What
are Drunken Trees?
Drunken
trees are a stand of trees displaced from their normal vertical alignment. This
most commonly occurs in northern subarctic taiga forests of black spruce under
which intermittent permafrost or ice wedges have melted, causing trees to tilt
at various angles. Some trees survive their soil eroding and continue to grow.
Others collapse or drown as the subterranean ice melts. As they are staggered
across the landscape, people often refer to them as 'drunken trees.'
Drunken
Trees are also called, tilted trees or a drunken forest may also be caused by
frost heaving, and subsequent palsa development, hummocks, earth flows, forested
active rock glaciers, landslides, or earthquakes. In stands of spruce trees of
equal age that germinated in the permafrost active layer after a fire. They
tilting begin when the trees are 50 to 100 years old, suggesting that surface
heaving from new permafrost aggradation can also create drunken forests.
What
is Permafrost?
Permafrost
soil or rock remains below 0 °C for at least two consecutive years. It forms a
solid matrix in the soil which can spread to a depth of hundreds of meters. Permafrost
is permanently frozen ground. Nonetheless, climate change has caused much of
that ground to melt at an unprecedented rate. The ground buckles and sinks,
causing trees to list at extreme angles. Further, the permafrost prevents trees
from developing deep root systems. Also, those areas where the permafrost
temperature is close to the melting point of water.
Drunken
Trees Relations with Climate Change
The
climate variations, or loss of surface vegetation from fire, flooding,
construction, or deforestation, can thaw the upper extents of the permafrost.
This is creating a thermokarst, “the scientific name for a ground slump caused by
melting permafrost”. The thermokarst undermines the shallow root bed of trees, triggering
them to lean or fall. Thermokarst lakes are enclosed by a ring of drunken trees
leaning toward the lake, which makes this land features simply identifiable.
When permafrost melts, it affects a lot of erosion; a lot of trees can't stand
up straight. If the erosion gets worse, everything goes with it.
Drunken
trees may ultimately die from their displacement, and in ice-rich permafrost. The
entire drunken forest ecosystem can be damaged by melting. Drunken trees are
not totally new phenomenon dendrochronological evidence can date thermokarst
tilting back to at least the 19th century. Permafrost is naturally in
disequilibrium with climate, and much of the permafrost that remains is in a
relict state. However, the rate of thawing has been increasing, and a great deal
of the remaining permafrost is expected to thaw during the 21st century. At
times the trees survive the pressure and continue growing, uprighting
themselves to vertical. However, on the other side, trees collapsed or drown
from rising water tables as subterranean ice melts. Because such trees seem to
stagger across the landscape, people often call them "drunken trees."
Moreover,
Al Gore cited drunken trees caused by melting permafrost in Alaska. This is as another
evidence of global warming, as part of his presentation in the 2006 documentary
film An Inconvenient Truth. Alike warming leading to permafrost thawing in
neighboring Siberia has been credited to a combination of anthropogenic climate
change, a cyclical atmospheric phenomenon known as the
Arctic oscillation.
Moreover, the albedo positive feedbacks caused
by both when melting ice expose bare ground and ocean which absorb, rather than
reflect, solar radiation. The melting
permafrost isn’t just affecting the trees. But it is also having an enormous
impact on the people that live and work in the zone. Thus, slumping land cracks
pavement breaks pipelines, and causes sinkholes to open, swallowing roads, and
buildings. Source: CP
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