Our artificial Christmas tree was a sound environmental choice 30 years ago, and it is about 20 years in credit (for carbon) now and still going strong

According to this Soil Association article:
https://www.soilassociation.org/take-action/organic-living/christmas/eco-friendly-christmas-trees-real-vs-fake/

"... a two-metre artificial tree has a carbon footprint of around 40kg, more than ten times that of a real tree that’s burned after Christmas.  In other words, you’d need to re-use an artificial tree 10 times to negate its carbon footprint, yet it’s estimated that [on average] fake trees are used only four times, regardless of improving quality."

A different source suggests average lifetime of an artificial Christmas tree in the USA is ten years:
https://www.independent.co.uk/voices/christmas-tree-real-artificial-environment-impact-b2464177.html

Our family's artificial Christmas tree is about 30 years old, and still comes out as our centrepiece every Christmas.  It seems, from the stats, that we are an unusual family in having had our tree for so long, but because of its longevity our tree is about 20 years in carbon credit compared with the alternative of having a specially grown real tree each year for those 30 years. 

At an aggregate level, on the basis of their average lifetime, it appears to be the case that the use of artificial trees in developed countries is justified on environmental grounds, compared with real trees grown for the purpose.  There are enough people like us, who use one for a long time, to make the average net environmental benefits acceptable.  The net benefits are improving all the time, as the environmental footprint of artificial trees gets smaller with progress in material sourcing, manufacturing methods and recyclability.