MANDY walks quickly along the long rows of oak trees with her nose to the ground, tail in the air, sniffing for the scent of truffle.

There is a sense of urgency about her; she has a job to do, and is very willing to work.

Following behind is trainer, owner and companion Simon Harvey.

It's a crisp-cool day when we arrive to speak with Mr Harvey, where we stand surrounded by oak trees and the gentle slopes of surrounding farmlands.

On most days of the week, during the truffle season between June and September, Mr Harvey works with his dogs, walking the rows of trees at some of Tasmania's prominent truffle farms.

Mandy sniffs, stops, starts to dig gently, and Mr Harvey stops and checks to see the ripeness of the fungus.

Each of his hands is inked with the markings of an animal, a lizard and a whale, both visible, as he carefully digs out the fungus with a pick, inspects and smells it, and places it in a snap lock bag that sits inside a satchel, slung over his shoulders.

His dog is rewarded and the pair move on.

The scene is different, and then, not so different, from some of the work that Mr Harvey has undertaken with his canine companions over the years.

Mr Harvey said he first worked as a dog handler in the Australian Army.

He rose to become senior instructor, helped train the US army to work its bomb detection dogs off leads, in preparation for the Afghanistan and Iraq military presence, has worked for a non- government organisation in Bosnia to rid the countryside of bombs, and later, rejoined the army in a security role.

When Mr Harvey and his family arrived at Mole Creek about five years ago to run a small hospitality business, he discovered the perfect opportunity to train a new set of working dogs - for the black truffle industry.

Mandy became his new working partner about three years ago after he selected her as a good truffle detection candidate.

She was found at the Spreyton RSPCA with burn marks on her body.

"Mandy was a cruelty case," Mr Harvey said.

"I don't see the point in spending thousands of dollars on a purebred dog when I could go to the pound and give another dog a second chance," he said.

"Mandy had her problems. She can't sit still, she is hyperactive but she won't give up."

Any dog that Mr Harvey chooses to train must be ball- possessive.

It is a trait required for any dog that will be trained to detect items for humans.

"You need a dog that is active, with a high-ball drive. I want them to be able to chase a ball, and to constantly want to chase a ball," Mr Harvey said.

"Mandy has an addiction, and I guess I'm using that addiction against her."

As we speak, Mandy is constantly on the move.

She never just sits, and if a ball is produced, never stops staring at it.

When Mr Harvey trains his truffle dogs, he uses a container that is infused with the scent of truffle, and a ball.

"You put the ball in the container, and you ask the dog to get the ball," he said.

"It puts its nose in the container and is breathing in, and starts to take in the smell of whatever is in the container.

"What I am doing is building an association between reward and what I want it to find - and that can be anything."

The training tactic takes advantage of the highly attuned scent-detecting cells that exist in a dog's nose, that allow them to identify smells up to 10,000 times more effectively than a human.

For example, a human may have up to five million scent receptors, while a dog such as a German shepherd may have up to 225 million.

Mr Harvey said training his truffle dogs could take up to six weeks.

He said training a bomb dog could take between 12 and 15 weeks.

"In a truffle dog, I imprint one scent and teach it one pattern, and that is to walk up a line of trees.

"For bomb dogs, you teach 15 different scents, and five different patterns."

Mr Harvey said when he trained dog handlers in the US Army, they did not understand the methodology of working dogs off- lead.

"You are using a dog to find a bomb on a 15-foot lead, and you are close to the dog," Mr Harvey said.

"They didn't have the capabilities of working dogs off- lead."

Mr Harvey said dogs were trained to search compounds, and were taught to go left and then right, around the walls of the building.

Their handlers then pushed the dogs inside with hand movements and voice commands, to search the rooms.

"The dogs would automatically start searching by themselves, because they were high-drive dogs and had a really good hunt drive," Mr Harvey said.

In Bosnia, Mr Harvey said he was training local Serbs, Croats and Bosnians to work with landmine dogs.

"The area is gridded off into 10 metre boxes, with safe lanes, and the dogs would go in and search the box.

"If they found a bomb, the dog would sit, be recalled, and you would put a marker on the front of the lane, would miss the next box, and keep searching until you had done your 10 rows," Mr Harvey said.

"We did some areas where we were working for three months, we are talking acres and acres of lands.

"There were accidents every once in a while ... fatal accidents, but that is what happens."

Mr Harvey said each and every dog he had worked with had their own characters, that a handler must work with, while training.

"Dogs are all individuals, they don't train the same way. Some dogs are quite quick, some are quite smart and can do it themselves, and some are not," he said.

"You have to understand how a dog works, what they like, what they are able to do.

"I have input in their training but I am coaxing them, to allow them to give me what I need. Once I have done that, it is all positive re-enforcement."

The bond that ensues between handler and canine is important.

"Military handlers have a very close bond with their dogs because the dog is the person that you are working with.

"They are with you 24 hours of a day, on the field, at camp, and your priority is your dog.

"Mandy is my working partner and we have a very strong bond ... yesterday we spent seven hours looking for truffles, with about a 20-minute break."

Mr Harvey said he found his latest form of dog work very relaxing.

"You haven't got the stresses. If your bomb dog misses something you could get killed, or someone else could," he said.

"If you miss a truffle, you miss a truffle.

"I listen to a book on my iPod and I really don't have to do much with Mandy."

Mr Harvey has worked with many dogs - German shepherds border collies, a Staffordshire bull terrier - but found it hard to name one breed that he preferred.

"I reckon all my dogs stand out," he said.

"They were really good dogs and when I was working with them I really appreciated them.

"They all have their own characters.

"I couldn't see myself doing anything else, and I've got plans for other types of dogs.

"I want to do a golf ball detection dog, to work and find golf balls in the long grass, or a bed-bug dog.

"Apparently, bed-bug numbers in Australia have gone up."

Grey clouds threaten to halt the interview, but Mr Harvey said he worked regardless of the weather, except if the rain was too heavy.

He said he had previously found 17 kilograms of truffle in one day - but the amount of fungus pulled from the ground really did not matter.

"I am just here with my dog," he said.

"My only companions for the day are my dogs and it makes for a damn good day, I reckon."