A Little Less Flood Control Might Help Save Unique Forests

(nat sound walking)

Doug Bechtel, Director of Conservation Science with New Hampshire’s Nature Conservancy, leads me into the woods.

We’re just a few yards behind New Hampshire Technical Institute in Concord, next to Interstate 393.

A few feet further, and we reach a beautiful floodplain forest…and it’s like stepping into a different world.

“the canopy over your head is this beautiful cathedral like silver maple canopy and some of the ferns like ostrich fern and sensitive fern can grow up to six feet tall”

The fern hasn’t begun to bud yet this spring, but in a few weeks, Bechtel says it will cover the forest floor.

Traveling a few feet more and it looks like we’ve hit a swamp.

(nat sound shoes)

“ floodplain forests are a wetland type, they’re classified as wetlands, they’re also forests, and they also only exist along rivers, so you have lots of different things coming together in one setting.13

More than 100 acres of floodplain forest lie along this stretch of the Merrimack River.

The forests typically occur in low, flat, flood-prone areas.

(the trees have a very distinct line on them sometimes that shows how high the water gets, sometimes there are bruises and places where ice scour has ripped the bark right off the trees) 12
When rivers overflow, the soils are enriched with nutrients that allow trees to grow large and provide unique and productive habitat for all sorts of wildlife.

(There’s something called the Cerulean warbler, we only know of about four nesting pairs in the state Cerulean Warblers are beautiful blue songbirds, there’s also something called the blue-grey knatcatcher and neither of these are extremely rare, but they’re unusual and they’re found mostly in flood plain forests)

(Nat sound birds)

The forests are also the only home to a rare plant called the Green Dragon.

But floodplain forests – as its name implies – need floods to survive.

(in some cases it’s really just inches)

Bechtel says their research shows the water level in these forests can make a huge difference in what survives.

"the elevation changes just a few inches, you get a completely different natural community type, based on the different plants that are there, and maybe the different kind of wildlife that is there.
But there’s a lot that scientists don’t know about these forests, such as how much water the forests need, at what times and at what elevation…and what types of soils help create these forests."

Kim Luntz, the Nature Conservancy’s Connecticut River Program Director, says it’s important they find out..because flood plain forests provide a huge service.

“Flood plain forests are our first line of defense against floods, they slow down flood waters, and when waters slow down, a lot of the stuff the water is carrying drops out.”

River dams have done a good job of controlling floods, but maybe too good…as they may harm the natural flood control these forests provide.

Luntz says they’re working with the Army Corps of Engineers, which regulates 14 of the dams along the Connecticut River basin, to study floodplain forests.

They want to find the delicate balance that will allow floodplain forest restoration, without harming people or communities.

For NHPR news, I’m Amy Quinton.