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Ozone and Giant Sequoias

Open Top Fumigation ChamberIn the 1980s, researchers conducted fumigation experiments to test the effects of ozone on giant sequoias in Sequoia and Kings Canyon National Parks. They tested sequoias of various ages, from seedlings to 2,000 year old trees, and even erected 30-meter tall scaffolding to reach the canopy of the more mature trees. These researchers found that giant sequoia seedlings are very sensitive to ozone until they are about 5 years old. If they survive past the age of 5, sequoias become relatively tolerant to ozone and show little evidence of ozone injury.

These results may seem positive, but they allude to a Seedling animationhidden danger. Sequoia seedlings are naturally "weeded out" by fire or drought so that only the heartiest survive. If ozone becomes a factor determining seedling survival, most seedlings will live or die depending on their ability to survive not only drought or fire but also ozone. Over time the sequoias could become less able to withstand additional stressors, a result which would threaten the very survival of the species.

 

Next Next - Air Quality Monitoring...
 

Air Quality Tour

Click on a choice:

  Smog in the Central Valley

  Clean Air in the Wilderness?

  Ozone Damage

  Ozone and Giant Sequoias

  Air Quality Monitoring

  Smoke from Wildland Fire

  Sustainable Practices

  What You Can Do to Help

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