One Man's War to Save an Endangered Jungle in Guatemala

Roan McNab went head to head with ranchers, corrupt officials, and narco traffickers to save the Americas' largest tropical rainforest outside of the Amazon.

by Saul Elbein
Apr 3 2017, 12:50pm

This story appears in the April issue of VICE magazine. Click HERE to subscribe.

Just after dawn in late February 2016, a dozen men left their camp in the forest of northern Guatemala and drove west toward no-man's-land. They rattled over the rough road hacked with machetes from the dense jungle, under a canopy of mahogany and acacia trees draped with hanging vines. Bright birds and forest mammals fled before the sound of their engines. As they drove, they heard the jungle wake around them with the cries of scarlet macaws and howler monkeys. It was two months into a summer of record-breaking heat, and above their heads, the sun beat down on a forest poised for explosion. Beneath the canopy, dead leaves and branches piled in heaps over the tall roots of the ceiba trees, drying into kindling. It waited for a spark. They were soldiers, park guards, and naturalists, stationed in the middle of the Maya Biosphere Reserve, an enormous Guatemalan reserve that encloses broad reaches of the Americas' largest tropical forest outside the Amazon. Their mission: to make sure that spark never came.

Four miles from camp, they left their trucks on the border of the wide fire line they called the "Shield." The other side of the line had once been one of the crown jewels of the Central American park system. Now it was a place where park guards entered only with fear, its wildlands colonized by illegal cattle and organized crime. They headed west into Laguna del Tigre National Park, or Tiger Lake, hacking a path through the stubby forest darting up amid feral cattle grass. On the far side of the river, they stepped out of the woods. They found themselves suddenly in another world. The forest was gone, replaced, as far as the eye could see, by sun-beaten limestone plains bristling with the green tufts of Brazilian cattle grass. And jutting above the grass was the thing they had come there to find.

To an outsider, it would not have looked like much: a seemingly endless line of crude posts spread across the plain. But to one man, taller than the rest, the fence line's meaning was clear. Roan McNab was a sandy-haired Florida native in his early 50s. He bore a faint resemblance to the actor Daniel Craig, with a soft-spoken intensity occasionally broken by a crooked grin. But he was not grinning now. He knew what a fence meant: This is mine. I've come to stay. Get back.

As director of the local Wildlife Conservation Society (WCS) mission, McNab had spent ten years dueling with the illegal land barons pressing into Laguna del Tigre, carefully cultivating the alliance that had not merely stopped their advance into the park but thrown them back. The year before, a team of park guards and forest police setting west from La Corona, the northernmost ranger camp of the Shield, had cut the fence, arrested the last fence builder, and thrown him in jail. But they had left that fence line standing against the sky like a bunch of upthrust middle fingers. Now, as the sun rose in that February sky, McNab was facing his most dangerous fire season yet. In a summer already tied for hottest El Niño on record, with invaders pressing against the Shield with their chainsaws and torches, he was undermanned and behind schedule. The fence was too big a challenge to be tolerated. It had to go.

Earlier that morning, McNab had pressed the Guatemalan sublieutenant, with his five assault-rifle-toting soldiers, to lead them in clearing the fence posts. " Ahora es la hora," he had said. Now is the time. His flat Spanish was tinged with a barely perceptible Florida drawl. The sublieutenant had objected. His men were too few, he said. The country was hostile. Well, McNab had said, let's at least scout it. And now here they were, drawing close to the fence line. McNab looked at the posts. He muttered a Spanish curse. Between the crude fire-blackened posts, the barbed wire they had cut had been replaced. It was a gesture as clear as planting the flag. This land, whoever placed that wire was saying, is no longer forest. This land belongs to me. It was the farthest point in an invasion that had cut Central America's largest reserve in two and threatened to destroy what remained.

And worst of all: Alongside the fence line, the high cattle grass on each side had been cleared in neat yard-wide lines. It was a firebreak, built to protect the fence from the next phase of the land conquest: a wildfire that would rage across the grassland and into the forest, clearing the way for a new grass crop. Clearing the way for additional expansion. The fence stood under the baking sun, a present danger to the forest McNab loved, marking a land ready to burn.

Guatemalan soldiers and members of the Wildlife Conservation Society walk through a field of Brazilian cattle grass. Photos by Santiago Billy

Unlike American forests, which burn naturally from lightning strikes, fire in the Maya forest that stretches from Guatemala up through Belize and Mexico's Yucatán has just one cause: humans. The forest is a place torn between climatic extremes. From May to November, rain pours down, filling the dry lakes and streambeds with water, turning hilltops into islands. During the long, hot summer, from December to April, the land dries. Lakes shrink and vanish, plants wither, the forest turns brown. An eternal tension drives life in the forest: In the winter, plants grow, and in the summer, they die.

Or burn. To this day, Maya peasant farmers use fire rather like commercial agriculture uses tractors. Fire clears last year's stubble and weeds in time for next year's planting. A thousand years ago, a traveler following McNab's route west from the camp at La Corona would have passed through a summer blazing with the fires of thousands of cornfields, which grew the corn that sustained civilization in the Maya lowlands. From about 250 to 900 AD, as many as 2 million people lived in what is now the Maya forest—ten times as many as today. They cleared the forest for corn plots, market towns, and extravagant temple cities. They shaped the land with plazas, causeways, and reservoirs.

Then the lowland Maya civilizations collapsed in an apocalypse of war and drought, and the fires went out. Forest retook the cities. Deer wandered in pastures grown over plazas. Crocodiles basked beside Maya reservoirs. Trees and ferns covered the pyramids, and the Maya cities vanished to history for over 1,000 years. Then, at the end of the 19th century, gum tappers from the highlands and Mexico began moving into the jungle, building their camps on the ruins of ancient cities. In Spanish, a homesteader on public land is called " invasor" (invader), and the gum tappers were only the first. In their wake came the archaeologists, and then the colonists clearing unclaimed forest for their own little corn plots. And behind them came Roan McNab.

McNab landed in northern Guatemala in 1997 as a lanky 33-year-old, tasked by WCS to shut down its field program in the country. He convinced his bosses, though, to keep it going. He was there more out of a sense of exploration than any particular mania for environmentalism. He had grown up in Gainesville, Florida, the son of a zoologist. But he had never quite bought the conservation dogma that parks should be empty of people. "The whole concept for me of the pristine wilderness is difficult to just grasp," he said. "I see humanity as part of nature in the first place, so separating humanity from nature is a difficult mental exercise to begin with. And every part of the planet is affected [by humans] at this point, and that's increasingly going to be true."

Which made the Guatemala project perfect. In 1990, seven years before, the Guatemalan government had turned the northern part of the country, about a fifth of the nation's entire land mass—an area the size of New Jersey, larger than Alaska's Denali—into the Maya Biosphere Reserve, an American-style patchwork of national parks and so-called sustainable-forestry concessions, where people were allowed to live from the forest. McNab ended up in the village of Uaxactun, a community of about 1,000 between the observatories and palaces of a Maya city of the same name. For 100 years, the Uaxactuneros had lived by selling logs and harvesting the forest for chewing gum and (of all things) xate, palm shoots for ornamental flower arrangements. Now the central government was threatening to throw them out and hand their concession to a logging company. McNab's job was to help them.

Illegal ranchers post signs, staking out their territory in Laguna del Tigre National Park.

McNab would have seemed, on paper, rather unsuited for this job. For one thing, when he arrived, he didn't speak any Spanish. He could not have stood out more among the short, dark gum tappers and xate cutters of Uaxactun. In the suspicious, divided atmosphere of Uaxactun, said longtime resident Erwin Macz, as factions fought one another over the community's future, "people asked, 'Who is this gringo anyway?'" But he earned their respect, learning Spanish slowly through sign language, swear words, and imitation. And he began to demonstrate a quality that would mark his later career: a subtle political skill, a soft touch that helped smooth out arguments and move deals along. Community members give him credit for playing a decisive role in the deal that saved Uaxactun. Rather than being evicted, the community got to run its own sustainable logging operation, the largest in Mesoamerica. McNab and WCS also helped broker the deals by which the community sold sustainably harvested wood to international clients like the Bronx Zoo, bringing Macz to New York to market the community's wood.

McNab was also captivated by the Maya forest, a place where it was still common to stumble over vine-shrouded stellae—limestome monuments carved with the portraits of ancient kings—and the towering mounds of lost cities. Rather than close the WCS program, he convinced his bosses to expand it. He spent almost every moment running around the forest park with local guides and Uaxactun friends, exploring the reserve by 4x4, boat, and foot, having experiences out of a boy's adventure novel. Though well into middle age, his eyes still light up when he talks about the Maya forest, the undiscovered cities it hides, and his close calls walking its paths. Like the time, for example, that he and Ramón Peralta, an old guide from Uaxactun, found the dig site of a pair of tomb raiders beneath the pyramids of the lost capital at El Mirador. On a whim, they followed the men's trail back to a camp—and found themselves ambushed, staring down the barrels of a pair of shotguns held by twitchy bandits.

"There was a moment," McNab said drily, "where you think , Oh my God, what have I done?" But Peralta had spent his life in and around the forest, and he was familiar with one of the raiders, a local lowlife known as "El Diablo." He turned his back on the guns and dared them to shoot. El Diablo lowered his gun. Within a few minutes, at the urging of McNab, an archaeology nerd, the raiders were showing off the priceless pre-Columbian pots they had unearthed. Peralta and McNab had been lucky. Later, back in town, they heard that El Diablo had murdered his buddy for his share of the loot and buried him in a shallow grave. "He was," McNab said, "a real bad dude."

Captivated by this and other diversions, McNab spent the late 1990s unaware of the "cancer" spreading into the reserve. He knew highland peasants were migrating into the reserve in an unending stream, cutting and burning corn plots from the trees. But like most conservationists and government personnel in northern Guatemala, he paid it little mind. He focused instead on traditional conservation: counting endangered species, writing management plans, and setting up community enterprises like that in Uaxactun, unaware that the threat was bigger than they had imagined.

The summer of 2003 changed everything. That year, in the midst of a scorching El Niño, McNab led the WCS field survey to a scarlet-macaw-nesting site on the fringes of Laguna del Tigre. They had barely begun to count when the wildfires came, smoldering through the substrate beneath the trees in hundreds of crawling tongues of flame. When a wildfire occurs in the Maya Forest, it's less a dramatic walled inferno and more a covert, relentless crawl through the leaf litter that sparks the understory and catches the trees above. It is hard to find, hard to track, and hard to stop. To the team's horror, the fires were heading inward toward the nests of the last 200 macaws surviving in Guatemala.

It was immediately clear to McNab and the WCS biologists if they continued their project the fire would take the nesting sites, spelling extinction for Guatemala's scarlet macaws. They dropped all pretense of counting and began hacking firebreaks through the burning woods with shovel, ax, and pulaski, clearing protective moats around the towering white acacia trees where the macaws lived. For a month, they battled under the trees. They slept on the ground, their clothes soaked with sweat and ash, until summer finally broke, and the heavy rains washed the fires away.

Ramón Peralta, an experienced forest guide, talks with McNab as they look at an area that illegal ranchers slashed and burned.

The 2003 fires came as a terrible shock to McNab and WCS, revealing suddenly and decisively just how vulnerable the Maya forest was—and how little understood. The main threat to the reserve, it was now clear, wasn't escaping embers from peasant corn plots. This was something on an entirely different scale. Fire had scarred a quarter of the reserve, sending out enough smoke to reach the airport in faraway Houston, Texas, about 1,000 miles north. Something much bigger was going on.

But what? The National Council for Protected Areas (CONAP) maintained a few scattered posts in the fringe of forest on the eastern edge of Laguna del Tigre. As far as McNab knew, no one had ever walked between them. CONAP's rangers entered the cleared lands at risk of kidnapping or worse. The next summer, McNab and a group of guards from CONAP set out to scout the frontier. They hiked south along the rim of surviving forest at the western edge of Laguna del Tigre. They found the forest broken by wide trails cleared by invaders. They crossed beneath trees carved with the names of land speculators. They found clandestine airstrips for drug planes and abandoned airplanes swallowed by vines.

Most strikingly, they found the land cleared not for small peasant plots but for vast cattle kingdoms sprawling over hundreds or thousands of acres. Around 80 percent of the forest lost in Laguna del Tigre National Park had been cleared, they found, not by individual families homesteading in the woods but on an industrial scale—with dozens of men working together to cut the forest, burn it, and fence ranches off for cattle. In one empty work camp, they found the cots and possessions of some of these men—along with several fresh rolls of barbed wire, which meant the men were there to clear the forest and fence it for pasture. McNab and the guards hacked the wire apart. "Then we got scared," he said, grinning. "So we had to hike all night. Ended up camping in a place totally without water." Starting in the late 1990s, farmers and ranchers had begun clearing forest and fencing pasture for cattle. But by the early 2000s, it had become an existential threat to the area. The forest broke before the advance of the outlaw cattlemen that Guatemala would come to know as the narco ganaderos, the "narco ranchers." In the early 2000s, as the United States closed the speedboat routes bringing cocaine across the Caribbean, the trade shifted over to Central America. A river of drug money flowed across Guatemala, leaving traffickers from the provinces along the country's eastern border awash in money they could not legally spend. But cash could buy cheap land in the forest along the Mexican border, with its hundreds of unguarded passages. And cash could buy cattle, to run across the border into Mexico.

In many places, said Salvador López, the CONAP regional director for the Petén region, they would come with their hired men to the peasant colonists and ask to buy the land. They were known locally as "sombrerrudos" (the men in big hats) because they dressed like cowboys. They were persuasive. "They would say, 'You can sell to me,'" López said, "or, 'I can negotiate with your widow.'" In this way, they assembled ranches so big they were measured not in acres or hectares but in the ancient Spanish measurement of caballerias—the amount of land a man can work by day on horseback. Ranchers claimed ten, 15 caballerias. Some in the far reaches of the park claimed as many as 100.

It was the cattle that brought the ranchers into conflict with McNab. As local head of WCS, McNab was tasked with protecting the 250 or so scarlet macaws remaining in Guatemala. The macaws dug their nests from the soft bark of cantemos, acacia trees that grow in the low, wet soil of Laguna del Tigre. It was just bad luck for the scarlet macaw and other species of Laguna del Tigre that their habitat, with its wide, shallow lakes, was also perfect for cattle.

What the narco ranchers had found in the park, McNab realized in the wake of the fires, was a "protected" area without effective protection. CONAP, technically in charge of patrolling it, was constantly short on manpower and other resources. Its rangers had few trucks, and those were in terrible repair. There was never enough fuel or food for serious missions. The guards on the line in Laguna del Tigre were few, unarmed, demoralized, and facing a terrifying opponent. "I realized we could generate great biological information," McNab said. "But if at the end of the day there isn't a way to neutralize some of the major threats that are out there—if you can't deal with fire, if you can't deal with powerful individuals who are usurping enormous tracts of land—then eventually the entire conservation model collapses like a big row of dominos."

A scarlet macaw feeds in a tree.

The conservationists, McNab realized, had a choice to make. They could keep counting Guatemala's scarlet-macaw population until it dropped to zero. Or they could figure out how to hold the line. The Shield was McNab's brainchild, a three-yard-wide, 30-mile-long lattice of trails and firebreaks anchoring the edge of the surviving forests of Laguna del Tigre. Ostensibly, it was to protect the surviving parts of the reserve from fire spreading east. But its deeper meaning was the same as that fence: This is our land. Stay back.

An important element of this territorial control was a new line of bases throughout the park—and particularly along the Shield. La Corona, the northern camp across from the fence line, had started small: a few huts of nylon or palm thatch, accessible only by a grueling hike through the sweltering jungle. But over time, beside the ancient site of Sacnite, CONAP and WCS built a compound of huts. They carved a narrow trocopas (truck pass) out of the jungle to give their pickups access to the fire line, which allowed them to easily move firebreak clearers, park guards, and soldiers right up to the front.

This cooperation between WCS workers and the Guatemalan armed forces protecting them in the field, one guard suggested, was like "if Greenpeace worked with the US Marines." In an atmosphere of corruption and governmental weakness, McNab quietly made WCS into a key driver in the campaign to take back the park. WCS funded the permanent camps along the Shield; paid for CONAP missions, fuel, and food; and transported soldiers and park guards to the front on WCS trucks. WCS even paid for life-insurance policies for CONAP officials threatened by ranchers. And in an environment with constant political instability, WCS provided a much-needed level of stability and institutional memory, snapping up the park service's most talented directors when their terms ran out. CONAP's directors in the reserve told me that by 2010 or so, they didn't bother asking the headquarters in Guatemala for resources. They just went to WCS.

And through it all, McNab ran back and forth, talking to the many fractious actors—police, judiciary, army, park guards, communities—and building coalitions for missions to take back territory. "Roan is very politically powerful," Macz said. "When he shows up at a meeting, he doesn't just propose an idea or suggest a way to stop an advance. He has a project, he has the funds, and he's already talked to the people you're going to need to execute it." McNab, as perhaps befits a gringo in Guatemala, is humble to the point of embarrassment about his successes. But several former high CONAP officials said that, if not for McNab and the Shield, there would be no macaws and the ranchers would be pressing even deeper into the vulnerable guts of the forest.

In February 2016, a couple of weeks after McNab found the restrung fence, I found him in the WCS office in Flores, an island city and regional capital on the border of the reserve. It was well over 100 degrees, so hot that the city's power grid kept shutting off, but unlike the rest of his staff, McNab eschewed air-conditioning. As I mopped sweat from my face, he stared at a map of the Shield, which had been so successful that over the previous years he and his staff had actually rolled territory back, as invader communities began to voluntarily return territory to the park service in the hopes of reaching a deal that would allow the new towns to stay.

But that year almost everything that could have gone wrong did. It wasn't just El Niño. For one, the president, Otto Pérez Molina, resigned and was eventually arrested after prosecutors discovered that the he had been running a massive fraud scheme through the nation's customs department. His eventual elected successor, Jimmy Morales, was a former comedian with no political experience and little apparent interest in conservation. Worst of all, LightHawk, the volunteer air corps that McNab relied on to spot invasions and fires, had closed its program in Central America. He was blind just as the invaders were stirring again, revving up their chainsaws and drying palm fronds for torches.

McNab pointed at a spot on the line, where a group of about 30 well-financed families of loggers was playing cat and mouse with the park guards, pushing back into the reclaimed forest and vanishing before they could be caught. Early reports suggested that they had already cleared some 15,000 acres. "They're outsmarting the army, WCS, CONAP." He shook his head in wonder. "It's like fighting ghosts." And then there was the fenced property they had found the week before near La Corona: owned by some unknown, shadowy rancher, standing brazenly on land claimed for the national park. In this slow war of attrition, McNab was desperate to make clear to the invaders that claiming government land was futile.

"We don't want to go after poor peasants," McNab said. He pointed at the fence line he had drawn, explaining that he wanted to catch the "biggest, toothiest crocodiles," the men who had sent the peasants there.

He did a rough estimate—with the area the scouts had found enclosed, the fence and posts alone would account for tens of thousands of dollars of infrastructure, paid for by some unknown rancher in an attempt to claim the land. Destroying that fence would send a distinct message. "We're going to hit them in their wallet," he said. His eyes were suddenly stern. He turned the pencil sideways and pushed it across the map he had drawn: the pastures, the fence lines. "And then we're going to push them back."

Soldiers examine a barbed-wire fence.

The next morning, I rode north from Flores with Luis Romero, an affable middle-aged Petén native who had served as a Guatemalan soldier and a national-park director, and now ran WCS's fire-prevention program. We headed into the forest in an enormous green pickup with extra tanks for fuel and water for the men on the line. But Romero himself was the main support: McNab had sent him to make sure the fence line was actually cleared. The men, Romero said, were often scared of acting. "They'll reach for any excuse," he said. He was there to make sure they didn't get one.

Like many of the guards, Romero had grown up in the forests around Flores—back when there was forest. Now the signs of cattle were everywhere, in flagrant violation of the law. We drove the back way up toward the Shield, up the narrow road through the protected forest concessions at La Pasadita, a small town at the front lines of the struggle over the forest. Humpbacked Brahman cattle watched us from roadside stock pens. After being illegally cleared by ranchers, the land had ostensibly been "recuperated" by the government, but the invaders still burned it every season, sometimes using fallen trees to bridge the firebreaks. Driving through those communities, Romero kept his hat brim pulled down over his eyes to shield his identity. Asked if we could stop and take pictures, he shook his head. " La gente aqui es mala," he said. Bad folk here.

The success of the Shield had brought unintended consequences: Big ranchers had simply gone around it, pressing into the unguarded south flank of the park. There they found community forest concessions like the one in Uaxactun, dedicated to sustainable logging. In the late 2000s, they bought them illegally, by promises or force, and cleared the forest.

When CONAP realized what had happened, it went to the government, with the help of WCS's legal arm, to throw the ranchers out. Results had been mixed. In the fall of 2015, an operation of more than 1,000 policemen had been routed trying to evict a big rancher named Maynor Palma. Far south of Palma's lands, near the area I had asked Romero to stop, the officers had found the way blocked by villagers burning tires. The police, unarmed in accordance with Guatemalan law, moved to clear the road. They walked into a trap. As they moved forward, high-caliber bullets ripped into their ranks, allegedly fired by the hired men of one of Palma's rancher friends. The police broke and ran, pursued by bullets fired from the ranches beside the road. Fourteen police were wounded, and a government truck was burned.

Romero had run with the rest. The villagers' resistance in that raid had been an ominous sign. "We hadn't expected anything like that," he said. "We weren't going after the community." They heard later that Palma and his friend had convinced the peasants that if he went they would be next. In the wake of the attack, the government had moved decisively. Palma's friend, the alleged ringleader, was arrested later at a police checkpoint; Palma, shaken, moved his cattle off the land he had taken. No one knew where they had gone. We rattled down trocopases for six spine-jarring hours and pulled at last into the base at La Corona, a cluster of wooden buildings beside a stagnant lake. Romero called to park guards walking back to camp—"Hey, socio"—and waved to a short, sinewy man in camos. "Sergeant Major!" The sergeant waved back. A member of Guatemala's feared Kaibil unit, he had fought jungle rebels in both Guatemala's civil war and the UN campaigns in the Congo. His presence there had been a major coup for McNab. When the local army commandant refused to give him soldiers to chase loggers, McNab had gone to Guatemala City, secured a meeting with the army's chief of staff (its highest official), and gotten the men assigned to the base for six months—an unimaginable luxury for park guards used to being terribly outgunned by the invasores. For the first time in recent memory, they would go into the field with more firepower than the invaders. I fell asleep that afternoon to the sound of them testing their chainsaws.

McNab's machete and binoculars sit on a tree as he waits for a boat to arrive in the San Pedro River.

The following morning, 15 of us got into the backs of three trucks. Romero laid out the plan, dressed like something out of Rambo: full camo, beaded machete sheath at his hip, a bandanna decorated with Uzis and AK-47s tied over his head. We crossed the Shield and entered the cleared lands, which was like being transported suddenly to West Texas in high summer, Apocalypto to No Country for Old Men. We crossed through cornfields drying in the summer sun, boots kicking up ash from the soil.

On the side of the cane field, the soldiers surrounded a pair of teenage girls in ragged clothing. They were Kekchi Maya from the mountains, the daughters of the land clearers, likely left behind in the knowledge that the rangers could not touch them. They stared at the ground. One chopped idly at a fallen tree with the back of her machete. A WCS ranger asked where their parents had gone. They would not answer. Whose land was it? "My mama," the girl said. Whack, whack, whack. "The army is coming here," he said. "This is a recuperated area. We're going to use it as a base. Imagine the cost of what you've done here—imagine the cost and time to grow back even one tree like the one branch you're hitting right now. It'll take 20 years to grow back." Stony silence from the girls. "You have to go," he said. "Your beasts are over there. The men have gone; please, girls, please leave. You can't come back."

The girls saddled their horses silently, and we followed them west until we came to the fence line yawning across the plain. The men hid under whatever pathetic bits of shade they could as they sharpened their chainsaws. No one had brought a wire cutter, so they used the flats of their machetes to break the wire into pieces. "What'll you do with the wire?" I asked. The Kaibil sergeant looked up. "Leave it," he said. "They will not be able to say that we're thieves."

The first cutter was Ronnie, a park guard with brilliant blue eyes and a frame so stocky he was almost square. He sliced down the posts with a grim satisfaction. In the early days of the Shield, he said, a group of 20 invaders on horseback had captured him and two comrades while they were out cutting firebreaks. The invaders had tied the guards "like bulls" and led them back to La Florida, one of the illegal settlements in the cleared lands, where a mob had gathered. A man in a wheelchair produced a can of gasoline. The villagers considered burning them alive but instead chased the terrified guards at pistol point around town until they collapsed from exhaustion. The invaders then made them sign a statement of support for the takeover and threw them out of town. This time he had guns at his back. Ronnie advanced post by post, watching with grim satisfaction as they fell.

Near noon, when everything was still and baking, a call went up: riders in the distance. The chainsaws shut off, their operators turning pale. "I think they're trying to envelop us," the Kaibil sergeant said. He climbed a barbed-wire fence, balancing atop it like a bird, supporting himself with the barrel of a Galil carbine held up by one of his men. For a moment, under the still hot sun, time seemed to stop. But the riders behind us, if that was what they had been, did not show themselves again. When the chainsaws ran out of gas, we hiked back to the Shield, passing by the fence builders' farm, where we rested in the shade of their one-room hut and filled our packs with their corn, chiles, sugarcane, and bananas, as much as we could carry.

Cattle graze on an illegal ranch.

The fence clearing took three scorching days. One morning, I begged off and hiked up into the ruins of Sacnite with Peralta, the elderly guide from Uaxactun who had saved McNab from the tomb raiders. The pyramids were now hills, the plazas open parks where howler monkeys roared and foraged in the canopies. Scattered among the ruins were the cantemo trees, the uneven pattern of their bark a surreal echo of the long-dead faces peeking from Maya stellae around us—and in the trees, high above, we saw the curious faces of scarlet macaws.

There was something like reverence on Peralta's face as he looked up. The men have a deep affection for the scarlet macaws. They name the birds' nests after wives, daughters, or girlfriends. (Asked why they named the nests all after women, one WCS biologist laughed, saying, "Think of how ugly it sounds to say, 'We have two huevos in Saul.'") At one—called Raquel, for McNab's daughter—I saw a mating pair of scarlet macaws doing what I can only describe as making out. One had its wing extended, and the other was carefully nuzzling its feathers. "This," he said, "is what we're protecting. Without us, va, they'd come in, put in their cattle, knock down this tree. The guacas [macaws] would fly, flee, or they'd die."

Back in Flores, McNab waited to see how the invaders would react to the raid. By cutting down those fence posts, he had stuck his thumb directly into the eye of the ranchers on the other side. What would they do? When I asked him, he shrugged. "You can't let that stop you," he said. "Concern can become a recipe for paralysis." The response was not long in coming. A week after the fence-cutting mission, a group of armed men surrounded some park guards cutting firebreaks, held them for a while, and forced them to sign a letter supporting the invaders' claim for land. Though the guards escaped without harm, the incident underscored the dangers remaining in the park.

But there were other encouraging developments. About a week after the raid, an elderly Maya woman appeared at the WCS office in Flores and introduced herself as the leader of the invader settlement at La Florida. She had lived there for 17 years with her children, she said. She was interested in making a deal. "We have nowhere else to go," she said.

McNab treated her courteously. He needed a deal too. There were now 33 settlements in Laguna del Tigre, the vast majority illegal. "We're not going to be able to get all those people out of the reserve," he said. "So how can we find a win-win?" Think of that peasant family placing the fence, he said. "It's a pretty bleak existence, isn't it? Wouldn't it be better off if they could do agriculture safely, with land rights? You think those kids go to school?"

The key, he thought, was targeting organized crime while reaching a separate peace with those peasants willing to follow environmental best practices in return for a place to live—as Uaxactun had. There was movement on this front as well. In March 2016, a federal prosecutor indicted several members of the Mendoza, a powerful local crime family, for seizing pastures from peasants on the edge of the reserve. WCS and its partners hoped to strengthen local democracy, doing things like donating bus tickets to community groups so they could go to Flores and badger their representative about, say, the water-catchment facility they had been promised during the election. "When big bad brother comes," he said, "we want people not to feel alone and isolated. We want them to feel like they have choices."

There was one more final piece of good news: McNab had a plane. He had convinced a pilot on a medical mission in Cuba to detour through Guatemala on his way home with a sleek four-seater. On April 9, 2016, he, McNab, and I took off over the reserve. The glider was light and maneuverable as a kite, and after fueling in a military hanger full of DC-3s and Cessnas confiscated from traffickers, we floated over Flores, the plains of Laguna del Tigre burning beneath us. We crossed into the reserve and flew along limestone cliffs that broke the thick forest like the prows of colossal ships.

The plane ride is one of McNab's favorite tricks, allowing him to show a skeptic the scope of the damage, the frontier between pasture and forest. Years before, a similar flight had helped him convert a skeptical bishop who had believed, until he saw it for himself, that the forest was going as homes to needy peasants. And the damage was extraordinary: Laguna del Tigre was settled country now, its lakes and rivers turned brown by illegal villages. We flew so low the autopilot screamed at us to pull up, passing over clearings where trees were tumbled like matchsticks and enormous cattle ranches were curiously empty of cattle. And everywhere below us fires burned. "It is such a bummer when they do that," McNab said, pointing at an eroding hillside. "It's going to take 200 years to come back. It'll erode right down to the limestone." He pointed to the fallen trees beneath. "Man, they're just going to burn the shit out of this. Now give me 360 over that, tight as you can hold it." There were the peasants he had been tracking. "That's where they are. That's where we'll lay our trap."

We spiraled over the surviving forest, the fire engulfing the plain beneath us in a carpet of green, breathing and seething against the line of burning pasture. Give it a few summers without fire, and it would push forward and overwhelm the grassland again, as it had taken the Maya cities. We flew over the skyscraper temples of the metropolis at El Mirador, covered in trees up to their very tops. McNab pointed down. "Look at that," he said. "The New York City of the Americas at the time of Jesus Christ." And now look at it. Two million people had lived here, and in a blink of the geologic eye, the forest had come back. "It's a real testament to the resilience of nature," McNab said. "Stop mucking around with it, and the forest recovers." We turned in a tight circle over the tallest temple, and the land spread beneath us green and unspoiled, the causeways and reservoirs barely visible outlines beneath the thick forest. "Alright," McNab said at last, "back to the land of fire." And we banked back west, toward the smoke rising like pillars below the setting sun.