Rows of firs and spruces of all sizes stretch across the Oxfordshire countryside, as far as the eye can see – 120,000 grow on the sloping hillsides of this family farm, in the aptly named village of Christmas Common.

Farmer Andrew Ingram sells around 14,000 Christmas trees each year from the Tree Barn, a seasonal shop in his farmyard. For many of his customers, buying a tree grown in this scenic rural location is tradition in itself, marking the start of Christmas celebrations.

But one more modern concern for the consumer is the environmental consequence of purchasing a cut tree, which inevitably needs to be thrown away after Christmas.

Ingram says his products are a sustainable choice, due the thousands of new trees he plants year.

The farm harvests around 10 percent of them, leaving the rest to grow over time. Some reach their full height of 10 meters – and the taller the tree, the more carbon it can capture. 

"All these trees are grabbing carbon dioxide and expelling oxygen," says Ingram. "And, yes, of course when we cut a tree down that one ceases to do it. But we have another little one in the ground ready to replace it."

The Carbon Trust, which advises on sustainability issues, says there are other factors in determining the environmental consequences of a cut tree.

"In the instance that a tree is cut manually, if it's going to a home near to where it's grown, or if it's recycled or reused, then there is a much higher likelihood of there being a net balance of emissions," says Sabrina Parker, project manager at the Carbon Trust.

The organization warns the cheaper alternative to a cut tree, a plastic version, could be much more harmful to the environment.

"That's roughly equivalent to about 40 kg of greenhouse gas emissions, so that impact is more than twice that of a real tree. And that could be a real tree that ends up in landfill, but it's more than 10 times that of a real tree that's actually recycled. 

"If we're looking at it over a longer period, that it's being taken care of and used for a very long time, probably more than 10 years, then it would have a lower environmental impact than buying a commercially grown tree very single year."

A popular alternative for the sustainably minded is a potted tree. Ingram says there is an increasing demand for a product that can continue growing after the Christmas season. 

"That side of the market has increased dramatically over the past five years," he says.

"Somewhere between 5 to 10 percent of our sales are now potted trees. Genuinely pot-grown trees, which will live and you can put it in your garden at the end of Christmas."

A start-up company, London Christmas Tree Rental, has taken this idea one step further. Customers can rent a tree in a pot and return it after the festive season for it to continue growing.

Catherine Loveless, the company's co-founder, says: "We first wanted to kind of explore, it was more the wastage element that we felt was such a shame. But then when we looked into it and realized the environmental impact, it was then like, ok there must be a different way to do Christmas trees. And so, we came up with the rental model." 

Her trees have individual names and customers are encouraged to rehire them for subsequent seasons. The company has had a huge response from the public, with all its rental trees booked out weeks ahead of Christmas.

For those who do buy a cut tree, the Carbon Trust advises careful disposal is a key factor in limiting emissions. Kew Gardens, for example, offers to convert used Christmas trees into acidic mulch, which helps plants such as Camellias and Rhododendrons thrive and there are other similar schemes elsewhere. 

Buying locally and finding a tree certified as sustainably grown also helps. For many, though, the thought of a tree of any kind will certainly bring some cheer during an otherwise difficult winter.