Girdle failure


5 year old buck +
I found a several chestnut trees on the north edge of a field a few weeks ago. They were probably planted by squirrels that carried the nuts off from the trees near the house. I released them by cutting down most of the competing quaking aspen, sassafras, and autumn olive. Two chestnuts were close together with a 8" aspen leaning out over them a bit. I didn't think I could cut down the aspen without hitting one of the trees. I figured it would break off rather than follow the hinge to the ground. So I decided to try girdling it. Well, that was a mistake too. That aspen has since fallen down It snapped off right at the girdle and fell between the two chesntuts. It took 3 limbs off the larger chestnut. The smaller tree had a Y a few feet off the round and one side of the Y was taken down. I should have left good enough alone and not touched that aspen.
Copper nails? What does that do?
Sounds like you went in too deep. All you have to cut into is the cambium layer, that is right under the bark. Goin deeper than that doesn't do you any good, besides making it unseafe.

The bigger tree will have no problem rebounding. Was the entire tree taken out on the smaller tree? If only one side of the crotch was, you'll be fine.
Clearly it was too deep for that aspen but I think most other species would have stood for a long time. From what I've read in the last day about aspens is that they tend to snap at the girdle.

The chestnuts should recover fine. It was just damage they did not need and did not have to happen.