We have a couple of filbert (hazelnut) trees that are the same age ( about 10-12 feet high ). One is doing really well but the other is doing poorly. We noticed this last year but didn't really get around to checking out what was wrong. Well this year it is looking even worse so yesterday I gave it the once over. I noticed in the clump of trunks coming up out of the ground that ants have built a nest about a foot high! :shock:' This just has to be the problem. This tree is in such hard shape and crowded, that I would like to remove it. It would give the other filbert and a high bush blueberry much more room. My question is, do filberts need to have another tree nearby for pollination purposes (cross) or would having just one be OK? Thanks.