The flammability of Christmas trees
Recently harvested Christmas trees contain some 50% water, and they are therefore - despite of their constituent substances - not flammable. However, the inflammability increases in step with the degree of drying-out, and in order to reduce the risk of a fire, it is important to use as recently harvested trees as possible to ensure that the tree preserves a high moisture level for a longer period of time.
In addition, before the Christmas tree is brought into the house, the tree should be placed outside sheltered and in the shadow to reduce the drying-out of the tree. It is highly recommendable that the tree be put into a bucket with water. Prior to that, 2-3 cm is cut of the stump.
It is also recommendable that the Christmas tree be brought inside immediately before Christmas to reduce the risk of drying out and thus the risk of needle loss. To preserve the tree for a longer period indoors, the tree can be placed in a stand with water (the tree can absorb 1 litre of water in the course of 24 hours!). The final piece of advice is that you should always ensure that you have a bucket with water near the tree, whenever it is lit.