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Twigs and branches killed by this disease may remain on the diseased host tree for several years. All of this damage caused by this fungal pathogen does not typically begin until the host trees are at least 10–15 years old. However, in landscape nurseries small branches of young blue spruce or occasionally white spruce may be killed.
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.
Wind throw is the toppling of a tree due to the force of the wind, this exposes the root plate and adjacent soil beneath the tree and influences slope stability. Wind throw is a factor when considering one tree on a slope; however, it is of lesser importance when considering general slope stability for a body of trees as the wind forces involved represent a smaller percentage of the potential ...
Spruce–fir forests can be found in cold regions at high latitudes or high altitudes throughout the Northern Hemisphere. [1] This includes both areas throughout the high latitude boreal forest of Canada and Russia, [2] [3] as well as mountain ranges at lower latitudes, such as the Rocky Mountains in North America, the Tian Shan in Asia, and the Carpathian Mountains in Europe.
Taiga spruce forest in the Kenai National Wildlife Refuge, Alaska. Trees in this environment tend to grow closer to the trunk and not "bush out" in the normal manner of spruce trees. The forests of the taiga are largely coniferous, dominated by larch, spruce, fir and pine.
I scanned the trees and saw that a maple tree had "exploded". The explosion caused a big crack in the tree about three feet high. When a winter wind stirs the frozen trees, they sometimes appear to burst vertically. When it was 40 degrees below zero at night, I lay awake and listened to the trees explode. That's a true wilderness thermometer!
The tree line is the edge of a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes . Beyond the tree line, trees cannot tolerate the environmental conditions (usually low temperatures, extreme snowpack, or associated lack of available moisture).
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.