Source: Earth PD http://bit.ly/1ESoBKp Rainforest CC http://bit.ly/1MG66eh Temperate CC http://bit.ly/1GMGAlH Taiga CC http://bit.ly/1FRlpk6 Deforestation, PD http://bit.ly/19ffTLd
Hi, I'm Jensen Morgan. We're going to talk about some great concepts in environmental science. Today's topic is Forests and Deforestation. So let's get started.
We're going to talk about three forest types, the causes of deforestation and its impacts. We're going to talk about three types of forests. Each differs largely due to the amounts of rainfall, sunlight, soil nutrients, biodiversity and ability to withstand disturbances.
First, taiga, which are forests located in colder areas and are usually in higher latitudes as you can see here. About half of the year they get very little rainfall and sunlight. They have low biodiversity and are mainly comprised of conifers. As a result of such factors, taiga forests grow slowly with their poor nutrient-dense soils and produce a low yield of biomass. In addition, if a taiga forest is cleared it will recover very slowly, and the soil might even blow away.
Next up, temperate forests. Temperate forests are those in mid-range latitudes and are located in regions with moderate sunlight, rainfall and temperature ranges. They tend to have a moderate amount of biodiversity and consist of a mixture of deciduous hardwoods and evergreen trees. Temperate forests usually have deep, fertile soils, are relatively resistant to disturbances and if cleared, they will often grow again.
Lastly, we have tropical rainforests in lower latitudes. They are generally highly biodiverse and are a mixture of deciduous hardwoods and evergreens. Tropical rainforests occur in locations with high levels of rainfall, temperature and sunlight. Rainforests tend to have shallow soils with little mineral content. If cleared, they rarely grow back.
Our key term for this tutorial is deforestation. Deforestation is the conversion of forested areas to non-forest land for human use of the land or resources from land. Causes of deforestation include-- human population growth, climate change, removal for agricultural use, general logging, harvesting for fuel, burning and grazing.
Deforestation does not just affect the local ecosystem and economy. It can also have impacts at the regional and global level. Such impacts include-- forests and trees specifically store large quantities of atmospheric greenhouse gas carbon dioxide, preventing it from contributing to global warming. As forests disappear or are burned, this capability is lost and global climate change is accelerated as the CO2 from that biomass re-enters the atmosphere all at once.
Another impact from deforestation is how it affects the water cycle. Trees are important to maintaining homeostasis of the water cycle, and forests affect regional climate. Without them things could be thrown out of balance.
Rainforests depend on heavy rainfall, yet heavy rainfall weather patterns also depend on rainforests existence. In addition, the destruction of forests have led to local and regional croplands being abandoned, because lower rainfall means less humidity and more extreme summer temperatures. Deforestation also increases soil erosion, increases exposure to direct sunlight and results in areas being unable to sustain much life at all.
Finally, a large portion of the world's biodiversity lives in tropical rainforests. As they are deforested, massive amounts of species are going extinct from habitat loss resulting in a significant decline in global biodiversity.
Efforts to sustain forests and protect them from deforestation have been-- planting trees to start new forests, establishing nature preserves and green zones that cannot be affected by human development, regulating logging practices to prevent unsustainable use and educational programs focused on forestry management.
Now let's have a recap. We talked about three types, certain causes of deforestation and its impacts, as well as efforts to address it. Don't forget our key term-- deforestation-- the conversion of forested areas to non-forest land for human use of the land or resources from that land.
Well, that's all for this tutorial. I look forward to next time. Bye.