A lot of forests have been cut off by private companies everyday, just because they need fields where to plant palm or cereals for animals (that afterwards are killed to feed us). You can watch this website, http://www.worldometers.info, to see actually how many hectares of forests have been destructed this year (under the section ENVIRONMENT). Trees are one of the most easy and natural air-cleaning system to save our planet from air pollution and overproduction of CO2. We (they) are basically destroying the most powerful natural filter that converts CO2 to O2, purifies water, regulates the Climate and give us prime material to build green houses. So what could we do to stop this destruction?
There are some schools that are making a project: plant a hundred (less or more) trees somewhere near the school to reduce the actual school footprint. Because if you plant a tree you can reduce your own footprint by a few kilos per year. One tree does not so much but it's a  place to start.
Another idea is to follow projects like this one: http://www.plantabillion.org that basically plants trees for you, for a little money.

I agree, man!