PARKLAND DRUG GROWERS TURN AMERICA'S WILDERNESS INTO WILD WEST

THERE was a time when a visitor to one of America's national parks only had
to worry about running into a grizzly bear with a sore head. These days
they have gun-toting drug dealers and armed park rangers to contend with.

With their M-16 rifles and their backpacks snagging on every bramble, three
national-park rangers in commando gear spit out mosquitoes on a pathless
mountainside of manzanita thickets and dense brush. Gun barrels raised to
give each other cover, they advance using hand signals, pausing only to sip
water in the 100-degree heat and gasp for air through mesh masks.

After two-and-a-half hours, one mile, and a 1,000ft gain in altitude, they
come across evidence of the criminal activity that officials describe as
the biggest threat to national parks since their creation more than a
century ago. Beside an abandoned camp scattered with rubbish and human
waste, lie empty bags of fertiliser, gardening tools, irrigation tubing and
spent rifle casings. Illegal marijuana farming, once the province of
small-time growers, has become big business on the nation's most visited
public land: national parks.

Since the late 1990s, marijuana cultivation has escalated dramatically in
the national forests. Marijuana seizures in California national parks have
jumped 10-fold, from 45,054 plants in 1994 to 495,000 plants last year.

But since September 11, drug farming has increasingly spread from remote
forests to more-public national parks. Tighter security at US borders has
raised the incentive for domestic cultivation. That makes for more armed
growers and potential clashes with those traipsing into the wilderness for
nature at its most pristine.

As well as growing more common, the enterprise has become more organised.
International drug cartels - made up largely of Mexican nationals - seem
especially drawn to the bounty. And their harvests can be huge: last year,
officials at Sequoia National Park in California seized the biggest stash
of all, with 34,000 plants in five locations at an estimated street value
of $140m (UKP84m).

David Barna, chief spokesman for the National Park Service, said: "The most
[visitors] used to worry about is running into a grizzly bear. Now there is
the spectre of violence by a masked alien toting an AK-47."

Although the problem is nationwide, affecting many of America's 388
national parks, it is greatest in California, Utah, and Arkansas, and in
parks with international borders, such as Big Bend in Texas and Glacier in
Montana.

Bill Tweed, chief naturalist at Sequoia National Park, between Los Angeles
and San Francisco, said:

"They are killing wildlife, diverting streams, introducing non-native
plants, creating fire and pollution hazards, and bringing the spectre of
violence."

Last year, officials destroyed eight tonnes of marijuana at Sequoia
National Park and counted thousands of plants that had already been
harvested. Eight Mexican nationals are due for trial in September.

A version of this article has appeared in the Christian Science Monitor