Bradford Pear

[scoutch]

I have a Bradford pear with a exposed root [about 5 dia" ]. we are looking to put in a paving stone patio,our contractor say's it will not harm the tree to install patio over the root or cut root out of way. Any thoughts thanks in advance

 

[Toddppm]

From what I've seen Pears usually don't have too many problems with surface roots so there must be something else going wrong there. Maybe it was planted too deep originally and that was an advantisious root that developed and is now a very important one to the tree! Or it could have come from a pot bound root that wasn't straightened out when planted. At 5" no matter why it formed probably isn't very important anyways, on a B. Pear they can take alot of abuse but that's a big root for any weedy tree. Being that big and on the surface it most likely provides support for the tree also not just a feeder root.
Without seeing the tree it's hard to say but if this patio is going to be within the dripline of the trees branches there's probably going to be alot of other roots disturbed besides that one. Usually have to excavate at least 5"-6" below the level of the material being used (brick, concrete etc.) and most roots of trees are within the top 12" of the soil. Alot of times depending on the type of tree you can get away with disturbing one side of the area if you stay away from the trunk of the tree a reasonable distance without too much concern of long term effects. But before I write a book on this subject, have you thought of taking out the B. Pear because as you might know, unless they were trained right from the beginning they don't last without having structural problems and falling apart more than 15-20 years?
But, that's probably the reason for wanting a patio under it because of the shade? I would take out the tree, put in the patio, making sure to install a proper base and then plant a nice shade tree near it, doesn't have to be right next to the patio to get a good amount of shade and worry about the patio heaving years later.
I'm assuming alot so I'll stop now

 

[tshanefreeman]

I haven't dealt much with Bradford's before, but I will agree with Todd in saying that they typically don't have huge problems with surface roots, at least that I'm aware.

Trees with evident surface roots of substantial size have typically run into some sort of physical barrier which restricts their journey in a somewhat downward direction. Now don't get me wrong, I don't mean that all roots grow straight down like that of taproots, I just saying withing the top 12-15" of soil. Examples of an impermiable barrier could be a heavily compacted layer of clay that had black top-soil placed over top of it. This is highly likely in todays unplanned urban environments. All thought and money goes into the actual building and visible vegetation, and not enough R & D into soil structure and horizons. There could be other reasons too, but this is a good place to start.

If you could get your hands on a soil probe to take a sample, you could easily find out if this is your problem or if you are dealing with something else.

If your patio is going to be built directly over the root zone of the tree, I would also give serious thought to removing the tree. Todds explanation of the majority of roots in the top 12" is right and if you have to dig down, then compact to achieve a solid base, you will most likely end up with a dead tree. Also, if there is an impermeable barrier a few inches down, the digging may remove all of the trees roots!

 

[Jay Banks]

You didn't say how big/old the tree was. If this is an older pear that has not had good structure pruning over the years it may just be a matter of time before the tree starts too self-destruct.

The tree has weak crotches and large portions tend to break out of the tree from wind/snow/ice.

So it may be a thought to remove the tree and build the patio and replant a better tree.