"There aren't many things in life that one can do that really extend into the far future with assurance," Howard said. "But this is just about the best way I can think of. Land is so precious. And once it's gone, it's gone."
Officials of the center signed an agreement Wednesday with the Natural Lands Trust, a nonprofit land-conservation organization, which will monitor the easement and, if necessary, enforce it.
"Philadelphia is blessed with a lot of open space . . . but when you think about the consequences of losing something like this, and what the impacts would be to the community and the ecology of this area, it's difficult to overstate the importance of this," said Molly Morrison, president of the trust.
Neighbors chimed in as well.
"It's an extraordinary thing they've done," said David Cellini, president of the Residents of Shawmont Valley Association in Upper Roxborough.
The center traces its origins to the mid-1960s, when descendants of Henry Howard Houston, a railroad magnate who died in 1895, donated land.
One of them was Henry Meigs, who secured the promise of preserving the land from Howard.
Meigs' son, Massachusetts sculptor Binney Meigs, is now president of the board. He grew up on the property - bordered by Spring Lane, Hagys Mill Road, Port Royal Avenue, and what is now the Schuylkill Bike Trail - roaming its woods, he said in a phone interview Thursday, and "it holds huge power for me."
The property encompasses two "first-order streams," Smith's Run and Meigs' Run, which are largely unpolluted from their headwaters to where they empty into the Schuylkill, a rarity in any city.
It has nesting populations of rare species like the blue-winged warbler and trees believed to be 250 years old.
