From the air, the neat rows of cannabis plants in a clearing carved into the tropical dry forest along Paraguay's lawless border with Brazil look like pine saplings.

But once our Vietnam-era Huey helicopter carrying members of the country's anti-narcotics special forces lands, it becomes clear why this small, conservative nation is one of the world's biggest producers of marijuana.

The heavily-armed troops jump out of the chopper and start hacking down the waste-high sativa bushes with swift swipes of their machetes. They clear the entire area of about seven acres in less than two hours.

They also torch the narcos' abandoned camps and several tons of harvested marijuana in various stages of processing, from being dried to ground up, and finally pressed into one kilo bricks ready to be shipped.

Luis Saprisa, the infantry captain in charge of this elite unit of Paraguay's national anti-drugs agency, known as SENAD_,_ says that though the drug gangs usually vanish as soon as they hear the Hueys, they do sometimes open fire. They also booby-trap their illicit plantations, most often with a homemade gun built from a tripwire, spring, and metal pipe.

"They are not looking to take us out," he says. "They know they are not going to win. They are just trying to force us to take cover and buy themselves time to escape."

Photo by Simeon Tegel/VICE News

From Rio de Janeiro's favelas to the streets of Buenos Aires, Santiago and Lima, "Paraguayan" is synonymous with the kind of cheap but readily-available grass that consumers associate with a hacking cough, splitting headache, and powerful high.

Nobody disputes Paraguay's status as easily South America's largest weed producer, but the figures vary wildly. SENAD estimates the national harvest at 10,000 tons a year but others put it at up to six times that number. A 2011 United Nations report even estimated that the country accounts for 15 percent of global supply.

And while other countries in the hemisphere from Canada to Uruguay, and Chile to Jamaica, experiment with relaxing cannabis laws, Paraguay has become home to the region's most intense war on weed.

For President Horacio Cartes it's personal. In 2014 he claimed to have seen former high school classmates "suffer and die" from marijuana.

That, despite the fact that cannabis consumption in Paraguay is among the lowest in the region, estimated at just one percent of the population compared to nine percent in Latin America's most stoned nation, Uruguay, and 13 percent in the US. Paraguayan law is actually lenient with users. Possession of less than 10g is not criminalized. Growers, however, can face up to 20 years behind bars.

The raid by Captain Saprisa's team was just a tiny part of a huge 12-day operation in the lush, rolling plains around Pedro Juan Caballero, the ultra-violent border town at the heart of Paraguay's booming drugs trade.

In total, SENAD says it cleared 326 hectares of cannabis during the effort. At about 10,000 plants per hectare, that represents 3.2 million plants in less than two weeks. The US Drug Enforcement Administration eradicated just over 4.3 million plants in all of 2014.

The size of California but with a population of just seven million, Paraguay has emerged as a major producer thanks to its abundant rain, year-round sunshine, and fertile soils. Along with cannabis, the country is a major global producer of soy, corn, and beef.

'The narcos have huge resources to corrupt officials'

Paraguay also borders Brazil, one of the world's largest marijuana markets and a country where punitive laws mean landowners can get into serious trouble for even inadvertently having the soft drug growing on their property.

The profits are also huge. According to SENAD, a kilo of marijuana retails at $30 in Paraguay but around $400 in Argentina, $500 in Brazil, and $1,000 in Chile, possibly South America's most expensive market.

The legacy of General Alfredo Stroessner's 1954-1989 autocratic rightwing regime also drives Paraguay's cannabis production.

It left 80 percent of the land in the hands of 1.6 percent of the population. That means ranches sprawling for more than 250,000 acres, vast areas that no individual owner can fully control.

The problem is compounded by an environmental law requiring natural woodland cover a quarter of each hacienda, creating the perfect environment for clandestine marijuana plantations. SENAD says 60 percent of the country's cannabis is grown on these private forest reserves.

"We understand the circumstances," says Commander Oscar Chamorro, who heads SENAD's special forces. "We know that most landowners don't want marijuana. We are here to protect them."

The agency says that another 30 percent of the national cannabis harvest is cultivated on a much smaller scale by impoverished campesinos. The remaining 10 percent grows within public nature reserves, causing serious environmental harm from deforestation and the heavy use of pesticides.

Photo by Simeon Tegel/VICE News

Meanwhile, the huge underground cannabis industry has fueled a wave of narco-violence.

As a whole, Paraguay remains a relatively safe country by Latin American standards. But the province of Amambay, around Pedro Juan Caballero, recorded a 2014 homicide rate of 67 slayings per 100,000 residents. Were it a nation, that would have ranked Amambay as the world's second most murderous, after Honduras, according to the United Nations' 2013 study of national homicide rates.

Much of the violence is related to cocaine, with Pedro Juan Caballero a transit point for Bolivian and Peruvian wares into the vast Brazilian market. The border is actually the town's main street, with no checkpoints. Crossing from one nation to the other is, literally, as easy as hanging a U-turn.

But the same gangs traffic cocaine and cannabis and it is frequently impossible to distinguish which drug a narco-hit is related to.

'There's no seeds and few leaves. That takes a lot of work'

The cannabis trade is also about crooked cops and dirty politics.

"Corruption is the best friend of the drug traffickers," says Rojas. "It is not just in the police. In SENAD we have our own issues too. The narcos have huge resources to corrupt officials."

And corruption often goes hand in hand with serious human rights abuses committed by police and anti-narcotics agents, abuses routinely denounced by the Defensoría del Pueblo, Paraguay's official human rights watchdog.

Small scale farmers in cannabis growing areas also say that — along with low agricultural commodity prices — the crackdown on weed keeps them trapped in a vicious cycle of poverty, narco-violence, and abuse from venal cops.

"If you only sell grains, it doesn't add up. The prices are too low," says Gabriel Dos Santos, a community leader in Camba Rembe, a remote village of around 80 families in the heart of Paraguay's cannabis country. "That is why people grow marijuana. But it just brings headaches. There is fear in the community."

Dos Santos is trying to persuade his neighbors to give up their illicit crop, and lobbying the Cartes administration for help developing alternatives in the community where earlier this year SENAD seized a 10-ton haul of packaged marijuana.

'They only get heavy if you don't want to pay, they shot at me nine times'

The government has lent the community bulldozers, to flatten fields and clear them of the tree stumps from the forest that once covered this land so they can use tractors and increase their productivity for conventional crops such as peanuts, corn, beans, and cassava.

Yet many locals need to make ends meet now and are not about to give up their most lucrative cash crop.

One, César, not his real name, says cannabis yields an annual profit of around $800 per acre.

"It's good quality," says the lanky 30-something in a frayed tracksuit and worn-down flip-flops, as he proudly fishes out of his pocket a bud sticky with resin and a golf ball sized lump of hash.

"I tried it once and it left me loco for five hours," he adds as chickens and pigs roam around us in the backyard of his lean-to sandwiched by an unpaved red dirt road. "There's no seeds and few leaves. That takes a lot of work."

Photo by Simeon Tegel/VICE News

Yet growing grass here takes strong nerves, with narco-violence rampant and the ever present threat of SENAD raids. Local cops, however, are more interested in bribes, which César factors into his costs along with pesticides and labor.

"They only get heavy if you don't want to pay," he adds, recalling a time when he survived an attack by local narcos after police told them he was an informant in an effort to get more cash.

"They shot at me nine times," César says with a grin. "They didn't hit me. I don't know how. But my motorbike was destroyed."

With the scale of the harvest pushing SENAD's $10-million annual budget and 300 staff to its breaking point, Luis Rojas, the cabinet minister who heads the agency, says Paraguay is closely tracking the trend towards narcotics liberalization.

Yet he also insists there are no plans to back off from Paraguay's old school war on weed.

"In Paraguay we know we can't be afraid of the debate or regional trends," he said. "But we can't just change everything because it is fashionable."

Someone who does want a new cannabis policy is leftist opposition congressman José Ledesma although he also acknowledges that Paraguay may "not be ready" to legalize. But the cartels' power and ability to corrupt the police and other public institutions requires fresh solutions, he insists.

"Uruguay has started the discussion from the perspective of consumers. In Paraguay, we need to look at it from the perspective of producers," Ledesma says in his congressional office. "The ones who are in jail are all on the bottom rung of the ladder. The big players are not behind bars."

Chamorro, the SENAD special forces commander, also acknowledges the need for debate, characterizing the narcos' continuing success in the face of Paraguay's mammoth eradication efforts as a high-scoring tie.

He even applauds Uruguay's "bravery" in fully legalizing cannabis in 2013. But the commander nevertheless still puts his trust in repression.

"Tobacco and alcohol are bad enough. Why allow a third substance?" he asks, dragging on a cigarette in a corner of a cannabis field as his men slash at more plants around us.

"I used to be able to smoke in a plane, in a restaurant. Now I can't. I am virtually a criminal. And what has been the effect of cracking down on smoking? Are there more or less smokers now? Prohibition works."

The Pulitzer Center on Crisis Reporting funded the travel for this story.