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Presentation about Threats to Boreal Forest
Good afternoon, everyone. Welcome to my presentation, my topic today is about threats to boreal forest ecosystem. At beginning, let’s talk about the climate, globe distribution and species in this system. For climate, look at the picture here, the climate in taiga is very cold normally (taiga is a nickname of boreal forest), its annual temperature is between 5 degrees Celsius and negative 5 degrees Celsius. According to average annual rainfall, about 20 cm of precipitation each year to over 200 cm(data is from http://w3.marietta.edu/~biol/biomes/boreal.htm). Something worthy to talk is much rainfall type in taiga is snow because of its cold temperature. “The winters in boreal forest system are extremely cold, and long, Summers are cool and short relatively.”(http://w3.marietta.edu/~biol/biomes/boreal.htm). Hence the growing seasons in taiga are really short, they’re usually less three months.
Globe distribution: in this image, Russia has a wild range of boreal forest in the southern area. And a little of them distribute in northeastern China, almost in Hei Longjiang province. Look at the America, south Canada has many taiga forests. And some in Alaska of USA.
Okay, now we go to the next part---organism. Most of plants in taiga can against low temperature with their special niche. For example, pine trees, they grow some narrow and long leaves like needles. So, why are such leaves? This kind of leaf shape can help pine trees reduce water runoff and resist cold, because of the small surface area. That is the reason. And the picture on the right side shows how pine cones survive in winter. They are able to make their body open in a warm condition or closed in a low temperature. When their body close, their surface area will decrease, almost same to pine leaves. Then we will watch some other plants in this system---pine trees we have talked, moss and lichen(both grow in everywhere in the forest).
With regard to animals, I put some typical animals here. Bobcat as we all know, they can jump into snow and hear tiny sound around. Due to this skill, they’re able to catch mouse that hide in the snows. Grizzly bear! Do you still remember this, they rub their backs on the trees in spring. Snowshoe hare, they keep the brown hair normally, when autumn come, they begin to shed their brown coat and replace with white fur that will help them hide them in the winter snows. And the last one is moose, they looks like deer but actually it’s not. Look at this picture, grizzly bear is on the top level---tertiary consumer. Bobcat is on second level called secondary consumer. About snowshoe hare and moose, they are both primary consumers which eat plants.
Threats: I will introduce three main threats to taiga ecosystem.
First, logging. In Canada, millions of ares of trees will be harvested yearly. Because timbers are a kind of important building material, and also they can made paper that people almost use everyday.
Next, oil and gas exploitation. Oil and gas are both fossil fuel that can provide energy for human. And most parts of energy come from fossil fuel. Hence they are important for our daily life. However, while people exploit fossil fuel, it makes some hazards to forest as well.
Last, desertification(also called deforestation). Normally, there are some lakes and rivers next to a forest, they provide water for the forest system. Sometimes, people build dams on the rivers to product electricity. It will cause some areas of forest dry-up.
Why we should protect boreal forest ecosystem (what functions does this ecosystem have):
Producing oxygen(if we don’t have oxygen, we will die)
Keeping earth in a certain temperature range(forest is rich for water, and water have high specific heat capacity---need absorb/release more heat to increase or decrease temperature relatively)
Solution to logging:
1. Cutting trees dispersively
2. Limiting cutting number per hectares
3. Planting new trees after cutting to keep ecosystem sustainable
Solution to oil and gas exploitation:
Developing renewable energy
Restoring original environment after exploiting
Solution to deforestation:
Don't build dams next to boreal forest
Planting more trees
Reducing exploitation of undergound water
http://water.usgs.gov/edu/heat-capacity.htmlal rainfall, about 20 cm of precipitation each year to over 200 cm(data is from http://w3.marietta.edu/~biol/biomes/boreal.htm). Something worthy to talk is much rainfall type in taiga is snow because of its cold temperature. “The winters in boreal forest system are extremely cold, and long, Summers are cool and short relatively.”(http://w3.marietta.edu/~biol/biomes/boreal.htm). Hence the growing seasons in taiga are really short, they’re usually less three months.
Solution to oil and gas exp