I've got a number of 10-12 year old Tipuana tipu trees that I've been pollarding annually for the past few years.
It is time to get rid of some though, and plant fruiting trees in their place. I was thinking I'd cut a stump about 6in from the ground level and nick it in many places with a hatchet to wound it, and then place a 1 - 1.5m tall, fine mulch pile diretly on top of the stump.
The hypothesis being that the fungi and bacteria would not only compost the pile, but would simultaneously infect and thermophilically compost what remains of the Tipuana tipu.
This would be a very ecological method for killing a tree and preparing a planting site, however I can also see it not working, and Tipu sprouts poking out of the mulch pile.
I have never worked with that tree, but would still probably do a hugel bed over the stump. Start with with woody debris of diverse sizes, topped with soil from an adjacent area that could become a path, and plant it right away. If the tree comes back, just cut back to the surface until it runs out of steam, it's just putting more organic matter into the deep soil for you anyhow. I plan to eventually do this with alders (our native n-fixator) I am planting.
This is all just my opinion based on a flawed memory
Dont kill them, just cut them low, plant your trees next to them, and every time the old trees try to grow just cut them low again and use that growth to mulch around your trees, if your trees are fine enough they will make a good shade and will suppress the growth of these old trees eventually, or plant some bushes to even further shade them. As long as the old trees are low but still growing then you can use that as an indicator how well you are utilizing sun energy, the moment they give up because of the shading, then you will know you have done it right, till then use them to improve your soil.(this may not be the right way for you though, if you dont have time for that)
I'm euthanizing a bunch of sweetgums, which I would assume to be a fantastic pollarding tree, but they spread via the root and are a primary colonizing tree here. My technique takes 2 years. Year one I ring the tree with a chainsaw as low as I can get without dulling the chain- hopefully low enough to bush hog over. This prevents the tree from sending sugars to the roots in the winter, but water can still go up and transpire. I'm not familiar with your species at all so not sure how applicable this is.
Year two the trees get cut generally a little above the ring, and I drill a few holes in the stump and cover with compost and mulch. Often the chickens perch on them and poop on the stumps. The tree trunks are perfect for mushrooms because they maintain a high sugar content even in the winter, so off they go. It takes, as Travis says, a couple years to degrade but that depends on the diameter. What is cool is that in this climate the same year you cut them you can see where the roots were because they will generally send up fruiting bodies from whatever fungus has colonized it. I no longer plan on taking the roots out at all, let the fungi do the work.
Standing on the shoulders of giants. Giants with dirt under their nails
A well-built compost pile will get up to 150 or 160 degrees and stay that hot for about 2 weeks. I would think that if you built two successive hot piles right over the top of the stump, and kept the temp at 150 degrees for a month straight, that would be enough to kill it.
But then again, tree roots are amazing, and there are documented stumps still living 200 years after being cut down (as neighboring trees feed the roots and keep them alive).
"The rule of no realm is mine. But all worthy things that are in peril as the world now stands, these are my care. And for my part, I shall not wholly fail in my task if anything that passes through this night can still grow fairer or bear fruit and flower again in days to come. For I too am a steward. Did you not know?" Gandolf
Borislav Iliev wrote:Dont kill them, just cut them low, plant your trees next to them, and every time the old trees try to grow just cut them low again and use that growth to mulch around your trees, if your trees are fine enough they will make a good shade and will suppress the growth of these old trees eventually, or plant some bushes to even further shade them. As long as the old trees are low but still growing then you can use that as an indicator how well you are utilizing sun energy, the moment they give up because of the shading, then you will know you have done it right, till then use them to improve your soil.(this may not be the right way for you though, if you dont have time for that)
This is probably what I'm going to do, as I don't really want to spend any money renting a stump grinder.
I did that to another Tipu tree a couple years ago, and there were only ever a couple shoots that I stripped off a few months afterwards. Nothing more has sprouted from the stump since then, which actually surprises me quite a bit, because I assumed this species was a lot more tenacious.
FWIW, I plan to plant saplings of Aristotelia chilensis next to the Tipu stumps. I hope the other Tipu stumps turn out ti be as weak as the other even though the remaining Tipus are considerably bigger.
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