I've explained this before and I have to again.
Sanaag, Sool, Bari, and Nugaal have the very same landscape. Absolutely the same. Both areas range from extreme desert to White sands (mainly Sanaag/Bari) to massive green mountainsides. In fact, Nugaal is 70% green pasture, but the big towns like Garoowe, Eyl, and Burtinle are all in the desert, which is easier to navigate and more welcoming to urban life.
http://img144.imageshack.us/img144/4163/greeenmd2.pngNobody in Bari lives in the heavily wooded areas because they're unlivable, same with Sanaag. Most Maakhrians live in Ceerigabo, Dhahar, Xingalool, Badhan, and Lasqoray, and all of those towns are as arid as anything you're likely to find in Bari. There is no preference for charcoal traders in Sanaag over Bari, its just that Reer Sanaag aren't getting a cut of the profits so they're less welcoming of the trade.
Just getting that out of the way.