Methods For Growing Lots Of Trees In A Small Footprint For Cost-Effective Silvopasture Establishment

[Casey Pfeifer]

I thought I'd share my current methods using air pruning beds to grow various livestock fodder trees for silvopasture establishment in hopes that some other folks in this network are doing the same.

My goals are to grow 1) healthy, well-structured trees that 2) can be harvested with intact root systems for maximum survivability during establishment 3) very little expense and ongoing management cost throughout the year for me (the grower).

I've been growing trees in air pruning beds for years now, and have just moved to Tennessee and am reconstituting my nursery here - building air pruning beds using mostly scrap lumber, repurposed shade cloth etc.

The air pruning beds I'm building now are still in the same basic style as the ones detailed in this video from a few years ago from when I was in CA (based on the work of Dr. Carl Whitcomb). Below are some photos of the beds - just simple frames with a 1/2" hardware cloth mesh fence stapled onto the bottom, overlain with old shade cloth to retain soil while also permitting roots to penetrate through and air prune. Beds are protected here by a single layer of 3/4"x1" x 7' wide deer fence over bamboo stakes. Growing medium is currently about a 3:1 mix of double ground red oak bark and mushroom compost. I've been making charcoal and will add some biochar to the mix once I get the charcoal crushed, inoculated and charged with nutrient.

Trees currently started from seed: Black Locust, Thornless Honey Locust, Siberian Pea Shrub, Leucaena, Paulownia, White Poplar, River Birch (we arrived in late May and missed a lot of the spring season, so I am starting whatever I can reasonable force-germinate now - other things requiring longer stratification will get started at the end of this year in cycle with the seasons).

Trees started from cuttings: Weeping willow, red mulberry and Austree Hybrid Willow. (basically whatever I can find around me that fits the livestock fodder tree category).Caragana arborescens) emerging.

Leucaena/White Lead Tree (Leucaena leucocephala) and Thornless Honey Locust (Gleditsia triacanthos inermis). Short beds were a mistake - the dog and the cat really seem to want to lay on these things.

Underside of one of the beds - 1/2" hardware cloth fence stapled on top of the 2x4" frame, with recycled shade cloth lain on top of that to retain soil while permitting air pruning of developing root tips.

For the Austree Hybrid Willow I hurriedly put in a "willow paddie" - basically I de-sodded the lawn adjacent the farmhouse we're in, made planting mounds, and planted a bunch of 15" long willow cuttings in the narrow trench by laying them down horizontally to maximize shoot production for making future cuttings. Installed and plumbed roof gutters to a downspout and into the paddie. Thus far it seems to be working well - the willows have been in the ground a bit less than a month as of 7/17/23.

The "willow paddie" - I'm hopeful that the cardboard sheet mulching, mulching with red oak, and the frequent inundation with lots of roof water will help to keep weed pressure down. More to come as this progresses!

For anyone else growing trees in nursery settings I'd love to see and hear what ya'll are doing!

With Gratitude,

- Casey

[Scott O'Bar]

I also found a source here for 1 gallon pots. They look like the same exact product to me.

 https://www.marleysplanet.com/es/rootbuilder-1-gallon

My question to you and anyone else who's reading, do you think it would be OK to grow a tree from seed in one of these one gallon pots for up to 5 months before planting out in the field? Or is that too much time in the pot? What happens if you leave them in the pot a lot longer?

I'm thinking about using these pots to sow Dipteryx spp., and Brazil Nuts. So basically it would be equivalent to starting hazelnuts, chestnuts or walnuts from seed in one of these pots.

Casey Pfeifer said:

I haven't heard of him, no - but that sounds like an amazing story, and if you have that transcript or any other resources I would love to read about his example.

Ultimately, I'd love to do it that way too - just put seeds in the ground where I know they're going to be for the long term. Heck, that's what we're trying to do with ourselves too :)

Scott O'Bar said:

Have you heard of the work of Ernst Gotsch? I was amazed to learn about his work in tropical Brazil where he started with a heavily degraded landscape with pH of 3.7- 4.5. and he reforested the entire area. The property and surrounding landscapes had been so badly desertified that people were no longer able to grow any commercial crops. I read a translated transcript of one of his speeches where he said that he did the whole property just by direct planting seeds.

[Casey Pfeifer]

Agreed, the black poly deer fence would be ineffectual against squirrels. When I was growing chestnuts out west I used a hard-framed cage 2' high over the entire APB with 1/2" hardware cloth to keep them out, anything less and they'd make off with chestnuts and sprouting seedlings alike.

The shade cloth bottom layer was added to retain finer soils - I was working with some sandy soil at the time, and have also built beds without access to hardware cloth, but we did have typicaly welded wire fencing with either 6x6" gaps or 2x4" gaps which were too large to retain the soil media, even with a rough mulched layer on the bottom, so we overlaid with shadecloth and that has worked well.

I'm still experimenting with ideal depth for the APBs - I do think the ones in the photos at the beginning of this thread are too shallow - after soil settling has occured there is probably about 4.5" of soil throughout the bed, which is right on what Dr. Whitcomb mentions to aim for with regards to taproot training, but yes, it would be ideal to plant them out into either a deeper APB at time time or some sort of raised nursery bed. Just haven't had the time or materials yet to make that happen, so I'm starting with what I've got.

The idea is to get an air pruning stimulus (and thus increase branching) within the first 4" of taproot development. This doesn't kill the taproot according to Dr. Whitcomb's research, it just makes the apical tip go dormant, which then back-propagates a hormonal signal up the root to increase lateral branching - basically engineering more shallow feeder roots early in the tree's life. I'm hoping to do some direct comparisons this coming spring between APB trees planted in different depths of media and in-ground direct sowing. I will certainly share here with anything that seems at all helpful.

L kas said:

My go-to person for air pruner beds is Sean of edibleAcres on youtube https://youtu.be/Q-htiLvbEd8 His series takes you through errors and a few design trials. The mesh fabric wouldn't last a day with the squirrels in the north east with any kind of a nut crop. We need the same hardware cloth in a frame above until seedling growth allows us to snap off the nuts - or they will clip down the seedling when removing the spent nut 🙄 Even in large beds, I have not found a need for an extra cloth to retain soil. I compact it as I am loading it in and it stays put well enough even with the torrential rains we've had this summer. I do put a half inch or so of wood shavings from a wood worker on top.
From the photo, your pruners look too shallow to establish a decent taproot. Maybe you're planting only non-tap root species or only grow for a couple of months before transitioning?
Thanks so much for a description of your willow beds. This looks like a great nursery setup - affordable and with water tied in.

[Casey Pfeifer]

I think up to and beyond 5 months would be just fine based on the various root dissections I've seen in various air pruning trials. In a pot like that with air pruning around the circumference and bottom, the roots will just keep branching every time one of them hits air at the side or bottom. You'll probably end up with a dense root ball, but no circling or girdling, and I imagine based on what I've seen the trees will take off as soon as they're in the ground and all of those dormant tips resume growing in every direction.

Scott O'Bar said:

I also found a source here for 1 gallon pots. They look like the same exact product to me.

 https://www.marleysplanet.com/es/rootbuilder-1-gallon

My question to you and anyone else who's reading, do you think it would be OK to grow a tree from seed in one of these one gallon pots for up to 5 months before planting out in the field? Or is that too much time in the pot? What happens if you leave them in the pot a lot longer?

I'm thinking about using these pots to sow Dipteryx spp., and Brazil Nuts. So basically it would be equivalent to starting hazelnuts, chestnuts or walnuts from seed in one of these pots.

Casey Pfeifer said:

I haven't heard of him, no - but that sounds like an amazing story, and if you have that transcript or any other resources I would love to read about his example.

Ultimately, I'd love to do it that way too - just put seeds in the ground where I know they're going to be for the long term. Heck, that's what we're trying to do with ourselves too :)

Scott O'Bar said:

Have you heard of the work of Ernst Gotsch? I was amazed to learn about his work in tropical Brazil where he started with a heavily degraded landscape with pH of 3.7- 4.5. and he reforested the entire area. The property and surrounding landscapes had been so badly desertified that people were no longer able to grow any commercial crops. I read a translated transcript of one of his speeches where he said that he did the whole property just by direct planting seeds.

[Casey Pfeifer]

I'd agree, the Smart Pot seems best - I could see the bottom of the other pots being a little less than ideal given the fewer number of holes on the bottom. Still all in all pretty decent though. The other thing I like about the Smart Pots is that you can set them on the ground and you'll still have what looks like a 1" air gap underneath the bottom disc, whereas with the Macetas if you sent that pot on the ground those holes will be plugged and ineffectual for drainage and/or air pruning, so you'd need a wire mesh table in addition to the pots.

My .02 - hope that helps! Definitely would love to see the results of your trial when its time to plant those trees out!

Scott O'Bar said:

These are the only options for air-pruning pots I've found in Peru:

https://perugrow.com/tienda/macetas-smart-pot/

https://agriplant.com.pe/product/maceta-ercole/

https://agriplant.com.pe/product/maceta-rete/

Of which, I think probably the Smart Pots would be the only ones to fit the bill. What do you think? Do those look like they would accomplish what Dr. Whitcomb discusses? The price is about $5.50 each for the 2 gallon ones, which seems a bit pricey, but not surpised.

Casey Pfeifer said:

I haven't heard of him, no - but that sounds like an amazing story, and if you have that transcript or any other resources I would love to read about his example.

Ultimately, I'd love to do it that way too - just put seeds in the ground where I know they're going to be for the long term. Heck, that's what we're trying to do with ourselves too :)

Scott O'Bar said:

Have you heard of the work of Ernst Gotsch? I was amazed to learn about his work in tropical Brazil where he started with a heavily degraded landscape with pH of 3.7- 4.5. and he reforested the entire area. The property and surrounding landscapes had been so badly desertified that people were no longer able to grow any commercial crops. I read a translated transcript of one of his speeches where he said that he did the whole property just by direct planting seeds.

[Scott O'Bar]

At first I was thinking about ordering 50-60 of the 3gal. ones. But then I realized costs add up. The total would be quite a bit. Then of course all those pots need to be filled with soil, and it's a hassle to try and scrape topsoil out of the forest here, and buying soil (it's about 14L per pot) would end up being pretty expensive. So I'm thinking of just getting 3 of the 1 gallons and 6 of the 3 gallons. We're getting a kilogram of Juglans neotropica (Andean Walnut) seed and a half kilo of Dipteryx alata (Almendro) seed very soon. We also have about 200-300 freshly harvested Cashew seeds right now

If it weren't for the costs, I'd want to do a lot more in the air pots, because we're having a bad dry season this year, and it looks like rain probably won't be reliable until at least November. The seeds we're going to receive soon are recalcitrant, so I won't wait to plant them. It would be good to control them in a nursery setting while waiting for the drought to end, but we're just going to have to direct-sow the vast majority of them out in the field and probably hand water for a while. 

Still I want to try a small number of those air-pots as I'm curious. So I'll probably do Andean Walnuts in the bigger ones and Almendros in the smaller pots. 

Casey Pfeifer said:

I'd agree, the Smart Pot seems best - I could see the bottom of the other pots being a little less than ideal given the fewer number of holes on the bottom. Still all in all pretty decent though. The other thing I like about the Smart Pots is that you can set them on the ground and you'll still have what looks like a 1" air gap underneath the bottom disc, whereas with the Macetas if you sent that pot on the ground those holes will be plugged and ineffectual for drainage and/or air pruning, so you'd need a wire mesh table in addition to the pots.

My .02 - hope that helps! Definitely would love to see the results of your trial when its time to plant those trees out!

Scott O'Bar said:

These are the only options for air-pruning pots I've found in Peru:

https://perugrow.com/tienda/macetas-smart-pot/

https://agriplant.com.pe/product/maceta-ercole/

https://agriplant.com.pe/product/maceta-rete/

Of which, I think probably the Smart Pots would be the only ones to fit the bill. What do you think? Do those look like they would accomplish what Dr. Whitcomb discusses? The price is about $5.50 each for the 2 gallon ones, which seems a bit pricey, but not surpised.

Casey Pfeifer said:

I haven't heard of him, no - but that sounds like an amazing story, and if you have that transcript or any other resources I would love to read about his example.

Ultimately, I'd love to do it that way too - just put seeds in the ground where I know they're going to be for the long term. Heck, that's what we're trying to do with ourselves too :)

Scott O'Bar said:

Have you heard of the work of Ernst Gotsch? I was amazed to learn about his work in tropical Brazil where he started with a heavily degraded landscape with pH of 3.7- 4.5. and he reforested the entire area. The property and surrounding landscapes had been so badly desertified that people were no longer able to grow any commercial crops. I read a translated transcript of one of his speeches where he said that he did the whole property just by direct planting seeds.