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Picea

Picea jezoensis - Hondo spruce

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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.

There are two thriving plantations of Hondo spruce at Mustila. Those growing along Maaherranpolku south of the Azalearinne, or Azalea slope are from seed sown in 1907, sent from Japan by Mustila’s ”collector royal”, Johannes Rafn. Another plantation, grown from Hokkaido seed planted out in 1936 as 12-year-olds, can be found at the western end of Etelärinne, or Southern Slope. Despite their age, both plantations are in excellent shape, unlike many of the American spruce planted there. This shows the suitability of both the species and the seed source to Mustila’s conditions.

Currently a test site for Hondo spruce seed from different sources is being created in the spruce collection area in the western part of the Arboretum. It has already been noticed that the young plants from seed from the Changai Mountains, on the border between Manchuria and Korea, start to grow in spring rather later than plants from other sources, which makes them hardier to spring frosts. Plants from other seed sources open their buds very early, thus needing protection from spring frosts to grow well.

 

Picea glauca - white spruce

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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.

There are many varied forms and colours of the white spruce. One of the most familiar forms is the pillar-like close-branched conical Picea glauca ‘Conica’, which needs protection in Finnish latitudes from severe frosts and winter sunlight to grow successfully.

In Mustila plantations dating from the early 1900s several different seed sources have been tried, from Ontario, Minnesota, Quebec. They are all smaller and slower-growing than local Norway spruce (P. abies), but have not suffered frost damage. However, they have aged faster than in their natural habitat. Only a few poor examples of the original plantings are to be found today, on Pohjoisrinne, or North Slope and in Lepistö. The latter are of the western form, var. albertiana, which in fact is an intermediate form between white spruce and Engelmann spruce.

In 2000, new plantings of both white spruce and the intermediate form were made in the spruce collection in the west part of the Arboretum. These plantings consisted of the best thriving provenances from central British Columbia.

 

Picea engelmannii - Engelmann spruce

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Engelmann spruce is a typical tree of the North American Rocky Mountains. It grows between 450-3700m asl (above sea level) and forms the tree-line with, among others, white fir (Abies lasiocarpa). Lower down the mountains it forms large single species forests. Typically, it grows in moist soil of normal fertility. This spruce can become a large tree with a dense conical or narrow spire-like crown.

At Mustila there are several excellent specimens mixed with indigenous species on the slope between Etelärinne (Southern Slope) and Terassi (Terrace); these trees are of the bluish-green southern Rockies form. In the western parts of the Arboretum, in the spruce collection, there is a small plantation of young Engelmann spruce of Kamloops, British Columbian origin. In the same area there is a small stand of an intermediate form between white spruce (Picea glauca) and Engelmann spruce, from seed collected at Kirkup Creek, British Columbia.

The best British Columbian provenances also thrive in small stands. As many American spruces, they have grown vigorously but their life span has been significantly shorter than in their natural range, and the trees have been susceptible to bark beetle attacks when aged.

The blue-grey southern form of Engelmann spruce, which demands an open space, is best suited to landscaping use. In the open it is relatively long-lived and the branches remain dense to maturity.

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