Video by Stephen Alvarez @salvarezphoto | An early morning flight over the eastern hardwood forest of the southern Cumberland Plateau in Tennessee. The forest here is beautiful and also a critical piece of Earth's ecosystem. Forests produce oxygen and lock up huge amounts of atmospheric carbon. But across the globe our forests are under siege. Right now the Amazon is burning at an unprecedented rate, and a NASA study out recently says that forest fires in the far north are burning with increased severity. Because of climate change, the fire season in the north is getting longer. Bigger, more frequent fires are releasing greenhouse gasses from the forest and also sending carbon that has long been locked away in the soil up into the atmosphere.