Tundra In Retreat

Trees and shrubs in parts of northern Canada are taking over what were once tundra landscapes at a much faster speed than scientists originally thought, according to a new University of Alberta (UA) study. The researchers involved say that the rapid northward advance of the treeline adds to the growing body of evidence supporting a warming planet.

With increasing temperatures, scientists had expected a reduction in tundra, but the new research shows that this shift will not always occur gradually, and can surge ahead. “The conventional thinking on treeline dynamics has been that advances are very slow because conditions are so harsh at these high latitudes and altitudes,” said UA’s Dr. Ryan Danby. “But what our data indicates is that there was an upslope surge of trees in response to warmer temperatures. It’s like it waited until conditions were just right and then it decided to get up and run, not just walk.”

Using tree rings, Danby and his co-researchers reconstructed changes in treeline forests in the southwestern Yukon over the past 300 years.

The team found that a rapid change in response to climate warming during the early mid 20th century was observed at all locations. Treeline advanced considerably – as much as 85 meters elevation – on warm, south-facing slopes and tree density increased significantly – as much as 65 per cent – on cooler, north-facing slopes.

“The mechanism of change appears to be associated with occasional years of extraordinarily high seed production – triggered by hot, dry summers – followed by successive years of warm temperatures favorable for seedling growth and survival,” explained Danby.

An advancing treeline could have a significant impact on tundra habitats and the species they host. “The problem is that in mountainous areas you can only go so high, so they get forced into smaller and smaller areas,” said Danby.

Worryingly, as the treeline advances, the reflectance of the land surface declines because coniferous trees absorb more sunlight than the tundra. This light energy is then re-emitted to the atmosphere as heat. This sets up a positive feedback effect, the same process that is associated with the rapidly decaying Arctic ice cap.

Related articles:
Pleistocene Era Methane Gatecrashes Greenhouse Gig
Feedback Loop Puts The Heat On Climate Predictions
Arctic Permafrost Not So Permanent
Climate Change And Vegetation – Complex Feedback
Possible Surge In CO2 From Arctic Soil

Source: University of Alberta

, ,

Comments are closed.

Toyota Tundra Tacoma TRD 4x4 Off Road Sport Truck Decal Sticker X2 picture

Toyota Tundra Tacoma TRD 4x4 Off Road Sport Truck Decal Sticker X2

$19.95



Crow, Volumes 1-3  1992 Tundra Publications picture

Crow, Volumes 1-3 1992 Tundra Publications

$49.99



Tundra: Bears It All - Paperback By Chad Carpenter - GOOD picture

Tundra: Bears It All - Paperback By Chad Carpenter - GOOD

$7.52



NORITAKE  Stoneware Tundra Mugs RARE Made In Japan ~ Off-White With Brown Trim picture

NORITAKE Stoneware Tundra Mugs RARE Made In Japan ~ Off-White With Brown Trim

$6.00



TOYOTA TRD TACOMA TUNDRA 4RUNNER RAV4 SUPRA KEYCHAIN TAG DOUBLE SIDED JDM picture

TOYOTA TRD TACOMA TUNDRA 4RUNNER RAV4 SUPRA KEYCHAIN TAG DOUBLE SIDED JDM

$14.95



Tundra Mini Comic 1 Rare FN Kevin Eastman Mark Martin 1990  picture

Tundra Mini Comic 1 Rare FN Kevin Eastman Mark Martin 1990

$19.99



Toyota Trucks banner sign racing motorsports off-road baja tacoma tundra picture

Toyota Trucks banner sign racing motorsports off-road baja tacoma tundra

$18.95



Artifice Tundra (white) Playing Cards picture

Artifice Tundra (white) Playing Cards

$7.49



CAGES 1 ~ CGC 9.6 W/PAGES ~ SANDMAN DAVE MCKEAN TUNDRA ~ HIGHEST GRADE COPY RARE picture

CAGES 1 ~ CGC 9.6 W/PAGES ~ SANDMAN DAVE MCKEAN TUNDRA ~ HIGHEST GRADE COPY RARE

$350.00



Gil Hibben Tundra Hunter Professional Fixed Blade Hinting Knife W/Sheath GH5077 picture

Gil Hibben Tundra Hunter Professional Fixed Blade Hinting Knife W/Sheath GH5077

$62.73



Powered by WordPress. Designed by WooThemes