Denmark's Christmas tree growers have been charged over claims of price-fixing and running a cartel.

Allegations that costs were deliberately hiked up by 25 per cent follow a police investigation. The allegations center on the Nordmann firs, coveted for their soft, long-lasting needles.

The Danish Christmas Tree Growers' Association has been accused of sending cost guidelines to members, suggesting a rise of between 10 and 25 per cent, reports The Telegraph. Presumably, the Association sent this out to stop growers from undercutting each other.

About 85 percent of Danish trees are exported, most of them sold to Germany, Britain and France.