Land that has been classified under this law is assessed in accordance with valuation schedules updated annually by the Department of Revenue (DOR). The assessor must determine which land qualifies and then assess the land according to DOR-certified forest land grades.

New applications are submitted to the Assessor's Office for approval or denial and must include a non-refundable application fee of $403.50 (includes mandatory recording fees of $303.50). A timber management plan may also be required as part of the application. If approved, classification will be effective in the assessment year following the year of application.

Once land is classified, the Assessor's Office is responsible for conducting periodic reviews to make sure the land is still being used for the purpose for which it was granted classification. When Designated Forest Land is removed from classification, there will be a Compensating Tax assessed.

According to RCW 84.33.140(7), the assessor has the option to require an owner of Designated Forest Land to submit a timber management plan upon the following: 1) An application for classification or reclassification as DFL is submitted; 2) DFL is sold/conveyed and the new owner has signed a notice of continuance; or 3) The assessor has reason to believe DFL less than 20.00 acres in size is no longer being used to grow and harvest timber.

During the 2014 legislative session, Senate Bill 6180 was passed by the Washington State Legislature. This bill allows counties the option of merging land classified as Open Space Timber Land with the Designated Forest Land program, reducing the administrative workload as well as reducing the processing burden on taxpayers. On July 15, 2014, the Board of Cowlitz County Commissioners passed Ordinance #14-062 to merge all Open Space Timber Land into the Designated Forest Land program under RCW 84.33, effective immediately.

All new applications for classification of timbered land in Cowlitz County must be submitted under the Designated Forest Land program.