Balsam Firs are the best trees for they have a wonderful scent, firm branching, and hold on to their needles for a longer period of time.
Fraser Firs, Abies fraseri
Fraser Firs are also very good and are known as the Southern Balsam. They grow well in the southern states and have many of the same characteristics as the Balsam Fir although they are less fragrant.
White Spruce, Picea glauca
White Spruce have a shorter needle but good green color. While their branches are firm, they drop their needles very fast and for that reason command less money as a tree.
Norway Spruce, Picea abies
Norway Spruce are very similar to White Spruce at this young age. They too will drop their needles quickly.
Colorado Spruce, Picea pungens
Colorado Spruce have a wonderful color and make a very shapely Christmas tree. Not only do they drop their needles quickly, the needles are very sharp and this makes the tree hard to decorate. Cats don't like to climb Colorado Spruce unlike other trees!
Douglas Firs, Pseudotsuga memziesii
Douglas Firs are not good indoor trees as their branches droop under the weight of ornaments.
Canadian Hemlocks, Tsuga canadensis
Great outdoor tree but they are even worse than Douglas Firs and will hold next to no weight without drooping.
Sheared or unsheared?
This is a personal preference. Sheared trees are very popular for the growers as the trees demand a larger selling price. Sheared trees do not hold ornaments well unlike a natural tree. An unsheared tree will have a space between the branch whorls and this space creates enough room to display ornaments. You can take a sheared tree and prune out spaces to hang ornaments.
Tree Safety:
Trees dry out extremely fast in a house where the humidity is often less than in a desert! The tree then becomes a moisture source for the house and the needles dehydrate and dry out very fast. Dry needles pose a huge fire hazard; here are a few safety tips:
Make a fresh cut on the stump before erecting your tree in its stand.
Water your tree every day.
Use cool lights to illuminate your tree and limit the time the lights are on.
Never have your tree up more than 21 days, 14 is better.
While tree location may not be an option, away from a heat source is the best choice.
