Like any avenue, they frame and divide. But unlike regular routes lined with trees they symbolise service and sacrifice and, with the centenary of the Anzac Gallipoli landing in 2015, they are prompting a new wave of interest.

The Avenues of Honour 1915-2015 initiative aims not only to document and preserve the 547 known avenues around the country, but to create new ones as well. The goal is to see a tree planted for each of the more than 100,000 Australians who have died at war.

While most avenues of honour were established close to 100 years ago in the aftermath of World War I, arboreal memorials are returning to favour.

Darren Peacock, a social technology consultant for Avenues of Honour 1915-2015, attributes this to the growing popularity of Anzac Day commemorations and an increasing environmental consciousness around the planting of trees.

"There is a momentum around the convergence of these ideas," he says. "Tree-planting has more cachet now than 50 years ago. We do need to plant trees and take care of them, but we can also use trees to express remembrance."

While the Canadians have named lakes after those who went to war and Australians became more inclined to establish swimming pools and other community facilities as a form of remembrance after World War II, Peacock says the original avenues of honour were a "spontaneous" community gesture.

He says it was driven, in part, by the fact that the graves of the dead were so far away.

"It wasn't possible to visit graves in France. So trees were planted locally," he says.

While the earliest recorded avenues of honour were planted in response to Australia's participation in the Second Boer War of 1899 to 1902, most avenues came about a couple of decades later. They were planted everywhere except for the Northern Territory, with about half of them located in Victoria.

About 3770 exotics were introduced along 22 kilometres of roadway in Ballarat from 1917 to 1919, while a 2.5-kilometre stretch of road in Woodend was lined with oaks in 1918.

The same year, 281 elms were planted (245 survived) over 3.3 kilometres in Bacchus Marsh, with an avenue of sugar gums planted in Melbourne's Macleod in 1919.

Photographer and horticulturist Sarah Wood has been documenting avenues of honour for about five years and is now involved with the Avenues of Honour 1915-2015 project.

She says one of the most interesting aspects of these plantings is the role communities have played in establishing and maintaining them.

"Groups of people sat around tables all over the country; communities were united in this activity and it was ongoing," she says.

"We are talking about years of care: people were planting saplings and even seeds, and who was going to water them every day and keep kangaroos away from them?"

But drought, compaction, neglect and the widening of roads and other forms of urban expansion have exacted their toll.

Peacock says Avenues of Honour 1915-2015 – established by Treenet, the urban tree research and education organisation based at the University of Adelaide's Waite Arboretum – will also gather information about which avenues have done better than others.

Success, Peacock says, has depended on the suitability of the species selected (both exotics and natives) and the subsequent treatment of the site chosen. Even some of those avenues where trees have done well are coming to the end of the plants' lives, with the focus now on how to replenish them.

Information gathered is to be shared on a website that was launched by Treenet last week.

The site (avenuesofhonour.org.au) maps existing avenues of honour (right down to the 100 oak trees that were recently planted in Willunga, south of Adelaide, in preparation for the Anzac centenary) and will provide a forum for people to discuss old avenues and propose new ones.

"Avenues of honour say a lot about our attitudes to life and death," Peacock says.

"They talk about what we value, which trees we favour and what we destroy. These are locally cherished symbols that people really care about and now there's a desire to continue the tradition, and also refresh it."

People with information about existing avenues of honour, or those who are considering planting a new one, can email: research@avenuesofhonour.net.au.