When buying, look for specific "Pot grown" Christmas trees - these are trees that have been grown from seed in a container and are much better than "potted" Christmas trees. The difference is, "potted" trees are dug up and put into a pot, which can damage the roots and reduce the chances of survival.
When Christmas is over, take the decorations off and put your tree out in the garden, perhaps in a slightly larger pot so it has room to grow!
When Christmas comes round again, simply bring the tree back inside and decorate!
If the tree grows too big to bring inside, find a place for it outside where it can grow and flourish.
Why is this important?
Although plastic trees last for a long time, they require fossil fuels to be produced unless made from 100% recycled materials. Depending on where plastic trees come from, there could be a vast carbon footprint used to transport the tree to your house.
Is it really justifiable to cut down a living tree just for a couple of weeks use? Why not opt for a living one, and keep it alive for years to come instead.