Tan is just dirt; no modifiers.
Light green is light undergrowth (20% concealment, double movement cost, can't charge or run, can't 5-foot step).
Dark green splotches are trees. Standing in the same square as a tree grants a +2 cover bonus to AC, and a +1 bonus to Reflex saves.
Thokram is in E10
Grey is in E11
Novihrek is in E12
Bathra is in I12
Serafina is in J11
Ǽlǽtan is in J12