How close is too close to a tree?

[Gorman]

Looked at saving a white oak 22" dbh where they are planning on digging a foundation for a house 10' from the trunk. I figured it's only losing about 20% of the roots so it's probable to save it if I cut the roots clean ahead of time using an air knife and fine saws. Combine that with some radial trenching and mulching. The drip line is 20' so the foundation is only coming halfway to it.

I can post pics later but is this a fool's errand? Should the tree just be removed?

 

[Tom Dunlap]

Dr gary Johnson from the university of Minnesota wrote a book about trees and construction. There is lots of good info there.

Do a search for it. It was a free download

If you find it paste the link back in here

 

[classictruckman]

if the drip line is at 20' you should be ok, just try and keep the excavation as far away as possible, tell them just the minimal amount needed to get the forms on and off.

 

[oldoakman]

Claus Mattheck gives as a "guideline" 5 times dbh as the root plate area of a healthy tree. 22"dbh is 9' 2". Obviously there will be an impact. The objective should be to minimize that impact. Fencing of the area not directly involved with the construction and the use of mulches to minimize compaction in the areas that must be accessed should be part of the protection plan. Communication with the contractor and subs that any activity within that area must inform the arborist. A water/fertilizer/mycorhizzia program developed. And followup to extend at least 5 years. White oaks don't take well to construction pressures.

 

[oldoakman]

I would also prescribe a "bio barrier" type material to be placed against the foundation wall to hopefully prevent roots from eventually damaging the foundation.

 

[Gorman]

I did prescribe a bio barrier. The home owner is really attached to the tree but the septic engineer won't budge on placement and the architect won't budge on placement.
I do know white oaks aren't so receptive to construction but I was told the excavator is "cool" and will work with me regarding saving the tree.

 

[Tom Dunlap]

Here's the link:

http://www.extension.umn.edu/garden...bs/protecting-trees-from-construction-damage/

Gary has some formulas for damage encroachment based on DBH too.

 

[Gorman]

I do have to prune some lower limbs as well for future roof clearance. Not much though.

 

[classictruckman]

I did prescribe a bio barrier. The home owner is really attached to the tree but the septic engineer won't budge on placement and the architect won't budge on placement.

isn't the home owner signing their paycheques?

 

[Gorman]

Yes, but the plans would have to be totally redone if they went outside the drip line. And then re approved.

 

[oldoakman]

Engineers are total assholes. I have to fight with them all the time. Sometimes I win and sometimes they win. I'd say the score is about even.

 

[Gorman]

Everyone is an asshole is some way. Now the homeowner is backtracking on putting the foundation back so it might be a removal. OYE VEY!

 

[Jeff]

Engineers are total assholes

Hey! Don't lump us all together! SRTSteve860 and Chris Girard, back me up, would ya?

Many times, though, you are right. People are often concerned only with their piece of the pie and don't care about the total picture.

 

[oldoakman]

Hey! Don't lump us all togknowing SRTSteve860 and Chris Girard, back me up, would ya?

Many times, though, you are right. People are often concerned only with their piece of the pie and don't care about the total picture.

I don't make that charge lightly, and my dad would roll in his grave knowing I made such a statement as he should have been an engineer, however MOST of the civil engineers I deal with are pinheads. I have recently "assisted" a young engineer in performing sample sites and calculating the tree densities for a permanent buffer zone around a heavy industrial site. The site is 207acres and requires 2070 tree density units for the site. I wound up laying out the sample sites, measuring the trees, checking her math not once, not twice, not three times, but four times before she got it right. I rest my case. Oh, and she had just taken the PE exam the week prior. Please someone, prove me wrong!

 

[fall_risk]

This Gary Johnson guy is a stud. More good stuff here.

 

[Jeff]

she had just taken the PE exam the week prior

Yeah, I know waaaaaay too many of them that give all engineers a bad name. Often incredibly book smart, but completely common sense stupid. And having your PE doesn't prove anything either. I've worked with several PEs who couldn't find their butt with both hands. Sad, and very frustrating!

 

[treegazer]

Sounds like saving the tree was an afterthought and they don't really care about it.
If they cared about the tree it would have been the starting point of the entire project.

 

[guymayor]

Formulas DO NOT apply. too many variables. pics?

 

[Gorman]

I misstated the dbh. It's about 26". They want to start digging just outside the stake. Where the dasani water bottle is.

 

[Gorman]

I also looked at some oak removals at another job where some construction goons reassured the homeowner that the trees would be totally fine after removing 45% of the roots and putting a retaining wall flush against the trees.
It's almost funny to look at. I'll post picks in a few weeks when I get to the work.