VOA慢速英语2021--气候变化影响了秋天的颜色

Climate Change Affecting Autumn’s Colors

Leaf peeping is a beloved yearly activity in many parts of the world, including parts of the United States. The northeastern and mid-Atlantic states are especially popular for beautiful fall colors.

Leaf peeping is when people travel to see the beautiful colors of fall foliage¹. Foliage is another name for leaves, and fall is another word for autumn.

However, recent fall leaf peeping seasons have been changed by weather conditions.

A lack of rain causes leaves to turn brown and die before they can reach the best color. Heat waves cause leaves to fall before autumn even arrives. And extreme weather events, like hurricanes, take the leaves off trees altogether.

Climate change also creates longer-term threats that could harm leaf peeping. The spread of diseases and insects is also tied to warming temperatures. These are all affecting autumns famous fall colors.

Scientists say that this is likely to continue as the planet warms. Some of these scientists recently spoke² with The Associated Press.

Typically, by the end of September, some leaves turn colors throughout the U.S. However this year, trees in many areas are still green.

For example, in northern Maine, the best time for leaf colors usually happens in late September. But on September 29, Maine forest officials had reported less than 70 percent color change of the leaves and only moderate leaf drop.

Across the country in Denver, Colorado, high temperatures have left "dead, dry edges of leaves" early in the season, said Michael Sundberg. He is a tree expert in the area. Sundberg told the AP that instead of slow change, trees are affected³ by abnormal weather.

"They change all of a sudden, or they drop leaves early," Sundberg said. "Its been a few years since we've had a really good leaf year ..."

The reason climate change can be bad for fall leaves has to do with plant biology. When fall arrives, days lengthen⁴ and temperatures drop. The chlorophyll in a leaf breaks down. And that causes the leaf to lose its green color. The green leaf turns into a beautiful yellow, red or orange autumn leaf.

Getting those beautiful colors requires a balance, said Paul Schaberg. He is a research plant physiologist⁵ with the U.S. Forest Service based in Burlington, Vermont. Warm fall temperatures, he said, can cause leaves to remain green longer.

Worse than that, Schaberg said, very dry summers can stress trees and cause their leaves to miss the fall colors completely. A 2003 study in the journal Tree Physiology⁶ that Schaberg co-wrote stated that "environmental stress" can speed up leaf decay.

He said in severe droughts trees experience difficulty.

That is happening already.

This summer's heatwave in the Pacific Northwest of the U.S. led to a condition called "foliage scorch⁷."

Foliage scorch is when leaves brown too early, explained Chris Still. He is a professor at the Forest Ecosystems⁸ & Society department at Oregon State University. In some parts of Oregon, leaves lost their color early and then quickly fell to the ground. This led to a shorter and less beautiful leaf peeping season.

"That's a really big example of color change just due to heatwave shock," Still said.

The economic impact of poor leaf peeping seasons could also be significant. Officials throughout New England have said fall tourism brings billions of dollars into those states every year.

Conservationists say that is one good reason to work to preserve forests and reduce the use of fossil fuels.

Words in This Story

hurricane – n. a tropical cyclone⁹ with winds of 74 miles (119 kilometers) per hour or greater usually accompanied by rain, thunder, and lightning

chlorophyll – n. the green substance in plants that makes it possible for them to make food from carbon dioxide and water

physiologist – n. a person specializing in the biological study of the functions and processes of living organisms and their parts

stress – n. a force that tends to change the shape of an object

decay – v. to undergo decomposition¹⁰

drought – n. a period of dryness especially when prolonged

scorch – v. to burn a surface of so as to change its color and texture¹¹

significant – adj. large enough to be noticed or have an effect

conservationist – n. someone who works to protect animals, plants, and natural resources or to prevent the loss or waste of natural resources : a person who is involved in conservation

1 foliage   

n.叶子，树叶，簇叶

参考例句：

• The path was completely covered by the dense foliage.小路被树叶厚厚地盖了一层。
• Dark foliage clothes the hills.浓密的树叶覆盖着群山。

2 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

3 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

4 lengthen   

vt.使伸长，延长

参考例句：

• He asked the tailor to lengthen his coat.他请裁缝把他的外衣放长些。
• The teacher told her to lengthen her paper out.老师让她把论文加长。

5 physiologist   

n.生理学家

参考例句：

• Russian physiologist who observed conditioned salivary responses in dogs (1849-1936). （1849-1936）苏联生理学家，在狗身上观察到唾液条件反射，曾获1904年诺贝尔生理学-医学奖。
• The physiologist recently studied indicated that evening exercises beneficially. 生理学家新近研究表明，傍晚锻炼最为有益。

6 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

7 scorch   

v.烧焦，烤焦；高速疾驶；n.烧焦处，焦痕

参考例句：

• I could not wash away the mark of the scorch.我洗不掉这焦痕。
• This material will scorch easily if it is too near the fire.这种材料如果太靠近炉火很容易烤焦。

8 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

9 cyclone   

n.旋风，龙卷风

参考例句：

• An exceptionally violent cyclone hit the town last night.昨晚异常猛烈的旋风吹袭了那个小镇。
• The cyclone brought misery to thousands of people.旋风给成千上万的人带来苦难。

10 decomposition   

n. 分解, 腐烂, 崩溃

参考例句：

• It is said that the magnetite was formed by a chemical process called thermal decomposition. 据说这枚陨星是在热分解的化学过程中形成的。
• The dehydration process leads to fairly extensive decomposition of the product. 脱水过程会导致产物相当程度的分解。

11 texture   

n.(织物)质地；(材料)构造；结构；肌理

参考例句：

• We could feel the smooth texture of silk.我们能感觉出丝绸的光滑质地。
• Her skin has a fine texture.她的皮肤细腻。