The U.S. Forest Service says 500 pine trees were planted in October near a campground east of Payson.

What grows from the seedlings will not be vulnerable to a parasitic plant that has infected ponderosa pine there.

The infectious plant is a kind of dwarf mistletoe that had sickened 500 ponderosa pine trees around the Colcord Ridge Campground in the Tonto National Forest.

Federal officials say the newly planted southwestern white pine trees are immune to the parasitic plant, which grew roots into the ponderosas for stealing nutrients and water.

The Colcord Ridge Campground lies close to the Mogollon Rim.

The well-known site is located off an unpaved road that descends into the town of Young.