First of all, it's important to identify the cause of the sewer drain clog before just assuming it's tree roots.
If you have access to the site plans for your home, determine where your main sewer line runs toward the street and see if there are any trees growing along that path. Of course, larger trees can have root systems that travel for many feet underground, so take that into consideration when surveying the area.
Also, try to determine if your sewer lines are clay. If your home was built prior to 1970, chances are good you have clay sewer lines. If not, there's a chance your lines are PVC, and tree roots will not be an issue. Of course, older homes may have had the lines replaced in the past, and some newer homes may have had clay lines installed despite PVC being the industry standard, so digging down to the pipe may be the only surefire way to find out that answer yourself.
If you do have clay pipes and you have trees within thirty feet of your main sewer line, there's a good chance your clog is caused by tree roots.
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