Each year, after speeches and wreath-laying, the firefighters observe a minute's silence.
They did it last September, a week after Christchurch's first devastating earthquake, when exhausted local firefighters were still searching for bodies in the wreckage.
But the rubble of Christchurch would have been dwarfed by the mountain left after the September 11 attacks. For 10 months after 9/11, a battalion of law-enforcement officials combed through almost two-million tonnes of material at a Staten Island landfill, sifting through toxic rubble for items that could identify the victims interred in the ashes and dust.
Eventually, forensic workers unearthed enough detail to identify more than 300 people. Among people's possessions were 4000 photographs and another 54,000 personal items, ranging from watches to ID cards.
As national president of the Professional Firefighters Union, Warner understands the close bonds shared by firefighters.
He says the reserve near the main Christchurch Fire Station was dedicated in 2002 to honour fallen firefighters, wherever they may come from.
Ten years after the attacks, Ground Zero in New York is gradually being rebuilt. A prominent construction is the new 541m skyscraper known as 1 World Trade Centre, once referred to as the Freedom Tower, due to open in 2013.
Another five office towers, one already complete, are included in the rebuild. So is the National September 11 Memorial, dominated by two huge reflecting pools set deep in the earth, flanked by waterfalls and marking the footprint of the fallen Twin Towers.
The pools will be unveiled on the anniversary of the disaster next month, when New York's biggest memorial service will take place at Ground Zero.
President Barack Obama and his predecessor, George W. Bush, are expected to attend, as are the families of those killed a decade ago in attacks on Manhattan, the Pentagon and Pennsylvania.
THE NUMBERS
* 3000 People killed.
* 372 Foreign nationals, excluding 19 hijackers, killed.
* 56 Countries that lost citizens.
* 70,000 New Yorkers suffering long-term health problems caused by toxic dust.
* 5.5 million tons of rubble from the collapsed buildings.
* 1.7 million work hours spent sifting through debris at Fresh Kills Landfill, Staten Island.