrown fields where grasses are just converting to trees. These zones are iconically untidy and wild; but skillful gardeners know the elements of these zones, like clay in a potters hand, have the best potential to form the most beautiful, lush gardens.

Riparian zones have many layers, with notably high numbers of low growing herbaceous and woody shrubs, many of which are nitrogen fixers. The quickest way to simulate this ecology is making ‘guilds’ of plants right around your fruit trees. Here is my manual of bed building for info on quickly clearing grass without tillage. Plan on expanding these plantings every year until the beds around your trees meet. If the tree is older, and larger, the bed should extend at least a couple feet beyond its drip line.

An example guild: 1. Fruit Tree 2. Comfrey 3. Siberian Peashrub 4. Amorpha fruticosa 5. Japanese Wineraspberry 6. Honeyberry 7. Blueberry 8. Turkish Rocket 9. Crambe cordifolia 10. Stepping stones, (or in this case, stepping logs). The green base is a ground cover of mint.
Any guild should include at least 2 woody nitrogen fixing plants, about 5 plants that do not fix nitrogen but can be cut for mulch, such as comfrey, or a groundcover of something like mint, then several fruiting shrubs like raspberry or honeyberry, and some perennial vegetables.

This is the best method if you already have fruit trees in the ground, like our engineer friend. If you’re just planning your food forest, Robert Hart, the father of the northern food forests, recommended planting full size or standard fruit trees at recommended spacing for their size, in rows like any orchard, but then semi standard or medium trees, then dwarf trees, then shrubs, then herbaceous plants, then vines to climb and fill in the cracks between them.

Photo credit: Graham Burnett.
I’d recommend mulching as much as you can, and planting that area with a complete planting like this. The space should be completly filled with plants, and will establish faster with less work overall.

This system gives quite attractive results that are increasingly less cost and labor than serial applications of even organic, clay-based sprays, pyrethrums and neems, let alone the more harsh chemicals. There is work later on, but this is of course dabatable, because its mostly harvests of fruit. Sounds like pleasant work to me.

The Garden of Mortal Tree

Such gardens arrive after some years of trials, where species themselves indicate their preferences, often in defiance of the dictates of literature. It is fortunate indeed that plants cannot read!

-Bill Mollison Permaculture ll

The sun bleeds a hotter light as it sets in the west, and this slope leans into it. It’s face to the setting sun, backed by trees to the east that swallow the gentle light of morning, days begin in shadow that lingers almost to the heat of midday only to be seared by the red light of evening.

The plants grow from these elements. Red-tan brushes of broomsedge grass (Andropogen) speckles the front in tall clusters like an artist’s idle tools, while at the back, messes of honeysuckle cling on piles of logs below scraggly chokecherries. Near the center, in contrast to the lush green Catalpa tree down the hill, stands the skeleton of what was once an apple tree. This is Mortal Tree, the sun scorched slope next to my house that’s becoming a vibrant, lush, productive food forest.

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2013

You might say I’m starting from scratch on this fourth acre of scrubby land; but I don’t plan on doing it alone. I know that every plant and tiny animal living here intends as much as I do to make the place burst with life. The aim of all nature is to create more life. My aim is not to take over, it’s to encourage and strengthen the process already at work. All this through carrying out a design.

Design works for me as the bridge between growth the garden wants, and yield I want. The more my design mirrors nature’s design, the more successful the project will be. In Mortal Tree, that design is a self-sustaining organism, every part interacting to make the whole, every part feeding the others, in care and nutrients, demanding little intervention from me.

Mortal Tree is the center of this design. Paths radiate from this point in fractile, lightning-like arms, and around this point the intensive planting starts -at the “nucleus” of the garden, growing out. The rest I let grow wild, mowing the grass and weeds with the quiet swing of my scythe, gathering excellent mulch. This mulch is fertilizer, moisture retention, and a tool for clearing space my edible plants and fruit trees need. It’s my main tactic, directing free growth of the ecology into my designs of hungry crops.

I’m experimenting with a no-till grain patch, fine-tuning PASSIVE gardening, enjoying the productive beauty in polycultures full of fruit trees and perennial vegetables. Nut and more fruit trees are scattered through the wild growth further down the hill that would perform far better if I had the mulch for them, but there lies my biggest problem:

It’s easy with the desire to power more plantings to overtax the free growth, and damage this delicate ecology. The current design has its limits. Over time, the area of free ecology I harvest for mulch is becoming smaller than the area producing food. What will happen when the need for fertility is greater than the supply?

I watch for what the garden offers. Mirroring the designs of nature in the yields, the design is improving. I’m using running plants to manage weeds, plants that produce massive amounts of mulch in the organized plantings to cycle nutrients and provide cover that protects the ground, and nitrogen fixers that can meet high demands of the hungry production plants. Slowly but surely, the two ends of the equation -wild carefree and productive, labor intensive -are drawing close.

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I have to remember design is only so good as the nature that informs it. Nature is only so good as the life that fills it. No matter how refined my designs become, they are still nature. They house the light that bleeds from the sun, stretching up as growing plants, spuring on change in every aspect. Sometimes that change is good, sometimes not so good; but with the hope of achieving an ever more harmonious design to harness this light, through the changes each day brings, this garden, and its designer, lean into it.

For those of you new to this blog, “The Garden of Mortal Tree” used to be my About page, but after placing it in the Visual Archive, it fell out of existence. This is a major overhaul of that page that better reflects the present Mortal Tree.