Riverdale Park natural area

Hudson River, W 254 St, Palisade Av, W 246 St.

Riverdale Park is known for its secluded beauty, thick woods, spectacular views of the Palisades along the Hudson, and for being a haven for birds. Twenty-seven bird species, including the screech owl (Otus asio), have been confirmed as breeding in the park. The bedrock of Riverdale is billion-year-old Fordham gneiss, the oldest rock formation in New York City. On top of the gneiss lies Inwood marble, which was once quarried in Riverdale for the production of lime. Remains of two lime kilns stand in the park today.

Riverdale Park contains about 50 forested acres, including mature oak-hickory forest, a forest that occurs on well-drained sites, often on ridge tops, upper slopes, or south and west facing slopes. Composed mainly of five species of oak with black birch (Betula lenta) and hickory (Carya spp.) interspersed, the woods are on their way to becoming a mature or "climax" forest: a forest whose shade-tolerant seedlings will survive beneath their parents. Red oak (Quercus rubra) is most common here, identifiable by its bristle-tipped leaves and vertically striped bark. Other oaks include black (Quercus velutina), chestnut (Quercus montana), white (Quercus alba), and the water-favoring pin oak (Quercus palustris) growing further downslope.

Although much of Riverdale Park has been cleared at one time or another, the southern end is covered by the same type of forest that existed in pre-colonial times, where tulip trees as tall as 110-feet rise from the slopes of the ravine. Red oaks, black birch, black cherry (Prunus serotina), and hickory are scattered throughout the canopy. At the end of the ravine, a small grove of witch hazel (Hamamelis vriginiana) grows on the eroded bluffs overlooking the Hudson. In the spring, woodland wildflowers like jack-in-the-pulpit (Arisaema spp.), bloodroot (Sanguinaria canadensis), and blue violet (Viola spp.) bloom along the shaded path. Later in summer, spikenard (Aralia racemosa), blue-stemmed goldenrod (Solidago caesia), and joe-pye weed (Eutrochium spp.) flower as well.

The Alderbrook wetland and surrounding forest was the site of restoration efforts in 2003 to reduce the dominant knotweed (Reynoutria japonica) and make space for native, locally evolved plant species. Breeding birds found in this area include yellow warblers (Setophaga petechia) and common yellowthroats (Geothlypis trichas), both of whom nest in the dense shrubbery.

The trails offer spectacular views and are at their most magical just before sunset, as light fades over the Hudson River. The Red Trail loop is easily accessible from the parking lot at Spaulding Lane and the entrance into the park at West 254th Street. At just under a mile long, it offers hikers views of the Hudson River through the shading mature canopy trees along the western ridge of this Forever Wild area while also passing through a small pine grove and mature oak-hickory forest. The Blue Trail is a short 0.6 miles hike through a red oak and tulip tree-dominated forest with varying sloping terrain.