harvesting submerged logs

I have an opportunity to harvest logs from a lake that was flooded 42 years ago (with the proper permit to harvest, unlike some of the guys on TV who are now being arrested) Local species include red gum, cedar, pine, oak, walnut, and probably a few more. These are standing trees that broke off at the water line many years ago. They will be cut around 12' long. They aree various diameters. There will be hundreds of cuttings. I know the cut ends of the logs need to be treated, but do not know what that entails. Does anyone have thoughts on what to use and how to handle that kind of volume? We are also looking for large volume buyers. Not interested in selling single logs.