Friday, November 9, 2012

The Colorado Christmas Tree

Species name: Abies concolor

Common name: white fir, Colorado fir

Location: Ontario

As you can probably imagine from the common name, this tree is native to western North America in alpine regions in and around Colorado. While this tree survives well in eastern North America as an ornamental tree, it doesn't make seeds willingly (while cones can be quite prolific, depending on the environmental conditions). In its native range, it hybridizes readily with the grand fir.

Throughout much of North America, this tree is a very popular ornamental tree due to the coloration of the needles. It's not nearly as big of a contrast from regular green trees as the blue spruce is, but it is still quite the contrast nonetheless. There are huge stands of white fir trees of all roughly the same age, which may look strange to visitors to Canada and the United States. If you drive past the stand often, you'll notice the trees never get very large before the entire stand is cut down. This might make you think they're being used for some sort of commercial or industrial purpose and you'd be correct: Christmas trees! The white fir (sometimes sold as the concolor fir) is the single most popular tree to use as a Christmas tree due to the softness of the needles, the colour of the needles, and the fact that the needles stay firmly attached to the tree even after they start drying out (this cannot be said for all fir trees, and certainly can't be said for spruce trees). It also has a great smell when the tree starts to dry out!

Other than commercial value of the white fir as Christmas trees, it has very few other commercial uses. It is sometimes used as a pulp and paper tree, but only when its growing where it isn't wanted in a stand of other trees; the lumber is very soft and very knotty. The tree also is not self-pruning like many other coniferous trees, and retains its lower branches when mature (even though they have long since lost their needles). This is of great concern for "lumber farms," and National and Provincial Park staff; the bottom branches of the tree act as a sort of fire ladder, spreading forest fires very quickly through stands of trees.

This species of conifer tree is important in forests for reasons other than just fire hazards and as the odd pulp source; they are also the host for fir mistletoe, a parasitic plant that grows off of the carbon sources produced by the host plant. It doesn't produce any of its own food, and doesn't ever produce roots that root the shrub to the ground. Instead it completely relies on the fir tree for shelter, food, protection, and water. The mistletoe likely doesn't ever weaken the tree to the point where it will kill it, but when a tree is weakened for any reason it is more likely to be invaded by insect pests or infectious fungi. Mistletoe can indirectly lead to stand-wide forest death.