Grape Growers in Napa County Tackle Fire Recovery, Drought

Farm Bureau Director and Napa County grape grower Dave Wilson inspects new growth on his vines. Most of his vineyards suffered fire damage last year, and he harvested less than half of his grapes because of smoke exposure.

Too much fire and not enough water have made winegrape-growing efforts more challenging than usual for Dave Wilson and other North Coast farmers.

After losing crops to severe wildfires and accompanying smoke last year, farmers monitor bud break in their vineyards amid concerns about drought and the potential for more fires in 2021.

The LNU Complex wildfire last August affected nearly 90% of Wilson's Napa County vineyards, creeping along the vineyard floor and forcing him to replace some 600 vines.

Wilson described the blaze as "a very, very long fire line that was just relentless and continued to wrap around. It stretched for miles long, and it just crossed over onto our ranch all at once."

His father, Terry, bulldozed firebreaks, and the ranch's homes and buildings were saved with the help of firefighters from Napa and Ventura counties.

As a result of the fire, Wilson said, he harvested only 40% of his grapes last year—the remainder were lost to smoke-exposure concerns. He said he also lost infrastructure, including fencing and end posts, and has had a lo of trellis repairs.

"We had so many pressure-treated posts that burned up here" that we're "going all back in with steel," Wilson said.

With 2020 in the rearview mirror, his attention now is on 2021 and its main challenge to date: drought.

"We know we're not going to receive any significant storms from here on out," he said while surveying some of his vines from a ridge near Wooden Creek. "We may get rain, but we know that our window has closed."

With that in mind, he plans to launch shoot-thinning work early.

"It will end up being about two weeks earlier than last year," Wilson said. "We're moving the practice a little bit earlier because of the moisture in the soil just being low. It's one of the things we can do to conserve the moisture in the soil."

Practicing no-till farming also helps keep soil moisture in, he added.

Although droughts bring challenges, "we've learned so much just in the stretch from 2012 to 2016," Wilson said. "We focus on things like managing our water, but also just making sure that we're paying attention to the nutrient status of the vines."

Down the hill in Carneros, winegrape farmer Tom Gamble said "we are definitely in a drought situation," with rainfall amounts similar to those seen in the drought of 1976-77—a formative experience for him.

"As a kid seeing his first big drought, it got my attention away from cars and girls, and I vividly recall helping sell off livestock and turning on overhead sprinklers in certain vineyards," Gamble said. "That drought really pushed the then-new technology of drip irrigation to become steadily adopted."

Gamble said one of the best lessons he learned was "plan for drought"—starting with deciding what to plant.

"Since vines are a permanent fixture, key decisions are made at time of planting to survive drought, mostly in choosing a drought-tolerant rootstock," he said.

"Those who did choose a hardier rootstock might have to reduce crop, but the vines will be OK," he said. "New plantings without water supplement are going to struggle, especially on porous soils."

So far, Gamble said, he's seen good bud break and pre-flowering vine fruitfulness, with many two-cluster shoots.

"However, we are going to have to keep an eye on canopy growth and ensure we don't overcrop the vine, and take measures to reduce crop if the canopy is weak and cannot support ripening," he said. "Given the loss of so much crop last year due to smoke taint, reducing crop this year is going to be a bitter pill to swallow for some."

Bud break has been going since early March in Sonoma County, said Karissa Kruse, president of the Sonoma County Winegrape Commission. Near-freezing temperatures posed another problem for the county's winegrape farmers, she added.

"The cold spring nights have caused many grape growers to be up in the middle of the night, managing frost protection," Kruse said, adding that the lack of winter rain represents "a big concern" for the region's farmers.

"Fortunately, grapes are very efficient crops and do not need much water," she said. "Water use is focused on vine health and frost protection."

Even when water is applied for frost protection, Kruse said, "a large percentage of it goes back into the ground and recharges the aquifers."

As the state gears up for another wildfire season (see story), being prepared is taking on urgency.

Kruse said Sonoma County Winegrowers has scheduled six fire-safety training classes for late April and May. The classes will cover evacuation and fire safety.

In Napa County, Wilson said his property maintenance is being adjusted to account for the yearly threat.

"Part of our annual plan for our property is going to be preparing for fires, disking firebreaks during our additional tree work, brush clearing," he said. "We're hopeful that there'll be some funding, because it's very difficult for us as a family farm to manage all that and farm."

The work will include maintaining buffer zones around vines with mature trees, and managing ladder fuels and vegetation.

"That's going to be extremely important for us around everything important to us, which is the vineyards, the homes, the roads, evacuation routes and access routes for firefighters," Wilson said. "It's going to be years of work. It's going to be a continuing project for us."

Even so, he said he has his eye on 2021 as well, with a new crop on the way.

"Our impacts were pretty severe," Wilson said, "but at the same time, we're back farming this new vintage."

(Kevin Hecteman is an assistant editor of Ag Alert. He can be contacted at khecteman@cfbf.com.)

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