1 . High-resolution (高分辨率) satellite imagery has been used to map every single tree in Africa, showing a technique that could help improve the monitoring of deforestation (森林砍伐) across the world. Florian Reiner at the University of Copenhagen, Denmark, and his colleagues used images from sate lies to map canopy (树冠) across the entire African continent.

Modern sate lies usually catch tree canopies at a resolution of 30 meters — fine for measuring the size of forests, but less good at mapping individual trees. The satellite data Reiner and his colleagues used had a resolution of 3 meters, enabling the study to map all trees, including those not part of a forest.

The results suggest that 30 percent of all trees in Africa aren’t in a forest and instead are across farmland, savannah and urban areas. “Many countries in Africa lack thick forests, but have a lot of trees.” says Reiner. “These trees are extremely important to the local ecosystems, the people and the economy. By tracking every single tree, researchers can start to monitor how these trees are coping with climate change or whether they are sensitive to deforestation.” It could also improve the monitoring of reforestation efforts, which are growing in popularity as a way of removing carbon dioxide from the atmosphere.

“At a local level, being able to consistently monitor when and where trees are disappearing or reappearing can lead to more actionable insights,” says John Francis at the Alan Turing Institute in London.

“The study is a proof of concept rather than a map ready for immediate commercial use,” says Reiner. “It’s research work. It’s showing what could be done,” he says. But he is already working with colleagues to scale up the tracking approach to cover the entire global canopy: “We’re hoping that this will be seen as a way forward in monitoring tree resources.”

1. Why is high-resolution satellite imagery used to map every single tree?

A．To know the exact height of the tree.

B．To have a clear picture of the canopy.

C．To help monitor the deforestation.

D．To improve the satellite technology.

2. What is John Francis’ attitude towards the map?

A．Doubtful.

B．Disapproving.

C．Indifferent.

D．Favorable.

3. What do Reiner and his colleagues expect to do?

A．Protect the trees only in Africa.

B．Put the map into commercial use.

C．Track the entire global canopy.

D．Improve the imagery technology.

4. What is probably the best title?

A．Ways to Measure the Size of Forests in Africa

B．Coping with Climate Change by Tracking Every Single Tree

C．A Map from the Satellite Ready for Immediate Commercial Use

D．High-resolution Satellite Imagery Used in Monitoring Deforestation

2 . With so many different kinds of plants out there, telling them apart can seem like an impossible task. But you don’t have to have a degree in botany to start putting names to the plants you come across. Learning to recognize various species begins with studying the plants’ unique physical features carefully and recording what you see.

    1     If you spot a plant outdoors and don’t have the first clue as to what it is, start identifying it by scanning your surroundings. In particular, consider the overall climate, the conditions of the terrain, and any nearby water sources. A quick glance should be able to tell you what you’re looking at.

Study the plant’s features carefully. Whenever you come across a species you’ve never seen before, stop and take note. Look over each of the individual parts, like the stems (茎，梗), leaves, and flowers.

    2    

Use viewing aids to take a closer look. A magnifying glass will allow you to zoom in and analyze a plant’s features in more vivid detail. Similarly, you may require a pair of binoculars or a telescopic lens when you want to inspect a particular specimen (样本) from a distance.     3    

Write down the plant’s key features.     4     Be sure to make mention of attributes like size, shape, color, and texture, as well as any unique patterns or other distinguishing marks. In order to learn to identify plants on your own, you’ll need to hone (磨练) your use of descriptive language to be as precise as possible.

Ask an expert to take advantage of their firsthand experience. Show your notes and any photos you’ve taken to a botanist, gardening specialist, or respected outdoorsman and see if they can help you discover the identity of a certain plant.     5     People who have spent years studying plants can often pick them out by sight or description.

A．Observe the plant carefully at first.

B．Take your environment into consideration.

C．Record each characteristic in your own words.

D．Judge the age and shape of the plants you have found.

E．Without these tools, you’ll be stuck doing a lot of guesswork.

F．You’ll have an opportunity to absorb a little of what they know.

G．Most plants can be grouped and distinguished by these structures.

3 . Contrary to the long-held belief that plants in the natural world are always in competition, new research has found that in severe environments adult plants help smaller ones and grow well as a result.

The research, led by Dr Rocio, studied adult and seedling (幼苗)plants in the ecological desert in the south-east of Spain. Dr Rocio said, “If you're a seedling in a poor land — the top of a mountain or a sand hill, for example-and you’re lucky enough to end up underneath a big plant, your chances of survival are certainly better than if you landed somewhere on your own. What we have found, which was surprising, is an established large plant, called a ‘nurse’, protects a seedling; it also produces more flowers than the same plants of similar large size growing on their own.”

Other benefits of nurse-seedling partnerships include that more variety of plants growing together can have a positive effect on the environment. For example, vegetation areas with nurse plants with more flowers might be able to attract higher numbers of pollinators(传粉者)in an area, in turn supporting insect and soil life and even provide a greater range of different fruit types for birds and other animals.

“The biggest winner for this system of nursing a plant is biodiversity(生物多样性),” Dr Rocio said. “The more biodiverse an area, the greater number of species of plants, insect life, mammals and birds, and the better the chances of long-term healthy functioning of the environment and ecosystems. ” This system is win-win for adult and seedling plants in unfavorable environments.

The research is of value to those who manage and protect plants in tough environments. Most home gardeners and farmers plan to ensure their soil and conditions are the best they can be for plant growth, but the findings might be of value to those who garden in bare places.

1. What is a common understanding of plants?

A．They can help each other.	B．They can survive ill conditions.
C．They compete with each other.	D．They grow well on their own.

2. What will happen to seedling plants if they grow under adult plants?

A．They will produce more flowers.	B．They will die owing to competition.
C．They will make adult plants larger.	D．They will get support from adult plants.

3. What is the effect of the nurse-seedling partnership?

A．It leads to unfavorable environments.

B．It produces long-term healthy chances.

C．It attracts higher and larger pollinators.

D．It provides a more variety of plant types.

4. Who will benefit from the new research?

A．People studying organic farming.

B．People protecting plants on sand hills.

C．People wanting to change biodiversity.

D．People keeping more animals on the farm.