About 11,300 acres on the leeward slopes of Haleakala on Maui will be dedicated to agricultural use, in a plan to preserve ranching and the rolling green hills at Ulupalakua.

The family-run Ulupalakua Ranch is scheduled to sign an agreement today with the Maui Coastal Land Trust to ensure the agricultural use of the lands.

“;From my family standpoint, we just want to make sure it stands that way,”; Ulupalakua Ranch President Sumner Erdman said.

The agreement allows the ranch to continue its operation but places a restriction on the land itself, barring its development for most urban uses, including residential subdivisions, the trust said.

By placing the restriction, the agreement inhibits the inflation of the land value and offers a tax incentive.

Under the agreement, the trust has the role of enforcing the covenants.

Trust Executive Director Dale Bonar said the agreement is the largest voluntary easement donation in Hawaii.

Bonar said the agreement by the Erdmans will also help promote sustainability by protecting agricultural lands.

“;Their goal is to have their land available for agriculture forever,”; Bonar said.

The agricultural easements consist of two parcels, one of 6,000 acres and a second of 5,328 acres, stretching from the ocean to the 6,000-foot elevation.

The mauka area is home to the 'Auwahi Habitat Restoration Project, part of the Leeward Haleakala Watershed Restoration Partnership.

Ulupalakua Ranch, purchased by Pardee Erdman in 1963 from the Baldwin family, is Maui's second-largest cattle ranch and operates on about 18,000 acres.

Prior to cattle ranching, the land was used to farm sugar cane, potatoes, corn, sweet potato, dry-land taro and specialty hardwoods such as sandalwood and koa, the trust said.

The trust secured a similar type of donation when Pu'u o Hoku Ranch on Molokai dedicated 3,000 acres about two years ago.