Sitka spruce grows along the west coast of North America from Alaska to California, and has many – sometimes surprising – merits. Few know that it was used in the building of one of the largest aircraft ever, Howard Hughes’ Spruce Goose. This majestic tree has been used throughout history by animals, plants and man.
The name red spruce derives from the generally reddish brown appearance of the forest in its natural range, where in the eyes of local foresters it is distinguishable from the darker black (P. mariana) and lighter white (P. glauca) spruces. All three species grow in the same area of eastern North America. The range of the red spruce is the most Atlantic of the three. At its southern limit it grows as a mountain species on the upper slopes of the Appalachians.
The alternative name for this species honours Peter von Glehn, a botanist of German-Baltic origin who worked in Russia. It has a long history at Mustila, having been among the species planted as seedlings from seed sent from Japan in 1908 by the Dane Johannes Rafn, the Arboretum’s ”court purveyor”. The stand, now over 100 years old, is still in fine condition, which can’t be said of many of the exotic spruce planted at Mustila. However, the visitor is more likely to see the Glehn spruce as a young tree, in the 1995 plantings along the Northern Slope road.
The white spruce of the South Dakotan Black Hills differs enough from its relatives that it is usually given its own varietal name. The cones are shorter, the needles a beautiful blue-grey, and the whole habit of the tree is tight and extremely attractive, which is why it is used in America as a Christmas tree and a garden ornamental.
The background of the Alberta spruce is a source of some disagreement. It is considered a south-western form of the white spruce (P. glauca), or perhaps as an intermediate form of a hybrid involving the Engelmann (P. engelmannii) and white spruces, which is what it undoubtedly looks like. The needles are longer than those of the typical white spruce, and the stems of the new growth are hairy, like the Engelmann.
Colorado spruce grows naturally in the southern Rockies of the United States, between 1800-3400m above sea level, together with Douglas fir (Pseudotsuga menziesii), Engelmann’s spruce (P. engelmannii) and Subalpine fir (Abies lasiocarpa), among others. It prefers open mountain forests and is quite happy on fairly dry sites. With its deep roots, it survives storms well. The needles often display the waxy blue-grey coating typical of many species of conifers from southern mountain zones.
A. F. Tigerstedt mentions the Meyer spruce (P. meyeri) in his book “Havupuut” (Conifers), published in 1921. He listed the various Chinese spruce species still missing from the Mustila collection and ended: “which may gradually, one by one, be obtained [for Mustila]”. In some cases, obtaining these species has taken longer than he might have expected: Meyer’s spruce was finally planted in the Arboretum in 1991.
Black spruce grows in North America in a broad belt from Alaska to Newfoundland, and as far south as the Great Lakes. In the southern parts of its range it grows mainly on mires, further north also on drier soils. This is a small slim tree with a narrow cylindrical crown. Needle colour varies: dark green, blue-green, or grey-green. The cones are small and ball-shaped, often growing in tight bunches near the crown, and remaining on the tree for several years. Black spruce can regenerate throughout most of its range by layering from branches in contact with the ground.
The attractive Hondo spruce is the most important spruce species on the coasts of East Russia and in Northern Japan, growing in favourable conditions up to 50-60m. Its layered branches grow straight outwards, slightly upturned towards the tips, while the branches of the crown – like many far eastern conifers – are distinctly upward-growing. The white stomata lines under the needles give the crown an attractive glitter in early morning or evening sun.
The range of the white spruce covers the whole of the northern parts of North America, forming the tree-line together with black spruce (P. mariana) and tamarack (Larix laricina), aka eastern larch, American larch etc. It grows well on drier soils and on rich moraine soils. For paper and sawn timber it is one of the major species in the US, and THE major species in Canada. The crown resembles that of the Norway spruce but is denser and bluish in colour. The needles of some origins carry a strong scent.