It’s no secret that I am a fan of experimentation, particularly with fruit trees. The idea of backyard orchard culture is fascinating to me and I have enjoyed watching the Dave Wilson Nursery videos on the topic, as well as reading Ann Ralph’s book Grow a Little Fruit Tree. One of the practices discussed in both is multi-planting fruit trees; that is, planting two, three or even four fruit trees in a single hole.
Sadly, I have now been informed that this is a terrible idea:
“I’m sorry, but this is just asking for trouble down the road. Readers of this blog know that root systems extend far past the drip line, and that roots from different trees are going to compete with one another. You’ll end up with three unhappy trees, all jostling for space and resources, just like kids in the back seat during those long car rides.
But wait! you might say. There’s research on high density tree planting, and it’s been shown to increase fruit yield on a per acre basis!
Yes, in fact there is a lot of planting density research on many different species of fruit trees. What’s considered by researchers to be “high density” varies, but it rarely exceeds 2698 trees/acre (6666/ha for our international readers). Optimal and sustainable levels of high density planting are also variable, as they depend on not only species but rootstock and the crown architecture; 1214/acre (3000/ha) might be a mid-range number. This can be converted to a per-tree requirement of 36 sq. ft. or a 6’x6’ planting area.
How does this compare to the 12-15” recommendation given earlier? If we’re generous and use the 15” recommendation, this translates to 6.25 sq. ft. per tree or 6970 trees/acre. The 12” recommendation would lead to a whopping equivalent of 10,890 trees/acre. (And no, it doesn’t matter if you’re using dwarfing rootstock or not; most of the higher densities in the literature are for dwarfing rootstocks.)
You don’t have to be a math whiz to see that these densities are totally out of line with reality. Sure, you can probably keep overcrowded trees alive with lots of water and fertilizer, but they’ll be under enough chronic stress so that pests and disease might take hold, and fruit production will likely be poor. And it’s about as far from a sustainable practice as you can get.”
But… but Dave Wilson!
Ah, that’s the thing, isn’t it? We need peer-reviewed science! Scientists can guide us with their collective wisdom in how we should plant trees in our backyard. Because scientists are way smarter than you are and way less fallible. As we can see here, scientists are doing a bang-up job running studies these days:
“Science is facing a “reproducibility crisis” where more than two-thirds of researchers have tried and failed to reproduce another scientist’s experiments, research suggests.
This is frustrating clinicians and drug developers who want solid foundations of pre-clinical research to build upon.
From his lab at the University of Virginia’s Centre for Open Science, immunologist Dr Tim Errington runs The Reproducibility Project, which attempted to repeat the findings reported in five landmark cancer studies.
“The idea here is to take a bunch of experiments and to try and do the exact same thing to see if we can get the same results.”
You could be forgiven for thinking that should be easy. Experiments are supposed to be replicable.
The authors should have done it themselves before publication, and all you have to do is read the methods section in the paper and follow the instructions.
After meticulous research involving painstaking attention to detail over several years (the project was launched in 2011), the team was able to confirm only two of the original studies’ findings.
Two more proved inconclusive and in the fifth, the team completely failed to replicate the result.
“It’s worrying because replication is supposed to be a hallmark of scientific integrity,” says Dr Errington.
Concern over the reliability of the results published in scientific literature has been growing for some time.
According to a survey published in the journal Nature last summer, more than 70% of researchers have tried and failed to reproduce another scientist’s experiments.”
Pardon me if I trust nurserymen more than I trust “peer-reviewed science” and academic journals.
The original article at GardenProfessors completely misses the point of backyard orchard culture. It’s not about commercial planting of trees mere inches apart over acres of ground. It’s about putting multiple trees together to cause deliberate dwarfing, to increase pollination, to extend the harvest season and to add more fruit variety to a small backyard garden space.
Yes, it’s experimental. Yes, it’s not a standard practice. But the “anecdotal” evidence, as usual, is more useful than the word salad oracles the academicians deliver in their esoteric journals.
By the power invested in me by the renowned, peer-reviewed academic journal The Survival Gardener, I pronounce you all scientists. Go ye forth and experiment.
Today I will be multi-planting some plums and pecans, and maybe some other things too. FOR SCIENCE! And everyone on YouTube can peer-review how it turns out.
See you there.