• Giant Sequoia Trees

    Sequoia & Kings Canyon

    National Parks California

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  • Road Construction Delays on Park Roads for 2014 Season

    Expect occasional 15-minute to 1-hour delays in Sequoia and Kings Canyon National Parks on weekdays only (times vary), including delays to/from the General Sherman Tree, Crystal Cave, and Grant Grove. More »

  • Vehicle Length Limits in Sequoia National Park (if Entering/Exiting Hwy 198)

    Planning to see the "Big Trees" in Sequoia National Park? If you enter/exit via Hwy. 198, and your vehicle is longer than 22 feet (combined length), please pay close attention to vehicle length advisories for your safety and the safety of others. More »

  • You May Have Trouble Calling Us

    We are experiencing technical problems receiving incoming phone calls. We apologize for the inconvenience. Please send us an email to SEKI_Interpretation@nps.gov or check the "More" link for trip-planning information. More »

Air Quality -- Nitrogen Deposition

Farm tractor plowing field with dust billowing behind

A dust cloud rises from a field being plowed in the Central Valley of California.

NPS Photo

Nitrogen is essential for all living things. It is found in solid earth and in the atmosphere. Small amounts of nitrogen move in a dynamic cycle involving the atmosphere, oceans, lakes, streams, plants, and animals. Depending on the form and amount in the environment, nitrogen can serve as a nutrient, enhancing growth and productivity, or as a toxin, causing ecological damage or harming human health.

Human activities (emissions from vehicles, electric utilities, industrial plants and agricultural activities) have added levels of nitrogen rivaling or exceeding contributions from natural sources.

There has been a slow, continuous increase in atmospheric nitrogen deposition in park watersheds as well as around the world. However, in spite of increasing nitrogen deposition, there has been a decrease in the dissolved nitrogen that has been measured in the water flowing out of mid and high-elevation park watersheds. More than four decades of research provide unequivocal evidence that nitrogen have altered, and will continue to alter our nation's lands and waters. In these parks we have measured increased nitrogen deposition and its effect on water quality and it has the potential to alter terrestrial plant communities in ways that we cannot anticipate.

For further information, visit the National Atmospheric Deposition Program web site.

Did You Know?

Sharp, rocky crest of the Sierra Nevada.

The Sierra Nevada is still growing today. The mountains gain height during earthquakes on the east side of the range. But the mountains are being shortened by erosion almost as quickly as they grow. This erosion has deposited sediments thousands of feet thick on the floor of the San Joaquin Valley.