Over this past long weekend, spent backpacking in California’s Sierra Nevada mountains, I was reminded of a memorable method for distinguishing two of our stateliest trees. Though these two specimens are similar in many respects, the pine cones of “prickly ponderosa” have small spikes that point outwards, while those of “gentle Jeffrey” curve inward. (The bark of Jeffrey pines additionally smells like butterscotch or vanilla, which makes ID’ing them doubly delicious.)

But lo, after a string of days spent with these gentle giants, I returned to some sobering news. The Associated Press reports that smog pollution is weakening the growth of ponderosa and Jeffrey pine stands in California’s Sequoia National Park. Ozone, the primary component of smog, inhibits the trees’ ability to perform photosynthesis, evidenced by a yellowing of their bundles of long needles.

If you need a refresher, photosynthesis is the process by which plants harness energy from the sun and convert it into cellular energy. That energy is conferred to us animals when we eat plants. So, you know, it’s really important.

Prickly ponderosa and gentle Jeffrey aren’t the only trees suffering from the shocking levels of air pollution found in Sequoia National Park. Seedlings of the park’s namesake, the giant Sequoia, struggle to take root due to the high levels of smog. Chris Jordan, Earthjustice’s multimedia producer, and I saw some evidence of this air pollution in Sequoia N.P. when we traveled to Mineral King last summer.

How is one of the country’s most beautiful, wild landscapes becoming so polluted? Well, west of the mountains, thousands of feet lower, massive dairy operations, factory farms, diesel trucking corridors and other appendages of heavy industry are releasing nitrogen oxides (NOx) and volatile organic compounds (VOCs). These alphabet soup air pollutants combine in the presence of sunlight to form ground-level ozone, which gets caught in a swirling vortex that carries the dirty air up the watersheds into the high elevations of Sequoia and neighboring Kings Canyon N.P.

“Ozone levels here [Sequoia N.P.] are comparable to urban settings such as LA. It’s just not right,” noted Emily Schrepf of the nonprofit National Park Conservation Association (NPCA) in the article.

Indeed, it isn’t right. Earthjustice filed suit in October 2011 over the Obama administration’s decision not to pursue stronger ozone standards, despite the advice of scientific and medical advisors. In addition to improving conditions in ozone-stricken wild places like Sequoia and Kings Canyon, an updated ozone standard could have saved up to 12,000 lives and prevented 58,000 heart attacks every year. Earthjustice is working hard to ensure those benefits become a reality.

We’re also working with the NPCA and other groups to reduce haze pollution in our national parks. Earthjustice attorney David Baron said of this important work: “People should not have to worry about breathing polluted, unhealthful air when they go to a national park.”

The right to breathe clean air is a necessity that extends beyond the human realm. Gentle Jeffrey and prickly ponderosa make that abundantly clear. Earthjustice will continue our work to protect that right, to ensure that our treasured places, urban and wild alike, are full of clean air for the benefit of all.