He talk in some moment about the water, that they fight to maintain the water in the earth... water=freshnes=not-so-warm but with the deforestation you get less water so.... maybe, just maybe this could be also one of the reasons why the temps also could go up on the planet but is not a good one for the wood industry... I never did hear about it, just that the trees give oxygen and that's it. They never talk about the water under the trees :)

Edit: also, less trees, less oxygen in the air and more CO2 because the trees take the CO2 (day time of course) to change it in oxygen when they do photosynthesis... something more to look about it