Plants change growth patterns according to their local environment. When plants grow it is called green-up; when they change color and lose their leaves it is called green-down. The study of the seasonal cycles of plant growth helps us understand climate change. These climate changes, such as temperature and amount of rainfall, influence plant growth and decline.


Values of plant color are referred to in terms of vigor, which is simply the strength and health of the plant. Vigor can be examined at a local level by monitoring the changes in vegetation color using the Plant Color Guide. Visual samples of this change help scientists understand how plants in different regions respond to seasonal changes in weather. Plant vigor comes in shades of green. Higher vigor produces darker shades. High values are seen in the rain forests of South America with blue-green shades, low values are seen in the Saharan desert of Africa, with a tan class color.


"GLOBE is the quintessentially ideal program for involving kids in science"
- Nobel laureate Dr. Leon Lederman.


Measurements and observations by GLOBE students serve several purposes.

  • Participating scientists use GLOBE data in their research programs to improve our understanding of the global environment.

  • Students learn how to carry out a scientifically rigorous program of Earth observations.

  • Students also learn how to use their own measurements––together with data from other GLOBE schools––as a key part of their study of environmental science.

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