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lving trees as retaining walls

 
paul wheaton
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Doug bullock suggested the idea of using trees like poplars to act as a retaining wall.  Anybody have any knowledge of something like this?  His drawing shows the roots of the trees going into the uphill stuff.
 
Emerson White
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To get good strong trunks you would need wide spacing I would imagine, are the trees supposed to hold up boards that act as a retaining wall?
 
Brenda Groth
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poplars (quaking aspens) are very weak trees, short lived..

are you talking about using them alive..or dead?

they also rot really funny..they  kinda become hollow when they rot and very very lightweight.

i'd be careful of what you plan with poplars structurally..either dead or alive..unless properly milled for lumber they aren't much good for anything but rotting ..so they are good for hugel beds..but not structurally

 
Emerson White
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Aspenoplar::Square:Rectangle

Aspen, cottonwood, and poplars are all in the poplar genus (Populus)
 
Paul Cereghino
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They take from cuttings so you could plant at such a density to not need cross pieces.  Or brush could be cut and stacked uphill of the stems to create a brush wall. You could reinforce the brush wall with other stem cuttings... snowberry, ninebark...

but they stump sprout easily, so you have a shade problem only resolved through cutting, but that is biomass which might be good if you don't mind the work, or you are planting an intercrop that ultimately out shades them.  Maybe part of a livestock systems, as' they'd be forage. 

The buds are medicinal.

What is the difference between a retaining wall and a hedge laid accross a slope.  Any experience laying cottonwood hedge?
 
Joel Hollingsworth
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Paul Cereghino wrote:What is the difference between a retaining wall and a hedge laid accross a slope.


Species for the former should probably be chosen so as to tolerate hilling? Probably some other differences, too.
 
Brenda Groth
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i love aspens because they are aggressive and opportunistic
i hate aspens because they are aggressive and opportunistic

in other words, aspens are aggressive and opportunistic, so if you have an area that you want to have forested, put in aspens, and one tree will grow into a forest.

if you have property where you don't want trees, don't put aspens near it or you will be battling them for the rest of your life.

i love aspens in my areas where i'm building forest..they make great nurse trees and they fill in areas really fast..esp open fields. I use aspens as nurse trees for oak, ash, nut and fruit trees, etc. as they are short lived and will die off as the more longer lived trees grow up..

however, they will take over a nearby garden area very quickly !!! i know, i'm pulling them out of my food forest like weeds..
 
tel jetson
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I'm trying this out, sort of on accident.  I built a temporary retaining wall out of black locust and apple stakes with fruit tree prunings piled up behind:



the idea was to plant chestnuts and/or hazels at the base of this wall in the fall to grow a permanent retaining wall.  the black locust stakes appear to have rooted and sprouted, though, so I may just leave them alone to see how they work.  the prunings behind the stakes likely won't last long, but the black locust should just root into the dirt as the wood behind it rots.

so I believe the idea is solid, though I've obviously chosen different species.
 
Jordan Lowery
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for those who live near a river or stream and want to do some terracing, i found this not too long ago and think its really neat.

http://www.willowbankservices.co.uk/simple.cfm?y=y&page_id=17&cat_id=5

i wonder if there is any eatable plants that we could do this with.
 
tel jetson
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soil wrote:
for those who live near a river or stream and want to do some terracing, i found this not too long ago and think its really neat.

http://www.willowbankservices.co.uk/simple.cfm?y=y&page_id=17&cat_id=5

i wonder if there is any eatable plants that we could do this with.


that is really, really excellent.  already had plans for willows, but I think I'm going to accelerate the planting a bit now.

willows do have some edible parts, and they can be great fodder for critters.  I bet rowans (Sorbus) would work if you want fruit, but they don't grow so quickly as willows.  there are probably others that would work that aren't coming to mind just now.
 
Brenda Groth
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i have seen so many structures grown from live willows..the only  problem i see is keeping them under control..ok if you have some animals that will graze them..i guess..

be careful around any septic or water sources as they will inifiltrate pipes.

people have formed fences and buildings of live willow for years..they make wonderful childrens play areas, nests and caves and mazes
 
Jordan Lowery
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what about olives in a less wet environment with almost the same method. they root pretty easily when layered or touching soil, can be pruned to keep close to the wall, and give you olive oil, they dont need that much water. what does anyone else think.
 
tel jetson
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soil wrote:
what about olives in a less wet environment with almost the same method. they root pretty easily when layered or touching soil, can be pruned to keep close to the wall, and give you olive oil, they dont need that much water. what does anyone else think.


I'm only a couple of years into growing olives and I'm really pushing their tolerances, so I don't have a whole lot of experience.  the only problem I see is that they grow rather more slowly than willows.  practically that means that gathering enough stakes for a retaining wall project could be more difficult and potentially damaging to existing trees.  could also mean that the wall isn't stabilized before some destabilizing event occurs, such as heavy winter rains.  other than that, it wouldn't surprise me if olives worked quite well.
 
Brice Moss
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I think I'd plant something woody with a fast growing root system above my retaining wall to keep the hill tied together where it don't want to fall in
 
Brenda Groth
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clumping bamboo is often suggested for stabilizing soil although i've never grown it.

lots of plants form good thickets quickly, but i agree, willow is the easiest i know of to start from cuttings for a fast growing tree..if you can come up with some free seedlings there are some other easy to transplant trees that might work for a nice wall, i am always looking for seedlings in the county right of ways, as they will be mown down eventually anyway..and are free for the taking in most cases..also abandond fields nearby a woods generally will have a lot of seedlings along the edges, generally more than will live if left to their own.

we have an open field that is GOING to evergreen trees, mostly pines spruce and hemlocks, we started out with a couple and planted a few more and as they matured they self seeded and now there are baby trees everywhere you look, white pine and scotch pine mostly..but those little seedlings would be easy to transplant and grow quickly, there are some deciduous trees that will do the same thing, seed and grow like crazy, ash and maple are two that grow like that around here..seedlings everywhere
 
Jordan Lowery
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I'm only a couple of years into growing olives and I'm really pushing their tolerances, so I don't have a whole lot of experience.  the only problem I see is that they grow rather more slowly than willows.  practically that means that gathering enough stakes for a retaining wall project could be more difficult and potentially damaging to existing trees.  could also mean that the wall isn't stabilized before some destabilizing event occurs, such as heavy winter rains.  other than that, it wouldn't surprise me if olives worked quite well.


thanks for your input. I think if you could pass those hurdles along the way, in 10-15 years a olive terraced hillside would be very long term. i was thinking maybe put an annual crop to hold the hill in the meantime, i know in asia they use certain types of grasses to hold the terraces. I am not sure on the species or there method of building the terraces though, wish i knew.

the propagation stock would have to be done by yourself and depending on the area terraced it would be far cheaper to yo it yourself. propagation stock would have to be collected from a few mature trees as not to collect all from one source.

our olives are growing at about 1.5-2.5 ft a year here at first planting, but then again were in a perfect olive environment.
 
                        
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Since I have been looking for material to make a living hedge I took some cuttings of willow on impulse  from a ditch I passed while travelling a couple of weeks ago and 26 out of the 27 bits seems to have decided to survive.YAY. The only thing is that it will likely be a couple of weeks at least before they have roots enough to plant outside and we are getting into cold enough weather that I doubt they  have time enough to  root securely enough outside to survive the winter in Saskatchewan.

I also have a bunch of green ash (I think) which volunteered in gallon milk jugs that I had melon seedlings in that died in a late cold snap this spring. I have land that presently has mostly yucky  largely unusable poplar and I really want to get some better trees going fast so now I have these  going what should I do with them over the winter?  I would imagine both these trees need a cold period in the winter but..put them in buckets on the north side of the house, mulch like crazy and hope for the best?  Help?
 
josh brill
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In planning with Sloping Agriculture land technology(SALT) they do ally cropping with densely planted quick growing nitrogen fixers that are regularly cut back and used as fodder or mulch.  After years of adding the mulch material and using the land above the hedgerow a terrace begins to form.  It has been used on lots of land in South east asia with success.
 
Joel Hollingsworth
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tel jetson wrote:gathering enough stakes for a retaining wall project could be more difficult and potentially damaging to existing trees.


Some olive growers coppice on a 10 year rotation. That would give a few 10-year-old stems from each crown coppiced, each year. The paper I read also suggests thinning the suckers from the center of the crown in the third year of the rotation, which would provide some smaller stems.

http://www.actahort.org/members/showpdf?booknrarnr=557_33
 
Brenda Groth
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Pam, poplar are wonderful nurse trees and will die off when the hardwoods that you plant among them grow up and take their nutrients..

I have always allowed poplars (aspen) to spread out over areas that I plan to reforest..they spread out very quickly esp if a green tree has been cut or fallen from wind. Then the most important thing is to get your seeds, seedlings or transplants of your more important trees in quickly, planted right in the duff of the new forest floor and allow some space between them and the poplars, or in other words, plant them slightly away from the actual trunks of the poplar trees but close enough for protection..i put the others about 6 feet or more away from the poplars if possible, but nature will actually seed them in much closer, and natures trees generally grow fine.

if you look at my blog, check out the photos on the page of forest trails..you can see the maples growing in the poplar woods on some trails and white ash growing in the poplar woods in other areas, also a self seeded apple tree deep in the poplar woods. I have also recently found several oaks growing.

I have recently gone through with cuttings from trees that I would like to have grow in the woods, and put sharpened branches down into the soil in some of the more clear areas, not only of trees but of favorable berry bushes and shrubs as well as seeds of flowers and herbs that I would like to have grow near my paths and in clearings in the woods.

click on my blog by my signature and you can see the popplar woods and some of the variety of growth that is now there.
 
                                    
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that is really, really excellent.  already had plans for willows, but I think I'm going to accelerate the planting a bit now.

willows do have some edible parts, and they can be great fodder for critters.  I bet rowans (Sorbus) would work if you want fruit, but they don't grow so quickly as willows.  there are probably others that would work that aren't coming to mind just now.
 
I agree. Here's the link: https://permies.com/battery
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