How many forests are there in the world? How much carbon dioxide is stored by the Earth's vegetation? NASA would like to answer these questions by creating the first comprehensive 3D visualization of the world's forests through the Lidar technology, using tools such as satellites and lasers.
Here's how it will work: a satellite will send a pulse of light from space all the way to the Earth's surface, passing through the forest's canopy. Then, a small fraction of that light, called a 'return pulse', will reflect back to the satellite and the time that it will take to get back will be a measure of how far it has traveled, that is the height of the reflected object. In addition, depending what kind of material the pulse reflected against, the signal will be slightly modified; so if the light will encounter a leafy tree top or woody trunk, the information transmitted will be different.
With 16 billion pulses sent from the satellite each year, scientists will be able to accurately measure the biomass of the trees in the world and the amount of carbon they contain. The mission, called GEDI (Global Ecosystem Dynamics Investigation) is planned for 2018 and it will lead to have better trees mapping techniques and to have better forest management policies.