In Northern California – north of San Francisco, Muir Woods presents as a redwood-vaulted oasis, a place so silent that the air can be heard circulating around the redwood branches, and the gurgling of Redwood Creek is unmistakable and exhilarating. One of the first things visitors to Muir Woods National Monument in Marin County notice is a noise level monitor.
This place wasn’t always this quiet.
Back in 2001, Muir Woods had already been abandoned by the native otter population decades earlier, and pileated woodpeckers had abandoned the national park as well. A familiar pair of northern spotted owl – endangered species, in fact – were not frequenting the redwood cove as often as they once had, and park rangers were growing concerned.
Adding insult to injury, an asphalt walkway that had been installed was interfering with the growth of the redwood’s surprisingly shallow root systems, causing at least one of the redwoods – age somewhere between 500 and 1,200 years old – to fall.
Still, the man-made noise issue was the most worrisome, as the clamor of garbage can lids and park maintenance vans infested the park. Tying its proverbial noose, it seemed, was the park’s proximity to a metropolitan area of seven million people.
For decades, park rangers and scientists have been worried about the affects of human noise on wildlife, but little was done about it. Eventually, however, an effort to restore the Muir Wood’s natural sounds took hold.
Slowly, mechanical sounds were silenced, and park visitors followed suit. With a concerted effort, human noise was all but squelched. Signs posted near Cathedral Grove in the center of the park request silence from visitors. The decibel meter near the gift shop entrance that measures the voices of visitors had one park visitor commenting that they could see themselves crunching on potato chips, as the decibel meter jumped with every crunch.
Today, there are times when the quiet in the park is so absolute, it seems possible to hear a banana slug slither by. According to scientists, this level of quiet is critical to the well-being of the native wildlife, which is recovering from the man-made cacophony that threatened its existence not too long ago.