On assignment for National Geographic.
       
     
 Harvesting black cardamom,  thao qua , is heavy work. The fruit is cut and kept in repurposed orange fertilizer bags to be carried later to the campsite for drying.
       
     
 A motorbike takes cardamom farmers Giang A Tru and his wife, Tan Thi Si, part of the way to their plot in Hoang Lien, but the final destination in the mountains must be reached by foot.
       
     
 Black cardamom farmers head up the mountains in Hoang Lien National Park, near Vietnam’s border with China. Many local Vietnamese families have cultivated cardamom here for decades. Enforcing conservation rules with precision in Vietnam’s protected
       
     
 For women, black cardamom fruit is cut and kept in baskets on their backs and carried later to the campsite for drying. McElwee, an associate professor of human ecology at Rutgers University, said the “cardamom model”—in which villagers harvest blac
       
     
 Cho, Lang's 27-year-old brother, who never had much interest in Sapa’s tourism industry, still sees cardamom as a key to his prosperity — even if the financial risks sometimes outweigh the rewards. Cho’s father put him in charge of the family cardam
       
     
 Giang A Tru and his wife Tan Thi Si are cardamom farmers driving to Hoang Lien Son National Park to harvest their crops.
       
     
 Rice terraces scallop hillsides in the mountains of Hoang Lien.
       
     
 Hoang Lien National Park, more than twice the size of San Francisco, is a rising destination for trekkers, who can hire guides in the gateway city of Sa Pa.
       
     
 A French family are guests at the H'mong Family Homestay. They are dining with the rest of Lang's family who are from the Black H’mong ethnic group. They live in a village outside Sapa that has benefited immensely from the boom in trekking tourism o
       
     
 A family settles in on an overnight train to Lao Cai, a gateway city to Vietnam’s northwest.
       
     
 A passenger enjoys the luxe surroundings of the Victoria Express train, which travels between Hanoi and Lao Cai.
       
     
 Lang's younger brother, Giang A Cho, carries a tree trunk that will be used as firewood at the campsite. After arriving at their black cardamom plantation everyone will stay for several days to harvest and dry the fruit.
       
     
 Farmers wash greens at a campsite near a stand of black cardamom plants in Hoang Lien National Park. They were part of a group that spent several days harvesting the spice and drying it on an open campfire before hauling it back to their village nea
       
     
 Freshly harvested pods of black cardamom,  thao qua , are red until roasted, then they turn dark brown or black. The spice is primarily sold to Chinese brokers and used in traditional medicines.
       
     
 Giang A Thao, a farmer who lives near Sa Pa, rests on a bag of freshly picked cardamom pods. During harvest season, he helps out his relatives, who own a cardamom plot in the Hoang Lien Mountains.
       
     
 Harvesting black cardamom is hard work. These women cut the fruit and store it in baskets they carry on their back. Later they’ll hike to the campsite to dry and roast the pods.
       
     
 Black cardamom plants grow below the forest canopy near streams. Farmers plant and cultivate crops near these streams where the plants flourish best inside Hoang Lien National Park, established in 2002. It is one of many protected areas in Vietnam w
       
     
 Stands of black cardamom blanket the ground. The plants grow along streambeds in high-elevation forests, under the canopy of tall trees in the state-protected Hoang Lien National Park. Enforcing conservation rules with precision in Vietnam’s protect
       
     
 Pods of black cardamom fruit are dried on a shelf made of freshly cut bamboo sticks above a makeshift fireplace. After drying, the cardamom is a third of its original weight. This makes it easier to carry the harvest out of Hoang Lien National Park
       
     
 Two villagers from the Red Dao ethnic group cross a footbridge on their way back from harvesting cardamom. People in their village, Nam Cang, earn much of their income from selling the spice to traders.
       
     
 Workers fill bags with black cardamom for a truck shipment heading for China, where a large percentage of cardamom harvests end up for use in traditional medicine. Through the years, rising Chinese demand has made Sa Pa an important hub for black ca
       
     
 Workers sort different grades of black cardamom for bagging. Black cardamom is primarily sold to Chinese brokers and used in traditional medicine to treat constipation and other ailments. Through the years, rising Chinese demand has made Sa Pa an im
       
     
 Stall selling spice and herbs inside Sa Pa Market. They also stock black cardamom or  thao qua . Black cardamom is used in much of Vietnamese cuisine. It is grown commercially in the forests of the Hoang Lien National Park and largely exported to Ch
       
     
 A canteen in Sa Pa Market sells pho (noodle soup). Pho broth traditionally is made with a mix of fragrant spices that includes black cardamom.
       
     
 At the top of Ham Rong Mountain, Vietnamese tourists wait for the fog to clear for better views of Sa Pa.
       
     
 A Vietnamese tourist poses in Sa Pa’s main square, where local Hmong children sell handmade trinkets. Sa Pa served as a retreat for French colonial administrators and now is a gateway for treks into the Hoang Lien Mountains.
       
     
 A farmer driving his chickens towards Sa Pa from Nam Cang, a Red Dao village at the far end of the Sa Pa valley, where many people have black cardamom,  thao qua,  plots in the nearby Hoang Lien National Park forest.
       
     
 Buffalo traders are one of a variety of vendors who gather at Bac Ha Market. Open on Sundays only, ethnic minorities from surrounding villages and hills come by foot, by motorscooter, by horse, and by water buffalo for a chance to socialize, eat, dr
       
     
 Customers at Ly-Ly 1-2 restaurant that specialises in a traditional Vietnamese dish made with horse meat known as Than Co Ngua in Bac Ha. The dish uses black cardamom as one of its key ingredients.
       
     
 Young local Vietnamese teenagers walk past a batch of black cardamom drying in the sun outside Hue Hoan, a black cardamom dealer shop. The shop buys the spice from local farmers and sells a large proportion to China.
       
     
 A Buddhist pagoda draws tourists at the top of Fansipan, Vietnam’s highest peak (10,312 feet).
       
     
 Tourists on a tram to the foot of Mount Fansipan where a cable car will take passengers partway to Mount Fansipan. The tram and cable car were completed in February 2016, making the journey to the top under 20 minutes today. In the past trekkers to
       
     
 With cooler temperatures and at an elevation of 4,921 feet, Sa Pa is often shrouded in fog.
       
     
 Ly May Vy boils plants atop a wood fire to prepare a traditional medicinal bath. Cardamom stems are among the many ingredients used at Tam La Thuoc Dao Do Herbal Bath Spa in Ta Van village, near Sa Pa.
       
     
 View of terraced rice fields harvested a couple of months ago from Topas Eco Lodge. Topas is a member of National Geographic Unique Lodges of the World.
       
     
 Outside Sa Pa, guests at Topas Ecolodge can swim in an infinity pool and sleep in thatched bungalows. Topas is a member of National Geographic Unique Lodges of the World.
       
     
 Harvesting black cardamom,  thao qua , is heavy work. For the women, the fruit is cut and kept in baskets on their back and carried later to the campsite for drying. Hoang Lien National Park, established in 2002, is one of many protected areas in Vi
       
     
 Black cardamom was first planted in the Hoang Lien Mountains in the 1990s as a replacement for opium, a banned crop that once helped prop up Indochina’s colonial economy. The national park, meanwhile, is a symbol of postwar Vietnam’s efforts to prot
       
     
On assignment for National Geographic.
       
     
On assignment for National Geographic.

An increasing number of intrepid adventurers are heading to Hoang Lien National Park, close to Vietnam’s border with China. The park is home to forests of black cardamom, thao qua, an essential spice in traditional pho and other Vietnamese dishes. The spice was first planted in the Hoang Lien Mountains in the 1990s as a replacement for opium, a banned crop that once helped prop up Indochina’s colonial economy. The national park, meanwhile, is a symbol of postwar Vietnam’s efforts to protect plant biodiversity. Hence this conundrum: How could a forest be a haven for conservation and cash-crop agriculture at the same time?

 Harvesting black cardamom,  thao qua , is heavy work. The fruit is cut and kept in repurposed orange fertilizer bags to be carried later to the campsite for drying.
       
     

Harvesting black cardamom, thao qua, is heavy work. The fruit is cut and kept in repurposed orange fertilizer bags to be carried later to the campsite for drying.

 A motorbike takes cardamom farmers Giang A Tru and his wife, Tan Thi Si, part of the way to their plot in Hoang Lien, but the final destination in the mountains must be reached by foot.
       
     

A motorbike takes cardamom farmers Giang A Tru and his wife, Tan Thi Si, part of the way to their plot in Hoang Lien, but the final destination in the mountains must be reached by foot.

 Black cardamom farmers head up the mountains in Hoang Lien National Park, near Vietnam’s border with China. Many local Vietnamese families have cultivated cardamom here for decades. Enforcing conservation rules with precision in Vietnam’s protected
       
     

Black cardamom farmers head up the mountains in Hoang Lien National Park, near Vietnam’s border with China. Many local Vietnamese families have cultivated cardamom here for decades. Enforcing conservation rules with precision in Vietnam’s protected areas is often impossible because so many people with modest incomes live nearby, said Pamela McElwee, author of Forests Are Gold: Trees, People, and Environmental Rule in Vietnam. “It’s just not going to happen, so you have to have some sort of alternate model.”

 For women, black cardamom fruit is cut and kept in baskets on their backs and carried later to the campsite for drying. McElwee, an associate professor of human ecology at Rutgers University, said the “cardamom model”—in which villagers harvest blac
       
     

For women, black cardamom fruit is cut and kept in baskets on their backs and carried later to the campsite for drying. McElwee, an associate professor of human ecology at Rutgers University, said the “cardamom model”—in which villagers harvest black cardamom inside the Hoang Lien National Park, and park rangers mostly ignore them—has so far worked reasonably well for both sides.

 Cho, Lang's 27-year-old brother, who never had much interest in Sapa’s tourism industry, still sees cardamom as a key to his prosperity — even if the financial risks sometimes outweigh the rewards. Cho’s father put him in charge of the family cardam
       
     

Cho, Lang's 27-year-old brother, who never had much interest in Sapa’s tourism industry, still sees cardamom as a key to his prosperity — even if the financial risks sometimes outweigh the rewards. Cho’s father put him in charge of the family cardamom plot a few years ago. He hopes to someday pass it on to the eldest of his two sons, aged 7 and 10. “But I don’t know if he’ll take it over,” he said. “It’s a hard job.”

 Giang A Tru and his wife Tan Thi Si are cardamom farmers driving to Hoang Lien Son National Park to harvest their crops.
       
     

Giang A Tru and his wife Tan Thi Si are cardamom farmers driving to Hoang Lien Son National Park to harvest their crops.

 Rice terraces scallop hillsides in the mountains of Hoang Lien.
       
     

Rice terraces scallop hillsides in the mountains of Hoang Lien.

 Hoang Lien National Park, more than twice the size of San Francisco, is a rising destination for trekkers, who can hire guides in the gateway city of Sa Pa.
       
     

Hoang Lien National Park, more than twice the size of San Francisco, is a rising destination for trekkers, who can hire guides in the gateway city of Sa Pa.

 A French family are guests at the H'mong Family Homestay. They are dining with the rest of Lang's family who are from the Black H’mong ethnic group. They live in a village outside Sapa that has benefited immensely from the boom in trekking tourism o
       
     

A French family are guests at the H'mong Family Homestay. They are dining with the rest of Lang's family who are from the Black H’mong ethnic group. They live in a village outside Sapa that has benefited immensely from the boom in trekking tourism over the past decade.

 A family settles in on an overnight train to Lao Cai, a gateway city to Vietnam’s northwest.
       
     

A family settles in on an overnight train to Lao Cai, a gateway city to Vietnam’s northwest.

 A passenger enjoys the luxe surroundings of the Victoria Express train, which travels between Hanoi and Lao Cai.
       
     

A passenger enjoys the luxe surroundings of the Victoria Express train, which travels between Hanoi and Lao Cai.

 Lang's younger brother, Giang A Cho, carries a tree trunk that will be used as firewood at the campsite. After arriving at their black cardamom plantation everyone will stay for several days to harvest and dry the fruit.
       
     

Lang's younger brother, Giang A Cho, carries a tree trunk that will be used as firewood at the campsite. After arriving at their black cardamom plantation everyone will stay for several days to harvest and dry the fruit.

 Farmers wash greens at a campsite near a stand of black cardamom plants in Hoang Lien National Park. They were part of a group that spent several days harvesting the spice and drying it on an open campfire before hauling it back to their village nea
       
     

Farmers wash greens at a campsite near a stand of black cardamom plants in Hoang Lien National Park. They were part of a group that spent several days harvesting the spice and drying it on an open campfire before hauling it back to their village near Sa Pa.

 Freshly harvested pods of black cardamom,  thao qua , are red until roasted, then they turn dark brown or black. The spice is primarily sold to Chinese brokers and used in traditional medicines.
       
     

Freshly harvested pods of black cardamom, thao qua, are red until roasted, then they turn dark brown or black. The spice is primarily sold to Chinese brokers and used in traditional medicines.

 Giang A Thao, a farmer who lives near Sa Pa, rests on a bag of freshly picked cardamom pods. During harvest season, he helps out his relatives, who own a cardamom plot in the Hoang Lien Mountains.
       
     

Giang A Thao, a farmer who lives near Sa Pa, rests on a bag of freshly picked cardamom pods. During harvest season, he helps out his relatives, who own a cardamom plot in the Hoang Lien Mountains.

 Harvesting black cardamom is hard work. These women cut the fruit and store it in baskets they carry on their back. Later they’ll hike to the campsite to dry and roast the pods.
       
     

Harvesting black cardamom is hard work. These women cut the fruit and store it in baskets they carry on their back. Later they’ll hike to the campsite to dry and roast the pods.

 Black cardamom plants grow below the forest canopy near streams. Farmers plant and cultivate crops near these streams where the plants flourish best inside Hoang Lien National Park, established in 2002. It is one of many protected areas in Vietnam w
       
     

Black cardamom plants grow below the forest canopy near streams. Farmers plant and cultivate crops near these streams where the plants flourish best inside Hoang Lien National Park, established in 2002. It is one of many protected areas in Vietnam where ethnic-minority groups earn a living from land that belongs to the state.

 Stands of black cardamom blanket the ground. The plants grow along streambeds in high-elevation forests, under the canopy of tall trees in the state-protected Hoang Lien National Park. Enforcing conservation rules with precision in Vietnam’s protect
       
     

Stands of black cardamom blanket the ground. The plants grow along streambeds in high-elevation forests, under the canopy of tall trees in the state-protected Hoang Lien National Park. Enforcing conservation rules with precision in Vietnam’s protected areas is often impossible because so many people with modest incomes live nearby, said Pamela McElwee, author of Forests Are Gold: Trees, People, and Environmental Rule in Vietnam.

 Pods of black cardamom fruit are dried on a shelf made of freshly cut bamboo sticks above a makeshift fireplace. After drying, the cardamom is a third of its original weight. This makes it easier to carry the harvest out of Hoang Lien National Park
       
     

Pods of black cardamom fruit are dried on a shelf made of freshly cut bamboo sticks above a makeshift fireplace. After drying, the cardamom is a third of its original weight. This makes it easier to carry the harvest out of Hoang Lien National Park on foot.

 Two villagers from the Red Dao ethnic group cross a footbridge on their way back from harvesting cardamom. People in their village, Nam Cang, earn much of their income from selling the spice to traders.
       
     

Two villagers from the Red Dao ethnic group cross a footbridge on their way back from harvesting cardamom. People in their village, Nam Cang, earn much of their income from selling the spice to traders.

 Workers fill bags with black cardamom for a truck shipment heading for China, where a large percentage of cardamom harvests end up for use in traditional medicine. Through the years, rising Chinese demand has made Sa Pa an important hub for black ca
       
     

Workers fill bags with black cardamom for a truck shipment heading for China, where a large percentage of cardamom harvests end up for use in traditional medicine. Through the years, rising Chinese demand has made Sa Pa an important hub for black cardamom trading.

 Workers sort different grades of black cardamom for bagging. Black cardamom is primarily sold to Chinese brokers and used in traditional medicine to treat constipation and other ailments. Through the years, rising Chinese demand has made Sa Pa an im
       
     

Workers sort different grades of black cardamom for bagging. Black cardamom is primarily sold to Chinese brokers and used in traditional medicine to treat constipation and other ailments. Through the years, rising Chinese demand has made Sa Pa an important hub for black cardamom trading.

 Stall selling spice and herbs inside Sa Pa Market. They also stock black cardamom or  thao qua . Black cardamom is used in much of Vietnamese cuisine. It is grown commercially in the forests of the Hoang Lien National Park and largely exported to Ch
       
     

Stall selling spice and herbs inside Sa Pa Market. They also stock black cardamom or thao qua. Black cardamom is used in much of Vietnamese cuisine. It is grown commercially in the forests of the Hoang Lien National Park and largely exported to China.

 A canteen in Sa Pa Market sells pho (noodle soup). Pho broth traditionally is made with a mix of fragrant spices that includes black cardamom.
       
     

A canteen in Sa Pa Market sells pho (noodle soup). Pho broth traditionally is made with a mix of fragrant spices that includes black cardamom.

 At the top of Ham Rong Mountain, Vietnamese tourists wait for the fog to clear for better views of Sa Pa.
       
     

At the top of Ham Rong Mountain, Vietnamese tourists wait for the fog to clear for better views of Sa Pa.

 A Vietnamese tourist poses in Sa Pa’s main square, where local Hmong children sell handmade trinkets. Sa Pa served as a retreat for French colonial administrators and now is a gateway for treks into the Hoang Lien Mountains.
       
     

A Vietnamese tourist poses in Sa Pa’s main square, where local Hmong children sell handmade trinkets. Sa Pa served as a retreat for French colonial administrators and now is a gateway for treks into the Hoang Lien Mountains.

 A farmer driving his chickens towards Sa Pa from Nam Cang, a Red Dao village at the far end of the Sa Pa valley, where many people have black cardamom,  thao qua,  plots in the nearby Hoang Lien National Park forest.
       
     

A farmer driving his chickens towards Sa Pa from Nam Cang, a Red Dao village at the far end of the Sa Pa valley, where many people have black cardamom, thao qua, plots in the nearby Hoang Lien National Park forest.

 Buffalo traders are one of a variety of vendors who gather at Bac Ha Market. Open on Sundays only, ethnic minorities from surrounding villages and hills come by foot, by motorscooter, by horse, and by water buffalo for a chance to socialize, eat, dr
       
     

Buffalo traders are one of a variety of vendors who gather at Bac Ha Market. Open on Sundays only, ethnic minorities from surrounding villages and hills come by foot, by motorscooter, by horse, and by water buffalo for a chance to socialize, eat, drink, smoke, get a haircut, and buy produce and meat for the following week.

 Customers at Ly-Ly 1-2 restaurant that specialises in a traditional Vietnamese dish made with horse meat known as Than Co Ngua in Bac Ha. The dish uses black cardamom as one of its key ingredients.
       
     

Customers at Ly-Ly 1-2 restaurant that specialises in a traditional Vietnamese dish made with horse meat known as Than Co Ngua in Bac Ha. The dish uses black cardamom as one of its key ingredients.

 Young local Vietnamese teenagers walk past a batch of black cardamom drying in the sun outside Hue Hoan, a black cardamom dealer shop. The shop buys the spice from local farmers and sells a large proportion to China.
       
     

Young local Vietnamese teenagers walk past a batch of black cardamom drying in the sun outside Hue Hoan, a black cardamom dealer shop. The shop buys the spice from local farmers and sells a large proportion to China.

 A Buddhist pagoda draws tourists at the top of Fansipan, Vietnam’s highest peak (10,312 feet).
       
     

A Buddhist pagoda draws tourists at the top of Fansipan, Vietnam’s highest peak (10,312 feet).

 Tourists on a tram to the foot of Mount Fansipan where a cable car will take passengers partway to Mount Fansipan. The tram and cable car were completed in February 2016, making the journey to the top under 20 minutes today. In the past trekkers to
       
     

Tourists on a tram to the foot of Mount Fansipan where a cable car will take passengers partway to Mount Fansipan. The tram and cable car were completed in February 2016, making the journey to the top under 20 minutes today. In the past trekkers to Mount Fansipan would take 2-3 days to reach its peak.

 With cooler temperatures and at an elevation of 4,921 feet, Sa Pa is often shrouded in fog.
       
     

With cooler temperatures and at an elevation of 4,921 feet, Sa Pa is often shrouded in fog.

 Ly May Vy boils plants atop a wood fire to prepare a traditional medicinal bath. Cardamom stems are among the many ingredients used at Tam La Thuoc Dao Do Herbal Bath Spa in Ta Van village, near Sa Pa.
       
     

Ly May Vy boils plants atop a wood fire to prepare a traditional medicinal bath. Cardamom stems are among the many ingredients used at Tam La Thuoc Dao Do Herbal Bath Spa in Ta Van village, near Sa Pa.

 View of terraced rice fields harvested a couple of months ago from Topas Eco Lodge. Topas is a member of National Geographic Unique Lodges of the World.
       
     

View of terraced rice fields harvested a couple of months ago from Topas Eco Lodge. Topas is a member of National Geographic Unique Lodges of the World.

 Outside Sa Pa, guests at Topas Ecolodge can swim in an infinity pool and sleep in thatched bungalows. Topas is a member of National Geographic Unique Lodges of the World.
       
     

Outside Sa Pa, guests at Topas Ecolodge can swim in an infinity pool and sleep in thatched bungalows. Topas is a member of National Geographic Unique Lodges of the World.

 Harvesting black cardamom,  thao qua , is heavy work. For the women, the fruit is cut and kept in baskets on their back and carried later to the campsite for drying. Hoang Lien National Park, established in 2002, is one of many protected areas in Vi
       
     

Harvesting black cardamom, thao qua, is heavy work. For the women, the fruit is cut and kept in baskets on their back and carried later to the campsite for drying. Hoang Lien National Park, established in 2002, is one of many protected areas in Vietnam where ethnic-minority groups earn a living from land that belongs to the state.

 Black cardamom was first planted in the Hoang Lien Mountains in the 1990s as a replacement for opium, a banned crop that once helped prop up Indochina’s colonial economy. The national park, meanwhile, is a symbol of postwar Vietnam’s efforts to prot
       
     

Black cardamom was first planted in the Hoang Lien Mountains in the 1990s as a replacement for opium, a banned crop that once helped prop up Indochina’s colonial economy. The national park, meanwhile, is a symbol of postwar Vietnam’s efforts to protect plant biodiversity. Hence this conundrum: How could a forest be a haven for conservation and cash-crop agriculture at the same time?