Christmas tree-growers have been badly affected by the hot summer which killed significant numbers of saplings, according to an industry group.
The British Christmas Tree Growers Association (BCTGA) said some of its members had lost up to half of what they had planted in the spring.
It could hit supplies in eight to 10 years’ time, while availability of smaller trees could be lower this year.
However BCTGA said older trees fared well in the sun and subsequent rain.
The group represents about 320 Christmas tree farms across the UK.
Rob Morgan, who runs Wales’ biggest Christmas tree farm in Gower, near Swansea, said he had lost a third of the 30,000 trees he had planted this year.
“The fierce sun of the summer baked the roots, and they dried out. It’s cost me around £7,000,” said Mr Morgan, who supplied the tree for 10 Downing Street last year.
He said it can take 10 years for a Christmas tree to grow to full maturity and he will have to plant an extra 20,000 trees next year “to keep supply going”.
He added: “I’ve gone through every emotion on my farm – from the BSE crisis to everything else. You go through highs and lows but it was hard to watch these trees struggle this year.”
Mr Morgan feared at one stage that his larger trees would also die as the unprecedented dry-spell wore on and admitted to “doing a dance around the fields” when rain eventually came.
Concerned that climate change will cause ongoing issues, he is now considering changing the types of trees he plants.
Stephen Reynolds, committee member for Wales of the BCTGA, agreed it had been an unusual year which had caused difficulties for many growers.
He has 500,000 trees across some 300 acres of land in Powys and also runs the smaller Ty Cerrig Christmas Tree farm in the Vale of Glamorgan.
“Any plants that were planted later in the season did suffer,” Mr Reynolds said.
“Up to 50% have been lost for some people, in some areas all the young plantings died.
“That will have an impact long term – and it’s already having an effect on the availability of small plants.”
But he claimed older, bigger trees – with their deep roots which can access reserves of moisture underground – had benefited from all the sunshine so there should be “a good crop of Christmas trees this year”.
“They really went for it, grew properly and are a deep, green colour,” he said.