mounding trees

Our drainage is miserable, I will have to mound trees.

Do you need to mound the trees to the depth of the roots? And if a tree has a tap root then you would have to mound it to the depth of the tap root? Or do trees adapt?

If I would plant walnuts trees on a mound onto the miserable drainage (maybe 30 cm below surface at least at some points) would I be likely to succeed?

Inspired by the Holzer ideas I would throw first a pile of woody material, then lawn clippings I get for free, then earth and last compost and manure. I would try to surround it by stones, if I find sufficient big ones. I would try to make the pile higher than a meter so I might up with a meter as it sits down over time.

Maybe I'll do the same thing with avocado trees and olive trees.

my only concern about planting a huge tree on a smallish mound would be stability..as the mound would be less stable than the surrounding soil..and could be a wind problem..so I guess if you do so you might want to do it in an area that might be protected by a windbreak.

some trees don't mind poor drainage and will help to drain your land..but most of those should NOT be planted near any drainage systems like septics.

the ones I would recommend to help drain your sloggy property  would be willows of all kinds, alders, some maples like red and swamp, aspens, wild cherries, elderberries, and on hummocks you could put things like blueberries and cranberries if it is acid enough. Canadian hemlocks and cedars.

once these trees begin to drain the property your other plants could grow well such as your walnuts..as the soil will be less sloggy  once these fast growing trees start to suck up all that water..they also will help provide a windbreak and stabilize the soil itself

Willows are a bog no no here. They have weed status.
We have fill (1.5m) over a swamp. You don't want to dry out that swamp water is precious here in Australia (this might sound rather strange now).
The wind issue, I forgot to think about this, yes this is true and the winds are strong here.

I am searching for a video I once seen on YouTube. The video was of someone turning an old lot, including parking lot into a food forest and they were mounding on top of the pavement with soil, and a tire around the tree.

That always stood out to me, and unfortunately I am not at the computer which I had saved the info on. Actually that computer has been wiped clean...

If you mound a tree, the roots might get further down than the tree. If these roots or a tap root goes further down and then becomes water logged does the tree die or only the piece of root? It then might be  a static problem.

G'day ediblecities,fellow Aussie here,
My understanding of trees with tap roots is,they usually go down to a depth 1/5th or so of the average expected hight of the tree in question.Saying that,I have planted trees that were only ment to reach 3m but,actually achieved 8m.You say you filled 1.5m,is there any trees that you can plant that only grow say,to 4-5m(Dwarf varieties) which might give clearence of the swampy underbelly?
If the trees you want are to be fruit trees then maybe a dwarf variety?.Where in Oz areya.

1/5 doesn't sound awfully lot, I think olives would be dwarfing enough. Strangely chestnuts grow on the place, but the one very close to the creek has the side to the creek which does not look so good, I reckon all this water recently.
We're in the Upper Mountains.
With all this weather stuff going on I start to plan for the next drought.

depending on the trees, some tree roots are much wider than the tree canopy, so you would have to build your mound up to 4 or 5 times the adult size of the tree canopy depending on the tree species..so that is a lot of mounding..most of your roots will be in the top few feet of soil but the tap rooted species the root does go quite deep ..of course again depending on the species..

the book Volume 1 of Edible forest Gardens by Dave Jacke has some good info on the size of plant and tree roots below ground, i borrowed it from the library

ediblecities wrote:
1/5 doesn't sound awfully lot, I think olives would be dwarfing enough. Strangely chestnuts grow on the place, but the one very close to the creek has the side to the creek which does not look so good, I reckon all this water recently.
We're in the Upper Mountains.
With all this weather stuff going on I start to plan for the next drought.

from what i understand olives dont like wet feet

Okay, I know this is post is a little old, but I think that it's still good info.

As a practicing Arborist, trees are a bit of an obsession with me, so I love seeing all the interest in trees that work well within the permaculture way of life. 

As a general rule of thumb, most conifers have longer tap roots than deciduous trees.  The real determining factor for root growth is soil quality, though.  Roots will go to where conditions help to support the tree, both nutritionally and physically.  The roots simply wont grow in an area that doesn't support them.  If your water table is going to be fluctuating enough seasonally then you do run the risk of drowning a number of newly developed roots if the level goes high for too long of a time, but I think that this will only stress, not kill, an otherwise healthy tree.  After a few floodings, the tree will have adapted with a shallower, wider root system.

When planting trees on a man made mound (which is a decent solutions to your problem - not the best, but the best is usually cost/labor prohibitive) one thing to keep in mind is that if your on a swamp, the mound will eventually sink into the swamp without a whole lot of extra prep.  Now this is going to take decades, so if your not worried about the trees after your gone, go for it, but if you're trying to create an area that your grandchildren's grandkids can enjoy just as you did, you might need a little bit different solution.

I would personally prefer to create one large, long hugelkultur bed for the trees I want, then, depending on where the ground water tends to flow, I would plant some water thirsty shrubs in strategic areas where I think that they would intercept the most water that is headed for my trees.  You would be amazed at the amount of groundwater that a few properly chosen trees or shrubs can soak up.  We have done invasive tree clearing on what looked like dry lots only to have a small stream appear the next year as all the extra groundwater made it to the natural drainage.  It was pretty impressive, I must say.

I think you might have a difficult time with the olives if they can't get dry soil somewhat regularly.  Here in CA, they only do one deep watering a month.  You will probably have a better experience with the avocado tree - shallower root system and better tolerance of wet feet.

Okay, enough rambling, hope some of this helped.

ediblecities wrote:
Our drainage is miserable, I will have to mound trees.

Do you need to mound the trees to the depth of the roots? And if a tree has a tap root then you would have to mound it to the depth of the tap root? Or do trees adapt?

If I would plant walnuts trees on a mound onto the miserable drainage (maybe 30 cm below surface at least at some points) would I be likely to succeed?

Inspired by the Holzer ideas I would throw first a pile of woody material, then lawn clippings I get for free, then earth and last compost and manure. I would try to surround it by stones, if I find sufficient big ones. I would try to make the pile higher than a meter so I might up with a meter as it sits down over time.

Maybe I'll do the same thing with avocado trees and olive trees.

What about insectiary plants around them on the mounds as well?  The mounds give you an opportunity to build guilds, don't waste it and plant it all at the same time.   

What about dwarf fruit trees? Wouldn't they tolerate a mound over swamp a little better? Their roots would naturally go less deep.