I know cyprus is one wood type from down south that can be waterlogged.I have a situation on the west fence line of my north west pasture in which there is an underground stream that flows under me fence then south a half mile accross my land to dump into the creek. This year when i repalced that fence there had been one old growth cedar fence post right smack dab in the middle of this stream. On the surface the ground is dry but two feet down it is flowing i could see that when i dug out the post to replace it. The old post was wobbly but still intact after 76 years. I know the complete history of my land because the family that pioneered it and owned the whole valley are my neighbors. When i replaced that post i used a section of old telephone pole 8 feet long as there were no cedar posts available. I also used a couple of bags of concrete dry then filled it and packed it. The reason for this stream is mostly because of my neighbor on that side that irrigate pasture 24/7 all summer and part of the fall with much of the water flowing back into the creek. Untill i dug out this post i had no idea that this streeam was flowing under my land or how much my neighbor was contributing to the problem. There are people that make good money searching for submerged trees, logs that have been under foir decades because the wood is often very hard and of high dollar value.