In 1996, the stage was set for new communities in Black Diamond when King County agreed to let Black Diamond expand its boundaries in exchange for well-planned communities with preserved open space. The agreement required property owners to preserve 4 acres of forest for every acre added to the city.

In 2005, Black Diamond and King County, assisted by the Cascade Land Conservancy, entered into several agreements that used development rights and $1 million of King County’s Conservation Futures Tax to permanently preserve over 2,500 acres of open space and working forests. Specifically, King County allowed Black Diamond to expand its Urban Growth Area, permitting 329 acres to be annexed into Black Diamond and developed by its owners, the Plum Creek Timber Company.


In return, an easement was placed on 1,600 acres of adjacent land, known as Ravensdale Ridge, permanently creating a greenbelt northeast of Black Diamond that Plum Creek can only use as a working forest. This easement also protects more than 10 miles of trails for hiking, mountain biking and horseback riding.

The result in Black Diamond last week is that 1,600 acres of heavily forested land stays under its green canopy and development rights are shifted into the town of Black Diamond, where apartments and homes go instead of atop Ravensdale Ridge, a place of wild beauty. At the town’s famous bakery last week, it was not just muffins and scones that were celebrated.

- The Seattle Times, June 12, 2005

Plum Creek also agreed to give King County another 645 acres of open space, including portions of the Ravensdale Creek stream corridor, which is critical to the water quality of Lake Sawyer. This action was used as a match for another $3.6 million worth of funding from the U.S. Forest Legacy Program, allowing the preservation of thousands of additional acres of working forests southeast of Black Diamond.

Plum Creek Timber sold much of its land to Oakpointe, formerly YarrowBay, in 2006.

County Councilmember Larry Phillips called the deals that allowed the city to expand “a monumental victory” against uncontrolled sprawl.