" I have seen wild American chestnuts growing in low lying swampy areas. At first glance, it seems that they can tolerate wet feet, but a closer look at the topography reveals something else. In older forests the ground is very uneven. As large trees topple over and are uprooted, a depression is created where the root mass once was. As the root ball breaks down, a mound is formed. This landscape feature is referred to as ‘pit and mound’ or ‘pillows and cradles’. It is commonly associated with almost all old growth forests.
Pit and mound landscapes are essentially covered with vernal pools and raised beds. Chestnuts, like almost all trees, prefer to grow on the mounds. If you have a wet field, and want to grow chestnuts or really any other fruit or nut tree, then make some mounds. The bigger they are the better they work and the harder they become to mow around. I have made them with everything from a shovel to a bulldozer. The pits catch and store water while the mounds provide drainage for the root crown.
Taking pits and mounds a step further, we can create swales and berms to plant rows of trees on. These rows can be set on contour lines to maximize water catchment and prevent erosion."
... and so much more makes sense now.
Direct link: http://www.twisted-tree.net/articles-links/how-to-grow-chestnuts-part-3/
Part 1 of the 4 part series: http://www.twisted-tree.net/articles-links/chestnut-the-bread-tree-part-1/