POLK COUNTY -- Firefighters from across Polk County and even Yamhill County were put to the test Thursday and Friday battling three blazes on local farms.In two cases the incident erupted into large and intense fires that burned a significant amount of both farmers' crop still sitting in the fields.Dallas Fire Chief Bill Hahn said the largest of last week's field fires were the biggest and most intense firefighters have had to battle so far this year. At least two of the three were ignited accidentally by farm equipment."It is extremely dry and unfortunately too much heat too close causes it to spread pretty rapidly," he said.The first in a series of three fires began Thursday afternoon when firefighters from multiple agencies responded to a fire in a field at Zeigler Farms at 4820 Highway 99W at about 2 p.m. Photo by Pete Strong An Amity Fire District crew looks for hot spots from within the burn area Thursday as trees to the south smolder. According to fire officials, an overheated catalytic converter on a truck working in the field started the fire as a crew was harvesting wheat.The fire quickly spread and eventually burned what is estimated to be 160 acres."The majority of the wheat was unharvested," Hahn said.Fire crews from Dallas, Polk County Fire District No. 1, Southwest Polk Fire, McMinnville, Amity, Dundee, LaFayette, Dayton and Newberg responded to the fire. Neighboring farmers and their workers also helped battle the blaze while firefighters rushed to the scene."There were a number of farmers that had people out there assisting them," Hahn said. The fire was contained mostly to the field, however firefighters remained on the scene extinguishing flare-ups for about eight hours. Hahn said no damage estimates were available at press time.While on the scene of the Zeigler Farms fire, a second one started near the intersection of Highway 99W and Smithfield Road at about 5:20 p.m. Crews who responded to the first fire, plus more firefighters and equipment from Dallas, Southwest Polk and Falls City, moved to that fire. Photo by Pete Strong Firefighters set up a hose line to battle a fire in hay stacks at Sunrise Trading Co. on Beck Road southwest of Perrydale Friday. No damage estimates were available. Hahn said hay stacking equipment struck a nearby power line, causing it to fall and ignite the field. Firefighters extinguished the blaze quickly and only three acres burned."They were able to contain that pretty easily," Hahn said.If back-to-back fires on Thursday wasn't enough, a third field fire broke out Friday at about 5 p.m. at Sunrise Trading Inc., 13895 Beck Road, southwest of Perrydale.The blaze consumed two-and-one-half stacks of hay bales measuring approximately 100 feet long by 30 feet high as workers were in the process of putting tarps over them.Farm owner Brian Domes said his business raises the hay and ships it overseas. The stacks that burned were destined to make the trip to either Japan or Korea in late September. He said it would be difficult to replace what was destroyed."It's possible to buy from others, but most everything is spoken for in the valley," he said.Domes is still trying to determine whether a fork lift was the source of the fire and didn't have enough evidence yet to say one way or the other. Hahn did not have a damage estimate and Domes declined comment on the value of the hay. Photo by Pete Strong A crew from Amity Fire District hoses down a flareup in a wheat field fire from the front of their engine Thursday afternoon north of Rickreall along Highway 99W. Sheridan Fire Department was the first on the scene and Hahn praised the crew for preventing the fire from spreading to a barn only about 120 feet from the hay stacks. The barn and contents are worth about $400,000, according to Hahn."We can't say enough good things about their efforts, or we would still be out there," Hahn said.Domes said he is especially grateful to firefighters and his neighbors for preventing the fire from getting to the barn."That was the goal from the beginning," he said. "The rest we knew was gone."Hahn said despite last week's onslaught, field fires of this magnitude and in quick succession are fairly uncommon. He said in decades past, farm fires happened much more often. Ironically, the improvement is partly due to farm equipment upgrades."To have these three incidents back-to-back is unusual," he said. "A lot of it is the better design of the equipment they are using these days."