There is one other option. Probably not a good option, but the one I would likely choose.
Chain saw them down. Use a tractor and chain to drag them out of the pond should they fall that way. Paint the stumps with tree killer so they do not sprout back. In five or ten years, get rid of the stumps when they have rotted out if you so desire.
Yes, I know the possibility of the roots going all the way through the dam and as they rot out creating a leakage path. That is probably ten to fifteen years down the road. By letting them grow they will only get worse, although still might have the same 10-15 years without problems.
I did not say it was a good idea, just the idea I would probably use. If the dam leaks ten years down the road, drain it enough to face the front side of the dam with clay. Problem delayed ten years and maybe not a problem at all. Playing the odds essentially
I pushed out a bunch of willow trees in a wet area of the inlet part of a pond I was renovating for my daughter. Where this shallow area was is now a deep area. Those trees were about 15 years old, were in clumps of 6-8" diameter and probably 25 feet tall. They had massive root systems (root ball almost hung up under the D6 dozer blade when I finally got it over), but out a ways from the trees the roots were very small, likely due to the abundance of water and nutrients available nearby. Just an observation that might not mean anything, but there is a chance the roots might only be half way through the dam.
One thing you did not show in a picture or describe is the back side of the dam. It might make a big difference it the back side is a 6 to one slope and goes way out into that field, compared to a 3-1 slope (or even a 2-1 like some of the old cow ponds around here) and a relatively narrow dam base. The wider that base is, the less likely that roots have went all the way through the dam. On the dam portion that we put nearest to our house, I wanted a transition very gradual so we have about a 6-1 slope so it more looks like a yard than a dam. If a tree was on that portion of the dam they would have to grow upwards or out a very long way to breech the dam. On the opposite side it is a 4-1 and it would be much easier for roots to transverse the dam. So how wide your dam is at the level of the trees could come into play also.
I had a huge (dead) tree stump on the face of the dam on my old pond I renovated. But I had lots and lots of fresh clay that I was essentially able to build a whole new dam with a gentle slope on the back side of the old dam. No leaks, but maybe I was just lucky, as I did not take out the old dam (just the 3' diameter tree stump on the front).
Hope this helps give you more ideas to choose from.
Last edited by snrub; 01/02/14 01:24 PM.
