DENVER - A bipartisan group of Western U.S. senators on Friday urged the Obama administration to focus more on preventing wildfires rather than taking money from programs that clear potentially hazardous dead trees and brush to fund efforts to fight the increasingly destructive blazes.

U.S. Sen. Jim Risch (R-Idaho) is one of four senators that signed the letter directed to Obama's budget director and the secretaries of agriculture and the Interior.

"It's kind of the opening round, if you will, in how to solve this issue," said Brad Hoaglun, Risch's communications director and senior policy advisor.

The administration is proposing a 31 percent cut in funding for the government's central fire prevention program one year after record blazes burned 9.3 million acres.

The federal government routinely spends so much money fighting wildfires that it uses money meant to be spent on clearing potential fuels like dead trees and underbrush in national forests.

"When the budgeted amount is insufficient, the agency continues to suppress fires by reallocating funds from other non-fire programs," the letter states. "This approach to paying for firefighting is nonsensical and further increases wildland fire costs."

The federal government is spending less in inflation-adjusted dollars on the main program to prevent forest fires than it did a decade ago. That's partly because of the increasing seriousness of the blazes. Firefighting costs have risen from 13 percent of the U.S. Forest Service's budget a decade ago to more than 40 percent today. Meanwhile, that agency's budget has been cut by 10 percent in inflation-adjusted dollars.

Eight of the nine most destructive wildfire years in U.S. history occurred since 2000. Drought, rising temperatures and increasing numbers of people moving to areas that border wildlands will continue to increase the risk. At least 65 million acres of federal lands - a swath of land larger than Oregon - is at risk for fires, officials say.

The letter was also signed by U.S. Sen. Ron Wyden (D-Ore.), U.S. Sen. Mark Udall (D-Colo.), and U.S. Sen. Lisa Murkowski (R-Alaska).

Staff writer Maureen Dolan contributed to this report.