Polar Husky A to Z

Treeline & Tundra

In Inuktitut, Tundra means "nothing" which at least at first seems pretty fitting considering it is the name given to the land (ecosystem) beyond the limit of trees. That's right no trees.
Some years ago our expedition leader Paul was part of an expedition passing through the small village Arviat on Hudson Bay when a little boy pulled his sleeve asking "Are there really trees?"

Try to count how many of the items in the room you are sitting in are made out of trees?

Tundra actually covers one fifth of the Earth's surface!


It is hard for us people below the tree line -- which is what we call the boundary between the thick spruce and larch forest of the taiga (right below tundra) and the openness of the tundra -- life without wood. Take a minute and look around you... Do you see lots of stuff made of wood? Now imagine what you would do without it!

Taiga or Boreal Forest cover the globe in a broad belt across the northern hemisphere. The forests cover so much word land area that they are considered the largest biome in the world. Named after Boreas, the Greek god of the north wind, boreal forests are found between 50 and 60 degrees latitude in North America, Europe and Asia. In northern Ontario, taiga can be further divided into two parts: the sub arctic open lichen woodland and the closed crown forest.

But why is the Arctic tundra treeless?

Most people think it is the extreme cold which keeps the black and white spruce you find along the tree line at bay. However, they are able to withstand temperatures down to minus 90 degrees F (-68° C). Actually, wind and permafrost limit tree growth. Notice how the trees on the picture to the left like one-sided Christmas trees pruned to stand in a tight corner! It is the harsh, bitter and plentiful wind with its sharp crystals of ice, that cuts and kills trees. If you look at a map of the northern hemisphere, you will notice that the tree line is not a straight line around the globe. It fluctuates in large depending the force of COLD winds.

Permafrost is the name for ground which is permanently frozen. Through out the arctic tundra, it is usually within 3 ft (1 m) of the top layer of soil and goes up to 3,250 feet (1,000 m) deep. The farther north you are, the closer to the surface the permafrost creeps. As a result, the trees are forced to anchor themselves with roots so shallow that eventually they are too weak to prevent the tree from tipping over!

The most important factor though is the strength of the sun - The very short summer. A tree needs a certain amount of warm summer days of at least 50° F (10° C) to survive or actually to be able to grow. If temperatures do not rise this high, not even the hardiest of trees can complete their annual growth cycle and will die.

That explains why the arctic tree line is a broad boundary sometimes many miles wide unlike the sharp alpine tree line you will find on most mountain sides.

Especially when you travel on a dogsled -- you are going at just the right pace to notice how the trees gradually get fewer and smaller and smaller. Some trees are only knee high and maybe 80 years old, but they have not had much time each year to grow! Finally, the trees surrender and disappear.

Tundra actually covers one fifth of the Earth's surface! There are several different types of arctic tundra. Let's take a look at the 3 you can meet most often.

The most "typical" is the sedge meadow which is found all all across the lower Arctic. It looks like a normal grass field, but it is made up of mostly "sedges" which are marsh plants not grasses. You see, it is so wet here. Each summer when the sun melts the snow and ice the water can not get away because of the permafrost right underneath which acts like a barrier stopping the melt water from being able to sink underground.

This makes Tussock tundra the worst nightmare for hikers in the summertime as it is for dog mushers in the winter. Imagine this; tough clumps of marsh plants growing in groups the size of basketballs attached to the ground by a flexible stalk so that when you step on top of them they TILT OVER, throwing you totally off balance. Now that is a challenge.

Much easier is the Mesic tundra. Its nickname is Rock garden and as you probably guessed for a good reason since it is mostly bare ground and rocks. Though in the summertime it is almost the prettiest form of tundra when covered in more than 100 species of blooming wildflowers.

Also very pretty is the Shrub Tundra which is characterized by lots of low to the ground bushes, such as willows, cranberries and blueberries which turn bright red, orange and yellow in the fall.

The high Arctic on the other hand is without much stuff as we enter the polar dessert. The harsh climate and short growing season eliminates all but the hardiest plants: lichens. Growing on rocks and between stones, it is still very colorful though. Water is unavailable here during most of the year. It is a cold dessert that receives very little precipitation - some places only 3 to 4 inches (7-10 cm) a year which is less than what falls places in Sahara! And remember there is "no water" in the ground - only frozen solid permafrost.

Because of the permafrost, houses in the high Arctic can not be built directly on top of the ground. If they were placed on the ground, the heat from the house through the floor would melt the permafrost and the house would start to tilt or sink into the earth!

Instead the houses are built on "pillars" sunk into the frozen ground. For the same reason not even the plumbing or water pipes can be put into the ground and you see elevated pipelines running to all the houses.

Permafrost is good for something though. It is a great big deep freezer. If you need to store your meat, you "just" dig a hole. And you can find some pretty cool Ice Age mammals buried in here such as extinct horses and bison. Not long ago scientists even found a whole woolly mammoth buried in Siberia.