Trees are more than just part of the landscape - they are life-support systems for the planet. From giving us oxygen to ...

Ever wonder what happens to oxygen levels when leaves fall off the trees? Joe lets us know how we are still able to breathe.

Dr. Universe: Do trees still create oxygen and clean the air after their leaves fall off? – Nova, 8, Palouse, Wash. The trees that lose their leaves in fall, such as chestnuts, oaks, aspens and maples ...