Here are all of the notes I've taken on this topic based on these discussions... these are not my words... this is largely all copy and paste from different replies.
Again, I thank everyone for helping.
Root Barriers
- So, if in 10 years the tree is growing that big and you are still worried about it, rent a Ditch Witch and trench a 4" wide, 2' deep trench inside your property line and disconnect any roots running in your direction. The trench would not have to be long, say 20' as the major roots will radiate out from the trunk. You could even dig a smaller test trench with a shovel is a couple of years just to check things out. You can take an axe to any roots on the surface.
- If you're REALLY worried, in five years, dig a trench inside your property line to, er, put down PVC for watering - or something. [this will cut any roots]
- If it really bugs you, spade through any major roots you see when you build the driveway. The rest aren't worth worrying your pretty little head over.
- Another slant might be to verify that the tree owner may be libel for damages to your property and also verify with a local professional that that tree in that location might damage your property. I would expect the owner to react.
- I would think it being Aristocrat pear at 17 feet would be more than a safe distance from your home. If you are going to make a barrier,
24 inches of corrugated tin buried should be sufficient.
- Heavy EPDM would work as a barrier, and be easier than tin to work with. That is what they use in the bamboo group as a root barrier. (Heavy black rubber-like material. Used for roofing, and ponds. Can be cut, and glued if you need to.)
- Another problem that occurs with trees is *reduction* of the groundwater from evapotranspiration in clay soils, consequent consolidation of the clay stratum, and settlements of the structure founded on the stratum. This is usually associated with large trees like oaks so a relatively small pear tree may not apply... The thing is, you neighbour by watering may be balancing the equation.
Q: Is this caused by the roots taking moisture out of the soil?
formatting link
A: Yes, But the tree is also providing shade, thereby reducing the amount of evaporation directly from the soil, so the likely net effect is zero.
Check this link for a discussion of the issue from a decidedly tree-friendly engineer:
formatting link
Since you are watering the soil to avoid too much drying out under the foundation, you probably do not have to worry about this. For more info about the International Society of Arboriculture, please visit
formatting link
For consumer info about tree care, visit
formatting link