tree spacing in new dry climate food forest?

I'm planning a small food forest in my old vegetable garden, which is a site with full southern exposure and native woodland on the west, east, and north. I'm planning a series of "hugelswales" on contour (swales with lots of wood in the berm). Climate is recently semi-arid; we're in a multi-year severe drought, but this site has in the past been under 4 - 6 inches of water during heavy flooding rains.

My question is how far apart should I plant my fruit trees? Fruit species contemplated are fig, mulberry, persimmon, pomegranate, goumi, goji, jujube, loquat, pineapple guava, pindo palm, with support plants of various leguminous shrubs and small trees. In the the PRI DVD "Establishing a Food Forest" the trees and other plants seem very close together, but that's a very different climate with more rain than here, I think. Lately we've been getting about 10-12 inches per year, with the average supposedly something like 28 inches per year, but every few years we get floods. Sun is intense most of the year.

Any spacing advice is welcome!

I run on intuition a lot, & it just jumped in and said "the distance of your arm span" "so you can go easily between them" I'm kind of a nutter so you can laugh and point it's ok.

Wondering myself tree spacing in similar climate (mediterranean, about 700mm of rain per year) in Tunisia.
I noticed in oasis more in the south of here (with average 250-400mm of rain per year) that fruit tree planting under palm trees was very close, 1-2m sometimes for relatively large fruit trees (fig, pomegrenate), it seems to me like a strategy to maximize shade and minimize evaporation, but I am not sure. Hope someone get us a better answer for this climate.

Sofien, do you remember if the trees under the palms were being irrigated or if they were surviving on rainfall?

I think the trees were irrigated, but I am not sure of that. Do you think it influences the spacing Tyler ?

I'm not sure, I think if they're irrigated they might be spaced closer than if they're surviving on natural soil moisture.

What I have been led to believe is you space your canopy for the understory LIGHT you want. You will have to irrigate INITIALLY, no way to avoid that in an arid climate.

I would copy what they did in Jordan. http://www.youtube.com/watch?v=reCemnJmkzI

I wish the video mentioned the actual spacing.

If you can, google Jsckie French's garden. Her garden in Oz covers acres, withstands frost, drought, mid/high 30'sC summers and is a paradise. She's a great authority on permaculture/self sufficiency/chooks and has books on that and is a famous children's author, too. She builds mcroclimates, has avocado etc flourishing, where they shouldn't, and you get to see wombats, wallabies, native Oz birds, as a bonus. Her garden is 30? years old

There is more on her site

http://www.jackiefrench.com/wildgarden.html

http://www.jackiefrench.com/groves.html

Thank you.

As in most other topics involving permaculture, the answer to a question of plant spacing is, It Depends. How big is the tree supposed to get? How much precipitation, how much wind, etc. A very tall, but relatively thin tree, like a palm, would likely be able to have more lower growing trees etc under it, and closer together, in a year-round growing season, than could fit under an apple or other temperate climate tree that grows much closer to the ground.

One standard I have seen for other mixed planting areas is to take the expected diameter of the trees you want to use, add them together, and divide by 2. For example, if 1 tree has a mature canopy spread of 25 feet, and another has a spread of 15 feet, add 25 +15=40 divided by 2 = 20--plant the trees 20 feet apart. Then, shrubs or understory plants could be planted in between those, because they wouldn't compete for the same space in the canopy or root zone.

In a cloudy/foggy area, if a full canopy is intended, or when planting a large forest garden, it might be desirable to leave larger gaps so all trees get enough sun for fruit production, and there is enough light beneath them for an understory. This was discussed in How to Make a Forest Garden, by Patrick Whitefield, on pp 32 & 33. He also recommended planting fruiting shrubs at least the diameter of the shrub away from young fruit trees, so the fruit tree is not distorted by leaning away from the shrub.

Kate, thanks for those links about the groves. I love it! I keep trying to figure out how to do something similar here. Of course, I have a much shorter season when things are actually growing, so I still need cold frames and covered garden beds to extend the season when I have fresh food to eat from my garden. I do love wandering in my young food forest in the warmer months to see what is growing there.

In semiarid climates we do have to plan for irrigating to get trees established. However, the ideal most of us seek for, I believe, is to space plants, and use land shaping, mulches, woody beds, etc to reduce the need to keep irrigating, and eventually let the garden become a self-watering, self-sustaining system. So I believe it is wise to maintain a wide enough spacing that the garden/grove is not dependent on continual watering just to survive, though it may be necessary to occasionally add water in time of severe drought.

Tyler, and others, one idea might be to make a list or chart of desired species, putting in the height and width, maybe divide them into groups of the layers: canopy trees, shorter trees, shrubs, etc. Then use the calculation I gave above to figure out the spacing for each layer, starting with the highest layers and moving down. Plot out the needed spacing for the biggest trees, and then add the understory. At least, that is what I plan to do, once I settle on which trees and shrubs etc I think might succeed here. Good luck. Look forward to seeing some pictures.

Thank you for those ideas, dj, they're very helpful.

Other thing to keep in mind, which I do, and discovered JF does as well, my equivalent of a Papal Blessing, is throw yummy fruit of all kinds, seeds, after eating, into nice soil, in a quiet place, and let them come up, and then plant out. INCLUDING, if you are establishing a new garden, tossing them in an area where you would welcome the tree, if it grows. Tip a bucket of mixed sand and manure over it, and cross your fingers. (I have to do this, or the possoms eat it). Some produce disappointing fruit, some produce jewels, but there is NEVER waste in a natural garden. If you are doing things right, there will always be native birds and mammals happy to take anything you don't want. Often, the seeds you are desperate to germinate, don't, but sometimes you get mysterious occurrances, as one off fruits, and it can be very exciting.

As well, with fruit that are floury, etc, whilst they are still a great feed for natives, you can always graft branches of loved fruit to the lower branches. Usually those seeds that flourish are great rootstock, that are coping with your conditions.

Unless a serious weed effecting local natives, NO tree that struggles to life should die, if you have space, and if you don't, give to someone else.

Tyler, to answer some of your questions:
- in Jordan, irrigation were big pipes in the bottom of the swales and on both sides there were driplines
- on the upside of swales support species were planted (5 support species for every fruit tree, fast growing legumes already growing in jordan)
- on the other side below the mound partly in the trench fruit trees were planted
- trenches were heavily mulched (old banana, tomato plants, eggplants, agricultural plant waste)
- wet cardboard in/around each tree hole + compost
- year 1 / irrigation is one month off
- year 2 / irrigation is three months off
- year 3 / irrigation is six months off
- year 3 / irrigation for support species is off forever
- closer you are to equator and more water you have, closer the spacing can be

I think your spacing would be quite normal, especially if you don't have irrigation.
Tropic food forest in DVD can handle close spacing because of water and sun exposure.

dj niels wrote:In semiarid climates we do have to plan for irrigating to get trees established. However, the ideal most of us seek for, I believe, is to space plants, and use land shaping, mulches, woody beds, etc to reduce the need to keep irrigating, and eventually let the garden become a self-watering, self-sustaining system. So I believe it is wise to maintain a wide enough spacing that the garden/grove is not dependent on continual watering just to survive, though it may be necessary to occasionally add water in time of severe drought.

There is also another aproach.
Heavily irrigate with intention to grow as much biomas as possible, thus creating humus which holds water in future.
Irrigation can be highly reduced afterwards or even eliminated.