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Drunken trees, tilted trees, or a drunken forest, is a stand of trees rotated from their normal vertical alignment. [ 1 ] [ 2 ] This commonly occurs in northern subarctic taiga forests of black spruce ( Picea mariana ) under which discontinuous permafrost or ice wedges have melted, [ 3 ] [ 4 ] causing trees to tilt at various angles.
The plant pathogenic fungus Leucostoma kunzei (formerly Valsa kunzei) is the causal agent of Leucostoma canker (also known as Cytospora canker or spruce canker), a disease of spruce trees found in the Northern Hemisphere, predominantly on Norway spruce (Picea abies) and Colorado blue spruce (Picea pungens).
The spruce beetle is the most serious pest of mature and overmature interior spruce in British Columbia; [8] small-diameter, rapidly growing trees were least susceptible to attack or death from spruce beetle, and the greater susceptibility of large-diameter, slowly-growing trees was more closely related to recent radial growth than to diameter. [9]
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Dendroctonus micans, the great spruce bark beetle, is a species of bark beetle native to the coniferous forests of Europe and Asia.The beetles burrow into the bark of spruce trees and lay eggs which develop into larvae that feed on the woody layers under the bark.
The peg-like base of the needles, or pulvinus, in Norway spruce (Picea abies) Pulvini remain after the needles fall (white spruce, Picea glauca). Determining that a tree is a spruce is not difficult; evergreen needles that are more or less quadrangled, and especially the pulvinus, give it away.
Girdling prevents the tree from sending nutrients from its foliage to its roots, resulting in the death of the tree over time, and it can also prevent flow of nutrients in the other direction depending on how much of the xylem is removed. A branch completely girdled will fail; and, when the main trunk of a tree is girdled, the entire tree will ...
A European species of bark beetle, Dendroctonus micans, which attacks spruce trees, is specifically preyed on by a predatory beetle Rhizophagus grandis. Research in China has shown that R. grandis will also attack D. valens , and the predatory beetle is being mass reared for release in China in a biological control programme for this invasive pest.