Essay代写范文：加拿大森林案例研究

本文是留学生作业网为大家整理的一篇优质Essay代写范文，题目为：Case study on Canadian Forests。本文主要讲述了2008年4月23日《自然》杂志发表的一份研究报告。呀就发现，甲虫将加拿大森林从碳盆地转变为碳的发源地。气候变化使山松甲虫从可控的害虫变成了不灭的灾难。灾难发生在不列颠哥伦比亚省，该省位于北美西北部。全省面积为9,500万公顷，其中森林为6000万公顷（CHEN等，2003）。它拥有世界上最大的温带森林。通常，山松甲虫的目标是老树和弱树，它们甚至可以在一定程度上促进幼树的生长。

Overview

On April 23rd 2008,Nature published a research report.Researchers found that beetles transform Canadian forest from carbon basin into carbon birthplace.Climate change turned the mountain pine beetle from a controllable pest to unremitting disaster.The disaster occurred in British Columbia,which is located in the northwestern part of North America.The province has an area of 95 million hectares,and 60 million hectares are forests(CHEN et al,2003).It has the largest temperate forest in the world.Normally,the mountain pine beetle’s targets are old and weak trees and they can even promote the growing of young trees in some extent.However,in recent years,the number of beetles erupted in large-scale outbreaks because of the climate change.In 2008,the pine forest of British Columbia faced the largest one ever recorded.Kurz,a co-author of this research report predicted that the outbreak occurred in 2008 would emit as much carbon dioxide as Canada’s whole transportation does in last five years(Kurz,2010).It would impose a huge impact on the atmosphere.

This research report is related to several environment issues I had learned in class.Firstly,one of the main reasons results to the disaster is the climate change.The increased carbon emissions elevated the temperature,which changed the living circumstance of the mountain pine beetle.This creature got the chance to propagate and finally resulted in a disaster.Secondly,it reminded me the“Spruce Budworm”case.People took these two creatures as harmful insects.It is undeniable that if their propagation is under control,they can bring certain benefits for the whole ecosystem.Last but not least,this research report also emphasized the role the forest played in the ecosystem.Every country in the world should attach great importance to protect the carbon dioxide sink.

Challenges Faced by Canadian Government

As most people know,forests and oceans are the most valuable carbon sinks.British Columbia's temperate coniferous forest can be seen as the most important carbon sinks of the world,however,the pine forest infringed by mountain pine beetle had become a carbon source(Brown,2008).The outbreak had imposed negative effects to both the local ecosystem and the forestry industry.Canadian government announced that the outbreak had destroyed nearly half of the province's forest resources that can be used for commercial purposes,and the mountain pine beetle had infested almost 13.5 million hectares of lodgepole pines(Mellec et al,2009).The outbreak also affected the inland areas of British Columbia.What was worse,mild winter played a negative role in this aspect,since it accelerated the beetles’propagation speed(Edburg,et al,2011).The beetles could kill trees and turned the needles of infected trees into red.Actually,the forest had helped Canada maintain the carbon dioxide emissions at a relatively moderate growth rate for numerous years.However,the mountain pine beetle destroyed the balance and transformed the local forest from a carbon basin into a carbon source.Kurz also developed a model to simulate the effects of the mountain pine beetle in the British Columbia area between 2000 and 2020.As a carbon sink,the forest may soak in 0.5 million tons of carbon every year.However,once widely infected by the mountain pine beetle,the falling forests turned into the carbon source.He explained that of all the carbon dioxide emitted by fossil fuel burning,nearly 50%of are absorbed by the land or ocean,while the other 50%are gathered in the atmosphere(Kurz,2010).However,for a long time,these damaged forests could not continue absorb carbon dioxide,and their decay would discharge even more carbon into the ecosystem.It is estimated that the amount of carbon dioxide released by the forest in 2008 is almost equivalent to that emitted by the forest fires in Canada(Kurz,2010).Scientists also notice that this issue isn’t limited to British Columbia.The mountain pine beetle also affected other parts of the world,such as North America(Edburg et al,2011).

Kurz hoped that his findings could draw the society’s attention.Everyone hoped that the forest could regrow and absorb the carbon dioxide emitted by those dead trees.To prevent they release more carbon dioxide when decaying,Kurz suggested clearing out the dead trees(Kurz,2010).At the same time,these woods can be used as raw materials to produce biofuels,which may not compete with other clean fuels,such as trash and crop waste.Mellec recommended that the Canadian government should strengthen the afforestation or reforestation,and plant millions of new trees to compensate for the disappearance of the forest(Mellec et al,2009).Government policy regulated that 35 million hectares can never be deforested.The annual deforestation area accounted for only 0.33%.Since 1993,the mountain pine beetle outbreak continued to spread.The disaster is more serious in the central inland areas,and it is confirmed that 4.2 million hectares are infringed by this pest(Anonymous,2009).The mountain pine beetle cannot survive below minus 20 degree(Kurz,2010).However,due to the global warming,it is difficult to be that cold in the forest(Brown,2008).Hence,currently,there is no good method to deal with the disaster and the outbreak may continue to spread in the next few years.

Case-Course Connections

In general,the case I choose is related to forest pest analysis and management.Also,to better illustrate the negative effect caused by the mountain pine beetle,the research report also mentioned forest fires.Through comparing the amount of carbon dioxide released by the infected trees in 2008 with that emitted by the forest fire in Canada,readers got to know the seriousness of the issue.Hence,I would like to compare and contrast the case with the ones I read in class from three perspectives.

First of all,to better understand the forest insects,our professor asked us to read a case about spruce budworm.Even though spruce budworm was the main pest we analyzed in class,the paper also pointed out that mountain pine beetle is also a well-know forest pest that have resulted in significant losses in value of Canadian forests.The case illustrated the economic and forest ecosystem impacts generated by these pests.However,among all the negative impacts,the case we analyzed in class ignored that these infected trees may release carbon dioxide and eventually affect the ecosystem.Secondly,for the negative effects caused by forest fires,the case we learned in class broadly summarized that fires may damage the nearby citizens and ruin large numbers of timber resources,resulting in unexpected losses.However,what may cover in the costly losses,the case failed to mention.Hence,from my perspective,I may ignore the issue of carbon dioxide emissions.After reading the research paper,I can better understand the forest fire’s harmful effects.Last but not least,both the ones I read in class and the research paper I illustrated above mentioned that climate change could be seen as a disturbance that may weaken native forests and leave them generally more susceptible to pest attacks.

Reference

Anonymous.temperature Gauge.24 Vol.San Francisco:Earth Island Institute,2009.Web.

Brown,Susan.Beetle Tree Kill Releases More Carbon than Fires.,2008.Web.

CHEN,JING M.,et al."Spatial Distribution of Carbon Sources and Sinks in Canada's Forests."Tellus B 55.2(2003):622-41.Web.

Edburg,Steven L.,et al."Simulating Coupled Carbon and Nitrogen Dynamics Following Mountain Pine Beetle Outbreaks in the Western United States."Journal of Geophysical Research.Biogeosciences 116.4(2011)Web.

Kurz,Werner Alexander,and Northern Forestry Centre(Canada).The Carbon Budget of the Canadian Forest Sector.NOR-X-326;NOR-X-326.;Vol.Edmonton:Forestry Canada,Northern Forestry Centre,2010.Web.

Mellec,Anne le,et al."From Carbon Sinks to Carbon Sources–a Concept for Studying Climate Change-Induced Insect Outbreaks and Forest Ecosystem Feedbacks."IOP Conference Series:Earth and Environmental Science 6.38(2009):382026.Web.