It’s literally an uphill battle.

As new vineyards spread from the crowded Napa Valley floor to the hillsides, environmentalists have succeeded in getting enough votes to qualify for the June 5 ballot that aims to protect the county’s watershed and oak woodlands by placing restrictions on the number of trees cut down.

The Watershed Protection Committee, authors of the initiative, say expansion or creation of new vineyards into oak and other woodlands in California’s premier winegrowing region is adversely affecting fish and wildlife.

The Oak Woodland Protection Initiative would establish buffer zones along streams to protect water quality and limit destruction of oak woodlands, they say.

The initiative garnered 6,300 petition signatures, more than the 3,800 needed, and on Jan. 30, the Napa County Board of Supervisors is set to consider placing it on the ballot, adopting it, or ordering more study of the issue.

Opponents of the measure, however, are taking issue with part of the initiative that states that after 795 acres of oak woodlands in the valley have been removed, they must be replaced at a 3-to-1 ratio.

The initiative has recently come under fire from the Napa Valley Vintners, which represents more than 500 winemakers. Although the vintners group initially collaborated on the creation of the initiative, earlier this month its board of directors voted to oppose it.

At issue are unanswered questions in the initiative around exactly how many trees can be removed and for what reason. Does the cap includes trees needed to be cut down because of the wildfires in 2017, for example, said Rex Stults, the group’s government relations director.

Earlier this month, the trade group held a town hall that included attorneys on both sides of the issue.

“Legal analysts left members and the board feeling some uncertainty on potential consequences for agriculture if this becomes law,” Stults said. “We heard it loud and clear from successful, accomplished people on both sides.”

Napa Valley Vintners is also reacting from feedback from its members, the majority of which oppose the initiative, Stults said.

“It was definitely not unanimous, but the majority are opposed (to the measure) by a rough estimate of 3 to 1. That doesn’t change or affect our commitment to the environment for future generations,” he said.

Mike Hackett, one of the authors of the initiative, said the vintner group’s has done a turnaround on the issue.

“There is a small subset (of winemakers) who are more interested in the bottom line than saving the watershed,” Hackett said. “There are a few very powerful entities who are very satisfied with the status quo. They have a lot of say and power and influence and are not interested in preservation.”

In a region known for its wine, Napa Valley’s visitor industry generated $80.3 million in tax revenue in 2016, according to Visit Napa Valley, and brought in 3.5 million tourists, 73 percent of whom said they participated in wine tasting at wineries.

The authors of the initiative say the 795 acreage limit is reasonable considering the historic rate of oak woodland removal associated with new vineyard development, and unlikely to be met given the amount of available non-woodland acreage available for development in keeping with the General Plan through 2030.

“We were looking for a trigger mechanism to stop deforestation,” Hackett said.“This is not anti-agriculture. We’re just saving trees and watershed.”

“There is no reason for that 795 acre limit to be reached. There is ample opportunity to farm where there are no woodlands. There is a big misconception it has something to do in relation to vineyard development. We are for a sustainable watershed and oak removal,” Hackett said.

Federal fisheries scientists have also expressed concerns that the wine industry is harming endangered populations of steelhead trout. Biologists with the National Marine Fisheries Service 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,” fisheries service scientists wrote in a 2016 report.

Napa Vision 2050, a grassroots environmental organization, also places blame on encroaching vineyards.

“Due to the spread of hillside vineyards in Napa County, natural oak woodlands are being destroyed at an alarming rate, causing pollution of water supplies and exacerbating climate change,” it states on its website.

Whether or not the initiative becomes law, mounting pressure from environmentalists has affected at least one new vineyard project.

Owners of Walt Ranch plan to plant vineyards totaling 209 acres on a 2,300-acre property located in the eastern hills of the Napa Valley. In all, 14,000 trees will be removed and replaced with 250,000 grape vines.

Walt Ranch has maintained that the project will have minimal affect on the surrounding area. Mike Reynolds, president of Hall Wines, which owns the property, told the Journal last year that 94 percent of the trees on the acreage will remain untouched.

The controversial project has been in the planning for about 10 years, and, due to environmental groups’ concerns, has been reduced from the original plans by about 42 percent.

Walt Ranch declined to comment on the watershed initiative or how the project is proceeding, but a spokesperson said, “We currently do still have opponents from this effort, however, we are continuing to move forward.”

As reported in the Journal in January 2017, several environmental groups have filed lawsuits challenging Napa County Supervisors’ 2016 environmental approvals for the Walt Ranch project. Officials at Walt Ranch at the time said they were disappointed the project spawned lawsuits.

The suits are scheduled for a hearing in February.

“Their attorney has indicated that Walt Ranch will not proceed with construction activity until the lawsuits are resolved, but that being said, there are no injunctions in place to prevent construction activity and we hope that this additional step will not become necessary in this already very costly litigation,” said Sue Wagner, adviser to the Circle Oaks Liaison Committee, one of the litigants.