Dutch Elm Continues its California Rampage

Although it doesn't get the headlines it garnered a decade or two ago, Dutch elm disease continues to prowl the urban forests of the Napa Valley.

The arboreal plague arrived in the Bay Area in the 1970s after wiping out tens of millions of American elms in the East and Midwest over the previous 40 years.

An import from Europe, Dutch elm disease destroys America's favorite street tree, prized for its towering shade canopy. Napa and Calistoga, like thousands of other communities, both have Elm Streets.

When the disease first arrived in Napa, the devastation was of "epidemic proportions," said Bob Carlsen, Napa's parks superintendent.

The majority of the elms that shaded the lawn and children's play area at Fuller Park were killed. One by one, the elms that dignified courthouse square wilted and died.

The state of California mounted a vigorous defense. Every elm was catalogued and evaluated annually. When a tree died, it was quickly cut down and the wood was buried.

When the disease continued to lay waste to California's elms, the state, in effect, gave up, said Greg Clark, Napa County's assistant agricultural commissioner. "They gave it their best shot and threw in the towel," he said.

Today the fight against Dutch elm is being waged by private property owners and cities that use a small arsenal of pesticides to slow the disease's progress.

Despite these efforts, every summer more elms die. Until several years ago, the Elm House Inn on California Boulevard was shaded by four giants. Today there are none.

"My place is called the Elm House. There are no elms," said inn owner Steve Wattz, who grieves their loss. "They kept the sun off the building. They added beautiful shade."

Wattz is upset that the city didn't fight to preserve the elms as signs of the disease appeared. "They seem to feel that once it has Dutch elm disease, that's the end of the tree," he said.

Nowhere are the ravages of Dutch elm disease more apparent than along the historic double row of trees that runs south of River Park Boulevard. The once stately promenade from South Jefferson Street to the Napa River is now blighted with 35 dead elms and gaps where another 60 once stood.

"It's been a real disaster out there," said Carlsen. The situation is so out of control that the city has given up trying to control the spread of the Dutch elm fungus there, he said.

The trees are planted so close together, Carlsen said, that once one tree gets the disease, it is spread through the interconnected roots.

Elsewhere in Napa, the city is fighting Dutch elm disease. Using a new product, the city annually injects the soil around its 78 remaining park and street elms with an insecticide that is absorbed into the branches.

Since injections started five or six years ago, the program has been a "huge success," said Rob Hansen, the city's tree superintendent. The die-offs have dropped, he said.

The reasons the spread of Dutch elm disease has slowed could be many, Clark said. There are new chemical defenses, but there are also fewer elms to defend, he said.

The city of Napa has lost hundreds of elms since the 1970s, Hansen said. Recently the city has begun to replant elms that have a proven resistance to the disease, he said.

At the Elm House, the city planted three disease-resistant saplings along California Boulevard, allowing the Elm House to legitimately still claim to be the elm house.

"In 25 years they will be nice and grown and I will be in an old folks' home," owner Wattz said.

At River Park Boulevard, the city is replanting elms, as the budget allows, with a mixture of species -- sycamores, red oaks, ash, ginkgoes and disease-resistant elms.

When a new tree row achieves maturity in coming decades, its diversity will make it less vulnerable to a single bug, Carlsen said.

The city has been slow to remove dead elms next to River Park Boulevard because it doesn't have the money, Hansen said. Trees that die in busier locations have higher priority, he said.

PG&E will be removing 13 of the dead elms on River Park because they threaten power lines if they fall, PG&E forester Greg Holquist said.

Joe Borden, owner of Britton Tree Services of St. Helena, said his company has two lines of attack against Dutch elm disease. A fungicide is injected into the trunk and an insecticide is applied to the soil for absorption. These applications together cost over $1,000 a year per tree.

If an elm can be kept healthy, it can live 200 years or more, Borden said.

Jim Haller, St. Helena's building and grounds superintendent, said his community hasn't lost any elms to Dutch elm disease in recent years. "We watch out for it," he said.

Yet he hears reports of the disease striking close by. There have been trees lost in Rutherford and one was recently removed from the "Avenue of the Elms" in front of Beringer winery, he said.

The Veterans Home of California at Yountville has a similarly historic row of elms that graces the drive from Solano Avenue to the central campus.

Two elms at the eastern end of the tunnel were removed several years ago when they contracted the disease, said Hank Miller, the Veterans Home's supervising groundskeeper.

His staff keeps a close eye on the remaining elms, knowing that a massive Dutch elm infection would be "devastating."

"It's a historic planting," Miller said. "It's a place of beauty, especially in the fall. The yellow leaves are dancing back and forth on the street."