It's certainly a possibility.
I cut and herbicide-treated(Pathway) a fairly large pecan seedling in a nursery row last fall. The two seedlings growing in close proximity (we're talking 12-18"), on either side of the treated seedling did not leaf out this spring. I'm presuming they were connected by way of root grafts.

I have more to remove this fall, but I'm considering trying full-strength glyphosate, as I suspect (perhaps mistakenly) that adjacent trees might be less likely to die outright even if they are temporarily 'stunned', than if they get a dose of picloram & 2,4-D.

is 2, 4-D labeled for stump killing???

ken

A very intelligent question.

Do not do it if the other locusts are important to you. You may get away with it, you may not and given the decade it takes to grow a tree to any reasonable size I would not risk it.

Now if you are feeling experimental go for it and let me know!

Thanks for the input. I don't think that I will risk it. The trees that I took down would have hit my house had they come down during Hurricane Sandy. They would most likely would have come down with a little heavier rain and a soaked ground. The other trees are within striking distance of the house, but it would not be as catastrophic were they to fall.

Ken: I was planning on using glyphosphate or triclopyr,

Thanks to everyone who responded.

ken,
Pathway (Tordon) is a combo of picloram and 2,4-D.

i buy RU in the 2.5 gal rural size container... full strength.. which is 41% .... actually i use generic ....

it comes with a .. i dont know.. 30 page booklet .... listing all of its uses ... and dilution rates .. etc ... perhaps you can find that online ....

i am pretty sure it is listed as a stump killer.... you can research that ..

on trees ... all you need treat.. is the cambian layer... which is the green band just under the bark ... consider ALL center wood as dead wood... as far as treatment goes... so you dont need much ...

i use a precision applicator.. like at the link ... so as to not waste product ... return unused product to the proper labeled container ...

but the most important info on the label.. is the 800 number.. call THEM.. and ask them .. MAYBE they have a better answer as compared to our mere speculation .... eh???

ken

Here is a link that might be useful: brand is not important.. its that small twist top ... which restricts flow ...