On Sept. 30 The Trustees of Reservations announced a significant milestone: the opening of its 100th reservation, Cormier Woods in Uxbridge. The opening celebration at the new reservation will take place on Oct. 18.

As well as a special celebration planned at Cormier Woods, including a ribbon cutting, ranger-led walks and live folk music, The Trustees will mark the 100th reservation with local celebrations around the state throughout the month of October.

On the Vineyard a celebration will be held at Long Point Wildlife Refuge tomorrow with a family frolic. The event, which runs from 1 to 4 p.m., will include kite flying, a sand activities station, a make-a-bluebird-box station, the debut of a new quest, and a Tisbury Pond Club walk. The day will end with cake. There is no admission charge.

Begun in 1891, The Trustees is the oldest land protection agency in the commonwealth.

Founder Charles Eliot was a landscape architect who apprenticed under Frederick Law Olmstead, the architect who is best known for designing Central Park in New York city. At the age of 27 Mr. Eliot, who lived in Boston, conceived the idea of creating an association to acquire parcels of land and hold them for public use, free from the burden of taxes. “Just as the public library holds books and the art museum pictures — for the use and enjoyment of the public,” he wrote.

Mr. Eliot died at the age of 37. But his idea took root and has since grown into a stunning, well-branched organization of properties throughout the commonwealth, including mountains and hilltops, formal parks, working farms, stately homes and gardens, country inns, 70 miles of coastline and five national historic landmarks. All are open to the public.

In all, today, The Trustees own and manage more than 25,000 acres in 71 communities.

On the Vineyard The Trustees’ first acquisition was Cape Pogue Wildlife Refuge on Chappaquiddick, in 1959, followed by Menemsha Hills in Chilmark in 1966, and Wasque Reservation on Chappaquiddick in 1968. Mytoi, a Japanese garden on Chappaquiddick, was a gift from the late Mary Wakeman in 1976, and Long Point Wildlife Refuge was acquired in 1979.

Conservation group is far-sighted. — Sam Low

In addition, The Trustees hold conservation restrictions on hundreds of acres, the most notable of which is at Seven Gates Farm in West Tisbury. Across the commonwealth The Trustees hold restrictions on some 35,000 acres of land.

Situated at Deep Bottom, Long Point is a mix of oak forest, sandplain grasslands and beach dunes bordering Tisbury Great Pond.

And tomorrow it is the place to come fly a kite and eat cake.