VOA新闻杂志2024--给世界最大的树“做体检”

World’s Largest Tree Passes Health Check

In the American state of California, researchers recently climbed the world’s largest tree to check on its health. The tree is a giant sequoia¹ named General Sherman.

The climbers had good news to report when they returned to the ground.

"The General Sherman tree is doing fine right now," said Anthony Ambrose. He is executive² director of the Ancient Forest Society and led the team of researchers.

They were looking for damage to the 2,200-year-old tree --- and possible evidence of a growing threat to giant sequoias: bark beetles⁴. The insects are native to California.

No one had ever climbed the famous 85-meter sequoia tree before the researchers. But, tourists from around the world come to Sequoia National Park to see the General Sherman and others of its kind.

Giant sequoias are the largest trees on Earth. They have survived for thousands of years in California's western Sierra Nevada mountains, the only place where the tree is native.

Hot and dry weather and wildfires have threatened the trees in recent years. In 2020 and 2021, record-setting wildfires killed as much as 20 percent of the world's 75,000 mature sequoias, park officials say.

Ben Blom is director of stewardship⁵ and restoration at Save the Redwoods League. "The most significant threat to giant sequoias is climate-driven wildfires," he said. "But we certainly don't want to be caught by surprise by a new threat, which is why we're studying these beetles now," he added.

Researchers are growing more worried about bark beetles. The insects were not a serious threat in the past. They lived alongside⁶ sequoias for thousands of years. However, park officials say recent bark beetle³ attacks have killed about 40 sequoia trees, mostly within the national parks.

Ambrose said researchers believe dry weather and fires make the trees weaker and less able to survive attacks.

The insects dig holes in the highest parts of the tree. Then they move down the trunk, destroying it as they go. The beetles are extremely small in size but large in number. Working together they can kill a tree within six months.

That is why park officials permitted Ambrose and his team to climb General Sherman. The experts looked for the extremely small holes that the bark beetle makes. They reported no sign of the insects.

But it is not possible to climb every sequoia tree and look at its highest part. So, scientists are considering other ways to check the trees, such as the use of drones and satellite imagery. The technology might be able to record and measure beetle activity over large areas of forest.

The health check of General Sherman was organized by the Giant Sequoia Lands Coalition⁷, a group of government agencies, Native tribes⁸ and environmental groups. They hope to establish a health check program for the tall trees.

If they discover beetle infestations¹⁰, officials say, they could try to fight the attacks with water or chemical treatments. They can also remove individual branches of affected¹¹ trees.

Bark beetles have severely¹² damaged some forests in the Western United States in recent years. But they did not threaten giant sequoias until recently.

Clay Jordan is superintendent¹³ for Sequoia and Kings Canyon¹⁴ National Parks. He said the sequoias “have really withstood insect attacks for a lot of years. So why now? Why are we seeing this change?" He added that researchers need to learn more to make sure they can protect the trees.

The sequoia General Sherman is named for William Tecumseh Sherman. The famous military leader helped lead Union forces to victory in the American Civil War.

Words in This Story

tourist -n. a person who visits a place for for pleasure or interest, especially when on vacation.

mature -adj. fully¹⁵ grown or developed

stewardship -n. the responsibility of taking care of property

restoration -n. the return of something to its original and undamaged condition

significant -adj. important

trunk -n. the central column of a tree supporting its branches

drone -n. a small flying vehicle without a pilot and controlled remotely

infestation⁹ -n. the presence of large numbers of insects or other unwanted animals causing damage

1 sequoia   

n.红杉

参考例句：

• The sequoia national forest is at the southern end of the sierra nevada range.红杉国家公园位于内华达山脉南端尽头处。
• The photo shows the enormous general Sherman tree in California's sequoia national park.照片显示的是加利福尼亚州红杉国家公园内巨大的谢尔曼将军树。

2 executive   

adj.执行的，行政的；n.执行者，行政官，经理

参考例句：

• A good executive usually gets on well with people.一个好的高级管理人员通常与人们相处得很好。
• He is a man of great executive ability.他是个具有极高管理能力的人。

3 beetle   

n.甲虫，近视眼的人

参考例句：

• A firefly is a type of beetle.萤火虫是一种甲虫。
• He saw a shiny green beetle on a leaf.我看见树叶上有一只闪闪发光的绿色甲虫。

4 beetles   

n.甲虫( beetle的名词复数 )

参考例句：

• Beetles bury pellets of dung and lay their eggs within them. 甲壳虫把粪粒埋起来，然后在里面产卵。 来自《简明英汉词典》
• This kind of beetles have hard shell. 这类甲虫有坚硬的外壳。 来自《现代汉英综合大词典》

5 stewardship   

n. n. 管理工作；管事人的职位及职责

参考例句：

• The organization certainly prospered under his stewardship. 不可否认，这个组织在他的管理下兴旺了起来。
• Last, but certainly not least, are the issues of stewardship and ethics. 最后，但当然不是微不足道的，是工作和道德规范的问题。

6 alongside   

adv.在旁边；prep.和...在一起，在...旁边

参考例句：

• There was a butcher's shop alongside the theatre.剧院旁边有一家肉店。
• Alongside of him stood his uncle.他的身旁站着他叔叔。

7 coalition   

n.结合体，同盟，结合，联合

参考例句：

• The several parties formed a coalition.这几个政党组成了政治联盟。
• Coalition forces take great care to avoid civilian casualties.联盟军队竭尽全力避免造成平民伤亡。

8 tribes   

n.部落( tribe的名词复数 )；（动、植物的）族；（一）帮；大群

参考例句：

• tribes living in remote areas of the Amazonian rainforest 居住在亚马孙河雨林偏远地区的部落
• In Africa the snake is still sacred with many tribes. 非洲许多部落仍认为蛇是不可冒犯的。 来自《简明英汉词典》

9 infestation   

n.侵扰，蔓延

参考例句：

• The premises were treated for cockroach infestation.因蟑螂成灾，这些房屋集中进行了灭蟑活动。
• Parts of California are suffering from an infestation of oriental fruit flies.加利福尼亚的部分地区正遭受东方果蝇的大肆侵袭。

10 infestations   

n.（害虫、盗贼等）群袭，出没，横行( infestation的名词复数 )

参考例句：

• The arrival of warm weather raises the specter of disease and increased rat infestations caused by rotting garbage. 天气转暖使人们担心垃圾腐烂会引起疾病传播和鼠群猖獗。 来自《简明英汉词典》
• Piperazine citrate is the drug of choice in the treatment of Ascaris infestations. 枸橼酸哌嗪治疗蛔虫感染是最好的药物。 来自辞典例句

11 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。

12 severely   

adv.严格地；严厉地；非常恶劣地

参考例句：

• He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
• He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。

13 superintendent   

n.监督人，主管，总监；(英国)警务长

参考例句：

• He was soon promoted to the post of superintendent of Foreign Trade.他很快就被擢升为对外贸易总监。
• He decided to call the superintendent of the building.他决定给楼房管理员打电话。

14 canyon   

n.峡谷，溪谷

参考例句：

• The Grand Canyon in the USA is 1900 metres deep.美国的大峡谷1900米深。
• The canyon is famous for producing echoes.这个峡谷以回声而闻名。

15 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。