We typically think of trees as the ‘good guys’; they shade our homes and yards, they take up carbon dioxide and pollutants from the air, they give us oxygen. What’s not to like? Well, like a lot of good guys, trees can also have a dark side. One of the more sinister habits some trees have is getting into sewer lines. Some studies estimate that trees are responsible for up to half of sewer line repair costs. The prospect of trees getting into residential sewer lines is troublesome, of course, because it’s an invisible problem; we usually don’t know there’s an issue until there’s an issue. Once tree roots get into sewers, they are often expensive and messy to deal with. And I don’t mean just messy in the sense of having to call in a backhoe to dig up your yard. Deciding who is responsible for the cost of cleaning up after a tree figures out its hit the mother lode can be a mess as well. What if your neighbor’s sycamore finds its way into your pipes? Or what if the culprit is the silver maple that you didn’t want but the city planted in the tree lawn anyway? In some cases there are city ordinances that cover these situations. For example, some cities will cover damage from city-owned trees provided they determine the city-owned tree caused the damage and the damage wasn’t due to a pre-exiting problem with the pipes. Therein lies the rub. As long as sewer pipes are intact and functional, tree roots have a hard time penetrating. The problems usually arise when pipes crack or joints fail. Once roots find an opening, it’s Katie bar the door. This is why tree-sewer problems are most common in older systems with clay or concrete pipes that can crack over time. Of course, the type of tree and location play a role as well. Other factors being equal, fast-growing bottomland species are the most frequent offenders. Danish researchers found that willow, birch, and poplar trees were responsible the largest number of root intrusions into sewer lines. In many parts of the US, sycamore, sweetgum, and tulip-poplar can be added to the list.
Tree roots and sewer lines: a bad combination
So what’s a homeowner to do to get some sleep and not worry about tree roots planning a silent assault on the drain-lines? Keeping fast-growing trees away from lines is a start. But tree roots can grow a long ways and are pretty relentless; if there is a crack or a weak spot in the pipes, they will find it. Keeping the system maintained and preventing entry is the key. If the system has cracks, “Root-stopper” or “root-killer” products are available. These are copper-based materials similar to ‘spin-out’ used on tree containers to prevent circling roots. These will kill feeder roots that have entered into pipes, but roots are persistent and they’ll be back. Plumbers have special tools that they can snake through the system that can cut through roots and clear blocked lines – at least for awhile. If you have old sewer lines and have fast-growing trees around, you may want to consider hiring a plumber do a video inspection of your lines periodically (think of it as a colonscopy for your house). If there’s a problem the plumber will be able to pin-point where it’s at and (hopefully) fix it before it becomes a major expense.
Friday’s puzzle was tough! Several of you were on the right track – this is a carnivorous plant. Right away Deb suggested a pitcher plant (then got sidetracked with chestnuts), but Derek was spot on with his guess of the “spiky bits” on a Nepenthes pitcher:
What the function of these spiky wings are is not clear to me; I did a little checking in the literature but failed to find anything convincing. It does seem to suggest a close relationship with fly traps. Perhaps the ancestral type was a fly trap type plant, which eventually evolved to an enclosed pitcher? (Perhaps someone out there has a better grasp of carnivorous plant evolution than I do?)
And the scientific name? Nepenthes alata, or “winged Nepenthes.”
OK, here it is, my one and only shameless plug — because my publisher says: Hey! You need to at least let people know that the book exists!
So — I’m excited to say that my next book, How The Government Got In Your Backyard, which I co-wrote with my good friend (and old college roommate) Eric Heberlig, who is an Associate Professor of Political Science at UNC Charlotte, is finally out.
In case it isn’t immediately obvious, I love to write. This is my fourth book — and in many ways I think it’s my best. In it Eric and I look at the science and politics behind a number of environmental issues — everything from Plant Patents and Illegal Plants (think marijuana) to Organic Food, Global Warming and Biotechnology. We look at the political right and left, investigate the science behind what they believe, and try to give unbiased opinions. Some people have already let us know that we’re wrong! (Which we find amusing — but that’s another story).
What we don’t try to do in this book is make up your mind for you — that’s your job based on your priorities.
You might remember back in October 2009 I gave one of the first Friday quizzes. The featured tree had epicormic shoots, and Monday’s answer revealed the neglected wire staking that was slowly girdling the main trunk. (Be sure you click on those links to see what the tree looked liked in 2009.)
I thought you might be interested to see what this tree looks like now:
A picture is worth a thousand words….many of those unprintable.
Update January 2022 – in response to a reader question, here is the tree in 2019 thanks to Google maps.
One of our international readers, Johannes, sent along this web site of photographs demonstrating what happens when trees meet immobile objects. The text is in German, but the photos are self-explanatory.
Our land has a nice buffer of big, old oaks, hickories, and maples between us and the two-lane highway. Power and phone lines thread through the middle of them. Thus, I have nightmares about orange Asplundh trucks.
So with much concern, I noted that utility crews and
subcontractors have been out in full force in our rural area,
inexplicably leaving one tree and then “pruning” another.
I pulled over and snapped this latest atrocity last night. The power lines are to the right (not in photo). As this is only a mere mile or two from our property, I may sit at home on the porch next week with the shotgun in my lap.
A short follow up to last weeks post on girdling roots. Just to reiterate, the point of the post was that we need to be careful not to jump to conclusions when assessing tree problems. It’s important to look beyond the first defect we see and consider additional causes. And to also reiterate, girdling roots can be a serious problem and can lead to tree failures. The photo below shows an example of tree that was both planted too deep and had stem girdling roots. The result was a weakened area in the trunk, which was subject to breakage during a windstorm.
Many people also assume that girdling roots restrict flow of water and nutrients in the xylem. They can, but trees also have the ability graft roots and re-establish connections between roots. In the study I mentioned last week, Phillip Kurzeja and his co-workers traced water flow in ’manifold roots’ (a series of interconnected, girdled roots) by injecting dye. The trees were subsequently felled and de-barked, allowing the researchers to determine whether the roots were still functional. As shown below the girdled roots were able to re-establish their vasculature and continue to translocate water up the stem. So trees can be efficient at fixing their own pipes!
Image: Phillip Kurzeja
It is important to note that this phenomenon occurs between roots but not between roots and the main trunk – hence the concern for impact of stem-girdling roots, especially for trees planted too deep.