Maples dangerously close to house - difficulty killing. Shoud we use salt?

Hello Permies! This is my first post. Thank you to all of you for sharing in the discussions I've been reading these past few weeks!

We just acquired our new/old homestead and the property hasn't been maintained very well over the past 10-15 years. There are maple trees popping up all over the place, and quite a few are growing within a foot of the foundation of the house (built in the 1700's). The previous owners would cut them down to 6 inches above the ground, but then new branches/trunks would grow. They have been repeating this for a long time, so the roots are quite well established and some trunks are 2-3 inches thick.

We had decided not to pull the trees out, to not disturb the soil - and also protect the foundation of the house in case there are roots touching it.

The solution I've used so far is to cut them down (to be used elsewhere), and then remove the bark down to the base, but this doesn't seem to be a sure-fire solution. After a week or two of dormancy, little baby shoots are still coming up from the root base/trunk.

Solutions I haven't yet tried, and would like your thoughts on:
- Drilling holes in the trunk
- Drilling holes + filling them with salt (In permaculture, is salt ok to use to kill plants?  I would be afraid of killing/damaging the microbes in the soil around the tree if I use that.)
- Digging around the base of the tree and cutting the roots that are underground

Looking forward to your ideas! Thank you all in advance.

If you just keep cutting them down the root system will eventually die. You said the previous owners had been doing that for a long time but if the trunks are two to three inches thick, they weren't very diligent at it. Just cut them down and every time they sprout back do it again when they are just little shoots. You might have to do it monthly for a year or two. Digging around and cutting the roots like you said might help too. They may try to sprout up off the roots farther from the stumps, so watch out for that.

Salt isn't poison, and it leaches away pretty quickly, I wouldn't worry at all about using it. Drilling the holes in the live stumps to apply it sounds like a good idea and do it while the weather is dry if you can, so it has time to do its job before rain dilutes and washes it away. Serious damage to microbes and or other plants is unlikely as long as you don't use too much. Even if you do use too much its effects won't last a long time.  

"The solution I've used so far is to cut them down (to be used elsewhere), and then remove the bark down to the base, but this doesn't seem to be a sure-fire solution. After a week or two of dormancy, little baby shoots are still coming up from the root base/trunk."

Really, I think that is all you need to do, you just have to keep at for a bit.

Copper nails. Roofers still use them and I suppose you might find them at Home Depot or one of those places. Or try a roofing outfit. This is an old and effective way to kill a tree if you need to do that.  Drive a few into the trunk and the thing will slowly die.  

I feel it would take a lot of salt to kill a tree.

If I were trying to remove a tree near my foundation I would first try to smother it with something.

Plants need light to grow so if you take away that aspect they will die.

Cut down to ground level.  Place cardboard over the area plus six to twelve inches of wood chips is what I usually recommend.

If you cut the tree to the ground and then cut a checkerboard pattern into the stump, fill the cuts in with Epsom salt, you will kill the tree.  Make the cuts as deep as possible and fill them level with the top of the stump.  It works pretty fast too.

I would suggest cutting them back to level with the ground.  Then mow and weed wack around the house weekly during the growing season.  If they aren't allowed to ever grow the roots will die.  If the stumps are two inches in diameter that suggest the previous owner let them grow uncut for alt least a full summer and probably 2 or 3 years.

Thank you so much everyone! I am incredibly grateful to you all for your input, and I'm happy to try all of your solutions.  Since there are quite a lot of trees in this situation on the property, I'd love to not have to keep trimming them back so frequently. And some are not in locations where I can easily cover them with cardboard (growing immediately next to a rose bush).  So, I'm happy to have a variety of ideas to try. Not sure where I'll find copper nails, but I already have a lot of Epsom salt! Thank you again!

Cut it back to ground level. It will attempt to regrow with multiple stems. This is called coppicing, and is used to produce poles for fencing and other crafts. Cutting back alone is highly unlikely to kill the stump unless you are extremely diligent.

Instead, I have had some success by covering a cut stump in thick black plastic and weighing it down with something heavy, so the regrowth doesn't lift it. You might try some thing like a car tyre for the weight.

Tammy Mayer wrote:... And some are not in locations where I can easily cover them with cardboard (growing immediately next to a rose bush).

Light blocking containers such as old paint cans might be an easier option than cardboard in some situations. So long as you pile dirt around the bottom edge so light can't sneak in.

Similarly, someone abandoned some of the thick heavy pond liner on a property we purchased. So long as you don't put it down and forget it (which you can do with cardboard as it is biodegradable) a section of it can cover over a stump and be tied in place.

Lastly, I agree with Michael Cox.  Basket weaving and biochar making are two potential uses I can think of off the top of my head for a large supply of coppiced maple whips.  

Jay Angler wrote:[Light blocking containers such as old paint cans might be an easier option than cardboard in some situations. So long as you pile dirt around the bottom edge so light can't sneak in.  

Yeah, I use all kinds of unusual stuff.  I haven't tried paint cans though I know that will work.   I have used ceramic flower pots covering the hole with something so light can get under it.

For the rose bush location the cardboard might be cut to fit and rocks place on top, etc.

Success may be climate/tree dependent, but I did manage to successfully kill a sycamore that was growing in a garden border too close to a house a few years ago. I intended to turn the stump into a bird table support (it was nicely near the kitchen window) so cut it at a couple of feet up. I then rubbed out any growing shoots over the summer every few weeks and that was enough for it to give up and not regrow the following year. This was a sapling that was probably about 4 years old, 12 feet tall and 2 inch diameter trunk.

dan bradley wrote:Copper nails. Roofers still use them and I suppose you might find them at Home Depot or one of those places. Or try a roofing outfit. This is an old and effective way to kill a tree if you need to do that.  Drive a few into the trunk and the thing will slowly die.  

We get Eucalypt roots in the septic system, occasionally the pipes, and copper sulphate works too.  New to this, so it might not be permaculture acceptable . . . bought supply from the local Feed/stock shop.  It doesn't need much.

Hello Tammy,

I want to echo Anne's previous remarks about how difficult it will be to kill a maple tree with salt and thus just how much salt it will take to accomplish the task.  Further, I suspect that if you do kill the tree with salt, I would be afraid of what that salt would do to the surrounding soil.  Honestly, I am just not certain how permie a solutions salt is when trying to kill a tree.

With that said, my approach would be to first cut the tree right flush with the ground.  I would then mow regularly so that ANY growth that would pop up would promptly get nipped in the bud.  If you wanted to go one further step, you could introduce a type of stump killer that is based on potassium nitrate.  First you would have to drill holes in the remaining stump in the ground.  Then fill those holes with the potassium nitrate granules and sit back and wait.  This will slowly oxidize/burn the stump over the course of days to weeks and the potassium nitrate is harmless to surrounding soil (actually, it will actually add some fertility to the soil.  This will probably kill the stump sufficiently that any surviving roots will be on borrowed time as long as you keep mowing around them,


I hope this is helpful and if you still have questions, please feel free to ask.

Eric

The most successful way I've seen of killing a tree is to girdle it. It is not immediate, but doesn't involve poison or frequent attention.  This will be harder to do on a tree that has previously been cut down and has many stems. Once you cut the top of the tree off, hormones in the tree trigger it to grow lots of shoots. So, if possible, avoid that step for now. Cut through the bark (being careful to not cut the wood much) and peel off at least 6 inches of bark around the  full circumference of the tree. Be sure you aren't leaving the inner bark (even a small strip in a fold of the trunk can sustain the tree). The spring when the bark slips is the easiest time to do this. If you don't damage the wood and only cut the bark, the tree won't even know it is dying. It won't be able to send food between the leaves and roots. It won't store any energy to make it through the winter and it won't come back the next year. It will stay green through the summer, so it will look like you haven't done anything,  but be patient.

Eric Hanson wrote:Further, I suspect that if you do kill the tree with salt, I would be afraid of what that salt would do to the surrounding soil.

I was wondering about this! For soil health, I'm quite reticent to pour salt onto the stumps. There are so many small trees and stumps to kill, we would be putting down a lot of salt if we were to go in this direction. At this stage, I've abandoned the idea.

Eric Hanson wrote:If you wanted to go one further step, you could introduce a type of stump killer that is based on potassium nitrate.

Thank you for this suggestion. I'm going to start with cutting the trees down to the soil and blocking the light. If they are still very persistent, I will try this method.