Anyone know of a city that manages root - sewer conflicts by actively removing problematic trees? If so, what criteria are used?
Reply to post by jps, on July 05, 2000 at 18:44:57:
Do any of the readers have copies or knowledge of the pressure forces that roots are supposed to create in order to break pipes, crack foundations, lift sidewalks and commit other antisocial mayhems?
If there are cities that either are, or are thinking of, removing "problematic" trees, I wonder if I should ask them for that information? Surely they've have it, considering on what they're planing to do. Here in Illinois, our Governor put a moratorium on capital punishment because we had 13 executions and 12 releases from death row. Those are sobering numbers if we intended that innocent people never be put to death.
Since trees face decapitation punishment, strickes me that people who care about trees should be asking where's the proof? Of course, if we can't be bothered with those fussy details, I understand.
Reply to post by wulkie, on July 08, 2000 at 11:09:23:
Getting real facts about whether trees actually initiate damage to sidewalks or foumdations or pipes rather than merely exploiting existing defects certainly can't hurt. But it does not solve the entire issue. Neither does crying "save the trees."
The questions which will get attention are: once the roots start entering the sewer do the clog the system or reduce it's function? If the do what's the cost of the impared function? What's the cost to remove the tree? Is there a net saving out of pocket as compared to replacing the sewer? If you replace the sewer will it require tree removal anyway? If you factor in tree value does it change the equation?
Trying to reduce it to blacks and whites, trees or pipes, right tree in right place IMHO ignores the true range of facts and the true calculus of decison makers.
Reply to post by Scott Cullen, on July 08, 2000 at 18:38:42:
You forgot one question, Scott. "If you remove the tree, will ou still have to repair the sewer?" Then you have to ask, if we're going to repair the sewer anyway, can we do it without losing the tree? And of course, what is the cost differential.
These are indeed questions that beg for attention- among those who care. Too often, the answer is assumed.
And we forget the animosity some people can generate toward perceived 'enemies'. "Look what those nasty termites did to my house!" Well, termites aren't nasty at all. In fact, they're rather sociable, as a group. And they sure had no intent to harm the guys house- they didn't see it as anything but dinner, about the way we view clams in the bay.
Reply to post by Russ Carlson, on July 08, 2000 at 19:11:53:
Answering Wulkies question concerning literature on root pressures on pipes, there is an in-depth analysis in Chapter seven of "The Body Languasge of Trees, 4th Edition" by Claus Mattheck and Helge Breloer,1998.
South East Water in Melbourne, Australia actively remove trees which cause damage and repeat blockages to their sewer system. Tree removal is negotiated with residents.
Their website can be found on:
and a general article on their tree root problem:
I do not agree that trees only enter 'defective' sewers. It has been shown in studies that trees can enter NEW defect-free clay pipes (and to some extent concrete and plastic pipes) by growing around seals and into joints. One such study can be found at:
.......keep in mind this was done by a plastic pipe manufacturer.
For evidence of tree roots growing in plastic and concrete pipes refer to "Tree Roots Research Project at SLU Alnarp (Sweden). email: firstname.lastname@example.org
As many cities (Chicago leading the way) are now proactively intent on becoming 'urban forests' tree/utilities issues will become more prominent.
an engineer from Australia
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