How to keep a cut tree fresh until New Year

A tree cut on the hill in December can easily last until Twelfth Night if it can drink (sample note).
When you get home, saw a thin slice off the bottom of the trunk and stand the tree in water within the hour. A fresh cut takes up water; a dry one seals over with sap.
A 7 ft tree drinks up to a litre a day in the first week. Check the stand every morning, keep the tree away from radiators and fires, and switch the lights off at night.