9 April 2007

This was a rare no-travel day for SnowSTAR, only the second time in the last 25 days that the expedition has had the luxury of staying in one place for more than one night. But they have hardly been idle. They are preparing now for a 20-day crossing of the rocky and windswept barrens. They have stops planned at a remote research outpost (Daring Lake about a week from now) the diamond mines, and a gas cache on the Thelon River, but Kugluktuk represents the crew's last opportunity to purchase food and supplies and make repairs to equipment before heading into the barrens. Matthew reports that they are sorting and drying gear that has gotten a bit damp during the above-freezing temperatures of the last several days. They will also be shipping a small quantity of gear home to Alaska--gear they have decided that they no longer need for the barrenlands portion of the trip. Tonights dispatch is about The Treeline, we also have a Spanish soundclip from Dr. Huntington. Enjoy:

CHUGIAK STUDENTS: Click here for Weather in Espanol


The Treeline

A prominent feature of much of the Arctic is that there are no trees. The
treeless region is known as the tundra. Other parts of the Arctic, likes
places throughout the world, have forests. In the Arctic, the forests are
typically known as "taiga," which we described in an earlier dispatch. The
boundary between the taiga and the tundra is the treeline.

The location of treeline is determined largely by climate. If the average
temperature in July is more than 50ºF (10ºC), then trees can survive. If the
average temperature is lower, then trees cannot survive. The quality of the
soil and the availability of water are also important.

In some places, the treeline is an abrupt line. In others, the trees
gradually get smaller and fewer, with little stands here and there in
protected areas, until eventually there are none left. As the earth's
climate warms, trees can survive in new areas. One measure of climate change
is the extent to which trees have moved into new areas, typically north of
where they used to be.   Life at treeline is harsh, which is one of the
reasons the trees move north slowly.  Until a dense forest is established,
blowing snow can kill the lower branches of trees (flag tree), or kill the
trees themselves.

Do you have trees where you live? If so, what kinds of trees do you have? Do
you think they have as hard a time as treeline trees?



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