樹(shù)木是具有木質(zhì)樹(shù)干及樹(shù)枝的植物茸歧，可存活多年荒给，人們一般將喬木稱作為樹(shù)丈挟。樹(shù)的分枝距離地面較高，可形成樹(shù)冠志电。樹(shù)木在減少土地侵蝕及氣候調(diào)節(jié)方面具備相當(dāng)重要的作用曙咽，樹(shù)葉可以從空氣中吸收二氧化碳，并將大量的碳儲(chǔ)存在自身組織內(nèi)挑辆，從而緩解“熱島效應(yīng)”例朱。
鐮刀菌 (Fusarium) 是一類世界性分布的真菌，它常常會(huì)侵染植物鱼蝉，引發(fā)植物的根腐洒嗤、莖腐、花腐和穗腐等多種病害蚀乔。鐮刀菌通常會(huì)侵染寄主植物維管束系統(tǒng)烁竭，破壞植物的輸導(dǎo)組織維管束，并在植物的生長(zhǎng)發(fā)育代謝過(guò)程中產(chǎn)生毒素危害植物吉挣，造成其萎蔫死亡，影響其產(chǎn)量和品質(zhì)婉弹。
本篇課程首發(fā)于2017年6月5日
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Trees Save Lives
Dead trees mean dead people, and scientists are finally starting to figure out why. It's only been in the past few years that anyone has been willing to go out on a limb and associate morbidity and mortality numbers with nature. Oh, sure, everyone agrees that trees pull particulate-matter pollution out of city air. Simply by dint of being shady, trees reduce the "urban heat island" effect that drives people to run their AC all the time, a contributor to climate change. And, yes, trees inhale carbon dioxide, another win for the climate.
A 2015 meta-analysis of the few studies that had tried to take up the issue showed that higher exposures to green space, even while considering things like poverty and education level, indeed resulted in a statistically significant reduction in death from cardiovascular disease.
The bad news is that a tree disease called Fusarium is on track to kill 26.8 million trees across Southern California in the next few years, almost 40 percent of the trees from Los Angeles to the Nevada border and south to Mexico. That's more than just an aesthetic tragedy. It means that thousands of human beings are going to die, too.
▍生詞好句
figure out: it means you have to think about it, and make an effort to solve it. Generally, we intend to figure out something. It does not happen by chance, as in find out.
find out: it means to discover information. Generally, we find out something by chance, in other words, we were not intentionally looking for the information. We happened to discover it.
go out on a limb: put yourself in a dangerous position / at risk because you are doing sth. risky or sth. that doesn't have the support of others. 處于危險(xiǎn)的境地睬魂；冒險(xiǎn)做某事
by dint of: sth. is done as a result of sth. 憑借......；靠......
meta-: meta-: a prefix added to a word, usually a noun that talks about or comments on its own subject or features; it's self-referential, refers to itself ("meta" is an adjective).
take up the issue:? if you take up an issue, a question or a problem, you act on it, or you discuss how you are going to act on it or deal with it.
indeed: adv. in fact / reality / truth 確實(shí)镀赌；實(shí)際上
on track (back on track): if someone / sth. is on track, they are acting / progressing / behaving in a way that is likely to result in success / a certain result
