Vaughn Logging and Lumber Company owns 3,130 acres of timberland on the north side of Mount Leno, which was purchased in 2008 at a cost of $560 per acre. In 2020, Vaughn began selectively logging this timber tract. In May 2020, Mount Leno erupted, burying the timberland of Vaughn under a foot of ash. All of the timber on the Vaughn tract was downed. In addition, the logging roads, built at a cost of $150,400, were destroyed, as well as the logging equipment, with a net book value of $280,600.

At the time of the eruption, Vaughn had logged 20% of the estimated 558,250 board feet of timber. Prior to the eruption, Vaughn estimated the land to have a value of $180 per acre after the timber was harvested. Vaughn includes the logging roads in the depletion base.

Vaughn estimates it will take 3 years to salvage the downed timber at a cost of $699,200. The timber can be sold for pulp wood at an estimated price of $3 per board foot. The value of the land is unknown, but must be considered nominal due to future uncertainties.

Required:
Determine the depletion cost per board foot for the timber harvested prior to the eruption of Mount Leno.