Environment Pollution California's Smog Problem Putting Giant Sequoia Redwoods at Risk By Jaymi Heimbuch Writer California Polytechnic State University, San Luis Obispo Jaymi Heimbuch is a writer and photographer specializing in wildlife conservation. She is the author of The Ethiopian Wolf: Hope at the Edge of Extinction. our editorial process Twitter Twitter Jaymi Heimbuch Updated October 11, 2018 CC BY-ND 2.0. iriskh Share Twitter Pinterest Email Environment Planet Earth Climate Crisis Pollution Recycling & Waste Natural Disasters Transportation iriskh/CC BY-ND 2.0 An icon of the California landscape is in danger. The biggest and oldest trees in California, the giant Sequoias, are at risk from air pollution coming in to the national park from the Central Valley where farming, food processing and major highways all contribute to smog pollution. The smog makes it hard for seedlings to become established, and is yellowing the needles of other types of pines, the Jeffrey and Ponderosa. According to The Atlanta Journal-Constitution, the national park in which the redwoods live has the worst air quality of any national park. "Signs in visitor centers warn guests when it's not safe to hike. The government employment website warns job applicants that the workplace is unhealthy. And park workers are briefed every year on the lung and heart damage the pollution can cause." If there is that much warning for the damage the air will cause to humans, just imagine the damage it is causing to the trees, as trees are considered the "lungs of the planet." While it's clear the impact the pollution has on young trees and other pines, it isn't yet clear what impact it is having on the established trees that are thousands of years old. According to AJC, the only way to improve air quality in the park is to improve air quality in the Central Valley, which at this point is a monumental -- and very long-term -- task. In the mean time, the future of the great Sequoias is shaky.