Two small planes collided near an Oregon state park Tuesday, sending one aircraft crashing to the ground and killing at least one of its occupants, authorities said.

Capt. Ken Summers of the Yamhill County Sheriff's Office said one body was recovered and investigators were looking into whether a second person had been aboard the plane that crashed and disintegrated, sending debris over a wide area in and around Champoeg State Park, about 25 miles south of Portland.

The second airplane involved in the collision managed to make an emergency landing in the park.

The planes collided at about 4:00 p.m. over farm country along the Willamette River. There are a number of small airports in the area.

Witnesses told investigators the plane that landed safely had struck the tail of the other plane, which broke apart in mid-air before crashing nose-first at the base of some tall trees and catching fire, Summers said.

He said investigators have information indicating the plane that landed safely may have been flown by a student pilot and a trainer who were practicing emergency descent drills. Summers did not elaborate.

Debris from the plane that crashed and disintegrated was strewn across both sides of the Willamette River, which abuts Champoeg State Park.

The Oregonian quoted a resident of the area as saying the impact was so great that he thought it was an earthquake.

"The whole house shook, the dishes rattled, and I thought it was the big one," Robert Nelson told the newspaper.

Witnesses said they saw a huge column of black smoke after the impact, KGW-TV reported.