just a little example … for a medium tree you get up to 9 wood … so if you want 24 wood you must set the farmer to sapplings, plant min 3 trees manually and later you must select the trees for cut down.
a normal house (tiny cottage) use 6 wood for the build and 4 for the furniture - so 10 ^^ but you doesnt only want to build houses etc. later in the game you need wood also for fires, electric etc. ^^ sooo you will plant lots of trees and trees manually just to hold your town at a normal level xD
at the moment its ok because there are lots of trees at the start and you doesnt need it 