Q.Killing trees
Four years ago my neighbor used your method of killing his tree by removing the limbs from his tree, cutting down the trunk and drilling holes into it, which he then filled with poison. It killed his tree. Here’s the problem, it was one of three in a row, about 6 feet apart from each other. They grew together to be very tall over a 25 year period.
What would the result be to the other two trees? Besides the fact that they look like two thirds of a very large tree…The two remaining trees are very sick and have been for about three years. They are shedding their bark and cracking. Is it likely it’s from the poison my neighbor used?
It is is certainly possible that the herbicide used could have been spilled or over sprayed onto the other trees.
Inspect your trees for other signs of pest or disease. Do the leaves have holes, spots or discolorations?
Is the tree trunk oozing or show signs of a canker?
https://www.gardeningknowhow.com/ornamental/trees/tgen/peeling-bark-on-trees.htm
