OLYMPIA — Logging on state lands on the North Olympic Peninsula and elsewhere could increase by about 35 percent over the next two decades, under a plan tentatively approved by the Board of Natural Resources on Tuesday.

Members of the six-person board said they hope the new approach will finally end the bitter timber wars of the 1990s, when state and federal regulators sharply curtailed logging to protect spotted owls and salmon.

But a truce remains elusive.

Environmental leaders attacked the plan, and said they may sue to block it.

Public Lands Commissioner Doug Sutherland says the state can have it both ways: increase logging and improve the forest environment.

The logging plan, if it wins final board approval this summer, will be the main achievement of Sutherland’s four years in office, he said.