影响美国北方森林的五个人为因素
文章来源:未知 文章作者:enread 发布时间:2014-04-19 07:13 字体: [ ]  进入论坛
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In the most densely1 forested and most densely populated quadrant(象限) of the United States, forests reflect two centuries of human needs, values and practices. Disturbances2 associated with those needs, such as logging and clearing forests for agriculture and development, have set the stage for management issues of considerable concern today, a U.S. Forest Service study reports. The report -- Five anthropogenic factors that will radically3 alter forest conditions and management needs in the Northern United States -- was published recently by the journal Forest Science and is part of the Northern Forest Futures4 Project, an effort led by the Forest Service's Northern Research Station to forecast forest conditions over the next 50 years in the 20-state region extending from Maine to Minnesota and from Missouri to Maryland. The study is available at: http://www.nrs.fs.fed.us/pubs/45716
 
"In our research, we found five short- and long-term factors that will be highly influential5 regardless of the nature and magnitude of the effects of climate change," said lead author Stephen Shifley, a research forester with the Northern Research Station. "Addressing these issues today will make northern forests more resilient to the effects of climate change and to any other natural or anthropogenic disturbances in the long term."
 
The five factors identified the study are:
 
Northern forests lack age-class diversity and will uniformly grow old without management interventions6 or natural disturbances. Nearly 60 percent of northern forest land is clustered in age classes spanning 40 to 80 years; young forests (age 20 years or less) are only 8 percent of all forests in the region; and forests older than 100 years are 5 percent of forests.
 
The area of forest land in the North will decrease as a consequence of expanding urban areas. Cities in the 20-state region are expected to gain another 27 million people in the next 50 years and grow by about 5 million hectares.
 
Invasive species will alter forest density7, diversity, and function. The U.S. North has the dubious8(可疑的) distinction of having the greatest number of invasive insects and plants per county due to nearly three centuries of active commerce, diverse tree species that provide suitable habitats, and the means for invasive species to spread.
 
Management intensity9 for timber is low in Northern forests and likely to remain so. A low propensity10(倾向,习性) or low capacity for forest management reduces options for addressing perceived problems such as low forest diversity, invasive species, and other insects or disease problems.
 
Management for non-timber objectives will gain relevance11 but will be challenging to implement12. An unintended consequence of reduced timber harvesting may be reduced capacity to subsidize other restoration activities -- either through revenue from timber sales or through manipulation of vegetation and woody fuels during logging.
 
Actions that researchers and land managers can take to address these issues include: Develop quantifiable state and regional goals for forest diversity. Understand the spatial13 and structural14 impacts of urban expansion on forests. Develop symbiotic15 relationships among forest owners, forest managers, forest industry and the general public to support contemporary conservation goals. Work to understand the many dimensions of forest change. 
 
"The northern quadrant of the United States includes 172 million acres of forest land and 124 million people," said Michael T. Rains, Director of the Northern Research Station and the Forest Products Laboratory. "In the next 50 years, the link between forests and economic and human health will grow. The Northern Forest Futures Project is helping16 identify the individual and collective steps needed to ensure healthy and resilient futures for trees and people alike."


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1 densely rutzrg     
ad.密集地;浓厚地
参考例句:
  • A grove of trees shadowed the house densely. 树丛把这幢房子遮蔽得很密实。
  • We passed through miles of densely wooded country. 我们穿过好几英里茂密的林地。
2 disturbances a0726bd74d4516cd6fbe05e362bc74af     
n.骚乱( disturbance的名词复数 );打扰;困扰;障碍
参考例句:
  • The government has set up a commission of inquiry into the disturbances at the prison. 政府成立了一个委员会来调查监狱骚乱事件。
  • Extra police were called in to quell the disturbances. 已调集了增援警力来平定骚乱。
3 radically ITQxu     
ad.根本地,本质地
参考例句:
  • I think we may have to rethink our policies fairly radically. 我认为我们可能要对我们的政策进行根本的反思。
  • The health service must be radically reformed. 公共医疗卫生服务必须进行彻底改革。
4 futures Isdz1Q     
n.期货,期货交易
参考例句:
  • He continued his operations in cotton futures.他继续进行棉花期货交易。
  • Cotton futures are selling at high prices.棉花期货交易的卖价是很高的。
5 influential l7oxK     
adj.有影响的,有权势的
参考例句:
  • He always tries to get in with the most influential people.他总是试图巴结最有影响的人物。
  • He is a very influential man in the government.他在政府中是个很有影响的人物。
6 interventions b4e9b73905db5b0213891229ce84fdd3     
n.介入,干涉,干预( intervention的名词复数 )
参考例句:
  • Economic analysis of government interventions deserves detailed discussion. 政府对经济的干预应该给予充分的论述。 来自辞典例句
  • The judge's frequent interventions made a mockery of justice. 法官的屡屡干预是对正义的践踏。 来自互联网
7 density rOdzZ     
n.密集,密度,浓度
参考例句:
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
8 dubious Akqz1     
adj.怀疑的,无把握的;有问题的,靠不住的
参考例句:
  • What he said yesterday was dubious.他昨天说的话很含糊。
  • He uses some dubious shifts to get money.他用一些可疑的手段去赚钱。
9 intensity 45Ixd     
n.强烈,剧烈;强度;烈度
参考例句:
  • I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
  • The strike is growing in intensity.罢工日益加剧。
10 propensity mtIyk     
n.倾向;习性
参考例句:
  • He has a propensity for drinking too much alcohol.他有酗酒的倾向。
  • She hasn't reckoned on his propensity for violence.她不曾料到他有暴力倾向。
11 relevance gVAxg     
n.中肯,适当,关联,相关性
参考例句:
  • Politicians' private lives have no relevance to their public roles.政治家的私生活与他们的公众角色不相关。
  • Her ideas have lost all relevance to the modern world.她的想法与现代社会完全脱节。
12 implement WcdzG     
n.(pl.)工具,器具;vt.实行,实施,执行
参考例句:
  • Don't undertake a project unless you can implement it.不要承担一项计划,除非你能完成这项计划。
  • The best implement for digging a garden is a spade.在花园里挖土的最好工具是铁锹。
13 spatial gvcww     
adj.空间的,占据空间的
参考例句:
  • This part of brain judges the spatial relationship between objects.大脑的这部分判断物体间的空间关系。
  • They said that time is the feeling of spatial displacement.他们说时间是空间位移的感觉。
14 structural itXw5     
adj.构造的,组织的,建筑(用)的
参考例句:
  • The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
  • The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。
15 symbiotic FrbwR     
adj.共栖的,共生的
参考例句:
  • Racing has always had a symbiotic relationship with betting.赛马总是与赌博相挂钩。
  • Engineering completely new symbiotic relationship is obviously not an imminent possibility.筹划完全新的共生关系显然是可能性不大。
16 helping 2rGzDc     
n.食物的一份&adj.帮助人的,辅助的
参考例句:
  • The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
  • By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。
TAG标签: nature forests effects
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