Deforestation in developing countries is a pretty big problem with a pretty easily identifiable source. The governments in those countries with such a problem (especially the Amazon countries) just hate poor/uneducated people more than they hate deforestation, so they don't do anything to fix the mess they've allowed to be created.
And jesus h., it's not like the forests don't do anything. I can't remember the exact number, but for every so many hectares of woodland which are razed from the earth, some absurdly high tonnage of carbon dioxide per year, instead of being photosynthesized and turned into diatomic oxygen, gets dissolved in oceans and rivers and does nasty shit to the aquatic ecosystems (usually involving a total breakdown of said ecosystem via the deaths of keystone species who are highly sensitive to the amount of dissolved CO2/O2 in the water.)
e: Another big goddamn deal is topsoil loss, but that's one that you literally never hear about in the news, so nobody knows about it.
