His family moved to the remote property in the 1970s, and he has spent most of his life there. He's built himself an "earthship" house out of compacted earth and tyres, with turf across its wooden roof, and he's put in gardens and orchards.
He's a bit vague about the details, but said Ruapehu District Council has said he owes $20,000 in rates, plus $18,000 in expenses. The rates bill for Horizons Regional Council is $2700.
He's lost his cars due to failing to register or warrant them or maintain his driver licence. To get to town once a week, he hitchhikes or gets rides with neighbours or friends. He says people have a right to electricity supply, and to telecommunications, without paying.
In his opinion, the Whanganui High Court, which is acting for the councils, has no right to sell what it does not own. He cites an article of the Magna Carta, a founding document of democracies, saying property cannot be taken without lawful judgment.
His intention is to fight the court's right to take the property, with representation from what he calls "First Nations" people rather than a lawyer. He compares his case to that of Auckland woman Charlotte Marsh, whose Manurewa house was sold after she refused to pay rates for five years. She had instead been paying a "tithe" to Arikinui o Tuhoe, Stuff reported.
Like her, Mr Dekker said he was not planning to leave his property, even if someone else said they owned it.
"Possession is nine-tenths of the law. I have no intention of moving out."
Laws passed in Parliament were binding on MPs, lawyers, judges and traffic officers, but not on people who did not choose them.
"The rest of us are free men. We're not under acts of parliament. You have free choices whether you fall under it."
A neighbour who owns the surrounding farmland has suggested he could buy Mr Dekker's 4ha, and leave him on it. Mr Dekker advised him not to get involved.
"It's not a workable arrangement."
He had a relatively self-sufficient set-up that many had admired, Ohakune resident and close friend Celeste Ventura said.
His house cost $25,000 to construct, and is warmer and with a better layout than the older house on the property. It has an earth floor and kumaras grow in a window ledge garden inside.
He was told he would need an engineer's report if he wanted a building permit for it, but decided he didn't need the permit.
Mr Dekker built an experimental tyre/earth and plastic hothouse, allowing him to get tomatoes in a month early. He's now working on a much larger version that will be high enough to house avocado, orange and lemon trees. There's also a goathouse under construction, and extensive gardens.
He grows his own tobacco, has kumara stored in a root cellar and beans, corn and nuts stored suspended in bags from the ceiling of the old house. He grows a lot of food and mainly buys basics such as tea, coffee, sugar and flour.
Mr Dekker also has a sawmill, milling native timber pulled out of the Ruatiti Stream. And he has a tractor, but digs his large gardens by hand, as "therapy".
"I am not playing their game. I will just go out and dig up the garden."
He decided to build and garden on the property because there was not much other work around now that "our government has sold our occupations to Chinamen".
Ms Ventura hopes her friend will be allowed to continue his lifestyle.
He was showing a lot of food could be grown in small areas on marginal hill country.
"Julian dances to a different drum and has remarkable vision. Such people go for their dreams and act outside the square. They achieve in ways that can inspire people towards different and important ideas - towards a more sustainable, human, way of being."