If you have a live tree, and you're anything like me you often forget to water it until late in the day when it's almost bone dry. The following is a tip to help keep the tree live and green even if you miss a watering or 2.
Take a large whine bottle, fill it with water, and stick it into the stand for the tree.
(You may need to use a zip tie, or string to hold it up, I had a limb that I was able to wedge it under)
If the water level drops below the mouth of the bottle the bottle will release and will keep some water in the stand.