As the red tail flies: the link between the Bay and the watershed forest
by Kate McPherson, Narragansett Bay Riverkeeper
Snow falls gently around the Narragansett Bay watershed; and the branches of the black oak, red maple and shagbark hickory are all bare. A month ago, despite the bitter cold, the white-breasted nuthatches in my corner of the watershed started singing, eking out territories and duking it out at the sunflower seed feeder. Now, the house finch, black-capped chickadee, mourning dove and tufted titmouse have started singing their territorial songs too. Red-winged blackbirds have returned, and grumpy flocks of robins complain loudly in the treetops. As the Narragansett Bay Riverkeeper, I’m always thinking about how the watershed affects the health of Narragansett Bay. But for many people, that connection is not immediately clear.
Birds are some of the most charismatic indicators of both the seasons and health of undeveloped areas in the watershed. A red-tailed hawk, as at home in urban areas as in forested portions of the watershed, is a good guide to lead us through the links between the Bay and forest where the red-bellied woodpeckers trill.
From the edge of the Bay into the rivers that flow into it
Imagine a red-tail perched atop our Bay Center at Field’s Point in Providence, overlooking the Bay. From its bird’s-eye, view the hawk looks for a meal in the tall grasses and shrubs of the buffer along the shore. The buffer protects the calm cold water of the upper Bay, where red-breasted merganser, goldeneye, and ring-necked ducks dive for fish. Nearby, a harbor seal hauls out onto a rock at low tide. Our hawk takes off and flies north—up the tidal Providence River, past the port and over the many bridges that span the river into downtown. It’s hard to tell when the Bay ends and the river starts.
The hawk veers west up the Woonasquatucket River, where a thin strip of trees provides perching sites and a little bit of shade. This portion of the river is in rough shape though, polluted with dioxin, bacteria, copper, lead, zinc, PCBs and mercury. It often lacks enough dissolved oxygen for fish and invertebrates to live. The physical connection between the Woonasquatucket River and Narragansett Bay is clear.
Further upstream to the wetlands
As the hawk heads on, several miles upstream, freshwater wetlands appear along the banks of the river. Wetlands next to rivers are valuable for many reasons. When the water enters a wetland, it slows, allowing sediment and pollution in the water to settle out; bacteria in the wetland soils break down the pollution. Freshwater wetlands have an incredible variety of plants. The most water-loving plants grow entirely beneath the surface of the water. Other water-lovers have parts that float on the surface of the water. Still heartier plants emerge from the water with stems that stand even in the deep February freeze. Shrubs range from low and sparse to tall and spindly. Finally, young saplings and tall mature trees, both deciduous, like maple, and evergreen, like white pine, give the wetlands their height.
This time of year, most freshwater wetlands have surface water; but even during drier seasons, they provide vital water-cleaning functions. In large rainstorms, wetlands help protect against downstream flooding by storing and slowly metering out stormwater. Undeveloped floodplain areas, although dry most of the time, also store and slow down floodwaters. The physical shape of the floodplain, and the presence of plant stems, decrease the water’s erosive force and prevent sediment and other pollutants from reaching Narragansett Bay.
Into the tiniest tributaries and the watershed forest
Flying even further upstream, our red tail passes many tributary streams, smaller watercourses that feed the main stem of the Woonasquatucket. Some of these tributaries have names and flow year round, but many are much smaller and dry up periodically. These smaller streams are just as valuable to the system that drains to the bay. As our hawk climbs even higher into the watershed, the neighborhoods thin, and larger tracts of forest and undeveloped land emerge. From our bird’s view in the sky, the woodlands look no different; inside the forest, a mosaic of trees is revealed.
Red maple is the most common species, but eastern white pine, northern red oak, black oak, eastern hemlock, scarlet oak, and sweet birch are also common. The forest isn’t just made of mature trees with giant spreading canopies. Smaller trees and saplings form an understory. Beneath them: tall shrubs that tolerate lower light conditions and groundcover plants, like ferns, clubmoss, and small wildflowers. They all play their roles in a healthy forest. Perhaps most important of all, a forest floor deep with leaves, fallen pieces of bark, and rotting logs must be present for forests to thrive and provide the most benefit to the watershed.
When rain falls over a forest, the water takes a while to drip down to the ground. First, the raindrops coat the leaves in the upper canopy. The drops spread out along the surfaces of the broad leaves and branches, and finally soak down the bark. The same thing happens with each layer all the way down, water slowly soaking into bark and sliding down branches. When drops do drip onto the leaf litter layer, the thick spongy forest floor absorbs the energy of the falling drop, and the water soaks down into the ground.
Even in heavy rainstorms on steep slopes, forests protect the landscape from erosion. When water from a storm erodes the landscape in the watershed, it picks up sediment and any pollution that happen to be on the ground. But pavement, lawn, or hard-packed areas do nothing to slow the water down, and muddy and polluted runoff can flow directly into waterways that feed Narragansett Bay. In this way, and others, the forests in our watershed have direct benefits to the water quality of our bay.
What you can do from wherever you are
The good news is that no matter where you live in the watershed, from the Pawtuxet to the Blackstone, the Ten Mile to Taunton, you and your neighbors can take various actions to protect the bay. Bay-Friendly Living provides lots of ideas, but simply letting leaves go un-raked in a portion of your yard goes a long way. Over time, seeds trapped in the leaves will sprout, and taller grass and shrubs will colonize under your tree.
Speed up the process by planting native trees and shrubs in an area that was previously mown and raked. Let branches, leaves, and other natural organic material accumulate in your restoration area. In these ways, you can not only help with water quality for the Bay; you might just attract more of our resident birds whose songs remind us that spring is on it’s way.