Allegations that costs were deliberately hiked up by 25 per cent follow a police investigation triggered by a complaint by the Danish Competition Authority.
The Danish Christmas Tree Grower's Association and its director have now been charged under the country's competition law for sending out price guidelines to its members.
In 2001 and again in 2005 the association was ordered to stop sending out guidelines but it continued to do so. So, after an investigation last year, the competition office referred the case to prosecutors.
"The association guided its members on how to calculate prices of Christmas trees and recommended certain prices," said Mimoza Memedi, head of the law and cartels section of the competition office.
"This is seen as an agreement according to the competition law, which is forbidden."
Kaj Oestergaard, head of the association, told the Financial Times that he had done nothing wrong and he accused "some wholesalers of trying to shut our mouth".
The association compiles statistics every year on what money its members make from Christmas trees and helps them calculate the cost of growing trees.
"The education of our members is not illegal and nor is sending out figures," Mr Oestergaard said.
He said Christmas tree prices had risen because supply of high quality trees had failed to match growing demand. A 6ft tall tree costs about Dkr240 (£23).
Poor prices in 1998-2004 because of excessive supply discouraged growers from planting trees, while EU subsidies gave them incentives to rip out plantations.
Danish exports peaked at 14m trees in 2003-2004 and are now about 10m.
Yet, over the past two to three years demand has risen rapidly for the higher-quality Nordmann firs, which have softer and longer-lasting needles.
Mr Oestergaard estimates sales of Nordmann firs in
Almost half of Danish exports go to
This mismatch of supply and demand has pushed up prices by 10-25 per cent this year, Mr Oestergaard said, and further increases should be expected.
Source: Daily Mail