Blue spruce needle courtesy of Scott Catron, flickr.

Interacting with Others

Christmas Tree, courtesy of Sarahpie. flickr. Humans rarely use blue spruce for lumbar or wood products because it is not abundant in nature and the wood is brittle and often full of knots.  It is more commonly used in ornamentals, general landscaping, or for Christmas trees because of its symmetry and unique greenish-blue foliage.  Many varieties of blue spruce have originated in cultivation.  These are called cultivars and are based on needle color and crown form.

Human are barely the only species to utilize blue spruce.  Many organisBlue Spruce Lodge, courtesy of josephleenovak, flickrms that live in the higher altitude use the foliage for shelter.  This relationship is commensal because the species are benefiting from using the blue spruce as shelter, but the blue spruce is not affected.

There are many species that are known to have a parasitic relationship with blue spruce.  One of the many insects that have this relationship with the blue spruce is the western spruce budworm larvae (Choristoneura occidentalis), which feeds on old needles in late April then mine developing buds and defoliate tree growth.  If this happens repeatedly it will kill the tree.  Several diseases attack the seedlings, leaves, stems, andDefoliated blue spruce, courtesy of Stephen Downes, flickr. roots.  An example of this is Phytophthora cinnamomi, which is a water-borne mold that kills new seedlings.  Pratylenchus penetrans is a nematode that feeds on the roots of the tree and cause reduced growth.  Leucocytospora kunzei is a widespread fungal disease that cause cankers on one-fourth to one-half of the branches of the infected host.  Keep in mind these are only examples of a few of the organisms that interact with blue spruce, there are many more.      

 Now let's find out a little about the history.