If you have or plan to get a fresh-cut Christmas tree, fill the stand with hot (NOT boiling) water. This keeps your tree fresh longer because when the tree is cut, the sap inside it solidifies making it impossible for water to travel to the branches. The hot water will soften the sap so the tree can drink. If you want to, every time you replace the water,  add 3 tablespoons of vodka to the water to ward off any bacteria!