The environmental pros and cons of Christmas trees go far beyond the climate impact of "real or plastic", scientists say. So what's the best choice for a green Christmas?

In 1800, Queen Charlotte, the German wife of King George III, set up what is thought to be the first Christmas tree in England, at Queen's Lodge in Windsor.

Decorated Christmas trees already had a long history in Germany, but this was the beginnings of their role as a fashionable part of the festive season for the English upper classes. By the 1850s they were a common sight across the UK. In the US, meanwhile German settlers helped to establish the tradition of displaying trees in the home, decorated with homemade ornaments, by the 1830s.

Some two centuries later, the now-cherished tradition of plonking a newly cut tree in the middle of the living room and covering it with lights and baubles is still alive and well across much of the world. Today, an estimated 25-30 million real Christmas trees are sold annually in the US, and around five million in the UK. Real trees may also be coming back into fashion among younger generations – a 2019 US survey found millennials are 82% more likely than baby boomers to get a live tree.

A millennial myself, I certainly fit this trend. I love real Christmas trees but have had countless conversations (and internal debates) about whether getting one is overindulgent wastefulness or an essential – and ultimately environmentally negligible – part of Christmas.

As I have delved further into the topic, though, I've found their assumed negative environmental impact may not be as clear cut as I once thought. These conversations often centre on the relative carbon footprint of real compared to plastic ones, but researchers say their wider influence, good or bad, goes far beyond this.

"I do think there's a lot more nuance to it, than just, 'Oh, we're cutting down a tree and removing it'," says Alexandra Kosiba, a forest ecologist at the University of Vermont Extension in the US.

After all, before it is cut down and displayed, a Christmas tree is grown – on land that might otherwise be used for different purposes, better or worse. In Vermont, for example, says Kosiba, Christmas tree plantations support the local economy and help to maintain the rural landscape.

How we use our land has become especially important in the face of two pressing and deeply connected environmental crises: biodiversity loss and climate change. Forests are a huge part of such beneficial land use.

"Well-managed forests really play a huge role in the climate solution," says Andy Finton, landscape conservation director at The Nature Conservancy, a US-based environmental non-profit. "Trees of all sorts are pulling carbon from the atmosphere, and storing it and reducing the amount of carbon pollution and thus the pace of climate change."

Christmas trees are certainly not a hugely significant use of land, or a big player in the global carbon cycle, especially compared to timber production or crops like maize or wheat. But they do provide an interesting area to consider, in part because many humans have far more direct engagement with them than perhaps any other forest product.

"There's a lot of folks that don't interact with nature a lot," says Kosiba. "It is pretty cool to think all these people are bringing a tree... into their house [and] sort of revering it and appreciating it." This festive appreciation may be a good opportunity to consider the wider role of different trees, and how and where they are grown.

Christmas trees are typically young spruce, fir or pine trees from plantations, which means their environmental impact will always very much depend on what might be grown on land instead. It goes without saying that ecologically valuable native habitats such as old growth forests or peatlands should never be used to plant Christmas trees.

The plantations are grown for roughly 10 years before harvesting, meaning that for every tree cut down one year, another nine or so stay standing. "It's quite nice as a way of maintaining a set of trees, because you always need the new trees coming through to be harvested the following years," says John Kazer, footprint certification expert at the Carbon Trust, a UK-based environmental consultancy.

Christmas trees are not included in the EU pledge to plant three billion additional trees by 2030, as they are considered too short-lived. "They are cut down more often than timber harvest or, of course, natural old growth forests," says Paul Caplat, an ecologist at Queen's University Belfast, Northern Ireland. "So there's not a lot of time for biodiversity to settle in and grow healthy populations."

However,

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