跟读练习: Why certain naturally occurring wildfires are necessary - Jim Schulz - 通过YouTube学习英语口语
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There was a time before our ancestors smashed flint and steel together, when they felt the cold lack of fire in their lives.
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There was a time before our ancestors smashed flint and steel together, when they felt the cold lack of fire in their lives.
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But anthropologists theorize that early hominids relied on lightning to cause forest fires, from which they could collect coals and burning sticks.
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Fire gave them the ability to cook food and clear land, and became central in many rituals and traditions.
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So instead of seeing forest fires as an exclusively bad thing, ancient humans may have learned to appreciate them.
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Yet, it wasn't just humans who benefitted from these natural phenomena.
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Even as they destroy trees, fires also help the forest themselves, however counterintuitive that seems.
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In fact, several forest species, such as select conifers, need fire to survive.
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But how can fire possibly create life in addition to destroying it?
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The answer lies in the way that certain forests grow.
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In the conifer-rich forests of western North America, lodgepole pines constantly seek the Sun.
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Their seeds prefer to grow on open sunny ground, which pits saplings against each other as each tries to get more light by growing straighter and faster than its neighbors.
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Over time, generations of slender, lofty lodgepoles form an umbrella-like canopy that shades the forest floor below.
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But as the trees' pine cones mature to release their twirling seeds, this signals a problem for the lodgepoles' future.
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Very few of these seeds will germintate in the cool, sunless shade created by their towering parents.
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These trees have adapted to this problem by growing two types of cones.
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There are the regular annual cones that release seeds spontaneously, and another type called serotinous cones, which need an environmental trigger to free their seeds.
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Serotinous cones are produced in thousands, and are like waterproofed time capsules sealed with resinous pitch.
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Many are able to stay undamaged on the tree for decades.
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Cones that fall to the ground can be viable for several years, as well.
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But when temperatures get high enough, the cones pop open.
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Let's see that in action.
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Once it's gotten started, a coniferous forest fire typically spreads something like this.
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Flames ravage the thick understory provided by species like douglas fir, a shade-tolerant tree that's able to thrive under the canopy of lodgepole pines.
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The fire uses these smaller trees as a step ladder to reach the higher canopy of old lodgepole pines.
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That ignites a tremendous crown fire reaching temperatures of up to 2,400 degrees Fahrenheit.
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That's well more than the 115-140 degrees that signal the moment when serotinous seeds can be freed.
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At those temperatures, the cones burst open, releasing millions of seeds, which are carried by the hot air to form new forests.
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After the fire, carbon-rich soils and an open sunlit landscape help lodgepole seeds germinate quickly and sprout in abundance.
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From the death of the old forest comes the birth of the new.
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Fires are also important for the wider ecosystem as a whole.
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Without wildfires to rejuvenate trees, key forest species would disappear, and so would the many creatures that depend on them.
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And if a fire-dependent forest goes too long without burning, that raises the risk of a catastrophic blaze, which could destroy a forest completely, not to mention people's homes and lives.
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That's why forest rangers sometimes intentionally start controlled burns to reduce fuels in order to keep the more dangerous wildfires at bay.
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They may be frightening and destructive forces of nature, but wildfires are also vital to the existence of healthy boreal forest ecosystems.
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By coming to terms with that, we can protect ourselves from their more damaging effects while enabling the forests, like the legendary phoenix, to rise reborn from their own ashes.
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关于本节课
在这一课中，学习者将聚焦于提高英语发音和口语技巧，特别是通过视频学习来理解复杂的环境主题，如自然野火的必要性。通过观看Jim Schulz的讲解，学习者将掌握如何在不同语境下使用相关词汇，同时练习他们的shadow speak能力，从而提高英语口语表达。理解和使用视频中的信息将帮助学习者在实际沟通中更自信。
关键词汇与短语
- 野火 (wildfire) - 指自然发生的火灾，往往对生态有重要影响。
- 生态系统 (ecosystem) - 指相互作用的生物群体及其环境，野火在生态中起着重要作用。
- 树木适应 (tree adaptation) - 表示树木为生存而发展出的生理和生态特征，尤其是在火灾的影响下。
- 常绿树 (conifer) - 在许多森林中占主导地位的树种，它们的生存与火灾密切相关。
- 控制燃烧 (controlled burn) - 森林管理人员有时为了避免更大危害而进行的有计划的火灾。
- 种子的释放 (seed release) - 指在高温条件下，树木的种子被释放，以促进新生代的生长。
实践提示
为提高英语口语水平，尤其是在观看如Jim Schulz这样的视频时，建议采用shadow speech的方法。注意讲者的语速和语调，尽量在他讲话时进行跟读。在本视频中，讲者的节奏较为平稳，但其中也包含一些技术性和学术性的表达，初学者可以选择暂停和回放，以便更好地消化内容。
另外，使用带有字幕的版本可以进一步帮助理解，尤其是陌生的词汇和短语。通过看YouTube学英语，学习者可以熟悉如何在不同语境下运用这些词汇，进行有效的英语口语练习。在模仿讲者的同时，注意语音的清晰度和表达的情感，可以有效地提高英语发音。
什么是跟读法？
跟读法 (Shadowing) 是一种有科学依据的语言学习技巧，最初开发用于专业口译员的培训，并由多语言者Alexander Arguelles博士普及。这个方法简单而强大：您在听英语母语原声的同时立即大声重复——就像是一个延迟1-2秒紧跟说话者的影子。与被动听力或语法练习不同，跟读法强迫您的大脑和口腔肌肉同时处理并模仿真实的讲话模式。研究表明它能显着提高发音准确性，语调，节奏，连读，听力理解和口语流利度——使其成为雅思口语备考和真实英语交流最有效的方法之一。