Over Logging is a type of Event and can only be triggered at the Lumber Mill. This event raises the Utopium harvesting limit for trees from 25u to 50u for 24 hours. Triggering this event costs you up to 75mil (depending on Expansion level).
"U Can Do Better: Daily harvest limit can be raised to 50u. Effect lasts 24 hours."
NOTE: Though it says the event lasts 24 hours, it does not last all 24 hours. The event lasts till midnight. So if you trigger the event at 11 am, the event lasts for 13 hours (till midnight).