What is happening to our monkey puzzle trees is a bit of a mystery, says Gillian Vine.
Although still quite common around the region, monkey puzzle trees appear to be a dying breed and no one seems certain why.
Like our kauri (Agatha australis), the monkey puzzle (Araucaria araucana syn. A. imbricata) belongs to an ancient family, Araucariaceae, which also includes the Norfolk Island pine and Australia's bunya-bunya and wollemi.
Despite being commonly referred to as pines, they are not, although their being pine-like conifers probably explains the confusion.
Brought to New Zealand by 19th-century European settlers, the monkey puzzle was being widely advertised by the 1880s as a desirable and beautiful specimen tree.
None of the ads mentioned the need to give it space, as a mature monkey puzzle can reach 40m-50m.
Nor did they point out that the scale-like leaves have very sharp tips.
Almost as savage as those of an Opuntia cactus, a monkey puzzle spine can inflict a nasty jab, so it is advisable to wear heavy gloves when pruning or picking up debris.
On the plus side, the fruit - which may not be produced until the tree is 20 years old - is edible and harvested when the nuts fall.
Dunedin man Michael Collie describes them as ''nutty, delicious and milky''.
Rats and possums also like them, he says, so don't leave the fruit lying on the ground.
As a monkey puzzle ages, old branches fall, creating patterns in the bark that add to its appeal, while the timber is hard with attractive markings.
Monkey puzzles seem to be a bit confused about their sexuality.
Most are dioecious, meaning male (pollen producing) and female cones grow on separate trees.
Occasionally, both types appear on the same tree or even on the same branch however.
The official tree of Chile and also found in Argentina, A. araucana is now considered endangered in South America.
In the winter of 2012, Sean Hancock, of Dunedin company Eco Tree Care, took out a 20m monkey puzzle in Helensburgh.
It was the first of three he has been employed to remove, all of them dying and unable to be saved.
In March this year, another dying tree was removed, this one from a Roslyn property.
Arborist and Otago Polytechnic arboriculture lecturer Alvar Del Castillo said it was ''one of the hardest jobs'' he had tackled but it was a good practical demonstration for his students.
Several theories have been advanced as to why monkey puzzles are dying but no conclusions have been drawn.
Mr Hancock thinks the trees might be at the end of their natural life, as they are close to a century old.
Asked about the claim they can live to 1000, he says an urban tree does not live as long as one in open country.
Pollution from smoke and car exhausts is partly responsible, as is compaction of roots from seal or concrete laid close to the tree, which is why notable trees like New Zealand's largest living kauri, Tane Mahuta, in Northland, are protected by boardwalks.
Mr Hancock rejects the suggestion that climate is the reason for monkey puzzles' demise, saying mature trees can cope with wet or dry seasons and are not frost-tender.
Another theory is that, being related to kauri, monkey puzzles may be the victims of Phytophthora 'taxon Agathis', a nasty micro-organism which has been known on Great Barrier Island for decades and more recently spread to the upper North Island.
There is no known cure for the soil-borne disease and the first symptoms tree owners see are gum bleeds from the trunk, yellowing leaves and dead branches.
''But no-one's got a definite answer,'' Mr Hancock says.
