User blog comment:D2r/Unanswered Questions of Redwall/@comment-99.98.209.91-20110417032601

Another question (which you may not fully understand if you have not read all the later books) - the map of the world of Redwall undergoes some drastic changes, most notably the removal of the giant mountain range separating Mossflower and Salamandastron. There are also other change that can be seen.

In terms of the bread question, BJ seems to have somewhat created a provision for that along the lines of 'greensap' - he mentions pollen flour and various nut flours. That being said, the milling question obviously still stands for the various barley and oat products mentioned frequently throughout the series.