What trees are okay around septic mound?

[pdqdl]

I just dug up the 6" clay sewer tile leading from a rental house. There wasn't a single tree within 60 feet, yet the sewer line was so obstructed with roots that it broke the plumbing snake off that we tried to clear it with.

And that wasn't a leach field with perforated pipes, that was clay sewer tile with rubber grommets at every joint.

Tree roots will go a LONG way to suck up the available water. Furthermore, that sewage water is particularly tasty to plants, and they will follow a nutritional gradient back to the source just to get what they like. Or to avoid what they don't like. Copper sulfate comes to mind, here.

I give the clay sewer lines at my shop a shot of copper sulfate about once per month. Not expensive, and it keeps the roots away. Shoulda been doing that at the other house, eh?

 

[wseibert]

I was once told that a trees roots extend laterally underground the same distance as its branches extend laterally above ground. Is there any truth to this?

 

[pdqdl]

Not much. If you guess three times the radius of the branches, You'll be a lot closer. They go down a long ways, too.

I've seen tree roots in the caves in Joplin, at over 170 feet down, as told by the tour guide.