New to Pond Boss - Am building a 3/4 acre pond and have stacked oak trees in a couple of bays - they are anywhere from 20-36 inches in diameter and 10-15 feet long. Locally I am getting answers all over the board from- "don't worry they will sink" up to "you will need 250 lb. weight for each tree" - now how is that for a wide range of answers? Hoping to get some help here as I don't want to fill the pond and then have the things floating all over the place. The sides of the pond are very steep and anything over about 75 lbs I would have to hire an excavator to place. I can buy blocks locally that weigh 75 lbs. each and have a hole in them that I can get down in the pond myself and run a cable thru. Don't want to overkill here- but don't want floating trees either --can anyone help on this?

thanks !!