Christmas tree prices can vary by up to ú25 for the same sized Nordman at retail outlets around the UK.
Garden centres are varying how they size trees but prices for 6ft Nordmans vary from £29.98 to £54.99.
British Christmas Tree Growers Association (BCTGA) secretary Harry Brightwell said at the unveiling of the 10 Downing St tree, from Garrocher Farm: "There are regional variations but growers tell me 6ft Nordmans are £35-£55 retail. They are a commodity now so it depends on the area and transport costs.
"Growers tell me prices should be similar to last year. The rain has been good for trees. Both wholesalers and retailers are resisting price increases. I'm not hearing any bad news for consumers that prices will shoot up. Supply is fairly good and there should be lots of trees out there. No one is telling me of shortages."
Wholesale prices are flat at £22-£24. The BCTGA has estimated eight million British trees are sold annually, but Brightwell said the figure "could be seven million". He added: "The amount of those that are imported, we don't know."
Meanwhile, Christmas tree buyers have been warned to be wary of scam websites after the Highland Council Trading Standards office closed down a website, www.scottishwholesalexmastrees.com.
It was offering trees grown at the Inverness Tree Farm near Aviemore, but trading standards officers' investigations suggested that the "tree farm" alluded to on the website does not exist.
Brightwell said: "They were offering trees at less than half the price of what you would expect."
Nordman Firs: Tree sizes and prices
B&Q 150-200cm: £29.98; 200-240cm: £44.98.
Homebase 4-5ft: £24.99; 5-6ft: £34.99; 6-7ft: £44.99; 7-8ft: £54.99; 9-10ft: £84.99.
Capital Gardens 100-150cm: £29.95; 150-175cm £39.95; 175-200cm: £49.95; 200-240cm: £69.95; 240-270cm: £89.99.
Garden Centre Group 135-165cm: £39.99; 165-190cm: £54.99; 190-230cm: £69.99.
Hillier 175-200cm: £49.99.
Scotsdale 5-6ft: 39.99; 6-7ft: £49.99 - Beautiful Gardens magazine offers £5-off voucher.