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Floodplain Forest

This habitat occurs along wide, slow-flowing streams and rivers where stream banks often overflow during high rains and spring run-offs. One such location is at the northern border of the Ward Pound Ridge Reservation where the Waccabuc River flows, just south of the Town Park along Route 35, just west of Route 124. The Great Swamp in Putnam County along Route 22 also has a very large floodplain forest.

Because the soil is often flooded, only trees that can tolerate flooding can live here, such as sycamore, cottonwood, black willow, red maple, elm and black walnut trees. Shrubs in this habitat include sweet pepperbush, alder, silky dogwood, elderberry, buttonbush and spicebush. Skunk cabbage is common along with sensitive, royal and ostrich fern, nettles and jewelweed.

Watch this beautiful video of the Great Swamp narrated by James Earl Jones.

The Great Swamp
The Great Swamp

Did you know?

Because silt and nutrients are constantly being replenished by flooding, the soils of the floodplain forest are highly productive. This has meant that they were the first areas to be cleared for farming. The few remaining floodplain forests have very high plant and animal diversity because of these ideal conditions.

Ecosystem Benefits

Trees that eventually succumb to flooding and die create nesting habitat for a great many birds and other wildlife. Waterfowl in particular benefit from these flooded forests. As the flooded forests are apt to be continuous along watercourses, they serve as important wildlife corridors. They are also a stop-over habitat for migrating birds.

There is a great deal of biodiversity in this habitat. The following were found in an inventory of the Great Swamp:

  • 20 species of mammals, including bear, beaver, otter, fisher, muskrat;
  • 185 species of birds, 10 listed as rare; 100 nest in the swamp;
  • 36 species of amphibians and reptiles, 8 listed as rare;
  • 64 species of butterflies;
  • 58 species of dragonflies and damselflies;
  • 29 species of fish;
  • 12 species of crayfish

Benefits to People

  • Floodplain forests absorb and slowly release rain and storm water, reducing flooding and siltation downstream.
  • Water quality is improved.
  • There are many recreational opportunities including hiking, birdwatching and kayaking.

Which Lewisboro Preserves Have this Habitat?

Invasive Species

Unfortunately, the downfall of the frequent flooding and soil depositions are invasions by non-native species which are adapted to grow quickly in disturbed areas. These include phragmites, stilt grass, Japanese knotweed, honeysuckle and wineberry. They often out-compete native plants which are so important to the survival of birds and other wildlife.

The Role of the Beaver

The return of the beaver to our area may expand floodplain forest areas. Beaver can create wildlife habit, as is the case of the heron rookery along Route 121 in Bedford. In other cases, the beavers’ handiwork may result in street flooding and other problems. Many volunteers in the Three Lakes have worked to clear beaver dams to prevent this situation, allowing people and beaver to live in harmony, rather than trapping or killing them.