Moving to the forest is one turn, chopping itself is 3, thus making the cost of chopping 4 worker turns. Well, you can get them via whip. Yes, "overflow" is mentioned very often on this forum for some reason. Whipping is not good because of overflow, whipping is good because it transforms to at a good rate with a granary. However, as already pointed out, if -cap doesn't allow, don't whip. If you don't whip, don't build a granary. Well, despite you get unhappy at size 5, double food allows you to grow quickly even with one unhappy citizen. Another possibility is putting a chop into the library and 2-pop whipping. If you are planning to run scientists, it's likely that you should skip the granary, too, as you won't be growing anyway.