A lot of trees are traditionally imported from large- scale growers like Denmark to meet demand in the UK.
But farm owner Rob Morgan said the falling pound meant prices had gone up 15 per cent and it is "good news" for the British industry which is growing and more able to meet demand.
The prospect will be discussed by more than 200 growers in Gower on Wednesday, the BBC reported.
Every year between six and eight million British trees are sold in the UK.
More From This Section
Morgan, owner of Three Crosses farm, Gower, has more than 300,000 trees growing on his land and one of his trees went to Downing Street in 2014.
"Now's the time I start having sleepless nights and getting anxious waiting for customers to show up," he told BBC Radio.
"We do have to rely on importing some trees to satisfy demand, and the price has gone up by 15 per cent or 16 per cent.
Harry Brightwell, secretary of the British Christmas Tree Growers Association (BCTGA), said it had been a challenging growing season because the mild weather made trees grow more quickly.
"It's 365 days a year, people don't realise the money we spend and dedication and time that goes in.
"I think the word out there is that there are good trees this year," Brightwell said.
"We ask people to look for a British grown tree because it is good for the economy, for agriculture and for the environment," BCTGA said on its website.
Brexit is the informal name for the United Kingdom's proposed withdrawal from the 28-nation European Union trading bloc. As of 2016, the UK government is planning to leave the EU following an advisory referendum held on June 23, 2016 in which 52 per cent of votes were cast in favour of leaving the EU.