Hardwood swamps are often dominated by trees: Green Ash (Fraxinus pennsylvanica), Black Ash (Fraxinus nigra), Silver Maple (Acer saccharinum) and others are common trees. Due to the invasion by the Emerald Ash borer, the ash species are likely doomed become minor players in American swamps, like the American Elm (Ulmus americana) and other native elm trees before them. Hardwood swamps are usually flooded in the spring and have a high water table for the rest of the year. Trees in all wetlands have shallow root systems to avoid oxygen depletion. These root systems make trees growing in wetlands less stable and more prone to tipping over during high winds, than the same species grown on uplands. This problem can be made worse by logging if too many trees are taken out of the forest because the remaining trees have to endure higher winds.
Floodplain forests have many of the same features and plant species found in hardwood swamps but have the addition of influences of rivers. Flooding rivers bring in silt, nutrients and seeds, the flowing waters also remove these same things. The water table can vary more seasonably than Hardwood Swamps, being above the water table in the spring, and then lower than that of the Hardwood Swamp in summer. For these reasons the Floodplain Forest is a more dynamic place. Eastern Cottonwood (Populous deltoides) is very common here; its seeds germinate on the exposed sediments, and its small broken branches will take root as water levels drop.
Unlike the Hardwood Swamp and Floodplain Forest, Coniferous swamps can vary considerably in the tree species that dominate. The trees give rise to the name of each type of swamp: Cedar Swamp, Tamarack, Black Spruce. Each type of swamp may have all three species of tree in them however.