Federal mismanagement of timber lands has cost the government at least $90 million since 1986, an Interior Department audit found.

Mishandling of Bureau of Land Management forests in western Oregon is the result of financial shortcuts prompted by budget cutbacks, the department's Office of Inspector General said.

The report said the BLM lost $90 million by failing to perform thinning, fertilization and other maintenance that resulted in fewer trees that could be cut. The BLM estimated it lost 94 million board feet of timber growth in the fiscal years 1986-89 due to inadequate management. A board foot is 1 foot by 1 foot by 1 inch.

In addition, the BLM has failed to acquire easements to 132,000 acres with 800 million board feet of mature timber valued at $302 million. Losses could total as much as $1.7 billion over the forests' 60- to 80-year life cycles, the report said.

The audit of BLM forestry operations on 2.4 million acres across 18 Oregon counties criticized the agency for failing to explain the magnitude of the losses to Congress and the Office of Management and Budget.

BLM Director Delos Cy Jamison said in response to the review that his budget requests have been "somewhat constrained" by funding targets provided by the Interior Department.

"These targets, which are less than ideal to accomplish the desired workload, are consistent with the goals of the administration to reduce federal deficits," Jamison said in a memo to the inspector general's office.