Echnidna's right, the volume of a cylinder is Area x Length, and Area (for a circle) is pi x r x r, or pi x r-squared, where r is the radius. For r=.15 m I get
Area = 3.14 x .15 x .15
= 0.071 m-squared
For a length of 1 m, the volume is 0.071 m-cubed, and for a length of 6 m the volume is 0.071 x 6 = 0.42 m-cubed.
A price of $16 per metre would amount to 16/0.071 = $225 per m-cubed.
Not familiar with the terminology of "large end diameter", but if the radius of the log varies you could find an average diameter (radius) and use that as above. Not familiar with "recovery rates" either.
Those are my principles, and if you don't like them . . . well, I have others.