Entrenchments and Terrain

[J6A]

Does an entrenchment in the jungle (I've been playing Saipan, it could apply to similar terrain elsewhere) give 4 column shifts against or 2?  The Direct Fire chart specifically says that an entrenchment in a town is a maximum of -2 shifts, however they are on the same modifier line, while jungles are on a separate one.  This becomes an issue when units come adjacent to an entrenchment.  The -2 for the entrenchment cancels the -2 for adjacent, and do the defenders still get additional protection from the base terrain?