While tramping through the Kauaeranga Valley near Thames this summer, he chanced upon what he says is his most exciting find yet.
Kauri were once abundant in the valley, before it was extensively logged between the 1870s and 1920s, with more than 60 dams built to help float the logs out.
Just two of the dams remain substantially intact, but Mr Standfield has discovered what he believes are other remnants.
He has found the remains of an old wooden boom beneath ferns and bracken.
"I knew exactly what it was as soon as I saw it."
He suspected the boom was once used at a site where logs were towed along skids by a steam hauler before being rolled on to a tramway to be taken to Thames.
The find came after years of exploring the undergrowth for such relics, which he has dedicated five months of each year to over the past decade.
In earlier days he discovered a hidden kauri he believed was among the largest in New Zealand.
"This is only part of what I've found in the valley, but as far as the Department of Conservation (DoC) is concerned, I think it could be something it could show tourists as they go through the valley."
Visitors can already take in much of the valley's history at a DoC visitor centre and along the Kauri Trail, following original pack tracks once used by bushmen and taking in relics such as the Christmas Creek and Dancing Camp dams.
In 2010, a team from DoC, including archaeologist Neville Ritchie, used picks, shovels and a small digger to recover a set of wheels from an old tramway bogie used to transport logs down the valley.
Auckland geologist Dr Bruce Hayward, author of Kauaeranga Kauri, said historic upper North Islandkauri country had hundreds of sites.
"The remains at most of them have rotted away, except in places where parts have been preserved underwater in streams."
Dr Hayward said the cost of preserving remnants would be "tremendous" unless tourist numbers could justify it.
Treasures in the bush
* Ron "Kauri Dundee'' Standfield might be one of New Zealand's most dedicated - and oldest - bushmen.
*The 82-year-old has been exploring the Kauaeranga Valley near Thames for three decades, first venturing into the forest to find kauri measuring more than2m in girth.
*Mr Standfield's bush expeditions have lately targeted relics of the valley's kauri-milling past.
*He spends nearly half the year at the valley, living in a campervan and venturing into the bush each day.