300+yrs White Oak

[Sudo Tsuga]

I work at the Wilmngton Country Club, and along side of our reservior we have a large 300+yrs old White Oak tree. The superintendent of the course has recently began reserching plans into expanding it's current size. One plan of concern to the resident arborist and I is the area under survey. They would dig a channel between the oak and a barn about 250' away. Our question is: What is the minimum distance they could excavate without disrupting the root system of the oak? It's drip line is 42' and it's diameter is approximitly 60".

 

[Jay Banks]

Mike,
What is the purpose of the channel? Can that be changed to a pipe of x-diameter? Then I would say the pipe could be put in a tunnel.

If that's not possible I would have to say a critical root zone for your tree would be based on 12 inches of rooting for each inch of diameter at DBH.

 

[Sudo Tsuga]

Jay,

Well the purpose of expanding the reservior is to increase the capacity of our fertgation system. We pump out one million + gallons of water a day from the current reservior and are only able to put one hundred thousand or so back. The channel, which is not a good way to discrbe it, is merely a narrow peice of the planned reservior to fit between the oak and the barn. It will then lead to large open feild that will also be excavated.

I thank you for your reply and the information we needed to facilitate a decision. So if the oak has a diameter of 60" than the critical root zone not to be disturbed is no less than 60'? Mike

 

[Jay Banks]

Mike,
Again, that's just a starting point for the CRZ. If you can go out further from the tree by all means do so.

It's hard to visualize the logistics of the project. Good luck.

 

[John Paul Sanborn]

I was doing this last night and power went out.

Th rule of thumb that jay uses is the same I'm told that City Of MKE uses. 1 ft per 1inch of dbh.

Harris (3rd ed. p. 325)has tables from both Londons and Toronto's forestry departmants. London wants a min of 10 ft for 30 inch and over. Toronto adds 2 ft for every 6 in of dbh after 6in.

If you use the drip line on a very old tree. you are going to run into a lot of large roots. I've dug 30 ft from a 15 ft crab and found 2 inchers. They'll go whaere there's O & H2O.

I's just that bigger trees wont be able to wall off as well.

Also try to get budgeting for hand cutting and quick cover of the roots that are disturbed. With white oak they will be deep. Maybe even treating with a root stimulant after the cutting to promote new growth

 

[John Paul McMillin]

thanks john and jay , that was my intern posting that question. The White Oak is very important to us and we will do all we can to keep the digging as far away from the oak as possible . the tree is also very important to the members ,so im sure they will support the info that you sent. The "trench " that Mike spoke of will probably be well over 30ft deep and 50 or more ft wide at the point that is goes by that oak tree. Like he said they are expanding the reservoir so we will have another huge pond going around this tree. john

 

[Sudo Tsuga]

Jay, John,

I appreciate you responces and we will keep in touch with the outcome of the situation.

Mike

 

[John Paul Sanborn]

JPM,

Any predictions as to what the lagoon expantion will do the soil around the white ok? Is there a posibility that it will cause any saturation problems?

 

[Jay Banks]

JPM,
It sounds as if you all most have an island with a large white oak in the middle. The chance that the water table will rise is unlikely if you are drawing down the water level to irrigate.

Is that the thought that your basing the project on?

 

[John Paul McMillin]

good points to consider . the pond will be only on one side of the oak tree. actually two sides since the existing reservoir is already on one side of it and will expand to the another side also . right now the tree is about 80 to 100 ft away but the new addition to the reservoir will bring it closer. thanks john