1 . Amid rolling farms and green pasture 150 miles northwest of Sao Paulo, Brazil, two tropical forests bloom as one. The first consists of a single species, row after row of non-native eucalyptus (桉树), planted in perfect lines like carrots. The other is haphazard, an assortment of dozens of varieties of native saplings.
There’s no denying it: This forest looks ridiculous. The gangly (修长的) eucalyptuses shoot like witch fingers high above patches of stubby fig (矮壮的无花果树) and evergreen trees. Yet these jumbled 2.5-acre stands of native trees, ringed by fast-growing exotics, are among many promising efforts to resurrect the planet’s forests.
The eucalyptuses, says Pedro Brancalion, the University of Sao Paulo agronomist who designed this experiment, get big so quickly they can be cut after five years and sold to make paper or fence posts. That covers nearly half or more of the cost of planting the slow-growing native trees, which then naturally reseed ground that has been laid bare by the harvest. And this process doesn’t hamper natural regeneration.
You needn’t look far these days to find organizations trying to save the world by growing trees. Too often, tree-planting groups are so focused on getting credit for each seedling planted that they ignore what matters most: What kind of woodland is created? At what cost? And most importantly: How long will it last? Using the numbers of trees planted as a magic “proxy for everything,” Brancalion says, you “spend more money and get lower levels of benefits.” You can literally miss the forest for the trees.
Tree planting seems like a simple, natural way to counter the overwhelming crises of climate change and biodiversity loss. Trees provide wildlife habitats and slurp carbon dioxide from the atmosphere. No wonder trees are hailed as the ideal weapon. Yet for every high-profile planting operation, devastating failures have occurred. In Turkey, Sri Lanka, and Mexico, mass plantings have resulted in millions of dead seedlings or have driven farmers to clear more intact forest elsewhere. Trees that have been planted in the wrong places have reduced water yields for farmers, destroyed highly diverse carbon-sucking grassland soils, and allowed for invasive vegetation to spread. Simply reforesting the planet isn’t going to do much if we don’t also start cutting down on our emissions from the burning of coal, oil, and natural gas. Tree planting also can’t replace old-growth forests. Saving them is even more important than growing new forests.
So, what should we do?
To Brancalion, the answer is obvious: Restore native forests, mostly in the tropics, where trees grow fast and land is cheap. While that may require planting, it may also call for the clearing out of invasive grasses, the rejuvenation (使有活力) of soils, and crop yield improvements so that farmers will need less land for agriculture and more can be allowed to revert back to forests.
The combining of eucalyptus harvests with native plantings is just one more reminder that successful restoration must provide value to local communities. In many cases, if we let nature do the heavy lifting, Brancalion says, “the forest can regrow quite effectively.”
1. What can we learn from the first three paragraphs?| A．The non-native eucalyptuses bring profits that can pay for planting native saplings. |
| B．The non-native eucalyptuses compete with native saplings for water, nutrients, and light. |
| C．The variety of trees being planted determines whether or not the restoration will succeed. |
| D．Planting fast-growing exotics together with local trees does harm to the natural environment. |
| A．emphasize the significance of protecting existing forests |
| B．explain why tree planting is regarded as the ideal solution |
| C．illustrate the serious problems planting campaigns can cause |
| D．indicate the most important point tree-planting groups ignore |
| A．clear more forest to improve crop yields for farmers |
| B．combine harvests of fast-growing exotics with native plantings |
| C．restore native forests in the tropics and clear out invasive grasses |
| D．take into consideration the benefits of reforestation to local communities |
| A．Plant trees—and time will tell. | B．Plant trees—but don’t overdo it. |
| C．Plant trees—and save the world. | D．Plant trees—but mind the variety. |
2 . Laughing together is an important way for people to connect and bond. And though the causes of laughter can vary widely across individuals and groups, the sound of a laugh is usually recognizable between people belonging to different cultures.
But what about animals? Do they “laugh”? And are the causes of animal and human laughter alike? In humans, people may laugh when they hear a joke, or when they see something that they think is funny, though it’s unknown if animals’ intelligence includes what humans would call a sense of humor.
However, many animals produce sounds during play that are unique to that pleasant social interaction. Researchers consider such vocalizations to be similar to human laughter. Recently, scientists investigated play vocalization to see how common it was among animals. The team identified 65 species that “laughed” while playing — most were mammals (哺乳动物), but a few bird species demonstrated playful laughter too. Reports of playful laughter were notably absent in studies describing fish, perhaps because there is some question as to whether or not play exists at all in that animal group. This new study could help scientists to analyze the origins of human laughter.
But how can we identify play? Unlike fighting, play is usually repetitive and happens independently of other social behaviors, said lead study author Sasha Winkler, a doctor of biological anthropology at the University of California. When it comes to identifying it, “you know it when you see it,” Winkler told Live Science. One sign is that primates — our closest relatives — have a “play face” that is similar to the expressions of humans who are playing.
When Winkler previously worked with rhesus macaques, she had noticed that the monkeys panted (喘气) quietly while playing. Many other primates are also known to vocalize during play, she said, so a hypothesis (laughter in humans is thought to have originated during play) supported by the play-related panting laughter of many primate species was put forward.
People now still laugh during play, but we also integrate laughter into language and non-play behaviors, using laughter in diverse ways to express a range of emotions that may be positive or negative. Human laughter notably differs from other animals’ laughter in another important way: its volume. People broadcast their laughter loudly, often as a way of establishing inclusion. By comparison, when most animals laugh, the sound is very quiet — just loud enough to be heard by the laugher’s partner.
“It’s really fascinating that so many animals have a similar function of vocalization during play,” Winkler told Live Science. “But we do have these unique parts of human laughter that are also an important area for future study."
1. What is the main purpose of the passage?| A．To explain causes of animal and human laughter. |
| B．To assess complexities regarding animal laughter. |
| C．To present findings on the existence of animal laughter. |
| D．To analyze differences between animal and human laughter. |
| A．Animal laughter is even noticeable in fish. |
| B．Animal laughter is hard to recognize during play. |
| C．People have learned to combine play with laughter. |
| D．People laugh loudly because they want to involve others. |
| A．Distinctive features of human laughter. |
| B．Different functions of animal laughter. |
| C．The origin and development of human laughter. |
| D．The relationship between animal laughter and intelligence. |
