VANCOUVER, British Columbia >> In the pot-friendly city of Vancouver, illegal marijuana dispensaries outnumber Starbucks outlets, and among the most popular is Weeds, Glass and Gifts. There, in a relaxed space reminiscent of the coffee chain, jovial “budtenders” sell coconut chocolate bars infused with marijuana and customers smoke powerful pot concentrates at a sleek dab bar.

When Canada legalized recreational marijuana, on Oct. 17, one of the central aims was to shut down the thousands of illegal dispensaries and black-market growers dotting the country. But taming an illegal trade estimated at 5.3 billion Canadian dollars ($4 billion) is proving to be daunting.

Many of the products sold at Weeds, Glass and Gifts are banned under the new law, which restricts licensed retailers to selling fresh or dried cannabis, seeds, plants and oil. Yet the retailer’s owner, Don Briere, an ebullient 67-year-old and self-styled pot crusader, has no intention of shutting down his four Vancouver stores or changing his product lineup.

He even has plans for expansion by launching a new line of outlawed canine marijuana treats, which purport to reduce pet anxiety.

“We’ll keep selling what we are selling,” said Briere, who in 2001 was sentenced to four years in prison for being one of British Columbia’s most prolific pot producers.

The Canadian government faces many challenges in stamping out the illegal marijuana industry. For one, there are too many black market shops like Briere’s for the government to keep track of.

And as sluggish provincial bureaucracies struggle to manage a new regulatory system, licenses to operate legally are hard to come by, giving illegal sellers added impetus to defy the law.

At the same time, the police and the public have little appetite for a national crackdown.

“The government taking over the cannabis trade is like asking a farmer to build airplanes,” Briere added.

Canadian policymakers say legalization is a giant national undertaking that will take years to be enforced. Mike Farnworth, British Columbia’s minister of public safety, argued that civic pressure and market forces would help gradually diminish the illegal trade.

“It’s a very Canadian way of doing things,” he said. “It won’t happen overnight.” There will, he added, be no mass raids, “guns and head-bashing.”

Yet hundreds of black-market-pot outlets remain defiantly open, abetted by provincial governments slow to implement the new law.

On Oct. 17, only one legal government pot retailer opened in British Columbia, in the city of Kamloops, nearly a four-hour drive from Vancouver. That assured that Vancouver’s illicit trade would continue to thrive.

And that day, none of the roughly 100 illegal pot dispensaries in the city had the provincial licenses they needed to operate legally, even those that had applied for one.

As cities across the country grapple with a new national experiment, Vancouver offers a striking cautionary tale about the challenges of policing the illegal trade.

A picturesque multicultural port city, less than a three-hour drive from Seattle, marijuana here is as much a recreational drug as a state of mind. Young professionals toke before work, take pot-fueled hikes and chat about strains of vaunted “BC bud” — grown illegally near snow-covered mountains in the southeast of the province — as if discussing fine wine.

For decades, cannabis has been so embedded in the social fabric of the city that illegal pot shops operated with impunity as so-called “compassion clubs” for those seeking medical marijuana, with police largely turning a blind eye.

But in 2015, City Hall officials, fed up with the proliferation of black market dispensaries, including some selling to minors, passed tough regulations stipulating, among other things, that shops must be about 1,000 feet from schools, community centers or other outlets.

After dozens of dispensaries brazenly flouted the new rules, the city in 2016 began fining transgressors, issuing 3,729 tickets amounting to more than $3 million in fines. But the dispensaries mostly ignored them; only $184,250 has been paid.

Then the city began trying to shut down illegal operators with injunctions.

In March of this year, 53 dispensaries banded together to file a constitutional challenge, saying closing the operators would breach Canada’s Charter of Rights and Freedoms by denying patients access to medical marijuana they purchased at the black market stores.

“The City is using legalization to try and impose Prohibition,” said Robert Laurie, the lawyer representing the dispensaries.

The case is before British Columbia’s Supreme Court.

The new legal marijuana supply chain was in full force on a recent day outside of Vancouver at Pure Sunfarms, where immigrant workers in surgical masks were trimming buds from cannabis plants next to a sprawling greenhouse that once housed tomatoes.

Rob Hill, chief financial officer of Emerald Health Therapeutics, a licensed producer which owns part of Pure Sunfarms, predicted that it was only a matter of time before black-market growers went out of business as consumers demanded the purity of government-approved pot, free of contaminants found in some street marijuana.

“We expect a new consumer market of women age 35-45 who will smoke pot instead of drinking chardonnay,” he said.

But Dana Larsen, owner of several illegal dispensaries in Vancouver, countered that underground cannabis cultivation remained deeply entrenched.

Legalization was doomed to fail, he added, because there was so little will to enforce it.

He said he had accumulated heavy unpaid fines from City Hall, had no intention of applying for a license, and was far more concerned about being able to provide cannabis to the elderly and ill customers who relied on him. “In Vancouver,” he said, “you have to make an effort to get busted.”