The sun is up, first rays streaming through the canopy, and the two hunters pause to inspect tracks – big, dusty imprints with five toes – on the forest floor. They move on, boots crunching twigs as they climb a ridge. "What you reckon the chances we'll get one?" asks Josh Brones, a muscular 37-year-old, adjusting his backpack. Dan Tichenor, 65, tall and rangy, scans the northern California landscape. "More than even."

We troop on, single file, in silence. The only sound apart from our footsteps is the panting of Cajun, a hound straining at Tichenor's lead. Up ahead, sniffing bushes and trees for clues, is another hound, Osage, Cajun's father, a grey-muzzled veteran. "He's beginning to show his age but compensates with experience," says Tichenor. An hour later, scaling the ridge, the hunters spot more tracks, fresher than the first. They quicken their pace. Somewhere ahead is an American black bear, Ursus americanus.

Osage scampers down a slope and vanishes from view. A few minutes later he begins to bark. Tichenor releases Cajun who takes off like a rocket. The hunters stop and listen to the barking as it wafts up from the valley floor. The dogs appear to be moving west towards Cotton Wood Creek. Tichenor closes his eyes and tilts his head to interpret the barks. He does not doubt his hounds are pursuing a bear. An adjustment in tone and frequency can signal the bear has stopped and the dogs are confronting him, or that it has climbed a tree. "If he's up a tree there'll be a cadence to the barking." Tichenor listens again. "They've stopped moving. Let's go down and see what's happening."

The hunters slide with sure feet down a rocky gorge and half an hour later climb the other side, pushing through bramble. Oaks, pines and firs soar overhead. There is a rustling sound behind us and a black shape races down a tree: a young bear, a yearling. It waited for the canine and human interlopers to pass before descending and sprinting away, a blur of fur.

The hunters leave him. The dogs are ahead, barking in a frenzy, for they have "treed" a different bear. It clings halfway up a 150ft fir tree, snout and eyes visible amid branches, and peers down at the dogs leaping at the base. The hunters unshoulder their packs. "Got you!"

It is the moment they live for. The moment, as they see it, when a millennia-old alliance, that of man and dog, is renewed. "It's reliving a part of our heritage; continuing an ancient tradition," says Tichenor in a Missouri drawl. "It's the ultimate test of a hound-hunter," says Brones, the younger man, a California native. "This is when you prove yourself, show that your dogs are tough and skilled enough to do this."

Some 1,700 black bears out of a population estimated between 23,000 to 39,000 can be legally "harvested" in California each year. (Hunters have "taken" – ie killed – 1,300 bears this season so far, so another 400 remain fair game.) Almost half are done so with the help of hounds. Hunters are required by law to eat the meat. But this recent scene in the woods of Yola Bolly, 160 miles north of Sacramento, will be one of California's last. These hunters who trace their lineage back to George Washington, Daniel Boone and Theodore Roosevelt are now the hunted. Last month Governor Jerry Brown signed a bill, banning the hunting of bears and bobcats with hounds. It takes effect on 1 January 2013.

A powerful coalition of animal rights activists and Democrats, led by senator Ted Lieu, declared the practice archaic and cruel. The ban will still let hunters kill the same number of bears – but without dogs. An opinion poll suggests 83% of Californians supported the proposal, as did the state's leading newspapers, following the release of video of bloody encounters between bears and dogs. "Allowing packs of dogs to chase bears and bobcats for miles until, exhausted, the animals climb trees to flee the canines and end up trapped, essentially waiting to be shot by a hunter below … is an animal version of The Hunger Games," said the Los Angeles Times.

Celebrities such as Ellen De Generes, Doris Day, Bill Maher and Hilary Duff backed the ban. Uggie, the dog from the film The Artist, "wrote" to the governor's dog urging support. ("I've chased a squirrel or two in my day but my people are always nearby keeping an eye on me and making sure I don't get lost or injured in a fight with other animals.") Pressure is expected to grow for similar bans in the 17 other states that allow hunting with dogs. The issue arouses arguably more passion here than Britain's badger cull. The impression of houndsmen as heartless yahoos who persecute wildlife is all the more damning because popular culture depicts their victims as cuddly, honey-loving furballs: Winnie the Pooh, Paddington Bear, Yogi Bear, Smokey Bear, Gentle Ben. Los Angeles has an ongoing love affair with a 400lb intruder who ransacks garbage – he has been nicknamed Meatball and has his own Twitter account (@TheGlendaleBear).

All of which raises the question: who are the houndsmen? (Or, to quote one critic: "Who are these animal-murdering scumbags?") And why do they do it? To find out I accompany them on a hunt.

Before resuming the scene in Cotton Wood Creek, rewind a day. Waiting outside Sacramento airport, all polished glass and steel, I am collected by Brones in an ancient, dusty Toyota pickup. He is president of the California Houndsmen for Conservation (CHC), which represents about 5,900 hunters. He wears shorts, boots, a baseball cap and a wary smile. I am half-disappointed he does not chew tobacco or play the banjo; Brones, it turns out, is a high-flying IT executive who has travelled the world for companies such as Intel and Apple. He is courteous and intense. "I'm very direct and very passionate. Don't take it the wrong way."

Cajun the hound, Dan Tichenor and Josh Brones in the woods of Yolla Bolly. Photograph: Rory Carroll

We head north, passing rice fields and orchards, and he tells his story. The son and grandson of hunters, as a boy he studied predators and hoped to be a wildlife biologist. Brones fell into IT – "it pays well and I have a wife and two young sons" – but continued the family tradition of breeding hunting hounds. "I don't enjoy being cooped up in an office. I like to be out, away from people, that's my idea of heaven." He loathes cities. "The natural world keeps us grounded. Go to Manhattan: nature is extinguished."

Brones is conservative and a member of the National Rife Association but also considers himself an environmentalist. He frets about pollution and opposes oil drilling in Alaska. "There are parts of the planet we should leave alone." He is lyrical about dogs. "They have the traits humans aspire to – loyalty, dedication, unconditional love. They're not moody, always glad to see you. The hound is the best of them, the hero of dogs." Hunting with them, he says, feels spiritual. He points to the hills. "My church is out there." Nothing is sweeter than the sound of their baying. "We call it music." I wonder what bears call it. Brones regrets Britain banned fox hunting with hounds. "I was rooting for the House of Lords."

Brones was 17 when he killed his first bear, whose chopped up remains filled his parents' freezer for a year. "He was old and the meat was very tough." Killing, he said, was a moment of sombreness and jubilation. "It's a duality. The culmination of a huge effort. But you have taken a life. You know that bear will never exist again."

So why do it?

His justification, elaborated as darkness falls and we drive into wilderness, is twofold: California's bear population, having tripled since the 1980s, needs to be controlled because it destroys hives ("contrary to what Yogi Bear will tell you bears are not after honey but baby bees"), kills deer and marauds into towns, threatening human life and property. Second, it is more humane to tree a bear before shooting to determine if it is a suckling sow (which is to be spared), and ensure a clean shot. "Point blank range is a good thing." The alternative, shooting from a distance with a telescopic sight, can inadvertently target sows and wound rather than kill, leaving bears to escape to slow, painful deaths.

We spend the night at Tichenor's cabin. It is furnished with bear pelts and mounted deer heads but the coffee table has copies of the Economist. Tichenor is an affable, craggy host. He hunts with a bow but is a retired nuclear-weapons scientist with a PhD in electrical engineering. "Trophy hunters get a bad rap but they'd rather come back empt- handed than take an unexceptional catch," he says.

Even so, why hunt at all? "There's no reason to feel guilty about being a member of a predatory species," he says. This is a different era to that which exterminated the Great Auk and American Passenger Pigeon. "There are rules making sure species are not wiped out." Urbanites, he says, tend to imagine wildlife as an extrapolation of the pets on their couch whereas nature is a merciless, pitiless cauldron. "Animals in the wild don't die easily. They get sick and wounded, they're killed by younger rivals, they starve." Adult male bears kill cubs they suspect are not theirs. Female mountain lions struggling for food abandon kittens to save themselves. "If all forms of mortality were equally visible it would be clear the human hunter of today is the most humane hunter in history."

But humans don't need to hunt to survive, I say. "Not any more," Tichenor agrees. "We simulate the situation from when we did it out of necessity. But I can't think of anything more natural." Those who buy meat in the supermarket, he says, turn a blind eye to the moral implications. "Think of how many people eat meat without ever killing an animal."

Dan Tichenor blows a cow horn to summon his hounds. Photograph: Rory Carroll

Tichenor, who has bagged countless racoons, deer and coyotes, then springs a surprise: he has led groups that treed 269 bears, of which 60 were "taken", but never killed one himself. (His sons killed those whose pelts adorn the couch and a friend killed the one turned into sausages we will eat during the hunt.) Chopping up and hauling a bear's remains out of the forest is arduous and you are permitted only one kill per year so once you take a shot your season is over. "I prefer to take pictures of the bear." Brones, it turns out, has for similar reasons not killed a bear since 2003.

I'm baffled. What's the point of chasing bears up trees if you're not going to shoot them? "You'll see tomorrow."

And so I find myself the next day scrambling up Cotton Wood Creek, on one of California's last bear hunts with hounds, following the yelping of the hounds Osage and Cajun.

We find the the dogs leaping at the base of a fir. Their master fishes a camera from his backpack and records the scene. Above us, half concealed in shadow and branches, perches a sow. She blinks at us in silence.

I wonder what she is thinking. A few minutes earlier she had probably been foraging on the forest floor with the yearling we saw descending from the other tree. Now she is being literally hounded. I'm still not sure of the point. "Catch and release," says Brones. "Fishermen do the same thing. Once we leave she'll come down and go about her day." And what do we do? "Look for another bear."

We leave the sow – hopefully to reunite with her yearling. Two hours later, hiking through Bear Gulch, the hounds catch another's scent. They race off. They have telemetry collars, helping the hunters locate them with radio equipment, but they prefer to summon the dogs back with a cow horn. There is something elemental about the sound, and I confess a stirring. It is not easy finding a bear. They evolved to elude wolves and each other. And it's not easy trapping one. They can reach speeds of 30mph and, if they choose to fight, can claw, crunch and disembowel.

So when the dogs pick up a scent – I am not proud of this – their excitement is contagious. Bear ahead! Or, as it turns out, bears. Osage and Cajun start baying across the valley, prompting a lung-busting trek after them, leading to a huge pine in which shelter a sow and yearling. They are different from the first couple. Their black faces peer down, inscrutable, from a branch about 40ft overhead. "Look, no trembling, no exhaustion," says Brones.

In this case he may be right since the chase was quick, just a few minutes. But some chases last hours.

There is no scientific consensus about the impact. Jim Akenson, a field biologist who collars bears for studies, and backs hound-hunting, says there is no evidence of harm and that it is the most humane way to capture the animals. Rick Hopkins, a field biologist cited by hound-hunting opponents, says the chase elevates stress and body temperature. "The issue is impact. We don't know if the stress wears off or accumulates."

An additional concern is that some bears confront rather than seek refuge. The dogs are not bred to attack, so such encounters tend to be more noisy than bloody but both sides can suffer grievous wounds and, on occasion, death.

In this case the treeing is bloodless. Tichenor records the scene, then yanks the dogs away. Mother and yearling watch us trudge back the way we came. Shadows stretch and a long hike out of the valley awaits. The hunt is over.

I sort of get it. There is, despite the telemetry collars and energy bars, something primal in chasing quarry with dogs. It requires skill and stamina. There's a thrill to the moment of capture. But this has been a sanitised hunt. No shooting, no chopping, no skinning. "When a bear is shot and falls to the ground, dead, it upsets people," says Brones. "It just does. So why show that? Does a commercial abattoir invite in cameras?" Back in Sacramento, hobbling on creaky knees, I relate the hunt to Jennifer Fearing, who as California senior state director of the Humane Society of the United States led the campaign against hound-hunting. Setting aside whether it is justified to kill bears at all, I say Brones and Tichenor clearly adore the wilderness and, in their own minds, respect it. Is it so bad letting them chase bears up trees?

Fearing rejects the idea they are forest guardians. "Hounding is a reckless sport that puts all the animals involved in danger. (It's) tantamount to suggesting a single woman living alone should feel safer because there's a creepy stalker guy 'keeping an eye' on her house and neighbourhood." Fearing, a vegan, has never been on a hound-hunt but says she has "enough of a sense of how it goes" through YouTube videos.

If comparing hunters to perverts seems provocative Brones is even more so when he compares Fearing and other foes to Nazi propagandists. Hound-hunting is a remote front in America's culture wars but both sides betray the familiar, mutual scorn and incomprehension. It is easy to caricature the other when you seldom meet it.

I end up siding with Fearing. Strip away the arguments about conservation, wildlife control and the (undeniable) hypocrisy of meat-eating urbanites, the hunters do what they do largely because their fathers did it, and because it's fun. That's poor justification to harass bears.

Yet, in many ways, the hunters care more about the woods than most urban opponents admit. Banning their tradition is one thing, doing so with whooping glee and contempt is another. Back in his cabin, watching a setting sun dip beneath mountains, Tichenor ponders the defeat. "You know, all we really want is to be seen as human beings."