Question

    Over their lifetimes, city trees will likely absorb less CO₂ from the air than forest trees. A new study finds that city trees grow faster and die younger than trees in forests. Studies have shown forests readily absorb CO₂. But there haven’t been much data on whether city trees grow, die and absorb CO₂ at the same rate that forest trees do. So Lucy Hutyra, an environmental scientist, and her colleagues at Boston University in Massachusetts decided to find it out.

To figure out how quickly trees were growing the researchers tracked their diameters (直径) of their trunks from 2005 to 2014. The team focused on red oaks and red maples growing on Boston streets. These grew four times faster than the same species did in a nearby forest. Faster -growing trees absorb more CO₂. Over the nine years the researchers have tracked these trees and found city trees absorbed four times as much carbon from the air as the forest trees did. The city trees also, however, were twice as likely to die.

City trees grow faster because they have less competition with their neighbors for light. In a forest, trees tend to grow close together, shading their neighbors. So few may get as much light as they want.

“Street trees also benefit from higher levels of nitrogen (氮气) in rainwater. Nitrogen is an element that helps plants grow. It’s also an ingredient (成分) of the. gas-burning cars’ exhausts. Some street trees also may have better access to water than trees in the country. That’s because the underground water pipes can leak,” says Hutyra.

Shaun Watmough, an environmental scientist, says it’s important to keep in mind that people plant city trees along city streets not just to absorb carbon. The trees also help clean the air, provide shade and make a city more beautiful even if it’s only for decades, not centuries.

1.What does the new research find?

A.City trees have larger economic value than forest trees.

B.Forest trees grow in a faster speed than city trees.

C.Forest trees are equal to city trees in number.

D.City trees have a shorter life than forest trees.

2.How did researchers know the growth rate of trees?

A.They exposed trees to strong sunshine.

B.They kept a record of the width of trees’ bodies.

C.They produced large amounts of car gases to trees.

D.They made trees compete for light against each other.

3.What can we infer about forest trees from the text?

A.They absorb more CO₂

B.They have stronger roots.

C.They have more competitors than city trees.

D.They live in a nitrogen-enriched environment.

4.What is Shaun Watmough’s attitude towards planting city trees?

A.Approving. B.Doubtful.

C.Uncertain. D.Pessimistic.

Answer

1.D

2.B

3.C

4.A

【解析】

本文是一篇说明文。文章主要介绍了一项新的研究发现：城市的树木比森林的树木生长得快，但是寿命要比森林的树木要短。

1.细节理解题。根据第一段中的A new study finds that city trees grow faster and die younger than trees in forests.(一项新的研究发现，城市树木比森林中的树木长得快，死得早)可知，城市的树木比生长在森林里的树木寿命短。故选D。

2.细节理解题。根据第二段中的To figure out how quickly trees were growing the researchers tracked their diameters (直径) of their trunks from 2005 to 2014. (为了弄清树木的生长速度，研究人员从2005年到2014年追踪了它们的树干直径)可知，研究人员记录了树干的直径（也就是宽度），以了解树木的生长速度。故选B。

3.推理判断题。根据第三段中的In a forest, trees tend to grow close together, shading their neighbors. So few may get as much light as they want.(在森林里，树木往往长得比较密集，树荫遮蔽了它们的邻居。所以很少有人能得到它们想要的光照)可推知，森林的树木比城市的树木竞争者要多。故选C。

4.推理判断题。 根据最后一段Shaun Watmough, an environmental scientist, says it’s important to keep in mind that people plant city trees along city streets not just to absorb carbon. The trees also help clean the air, provide shade and make a city more beautiful even if it’s only for decades, not centuries.可知，人们不会仅仅为了吸收二氧化碳而在城市街道上种植树木。树木还有助于清洁空气，提供树荫，使城市更美丽。由此判断出，Shaun Watmough对树木的态度是支持的。故选A。