‘Real’ trees are recyclable, however artificial ones are not. Local councils often arrange special collections of ‘real’ trees in early January and advertise the dates this will take place with any other changes to collections over the Christmas period.
You may receive a leaflet from your council, find an information sticker on your bin or see an advert in your local paper detailing when the ‘special collection’ will take place. If you don’t come across any of these, contact your council and ask if they are collecting them in your area.