I am not a tree expert.

If i were to take a standing tree and essentially bury 6 feet of the trunk in a hugelkultur bed, would this harm the tree?

My understanding is that the trunk would send out roots in time.

Attached is a drawing.

While there are some trees that would probably do ok in that situation (ficus comes to mind) most trees in temperate climates aren't really adapted for it. As a general rule you shouldn't be piling things against the bark of a tree because it allows for a protected space where bugs, fungus and even rodents can attack the bark and compromise or even kill the tree. In a hugelkulture I would be especially concerned about rodents gnawing the bark off the tree and girdling it. It might be worth experimenting with to see if some species can handle it but if you consider the tree in question valuable at all I wouldn't do it.

Something where I can speak from direct personal experience!

I built a couple of hugelbeds that I put in place despite the presence of a couple of young pines that had volunteered. They were perhaps three or four feet tall. The hugelbed came up about half the height of the trees.
In under two years both trees have died.

I am fine with that outcome, the trees were not in great spots, so now they are part of the hugelbed in a different way

In general, it is not advised to add more than around 6" or so of dirt over a tree's roots (usually the area of its branches). More than that can choke off aereation of the root zone and injure the roots. This is aside from damage to the trunk from burying it.

I know from experience of a couple of species that can stand this treatment, willow and sycamore: both waterside-adapted trees that have evolved to handle drastic changes in their soil conditions from floods. Silver maple is probably also in this category.

I also think it would kill the tree. If it didn't the tree roots would likely start coming up into the berm.

That being said, 20+ years ago I let some workers talk me into filling around a 70' poplar to a depth of about 5' where I was developing a patch of lawn for the kids to play in.
They stacked rock against it -they said for protection. Within a year or two 10' of bark split and made a huge vertical sore on it. Ants have worked it. Not a pretty sight.
It has stunted the growth and the top looks thin. It has lost maybe a few more than average limbs for a tree it's age, but it's still alive.
I wouldn't do it again though.

we will be starting our third bed this year and there will be a 12'' maple in the middle of it [with the intentions of eliminating it]
1/2 of the tree didn't do very well last year so we will ''prune'' it at 5' and leave the roots and stump in
then start the bed at the trunk and go both directions with the top and what ever available wood
I figure the root system will wick water into the bed in a few years once it stabilizes

Mike

That may do just fine, Mike, but I'd have a couple of reservations. Unless steps are taken, the tree may live for a couple of years or more after the sever pruning alone. The bed probably won't kill it instantly either, so some root intrusion might be expected, with nutrient and water loss possible. I don't think maples are prone to this, but worse might be root suckers. They could become a perennial issue, it can be with some tree species at least.

Mike Hamilton wrote:we will be starting our third bed this year and there will be a 12'' maple in the middle of it [with the intentions of eliminating it]

If I were going to be expecting the tree to die off, I'd cut it to about a 5 or 6 foot stump and inoculate it with as much tasty mycellium as I could! Or, if you really don't want the tree, chop it up and fold it into the new hugel.

Burying a trees trunk is a sure fire way to kill the tree. Even a Ficus tree will die if treated this way.

If you want to do this, and try to keep the tree alive, there are things you will have to do. 1) make some cuts through the bark to the cambium layer (about 1/2" wide and 3-4 " long) all the way around the tree. Into these wounds you will need to dust .6% rooting compound just before piling on the dirt to about 2" above the top edge of the wounds, lightly water the soil. Now it is just a matter of keeping this soil moist but not wet for about 6 weeks. at that time, the trunk will have started forming new roots from the treated wounds.

kyle saunders wrote:

Mike Hamilton wrote:we will be starting our third bed this year and there will be a 12'' maple in the middle of it [with the intentions of eliminating it]

If I were going to be expecting the tree to die off, I'd cut it to about a 5 or 6 foot stump and inoculate it with as much tasty mycellium as I could! Or, if you really don't want the tree, chop it up and fold it into the new hugel.

that's the game plan and use the top for the new bed [chop n drop]
I don't like cutting down good trees but this one is a problem and needs to go
another maple has center rot starting but my wife is not in favor of removing it yet [a little at a time]

Mike

Here's a thought, cut the offending maple down and turn it into lumber. Maple wood makes very nice furniture, can also be used to create a wonderful cider press.

Bryant RedHawk wrote:Here's a thought, cut the offending maple down and turn it into lumber. Maple wood makes very nice furniture, can also be used to create a wonderful cider press.

Ill keep that in mind, a lot depends on the center of the tree
all ready have the equipment to slab the trunk and any good branches
and a new press is on the to do list this year

Mike