Marijuana plants, mixed with scattered corn stalks, grow in a field in the Tirah Valley in Pakistan’s belt near the border with Afghanistan. (Fahim Khan Afridi)

For decades, Taj Muhammad Afridi had been making stoners mellow around the world.

By now, at his family homestead in the Tirah Valley in Pakistan’s tribal belt, hundreds of marijuana plants should be full-grown, some as tall as a one-story house. The traditional harvest would be in October, and that’s when Afridi would start making some of the world’s most sought-after hashish.

But Afridi’s crops — and those of others nearby that produce eye-popping amounts of marijuana — have been abandoned, and are in danger of becoming another casualty of Pakistan’s decade-long war against terrorism and Islamist militancy.

After Afridi planted his marijuana seeds in February, the military began a series of military operations in the Tirah Valley against Taliban fighters who had found refuge there. The operation displaced Afridi and a quarter-million other residents, many of whom are still waiting to go home.

“We know that our crops are still there,” said Afridi, 65, noting the region’s moist climate allows marijuana to grow with little maintenance. “But I don’t know what the future will be. Will the military allow this?”

Zakir Wan Afridi, 35, right, watches Niaz Gul Afridi, 40, as he lights a ball of hashish. Both are from the Tirah Valley in Pakistan, where growing marijuana and producing hashish is big business. (Tim Craig/The Washington Post)

The answer could prove to be a buzz-kill.

According to other residents who have gone home, security forces are targeting Pakistan’s lucrative hash industry to try to establish more government control over the historically lawless border region.

In recent weeks, paramilitary forces have erected a dozen checkpoints and are enforcing a ban on transporting hashish through tribal areas. Dozens of roadside stands that previously sold hash openly have been shuttered. And residents say private homes are being raided.

That spells big trouble in the Tirah Valley, where growing marijuana is part of the culture as well as the chief source of income for several tribes, including the Afridis. Hamid-ul-Haq Khalil, a member of Pakistan’s Parliament, said at least 100,000 people make their living cultivating or selling hash.

Families in the Tirah Valley, on the southern edge of the Hindu Kush mountains, grow marijuana on small or medium plots of land that cascade down from an elevation of 8,000 feet. The valley typically produces at least 100 tons of hash annually, residents say.

Much of it ends up in Pakistani cities, one reason hippies and college students from the United States flocked to Pakistan in the 1960s, 1970s and early 1980s. But the drug is also smuggled around the world, and terms such as “Hindu Kush marijuana” and “Pakistani hash” are mainstays of pot-lovers’ lexicons.

Along with the Tirah Valley, high-quality hash is also produced in parts of Afghanistan, Morocco, Lebanon and India, according to Sheshta, who only uses a first name and writes for Amsterdam-based Sensi Seeds, a Web site that sells marijuana seeds.

But residents of Tirah Valley claim no one can produce hash quite like they can.

While marijuana grows wild throughout much of northern Pakistan, most of it lacks enough tetrahydrocannabinol (THC) to be considered a mind-altering drug. In the Tirah Valley, however, residents say they have been refining the quality of their marijuana for decades.

The drug was introduced to the valley about 120 years ago when a Sufi tourist from the eastern part of India, then a British colony, stumbled into the valley, tribesmen say. Sufism is a mystical form of Islam that stresses peace and love.

“He brought us the plant from India and convinced us we should grow it,” said Shah Nawaz Afridi, a social justice activist from the valley.

The summer climate of the Tirah Valley — warm days, brief rain showers most evenings and cool nights — allows pot seeds to grow into monster marijuana plants that can exceed 15 feet, residents say.

In October, the plants are cut but left bundled in fields for another two months. Then they get covered in snow, which residents say is the secret to producing powerful hashish. The snow turns once-green buds red — “like a radish,” one farmer said.

After the plants are dried and brittle, entire families gather to make hash. It’s produced by beating marijuana buds with sticks so dust-like residue floats to the ground. The residue is then swept up and packed into a bag — or the hide of a freshly slaughtered sheep or goat — so it gels into a substance that resembles smashed chocolate cake. It can then be smoked.

“The students, the doctors and other people who know, all want charas from the Tirah Valley,” said Zakirullah Afridi, 35, using the local name for hash. As he spoke, he rubbed a half-dollar-size ball of hash between his fingers. “The taste is good. It’s sweet. It’s oily. And it makes you drowsy.”

In a part of Pakistan so rugged residents say the first paved road opened just this year — after the Pakistani army built it to transport military supplies — tribesmen consider hash to be a vital “medicine” for six ailments.

Diabetes. High blood pressure. Constipation. Poor sexual performance. Unhappiness. Being overweight.

“We also give it to the chickens in the field so they produce more eggs,” said Sadar Khan Afridi, 36, who estimates his family can produce about 15 pounds of hash annually.

But most of the hash is sold on the black market. Several Tirah Valley pot farmers say they earn $5,000 to $10,000 annually, a respectable income in one of the world’s most remote regions.

When the Pakistani Taliban controlled the area, it taxed marijuana crops but otherwise did not interfere in the trade, residents said.

Even as Pakistan tries to exert more control, residents insist they are still governed by colonial-era regulations that gave them wide latitude to set their own laws.

Pakistan’s army, which entered the Tirah Valley for the first time in 2003, appears to be taking a different view. Shah Nawaz Afridi said at least 100 Tirah Valley residents have been arrested in recent months for drug offenses.

“Even carrying one kilogram is now a difficult task,” said Mohammad Karim Afridi, 43. “They are checking every vehicle . . . even the nuts and bolts . . . and if they have any idea someone is keeping hashish at home, they raid.”

A spokesman for the Pakistani military declined to comment. Pakistan’s Anti-Narcotics Force also declined to comment, except to point to statistics showing it has seized 57 tons of hash between March 1 and Aug. 31.

“The operation in the Tirah Valley was launched to clear the area of terrorists, but the drug problem is also part of counterterrorism operations,” said one Interior Ministry official, who asked not to be identified because he was not authorized to discuss the matter. “Drug money is being used to fund militancy. . . . It will be done away with completely.”

Now, there is widespread concern in the Tirah Valley that the army will not even allow the crop to be planted next year.

With smuggling a mainstay of the tribal economy, it is hard to imagine Pakistan’s hash trade will totally dry up. But residents say even a partial disruption will cripple them financially because little else grows in the Tirah Valley except corn, walnuts and apricots.

“In the past, we had thick forests, but now the forests are depleted, so this is the only source of income,” said Nisbat Afridi, 27.

But as some countries in the West liberalize marijuana laws, tribesmen and even a few Pakistani lawmakers see opportunity.

“We want permits and licenses for hashish, so we can show more people about the benefits, and if they allow us, we can export it,” Sadar Khan Afridi said. “We could offer people better products, better prices.”

Haq Nawaz Khan and Shaiq Hussain contributed to this report

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