Applications of leaf spectroscopy have many different end uses. Leaf level information is crucial to quantify the state of physiological processes, for example the energy budget and transpiration. It is used to monitor photosynthetic rates and respiration rates. It provides a basis to scale environmental processes from the molecule to the planet. Leaf spectroscopy is also used in remote sensing studies to calibrate processes and provide ground truth data for interpretation, and in agriculture to indirectly calibrate foliar nutrients like nitrogen concentration.