A NASA research document came to the conclusion that “house plants can purify and rejuvenate air within our houses and workplaces, safeguarding us all from any side effects connected with prevalent toxins such as formaldehyde, ammonia and also benzene.”� Trees are often seen as part of the answer for improving the environment and slowing climate change. Tree leaves utilize sunlight and absorb carbon dioxide from the air. Photosynthesis produces liquid sugars that go down into the root system to combine with soil water and minerals. Some of this goes back up the tree to produce more leaves, woody tissue, flowers and seeds or nuts. Some is stored as starch in the roots themselves, to be used during the winter or when the tree is stressed. The process of respiration converts these starches back into usable sugars, and also releases some carbon dioxide back into the air. Other pollutants can be removed too and are sometimes used as a design in remediation projects.

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