Central Park Conservancy
The conservancy's site offers plenty of options for contributing, including planting trees and adopting a bench. Donate $1 for a daffodil.
New York Audubon Society
The society offers educational programs and bird walks as well as running several sanctuaries around the state.
New Yorkers for Parks
An independent advocacy organization, NY4P strives to increase awareness about the importance of parks as a vital public service. Donations support the organization's work towards the creation of a more equitable and efficient parks and recreation system.
Prospect Park Alliance
This public/private partnership works to preserve Brooklyn's 526-acre expanse through membership and other donations, such as commemorative trees.
Wildlife Conservation Society
Headquartered at the Bronx Zoo since 1895, the WCS works both locally and worldwide to educate about and conserve wildlife.