Investigators are seeking the cause of a grass fire that burned between 6 and 8 acres of abandoned farm land on the outskirts of Phoenix just after midnight Wednesday.

Investigators are seeking the cause of a grass fire that burned between 6 and 8 acres of abandoned farm land on the outskirts of Phoenix just after midnight Wednesday.

Callers from the Barnum Drive area called 9-1-1 to report the fire at about 12:20 a.m. Crews from the Medford Fire Department, Jackson County Fire District No. 5 and the Oregon Department of Forestry responded to corral the flames, which neighbors estimated came to within 200 feet of homes.

Cool nighttime temperatures and light winds helped crews bring the fire under control as it swept north from an ignition point near the Phoenix Canal, Medford Fire Marshal Greg Kleinberg said.

A forestry department bulldozer arrived by 1 a.m. to cut a fire line around the blaze, he said. It had encircled the fire by about 2:30 a.m., letting Medford crews clean up the scorched terrain.

The flames chewed through weeds more than 6 feet tall and tangled blackberry brambles that cover the abandoned orchards and farmland.

The property, now zoned for industrial use, is owned by Jackson County and the city of Phoenix.

The blaze lit up the night sky and attracted Phoenix residents who watched nervously as fire crews and equipment flooded their neighborhood.

"A neighbor called about 12:30 and said the back field is on fire again," recounted Doug Dillemuth, who lives on Arana Drive.

"I freak out each time because I have a bunch of blackberry bushes right behind the house."

As he and his wife walked around the charred area Wednesday morning, they noted that the number of fires has increased as foot traffic has picked up along the railroad line, where trains now are rare.

A fire swept across the same fields last summer, moving from north to south.

It was linked to a youngster playing with fire, Kleinberg said.

He and other investigators examined burn patterns and looked for evidence in the wake of Wednesday's fire, too.

Kleinberg said it could have been started intentionally or could have escaped from a transient campsite.

Campsites were found in the area along the canal where officials suspect the fire started, he said.

Reach reporter Anita Burke at 776-4485, or e-mail aburke@mailtribune.com.