DISASTERS

Homes on edge of the wilderness complicate wildfire efforts

  • Resident Laurent Lacore, 48, returns to his home near Sand Canyon Road in Santa Clarita, Calif., Monday, July 25, 2016. The majority of some 20,000 people forced from their homes by a wildfire that exploded during the weekend were told they could return home Monday night, though an army of firefighters continued battling flames in the rugged hills and canyons northwest of Los Angeles. (AP Photo/Ringo H.W. Chiu)

    Resident Laurent Lacore, 48, returns to his home near Sand Canyon Road in Santa Clarita, Calif., Monday, July 25, 2016. The majority of some 20,000 people forced from their homes by a wildfire that exploded during the weekend were told they could return home Monday night, though an army of firefighters continued battling flames in the rugged hills and canyons northwest of Los Angeles. (AP Photo/Ringo H.W. Chiu)  (The Associated Press)

  • Resident Laurent Lacore, and his wife Florence, check their house after they return to their home near Sand Canyon Road in Santa Clarita, Calif., Monday, July 25, 2016. Lacore, a native of France who lives in Santa Clarita, was among those who evacuated on Saturday, the last of his family of four to leave as the fire bore down on his house. "The flames were right behind our backyard," he said. (AP Photo/Ringo H.W. Chiu)

    Resident Laurent Lacore, and his wife Florence, check their house after they return to their home near Sand Canyon Road in Santa Clarita, Calif., Monday, July 25, 2016. Lacore, a native of France who lives in Santa Clarita, was among those who evacuated on Saturday, the last of his family of four to leave as the fire bore down on his house. "The flames were right behind our backyard," he said. (AP Photo/Ringo H.W. Chiu)  (The Associated Press)

  • Resident Laurent Lacore, checks his property after returning to his home near Sand Canyon Road in Santa Clarita, Calif., Monday, July 25, 2016. Lacore, a native of France who lives in Santa Clarita, was among those who evacuated on Saturday, the last of his family of four to leave as the fire bore down on his house. "The flames were right behind our backyard," he said. (AP Photo/Ringo H.W. Chiu)

    Resident Laurent Lacore, checks his property after returning to his home near Sand Canyon Road in Santa Clarita, Calif., Monday, July 25, 2016. Lacore, a native of France who lives in Santa Clarita, was among those who evacuated on Saturday, the last of his family of four to leave as the fire bore down on his house. "The flames were right behind our backyard," he said. (AP Photo/Ringo H.W. Chiu)  (The Associated Press)

Millions of homes built on the edge of wild areas are complicating the work of wildfire managers who must decide how to deploy the nation's firefighting resources.

Some 44 million homes have been built in what scientists call the wildland-urban interface, most in recent decades. The areas are often scenic but susceptible to fire.

Protecting those homes from flames is expensive and drains resources that might otherwise protect forests, rangelands and critical habitat for wildlife. Besides the financial burden, there's also the human cost. Three firefighters died in Washington state last year, and 19 perished in Arizona in 2013 while working in those areas.

Fire officials emphasize the need for homeowners to put so-called defensible space between their homes and vegetation to protect against wildfires.