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Pine tree roots

Posted by frnc SoCal (My Page) on
Sat, Apr 14, 07 at 23:36

I have 15 beautiful mature pine trees (probalbly 75+ ft tall). I had to cut one down and have it's stump ground to 1 ft below ground level because it's roots were discovered to be attacking my septic tank. Now I've been told by the septic tank clean-out company that the tree's roots will continue to grow underground even though the pine tree has been cut down and the stump ground out. I've done "Google" searches but cannot collaborate this info. Any opinions or arboristis out there with knowledge of this problem?


Follow-Up Postings:

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RE: Pine tree roots

Only because of the remote possibility that what you have there is a tree that I don't know about and which behaves differently than any other pine tree I do know about........do I not say it sounds like hogwash. But I strongly suspect it's hogwash.

+oM


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RE: Pine tree roots

If the stump produces any upward shoots again, then you need be concerned, but only then.

Dax


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RE: Pine tree roots

One possibility is that the tree you cut down has an undergound root graft with an adjacent pine tree. This is quite common. If this has happened the roots will continue to live and grow. Unfortunately you have had the pine stump ground out--the easiest way to know if you have an underground root graft to an adjacent pine tree is to see if the stump dies. I am thinning my pine trees all the time in my forest stands. A good percentage of the trees I cut have an underground graft to one or more adjacent trees. Within one growing season I can easily tell if there is a graft because a bit of new wood growth starts under the bark around the top of the stump. The stump also tends to bleed pine resin much more than an ungrafted one. This is not a fool proof indicator, but it is a more immediate one.

Maybe what you can do is where you have ground out the stump, dig down to expose the roots that radiated out from that stump, especially in the direction of the nearest living pine tree. After a year or so you can check to see if these roots are still alive. If so you have a graft. If you have ground your stump down to where the large individual roots are separate from the stump, the graft connection with the adjacent tree will have been severed except for the one root that actually made that graft. So in all likelyhood, that will have killed the root that has been causing the problem, unless, of course, it is the very same one that had formed the graft.

I hope all this is not too complicated--if you have any questions or want more clarification, I will try to explain more.

--Spruce


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RE: Pine tree roots

how do you know that the one you cut down .. was the one that had its roots in the septic tank????

a 75 foot tree can have roots a long way from the plant ... and you have how many more trees that size?????

ken


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RE: Pine tree roots

This whole thing sounds pretty questionable. Does the sewer contractors brother have a tree care firm?

+oM


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RE: Pine tree roots

"This whole thing sounds pretty questionable. Does the sewer contractors brother have a tree care firm?"

My guess would be more likely complete tree ignorance on the part of the sewer contractor. They probably don't know that pines don't do the same as aspens, and are following the 'worst case scenario'.

Resin


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RE: Pine tree roots

LOL !! Thanks so much for the many replies. This particular tree was located at least 100 ft. from the other pinetrees. I believe the concensus would be that the roots would not continue to grow, but I will take sprucemans suggestion and will locate the radiating roots and watch for future growth via a graft root.


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RE: Pine tree roots

You'll need some underground binoculars of course:)

Dax


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RE: Pine tree roots

If the trees are 100 feet apart, I would not bother--a root graft between pines that far apart would astonish me. There would have to be some very unusual set of circumstances for that to happen.

--Spruce


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RE: Pine tree roots

Spruce -- I believe 50 feet is the longest distance I've measured between a living stump and the closest tree of its own species. (Using a living stump as an indicator is a lot easier than digging) But conifer roots can extend a long way, and I don't see why, in principle, >100 ft. would be unachievable. Of course the closer, the more likely to make contact.


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RE: Pine tree roots

Pinetree30:

I agree, but in this situation, highly improbable and not worth thinking about. Roots not only have to make contact, but have some pressure pressing them together to get them to graft. In any case, people need to be aware of the frequency of root grafts and the effects they can have. Many people who have an interest in trees have no idea about root grafts and/or trees that grow up from a common root system, such as aspen, and in a different way, beech.

--Spruce


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RE: Pine tree roots

Thank you again guys.......I will sleep soundly and comfortably. My septic contractor may be have been trying to set me up for alteternative blame if his repairs don't work. He's a good hard-working guy but maybe a little "looney".
This is a great forum...found it through a "google" search.


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RE: Pine tree roots

Spruce, as long as there is contact, there is sufficient pressure as the contact areas increase in diameter. Even seedlings in nursery beds have been reported to graft.


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RE: Pine tree roots

Well, I beg to disagree. I have many acres (about 30) of pines and spruces and I see roots in contact with each other literally millions of times, often even wound around each other, both above ground, and not too infrequently below ground when I am digging (something I do in my groves occasionally), and a very small percentage of these are grafted together. On the surface where obviously the vast majority of my observations are, I see grafts often, but as a percentage of the total I see in contact, it is very small. The risk of a graft as a percentage of roots in contact is very low from my observations.

However, if two small roots are in contact, and then they grow in diameter, and the soil on either side is not loose enough for the roots to push away from each other as they grow in diameter, then there will be sufficient pressure for there to be a graft.

Sometimes the pressure comes from the roots being very tightly strung across each other, and the pressure from that is what enables the graft. But often I see roots tightly strung across each other, so much so that when I cut one it literally snaps away, with no graft. Often the pressure from one leaves an indentation in the other, with no graft formed, at least not yet.

These observations of actual roots in contact is, I think, reflected in the number of my pine and spruce trees that actually are grafted together. I have cut down literally thousands pines and spruces in my groves through the years. These trees were originally planted 6 X 6 and they are now about 45 years old, 80 feet tall, and an average of 18 inches in diameter. Average spacing now is something like 18 feet. Of those I have cut down, I would say the percentage of stumps that have lived because of a graft is maybe 15% or less. Now if the grafts happened as easily and spontaneously as you suggest, there would certainly be a much, much larger number that would have formed a root graft with one or more of the 6 or 8 trees that would be close enough to make a graft relatively easy, and a somewhat larger number would be involved if just one simple root contact would result in a graft. If we were to systematically dig up the roots of some sample trees, I have no doubt that we would find hundreds and hundreds of places where the roots of one tree are in contact with those of another tree.

So here I am in this topic warning of the possibility of a root graft, and to some in this forum seeming to exaggerate an issue, and then I find you going far beyond what I would ever suggest is the likelihood of these kinds of grafts developing.

I grant that in the case here there is a theoretical chance of a graft between these pines 100 feet away from each other, but to me it is only that--a theoretical chance--hardly a real one in my mind. A root 50 feet from one of these pines, unless it were an unusually large and old one, meeting a root from a similar pine 50 feet on the other side, and then these roots that far away from the parent tree growing enough in diameter after meeting to create enough pressure to graft, even if the soil were not one that would give way a bit to the expanding roots, is a chance poorer than I would have on a lotto ticket!

Well, these differences of opinion are what makes these forums fun for us participants, and fun for others to read!

--Spruce


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RE: Pine tree roots

Well Spruce, I envy you your acres of thinned pines, etc., but what they do is not necessarily indicative of what has happened outside your fence. The seedlings I refer to were red pines in a forest nursery back in the 70s I think. Don't remember the reference. Living stumps do indicate functional grafts; but dead stumps do not indicate lack of grafts. So grafting frequency as judged by frequency of living stumps is always an underestimate (I'm not positive but I think I coined the term "living stump" in a 1961 paper). And a living stump may be grafted to a tree ten feet away -- but that doesn't mean it is not grafted to a tree fifty feet away as well. Like with Vegas -- what happens underground stays underground. Unless you're crazy enough to dig, dig, dig....... I once tried to replace digging with injecting isotopes, but it just resulted in the rocking chair bunch at the general store complaining I had got their sciatica to flare up.


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RE: Pine tree roots

I didn't know! What you say makes sense from my observations of the spread of annosus root rot. It spreads more readily than my observations of living stumps would suggest, unless of course it can spread by root contact and not just grafts. And you say a root graft does not mean that the roots that are grafted to a living tree will also live--they often will die even though grafted to a living root system? Humm. I didn't know.

--Spruce


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RE: Pine tree roots

Spruce, I believe annosus does spread by root contact, whether the roots are grafted or just touching. Unlike oak wilt, for example, that actually spreads spores through the sapwood of an infected to an uninfected tree.
I'm not sure I understand your question. What I meant was that grafts may not guarantee that when a grafted tree is felled, the stump will necessarily stay alive. Maybe just some roots will stay alive, but not all the way to the origin at the trunk of the felled tree.
And if you think I am extravagant about the commonness of root grafting, what about the guy who has described a forest as a superorganism of grafted trees?
And the Russians back in the Lysenko days who claimed Scots pine grafted to Norway spruce? Compared to them, I'm a piker.


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RE: Pine tree roots

What I find most surprizing, but I have not made "destructive" analyses of root systems, so I can claim ignorance of facts underground, so to speak, is that there would be a root graft between two trees, and when one is cut, the stump of that tree would die. If the stump dies, then all the other roots except that one would die(except those that might be cross grafted with other roots of the same tree). But if the root of the cut tree is alive, then why would it not be alive all the way back to the stump, and keep that alive? Would the root, which is getting thicker as it approaches the stump it came from, suddenly meet some kind of abscission layer that cuts off the life before it reaches the stump?

One other idea could fit my sense of how things might happen. If the graft happens between a root of the living tree and a very small one from the tree that is cut, I could imagine that this very small root would not have enough "transport capacity" or whatever a good official term for it might be, to carry enough nutrients from the uncut living tree to the entire root system of the cut tree and its stump to keep them alive.

Understand I am not trying to be cantankerous, but I am just trying to use my sense of how trees and roots live and die. I don't have the kinds of observations you have to go on. I would be interested in any articles/research you could refer me to.

--Spruce


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