A team of scientists measure a truly giant sequoia in Sequoia National Park, California.

Photograph by Michael Nichols, National Geographic
  • On September 25, 1890, President Benjamin Harrison created Sequoia National Park in California. Sequoia National Park is named for the giant sequoia, a type of redwood tree that is the world’s largest living organism. Giant sequoias can live for more than 2,000 years, and grow to have a mass of more than 544 metric tons (600 short tons).  

    Even though Sequoia National Park is protected, it is not completely pristine. Sequoia and neighboring Kings Canyon have some of the most severe air pollution problems of any national park. Warm winds carry pollution to the parks, which buffer the Sierra Nevada mountain range, from the heavily industrialized Central Valley and San Francisco Bay Area.

  • Term Part of Speech Definition Encyclopedic Entry
    air pollution Noun

    harmful chemicals in the atmosphere.

    Encyclopedic Entry: air pollution
    buffer Noun

    a cushion or shield.

    giant sequoia Noun

    largest species of tree on Earth.

    industrial Adjective

    having to do with factories or mechanical production.

    mountain range Noun

    series or chain of mountains that are close together.

    national park Noun

    geographic area protected by the national government of a country.

    organism Noun

    living or once-living thing.

    pristine Adjective

    pure or unpolluted.

    protect Verb

    to take action to prevent injury or attack.

    severe Adjective


    wind Noun

    movement of air (from a high pressure zone to a low pressure zone) caused by the uneven heating of the Earth by the sun.