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| Black Spruce | ||||||||||||||
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| Picea mariana |
The Black Spruce (Picea mariana) is a common coniferous tree in North America. Old synonyms include Abies mariana, Picea brevifolia, Picea nigra.
Natural hybridization between species of spruce is usually rare, but does occur regularly with the closely related Red Spruce Picea rubens.
It differs from true firs, such as Balsam Fir Abies balsamea, in having pendulous cones, persistent woody leaf-bases, and four-angled needles, scattered and pointing in every direction.
It differs from White Spruce Picea glauca, in having shorter needles, smaller and rounder cones, and a preference for wetter lowland areas.
It is a coniferous, slow-growing, small upright tree or dwarf shrub, having a straight trunk with little taper, and a narrow, pointed crown of short, compact, drooping branches with upturned tips. Through much of its range it averages 10-15m (30'-50') tall with 15-25cm (6"-10") diameter trunks at maturity. Growth varies with site conditions. In swamps it shows progressively slower growth rates from the edges toward the centre.
The needles are 8-12mm (½") long, stiff, four-sided, dark bluish green and the bark is thin, scaly, and grayish brown. The roots are shallow and wide spreading with most in the upper 20cm (8") of organic soil. It is very susceptible to windthrow except in the densest stands.
The 2-4cm (0.6"-1.25") cones are the smallest of any spruce; spindle-shaped to nearly round, dark purple ripening red-brown, in dense clusters in the upper crown, opening at maturity but persisting for several years.
It is transcontinental in North America from Newfoundland to Alaska, south to British Columbia, Minnesota, and east to Rhode IslandAlternate uses: see RI (disambiguation The State of Rhode Island and Providence Plantations (commonly known as Rhode Island is geographically the smallest state in the United States. Rhode Island (pronounced "Road Island") is part of the New England regio and MassachusettsMassachusetts is a state of the United States of America, part of the New England region. postal abbreviation is MA and its traditional abbreviation is Mass . It is properly called the Commonwealth of Massachusetts although there is no legal distinction b.
It grows in both lowland and upland sites. In the southern portion of range it is found primarily on wet organic soils, but farther north its abundance on uplands increases. In the Lake States it is most abundant in peat bogs and swamps, also on transitional sites between peatlands and uplands. In these areas it is rare on uplands, except in isolated areas of northern Minnesota and the Upper Peninsula of MichiganMichigan is a state in the United States. The name is derived from Lake Michigan, which in turn is believed to come from the Chippewa Indian word meicigama meaning "great water. Bounded by four of the Great Lakes, Michigan has the longest state shoreline.
Most stands are even-aged due to frequent fire intervals in Black Spruce forests. It commonly grows in pure stands on organic soils and in mixed stands on mineral soils. It is tolerant of nutrient-poor soils, and is commonly found on poorly drained acidic peatlands. It is considered a climax species over most of its range. However, some ecologists question whether Black Spruce forests truly attain climax because fires usually occur at 50-150 year intervals, while "stable" conditions may not be attained for several hundred years.
The frequent fire return interval perpetuates numerous successional communities. Throughout boreal North America, Paper Birch Betula papyrifera and Quaking Aspen Populus tremuloides are successional hardwoods that frequently invade burns in Black Spruce. Black Spruce typically seeds in promptly after fire, and with the continued absence of fire, will eventually dominate the hardwoods.
It is a pioneer that invades the sedge mat in filled-lake bogs, though often preceded slightly by Tamarack Larch Larix laricina, with which it may in time form a stable forest cover in swamps. However, as the peat soil is gradually elevated by the accumulation of organic matter, and the fertility of the site improves, Balsam Fir and Northern White-cedar Thuja occidentalis will eventually replace Black Spruce and Tamarack.
The larvae of the Spruce BudwormSpruce Budworm Choristoneura Species Scientific Classification : Eukaryota : Animalia : Metazoa : Arthropoda : Hexapoda : Insecta : Pterygota : Neoptera : Endopterygota : Lepidoptera : Ditrysia Division: Microlepidoptera : Tortricoidea : Tortricidae : Tor mothA moth is an insect closely related to the butterfly. Both are of the order Lepidoptera. People who study or collect these insects are called lepidopterists. Most species of moths are nocturnal, but there are crepuscular and day-flying species. They can b cause defoliation and if it occurs several years in a row will lead to death, though Black Spruce is less susceptible than White Spruce, or Balsam Fir. Trees most at risk are those growing with Balsam Fir and White Spruce.
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