The unit of measurement might be tons, tonnes, cords, truckloads, cubic feet or cubic meters is irrelevant. We use tonne to represent some measure of production.
Determining the production for a particular piece of equipment or logging system can be more complex.
For instance if you run two feller bunchers, you cannot easily determine the share of total production that each contributes to. In this case, it is necessary to watch the machines. Count how many units of volume each machine does over a day, or better yet a week or a month, then divide by the total number of hours the machine actually worked. You will then have a good idea of what your production per working hour is. The longer the period of time you take your measurement over, the more accurate your average number will be.
If your machine operator is running an eight hour shift and you are keeping careful track of the number of actual productive machine hours per shift you will very likely notice that it is some percentage eight hours. It is instructive to figure exactly where the downtime is coming from. Employee breaks, daily maintenance and mechanical breakdown all contribute to machine downtime. This analysis is called machine availability and utilization.