Just for interest of how much lumber you gain each minute. Just made 160k in the last game i played and i must have been at 4k per minute if not more by the end (solo lumberer).
Suggestions on how to count it:
1. Count the increase of lumber (or preferably how much has been produced) in the last 10 seconds and multiple by 6 (or in last 5 secs, multiply by 12)
2. Count how many of each type of lumber mill you own (include only 4 upwards maybe?) and multiple by how much it earns in x amount of seconds etc and work it out that way.