Different types of spruce trees
Spruce trees are of the species Picea of which there are about 35 different species that grow in the Northern Hemisphere. This work will provide a brief general description of the species and provide brief comment about 6 of the most common types of spruce; the Colorado Blue, the Red, White, Sitka, Black, and the Engelmann spruce.
Description
Spruce trees yield cones that grow on the end of branches and have needles for leaves which stay green all year round and therefore it is considered a coniferous evergreen. They can grow to great heights sometimes reaching 200 feet and also come in dwarf versions which grow to about 8 feet tall.
Spruce can be extremely long-lived if left alone. Wikipedia informs that in western Sweden a group of Norway Spruce, with the nickname of Old Tjikko, are thought to be the oldest living trees in the world with an age of 9,550 years
Colorado Blue Spruce (Picea pungens)
This spruce can reach heights of around seventy five feet in the wild but in human landscaped areas it is usually grown to heights of between thirty to fifty feet. When transplanted it may grow slowly to begin with, sometimes for several years. However, once established it can grow about twelve inches a year.
At first the needles appear as a soft tuft, but become stiff and sharp as they mature. The shape of the tree ranges from conical to column-like and can be ten to twenty feet in diameter.
The Colorado Blue spruce is often used in landscaping as a specimen or as screening when planted ten to fifteen feet apart. Many think their bluish green foliage and upright trunk and horizontal branches give a formal air to an area.
Red spruce (Picea rubens)
In the Acadian Forest region this is a common tree that prefers damp soils of sandy loam but also grows on dry, upper, rocky slopes and also in bogs. In some areas it can be found to overshadow other trees in established forests. Red Spruce can live to be about 400 years old.
Its North American range extends from western North Carolina, north along the Appalachian range to Canada where in Nova Scotia it is the provincial tree. The Red spruce is one of the most valuable commercial conifer trees in the north eastern parts of the US and south eastern parts of Canada.
White spruce (Picea glauca)
This spruce is known by a number of names including; Alberta White spruce, Canadian spruce, Cat spruce, Black Hills spruce, Porsild spruce, Skunk spruce, and Western White spruce. This tree has a wide range and is at home in a various climate and soil condition that are found in the Northern Coniferous Forest.
Its wood is straight grained and light in colour and its main commercial uses are for general construction work and for pulp wood.
Sitka spruce (Picea sitchensis)
This tree is also known by the names of Tideland, Yellow, and Coast spruce. The Sitka spruce is the largest spruce in the world and one of the most notable in the North American forests.
It has a preference for humid conditions and is rarely found far from the coast where the damp sea air and fogs provide the conditions it requires for growth.
The Sitka spruce ranges from northern California to Alaska and is often found growing along with Western hemlock (Tsuga heterophylla).
Black spruce (Picea mariana)
The Black spruce is also called the Bog, Swamp, and Short Leaf Black spruce. It has a yellow-white wood which is both light and strong and is important commercially to Canada and the Great Lake states such as Minnesota.
Engelmann spruce (Picea engelmannii)
This species of spruce is widely distributed in western North America and found in all the western states of the US from Arizona and New Mexico up to British Columbia and Alberta in Canada.
Landscaping
Spruce trees are admired for their conical symmetry and evergreen foliage which keeps them looking good all year round. This makes them popular in landscaping and the dwarf varieties are particularly versatile for this purpose.
References
http://en.wikipedia.org/wiki/Spruce
http://www.wisegeek.com/what-is-a-spruce-tree.htm
http://forestry.about.com/od/treehabitatandrange/ig/ Common-Spruce-Tree-Ranges/