Keep The Fish In The Trees

Marine isotopes in redwood forests point to a cosmic salmon-redwood connection. Silicon Valley Gives, a community day of giving for the South Bay, offers a chance to support Sempervirens Fund's work keeping fish happy and redwood forests whole.

by Traci Hukill

May 5, 2015—A few years ago I was researching an article about coho salmon and steelhead trout in the Santa Cruz Mountains when one of the scientists I was interviewing casually mentioned something that blew my mind. He told me that the redwood trees that grow in these mountains contain, deep in their tissues, marine isotopes that could only have been introduced to the terrestrial environment by the anadromous fish that live most of their lives at sea only to return, at life's end, to the mountain stream of their birth to spawn and die.

Of course I knew about the miraculous journey made by salmonids, the family of anadromous fish to which steelhead and coho belong: how they're born in freshwater streams and migrate to the ocean to live as saltwater creatures for years before undergoing a dramatic physical transformation that enables them to re-enter the freshwater environment and return to their native streams to lay eggs. Most salmonids die after spawning (though steelhead don't always die onsite); others are eaten en route. Some steelhead even return to the ocean to repeat the process.

So I knew the basics of all that. But the philosophical implications of those marine isotopes, those atomic markers, frozen in the rings of the redwood trees bowled me over. What better illustration of the cycle of life and the interconnectedness of all things? The physical essence of the salmon disperses throughout the forest as it decomposes. Maybe its nutrients fall like rain into the bottom of the streambed, to be taken up by redwood roots nearby. Maybe a fox scavenges the carcass and then leaves scat at the base of a tree. However it happens, it's nature's steady engine at work, and it's miraculous.

The phenomenon is so reliable that scientists at UC—Davis have used isotope analysis of redwoods and Douglas firs to estimate the historic abundance of salmon runs.

Read more about Steelhead Trout

The Sempervirens Fund Connection

These morning (now noon) musings were triggered by word that for Silicon Valley Gives, the Sempervirens Fund has chosen as its project the rehabilitation of a piece of property that abuts the South Fork of Gazos Creek, a steelhead spawning stream that runs through Big Basin Redwoods State Park. The Gazos Wildlife Corridor Restoration Project will be undertaken with the San Mateo County Resource Conservation District.

It's not a big, glamorous project. The 40-acre parcel, purchased in 2007, has a 1300-foot driveway that's become a mess; a crew needs to take out manmade soils; reshape the driveway so water can drain properly into the creek without dragging loads of silt, mud and debris into the waterway; and install some rocky areas for extra filtering of sediment. All this is so the steelhead can find the clear water and gravel beds—as opposed to the turbulent water and muddy bottom—they need to successfully reproduce.

It's a small, workaday project—the kind of thing we as citizens hope organizations are doing behind the scenes to keep the environment in the best possible shape after a couple of centuries of enthusiastic colonization. This is one of those times when we can actually help by contributing. Silicon Valley Gives lasts 24 hours today, May 5. Contribute to Sempervirens Fund's Gazos project, and the Merrimac Fund will match up to $2,000 in donations.

Click here to donate to Sempervirens Fund's Gazos Wildlife Corridor Restoration Project. Help keep the fish in the trees!

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I've read this article twice already and still can't fully wrap my mind around the idea that isotopes from fish exist within the redwoods. I'm intrigued and am happy to donate to this project. Thank you for writing this.


Thanks, Carol. It's a trip, right?! Glad someone else is mind-blown!