People have been urged not to take the piles of logs left along the Norwich Northern Distributor Road - because they are hibernation refuges for wildlife.
Norfolk County Council says one of the refuges, near the Wroxham Road roundabout, was stolen earlier this week and has urged others to leave the logs alone.
John Birchall, community liaison officer for the NDR, said: 'They may look like untidy piles of unwanted firewood, but amphibians, including Great Crested Newts, rely upon them as safe places to hibernate - and hedgehogs also need somewhere snug to avoid the winter cold.
'When it comes down to it, taking this wood is theft - and destroying the habitat and possibly killing protected species is also a crime.'
Mr Birchall said it would have been an 'organised operation', with chainsaws used to chop up the wood, while vehicles would have been needed to take it away.
The plea for people to leave the wood alone received a mixed response on Facebook. Some condemned those who took it, but others accused the county council of hypocrisy, given wildlife habitats had been destroyed so the road, which will cost at least £205m, could be built.
But Mr Birchall said biodiversity would actually increase because of the planting which had been done along the route of the 12.5 mile road, with five trees planted for every mature tree which had been felled.
There were also claims that permission had been granted for the wood to be taken, although Mr Birchall said no permission had been given by those with the authority to do so.
He said the incident was not being reported to the police, but urged people to leave the rest of the logs where they are.
He said: 'We are not taking this any further, as we understand that people might have thought the logs were unwanted.
'But we want to urge people to leave the refuges where they are and to assure them that they are being put to good use.
'People think they're just piles of logs, but they are not.'
He added in the years that the road, which will stretch from the A1067 Fakenham Road to the A47 Postwick Road, has been under construction there have also been thefts of fuel and of newly-planted trees.
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