Tried searching the forum for an answer and found both yays and nays, so I'm hoping to get peoples thoughts on trees close to clay lined ponds.

I'm in the middle of digging out a ~ 1/2 acre pond which will end up being about 12-14 feet when done. I live in the low Sierra Nevadas and have a mix of oaks and pine on the property. I've removed some from the immediate area for the pond, but there are several nice, large trees that will be around 5 feet from the edge when completely full. My soil is "okay", with areas of solid clay and some of sandy loam. Because of this, I'm planning to line it with bentonite clay.

Would leaving the larger trees be high risk for roots getting into the pond and creating a leak? I don't mind a little extra plant material in the pond and want it to look natural with the landscape, so I'm hoping to keep the trees. If it's a huge risk, I'll go ahead and take them out.