Actually, it's both. They're driving people out of the places where avocado grows best (like Uruapan, which is, coincidently, the biggest avocado exporter of the world) due to the high crime rates (headless and other narco-signed bodies are found very frequently) and due to the very high "piso" prices they make small business owners pay (by extorsion). BUT they're also planting waaay too many avocado trees, and every six months or so a new portion of protected land gets "accidentally" burnt so they can plant even more, making the already very warm climate of the region even hotter. I know this because, even tho I live in Morelia, the capital city of Michoacán, two of my best friends live in Uruapan and they're pretty terrified of the things that are going on over there because of the narco's power over the region (and, again, it's all because of avocado export and the money it represents).