Chop down trees formula

[whoward69]

Does anyone know the formula for chopping down trees? At standard speed it's 20/13/7 depending what "city ring" they are in, but I assume that changes for other game speeds.

 

[Machiavelli24]

Based on the FeatureProductionPercent column in the GameSpeeds table it looks like the final production is modified by:
quick: 67
standard: 100
epic: 150
marathon: 300