Alastair Bland, GREENBIZ
Kellie Anderson stands in the understory of a century-old forest in eastern Napa County, about 70 miles north of San Francisco. To her left is a creek gully, a rush of the water audible through the thick riparian brush. The large trees here provide a home for deer, mountain lions and endangered spotted owls, while the stream supports the last remnants of the Napa River watershed’s nearly extinct steelhead trout.
“They want to take all of this out,” said Anderson, who sits on the steering committee of a local environmental organization, Save Rural Angwin, named for a community in the renowned wine country of the Napa Valley. She is studying a project-planning map of the area as she waves her free arm toward the wooded upward slope. “It looks like this will be the edge of a block of vines,” she said.
Anderson and two fellow activists, Jim Wilson and Mike Hackett, were visiting a property of several dozen acres that the owners plan to clear and replant with grapes, the county’s principal crop. The project is one of many like it pending approval by Napa County officials, who rarely reject a vineyard conversion project in the Napa Valley, a fertile strip that runs northward from the shores of San Francisco Bay.
In Napa County, neighboring Sonoma County and farther to the north in the Willamette Valley of Oregon, concern is growing among some residents, environmentalists and scientists about the expansion of vineyards into forested regions and the impacts on watersheds and biodiversity. In Napa, an aerial view reveals a carpet of vines on the valley floor, which is why winemakers hoping to plant new vines increasingly turn to land in the county’s wooded uplands. At these higher elevations, “about the only thing standing in the way of winemakers are the trees,” said Hackett.
“Napa is getting really carved up,” said Adina Merenlender, a conservation biologist at the University of California at Berkeley, who began studying the ecological impacts of vineyard conversions in the 1990s. “We see it all over the western and eastern ridges — it’s been relentless.” The transformation of shrub, oak and conifer habitat into new vineyards threatens wildlife migration corridors, she said. “We’re down to the final pinch points,” said Merenlender, referring to narrow corridors that eventually could become functionally severed from the relatively expansive wilderness areas in the mountains north of Napa County.
Federal fisheries scientists also have expressed concerns that the wine industry is harming endangered populations of steelhead trout. The creeks flowing off the hills of Napa County are critical to remnant populations of steelhead and salmon, and biologists with the National Marine Fisheries Service (NMFS) say the irrigation of vineyards has reduced stream flows and clogged waterways with eroded soils. “Extensive water diversions, groundwater pumping, and increased agriculture (vineyards) water use during the dry season have reduced the extent of suitable summer rearing habitat … throughout much of the Napa River watershed,” NMFS scientists wrote in the Napa River chapter (PDF) of a 2016 report.