Forestry and Farming
The difference between healthy and unhealthy crops can be determined by satellite measurements of very specific frequencies of light. Red light, for example, is absorbed by the chlorophyll in healthy plants, whereas infrared light is absorbed when plants are suffering internal leaf damage from bad weather, infestations or other stresses. As a result, farmers can use regular satellite views of their farm to monitor the health of their crops, and even to identify areas of their fields that may need more water or fertilizer. Other satellite tools like radar can distinguish between different types of crops, allowing government agencies to conduct large-scale studies of what farmers are growing. Similar techniques can be used to monitor forests, keep track of clear-cutting and assess the health and species of remaining trees.