The largest ecozone in Canada, the Boreal Shield covers 1.8 million square kilometres and is roughly 3,800 km long. It stretches from Saskatchewan to the very tip of Newfoundland and Labrador. Although it houses only about 10% of Canada’s population, it is one of the most important economic areas in Canada due to the large lumber and mining industries.

Map of Ecozone

Landform Region30-000-island-aerial-photo.jpg

The Canadian Shield, which makes up most of the Boreal Shield, was once an ancient Precambrian mountain range formed by the buckling and cracking of plates. Some of the oldest rocks in the world can be found here, dating back to as early as 3.96 billion years ago. The huge mountains were slowly eroded over the duration of many ice ages by glaciers and other forms of weathering. The landscape is dotted with a drainage system of lakes, rivers and streams. Bodies of water make up about 20% of the Shield.

Rock Types and Minerals
The Boreal Shield is made up of two rock types: igneous and metamorphic. The bedrock is exposed due to the thin soil, as well as ancient glacial movements, and is composed mainly of granite. The mining industry is large, and minerals such as lead, gold, nickel, copper zinc, and even uranium are abundant, although iron ore makes up 97.5% of the mining industry output. Recently, there have also been discoveries of diamond deposits in the area. Unfortunately, due to the sheer age of the rocks and the area, bacteria that produced fossil fuels (such as coal and gas) didn’t exist and so there are almost no fossil fuels to be mined in the Shield. Mining is the main source of income for more than 80 percent of communities in the Shield.

The Boreal Shield has a very large diversity of trees and vegetation. The southern part meets the Mixedwood Plains and the vegetation is deciduous, while the northern part is coniferous forest. Most of the shield is covered with white and black spruce and balsam fir,
which are the most adaptable types of trees, especially to the harsh conditions on the Shield. Rivers and creeks are lined with willows, birch and alder trees. Wetlands are common and can be home to many species of plants and animals; they are considered to be the most diverse habitat in Canada. Fires are common in this area, due to the dry and hot summers. The heavy forests, both in the north and south of the ecozone are cut for the very large logging industry in the area.

The thin soils caused by the harsh climate and exposed rocks are quite unsuitable for farming, due to the low hummus and organic material content. The soil is mostly sandy and in some areas silty, except in north-eastern Ontario and south-western Quebec, where ancient glacial lakes formed deposits of clay. The soil is usually leached because the bedrock is impervious, and doesnt let water pass. Unfortunately, many studies show that the effect of acid rain from nearby factories greatly damages this ecozone, especially in Southern Quebec and Ontario.

The Boreal Shield experiences long cold winters, and short but very warm summers, which makes some areas (primarily Northern Ontario an ideal summer vacation spot). There are multiple air masses at work in the Boreal Shield area. An orographic mP air mass moves in from the west, but because it hits the Rocky Mountains first, the moisture leaves the air mass, making it dry and warm. A convectional cA air mass blows in from the north, and cols the area down quite a bit. The mP air mass doesn’t always reach the eastern part of the Sheid, and so the eastern part is mostly affected by the cA air mass.The temperature ranges from around -15 C in the winter to around 17 C in the summer. Precipitation is from 400mm a year to about 1000 mm a year, and the growing season is 130-190 days.


Trivia and Fun Facts
The Boreal Shield is one of the most popular summertime vacation areas in Canada
Alex Trebek was born in Sudbury on the Boreal Shield
The Boreal Shield is the largest ecozone in Canada
The Boreal Shield touches Alberta and the Atlantic at the same time
By 2010, about 800,000 square kilometers in eastern Canada will recieve harmful levels of acid rain
The Boreal Shield is also known as 'Shield Country' locally
Sudbury is the largest mining city in Canada
The rivers and lakes on the Boreal Shield account for 22% of Canada's freshwater

Test Questions
1. Why would an mP air mass lose its moisture as it moves towards the Boreal Shield?
2. True or False? The Hudson Plains are located north of the Boreal Shield
3. Why does the Boreal Shield experience long winters and short summers?
4. True or False? The Boreal Shield stretches all the way to the Atlantic

5. Why are spruce and fir the most populous types of trees on the Shield?

1. Clark, Bruce. Making Connections Canada’s Geography. Toronto: Pearson Education, 2006
2. http://canadiangeographic.ca/atlas/themes.aspx?id=shield&lang=En
3. http://canadianbiodiversity.mcgill.ca/english/ecozones/borealshield/borealshield.htm
4. http://wiki.answers.com/Q/Where_can_you_find_more_information_about_the_Boreal_Shield
5. http://en.wikipedia.org/wiki/Boreal_Shield_Ecozone_(CEC)