The Klamath-Siskiyou ecoregion, which includes all of Del Norte County, is considered a global hot spot of biodiversity, holding one of the three richest temperate coniferous forests in the world.
Rachel McCain, left, talks about the unique geologic features of the Smith River to a boatload of people anxious to learn. Photos courtesy of Siskiyou Field Institute
The Siskiyou Field Institute, a Selma, Ore.-based organization that offers field-based natural history classes, has a mission of introducing the public to the special qualities of the Klamath-Siskiyou Mountains.
For SFI’s inaugural adventure tour, the organization chose the Smith River as its setting.
“The Smith River is a pretty important part of our bio-region,” said Kathleen Pyle, SFI’s program coordinator. “It’s got all of the serpentine geology that characterizes the region.”
And it all starts with the geology.
“The geology determines what is here; geology is destiny,” said Rachel McCain, a local National Park Service employee who is a mine of local natural history knowledge. SFI hired her to teach their guests about the Smith River, first from aboard a raft floating through Hiouchi’s section of the river.
McCain explained how the geology of the banks of the Hiouchi Forks, where the South and Middle forks converge, is composed of exposed bedrock of the Josephine Ophiolite, which was once bedrock at the bottom of the ocean. At McCain’s cue, guests noticed that trees and other plants are sparse there “because that type of rock isn’t as productive and has less nutrients, so you end up with less plants and a stunted growth pattern,” she said.
Even when plants do grow there, they are subject to the frequent landslides that are common to the Josephine Ophiolite, because that rock “is not meant to be terrestrial — it’s been at the bottom of the ocean, so it can’t handle the elements well, particularly oxygen,” McCain said.
After the raft passed a couple river bends, entering Hiouchi’s house-lined stretch of the Smith, McCain pointed out how the river bank’s vegetation had grown lush and abundant. The raft had entered the geology of the Franciscan Complex, composed of ocean sediment, rich in nutrients and organic material from millions of years of dead things on the bottom of the ocean.
As oceanic crust tectonic plates meet continental crust plates along California’s coastal fault lines, the heavier oceanic plate sinks below the lighter continental crust. The sediment of the Franciscan Complex is scraped off in the process like spreading peanut butter, piling rich soils along coastal California, like the fertile agricultural land of the Smith River floodplain.
The group stopped for lunch at the mouth of Mill Creek, which served as the starting point for a short stroll around the redwoods of Stout Grove, less than 200 feet from the massive Stout Tree.
“If we’re ever going to bring them back, Mill Creek is going to be one of the areas where they recover,” McCain said.
Twenty-five thousand acres of Mill Creek watershed were obtained by Redwood Parks more than 10 years ago, and restoration work aimed at improving salmon habitat on the logged land is ongoing.
After rafting, SFI’s guests spent the afternoon wearing wetsuits and snorkel gear in South Fork Smith River to see fish first-hand.
“They were surprised at how many fish were there,” McCain said.
The remarkable clarity of the Smith River is one factor that attracted SFI to lead an eco-tour here in the first place.
“It’s so clear, so it’s more possible to study things in the river and actually see them,” Pyle said.
After a night spent on the South Fork, the guests completed the tour of the Smith’s ecosystem with a visit to Yontocket Slough, near the Smith’s mouth, where the group saw a bald eagle swoop in within 50 feet.
“They hang out where there’s lots of food, lots of fish,” McCain said.
SFI is offering two other classes in Del Norte this season: a two-day geology class Aug. 3-4, titled “Between a Rock and a Hard Place,” will explore the Smith River Canyon to look at serpentine. Cost is $100. On Sept. 14, “Birding on Bikes” will be an easy-pedaling birding class at Tolowa Dunes State Park. Cost is $50, bring your own bike. Go to thesfi.org for more information.