Plantspeople have their own enthusiasms. New Zealand has several who are keen to know more about these ancient trees. In Auckland, award-winning ecologist Graeme Platt has been putting together an Araucariaceae collection in the Auckland Botanic Gardens' Gondwana Arboretum. In Tauranga, Graham Dyer has a collection of kauri at Sydenham Botanic Park, including one labelled Agathis silbae.
In Wanganui, Clive Higgie is a fan of Araucaria timber and beauty. He would like to grow as many varieties as possible in his and wife Nicki's extensive Paloma Gardens near Fordell.
The kauri relatives grow from coast to mountains on the Vanuatu Island of Espiritu Santo, and there are visible differences between the coastal and inland trees. A New York botanist decided the coastal ones were a separate species, Agathis silbae, based on cones brought to him.
New Zealand plantspeople disagree. They think the coastal and mountain trees are the same species, Agathis macrophylla, which has been in Zealand since 1866.
How would you know whether there are two species or one? There are physical differences, but they can happen within a species. You could chart plant DNA, but that isn't always a good guide. The best way would be a massive study comparing all kauri across the region.
Even then botanists might not agree. Some are "lumpers", who like to group species together. Others are "splitters", who like to split off new species.
Which of them is right? The trees on Espiritu Santo are especially difficult to place, and have already been given three different species names.
"Botany isn't a science. It's an arena of conflicting opinion," according to Auckland ecologist Graeme Platt, and Clive Higgie agrees.
"At the end of the day, no one is right or wrong, because a species isn't a lawful identity. It's an opinion," he said.
Amid all this botanical debate, enter the Ministry for Primary Industries (MPI), formerly MAF.
One of its jobs is to keep New Zealand free of potentially harmful species from other countries.
The ministry has a list of all the plant species allowed to be here, called the Plant Biosecurity Index or PBI.
Since July 29, 1998, permission has been needed to bring in plants deemed new organisms.
Operation Silbae had its tiny beginning when a former Auckland Botanic Gardens employee told an MPI staff member the gardens were "full of illegal plants", say the Higgies and Mr Platt. The informer was threatened with prosecution unless he made a written statement about it, they say. He made the statement.
Meanwhile, plantspeople wanted all of the Araucaria family growing in New Zealand for study purposes. In 2001 Graeme asked permission to bring in 11 species, including Agathis silbae. He says plantspeople support MPI's efforts to keep pests out of the country, but kauri is not a pest. The permission was refused.
In April 2005, Graeme Platt, Graham Dyer, Clive Higgie and other keen plantspeople made a trip to Vanuatu. Mr Platt returned to New Zealand with seed from a tree reputed to be Agathis silbae but which they believed was Agathis macrophylla. On re-entering New Zealand, Graeme said the seed was Agathis macrophylla and it was allowed in.
It was grown and the seedlings distributed. Some were for the Auckland Botanic Gardens.
MPI may have put all the Vanuatu travellers on watch. Its methods can only be guessed, because the ministry has declined to be interviewed. (It did answer emailed questions). Anyway it took notice, but did not begin its investigation by talking to the plantspeople.
Instead, seven years after the 2005 trip, it made early morning raids on suspects.
Clive and Nicki Higgie had six ministry staff and two police arrive at their Denlair Rd farm and gardens at 9am on February 22, 2012. It was Mr Higgie's birthday.
The visitors had a search warrant. They looked through Paloma Gardens and took away computers and records. They did not say what they were looking for but seemed especially interested in kauri. They made a second visit in July and took plant samples.
Mrs Higgie expected to hear more about it. But it took a while.
The ministry's next move was four simultaneous dawn raids in Auckland at 7am on October 11, 2012. They were on Graeme Platt's house, the curator of the Auckland Botanic Gardens's house and his holiday house, and the gardens themselves.
Again search warrants were presented and plants and plant material was scanned and taken and computer records taken. Again no one was told what offence was suspected. Mr Platt had a good guess because he glimpsed the word silbae among the officials' equipment.
Nearly two years after their first raid, the Higgies were charged with having an "unauthorised plant, a plant not on the ministry's PBI. But it wasn't a kauri.
They were charged with having an Australian fig species, a cutting they were trying to grow which later died. They had a young tree of the same species already established in their gardens. The charges were alarming and Mr Higgie travelled the country to gather evidence the plant was here before 1998.
He said the ministry's PBI was at fault because it did not include the fig.
"The big problem is the list is so incomplete. It's their inefficiency rather than my naughtiness."
Then, three months later, he was charged with having Agathis silbae. The Higgies have two trees in their gardens that could be that species - if it is a separate species. One is labelled Agathis silbae, the other Agathis macrophylla.
It was a stressful time for them. They faced possible fines of hundreds of thousands of dollars and years of imprisonment. Neither had ever been in trouble with the law. They spent $55,000 on legal fees, helped by friends and family.
"Neither of us are sleeping well at night, even though we are innocent," Mr Platt said at the time.
Auckland Botanic Gardens curator Jack Hobbs and Tauranga's Graham Dyer were never charged, but nearly two years after his raid, Mr Platt faced the same three charges as Mr Higgie, over Agathis silbae. His fourth charge, from evidence gained in the raid, was of trading in an endangered species.
That species was the monkey puzzle tree, Araucaria araucana, a South American kauri relative. Back in 2000 Mr Platt brought 30kg of its seed, bought in a market, back to New Zealand from Chile. The seed was mainly to eat and apparently tastes like a cross between a chestnut and a kumara.
Monkey puzzle trees are far from endangered, he said.
"There are 400 square kilometres of it in Chile, and more in Argentina."
Graeme Platt appeared in Auckland District Court many times on the charges. At his last appearance, on June 16, all the charges were dismissed.
Judge Mary-Elizabeth Sharp had seen him in chambers on May 20 and 21. Her written judgment said the search warrant MPI used in his raid was sloppy, improper, reckless and deficient, though not issued in bad faith. None of the evidence gathered through it could be used, and that was all the evidence there was.
She called Operation Silbae "overkill" and an unwarranted use of resources. The plantsmen estimate it has cost more than $2 million. MPI has not revealed the price.
Mr Platt was more outraged by the charges than worried, and defended himself in court. He said MPI staff were "botanically and ecologically illiterate". He accuses them of being rude during the raid and illegally taking away confidential computer records and plant samples.
All the charges against the Higgies have been dismissed too - the ones over the fig in December 2014, and the final ones over the kauri on May 7 this year.
No one from MPI appeared in Wanganui District Court on that day. Instead it was the work of a few minutes for Crown Prosecutor Lance Rowe to say the ministry could see little public interest in a two-week trial over the identity of a Vanuatu kauri.
If having all the charges dismissed sounds like a debacle, MPI's compliance director, Dean Baigent, isn't admitting it. He said the ministry took its role in protecting New Zealand from foreign organisms seriously. It had taken advice on the operation from the Crown Solicitor's office. The "sloppy" search warrants were the first to be used under new legislation, and it had not made that e mistake since.
The Higgies agreed not to pursue costs against MPI because they wanted the case to be over. They agreed to the removal of the tree labelled Agathis silbae from their gardens and they want to meet ministry staff, "to prevent similar ordeals happening to others".
Two months after the last of their charges were dismissed, MPI has made no move either to meet them or to remove the tree.
"I don't think they will come and get it, because there are so many around the North Island."
The last word is left to Mr Platt. He said the ministry officials were "crazy buffoons" led by a "useless Pommy cop" who had since returned to the United Kingdom.
The Agathis silbae or macrophylla plants grown from Espiritu Santo seed are now rootbound in their pots at the Auckland Botanic Gardens, and will have to be revived. Fellow plantspeople have congratulated him on his stand, and a human-rights lawyer is asking about it.
He's still irate that MPI staff took plant material from his property and from the botanic gardens, and took confidential computer files from his house.
"It's a piece of mindless bullying, trying to control some of the best plantsmen in the world. MAF has morphed into a Nazi police organisation. It's an absolute disgrace."
He's now collecting evidence and planning to sue MPI.