There’s nothing better than a walk in the countryside for lifting our spirits. Connecting with nature can help our mental health. For many people, it feels great to take a walk through a forest, but as we admire the trees around us, it’s worth knowing these trees are doing more than just being nice things to look at.

We have already noticed that trees play an important role in taking care of our world—they produce oxygen and clean the air we breathe by taking in about a quarter of all human-caused carbon dioxide emissions（二氧化碳排放）.

But there’s more to these trees than we might think. Researchers have discovered that they are actually very smart.

It’s thought that trees use a fungal network（真菌网络）to talk and share resources right under our feet. Under the ground are tree roots, bacteria（细菌）and super fine threads of fungi（菌丝）. And research has shown that they are all mixed together. They can help each other by sharing “food”, and they can even tell them some coming dangers. Scientists say it’s like the trees are talking to one another.

Ecologist（生态学家）Suzanne Simard has called this network the Wood Wide Web. She discovered that parent trees use this network to help their children. She also found that trees are smart enough to change their behaviour to live in a changing environment.

So it seems trees really are the stars of our natural world, and with around three trillion of them on our planet, it’s time to show them some respect if we want them to grow better.

Do dragons exist today? Although often mistaken for a mythical（神话的）creature, we actually live among several different types of “dragons.” For example, you may have seen dragonfly flying over a summer garden or read about a Komodo dragon lizard. The ocean has its share of dragons, too.

The blue dragon is a marine（海洋的）snail without a shell. It is commonly known as a blue sea slug（海参）. This particular species of marine snail can swallow a bubble of air（which it holds in its stomach）that enables it to float upside down on the surface of the ocean. The underside of the slug is blue, and it back is a gray color. This helps to conceal it from birds flying overhead and from fish swimming below.

Blue dragons feed on poisonous jellyfish and other similar species. When food is in short supply, they will eat each other. They collect toxins（毒素）from the jellyfish and store it in many finger-like structures. This ability to store poison gives them a much stronger sting（刺）than the jellyfish itself. They use this poison as a defense against enemies. The sting can also be felt by people.

These creatures are rarely visible for study and observation except for when they come close to land during times of onshore winds. They have been seen in Hawaii and in tropical（热带）waters around the world. Beware（当心）of the blue dragon’s sting!

Walk or drive to work? Which way is lower in carbon (碳)? To be friendly to the environment, you may choose to walk. Have you ever tried to live a low-carbon life through your diet (日常饮食)?

A new study from the University of Oxford has looked into the health and environmental influences of 15 foods common in western diets. Among these, plant based (基于植物的) foods included fruits, vegetables, nuts and potatoes. It also studied animal-based foods, including red meat, chicken, milk products, eggs and fish.

According to the study’s lead researcher, Michael Clark, “Choosing better and greener diets is one of the main ways people can improve their health and protect the environment.” That is to say, plant-based diets are much healthier for us and kinder to the environment.

To get this result, researchers compared the influence of eating another portion (一份) of each food with the increased risk of a few illnesses. They also found out the environmental harm for each animal-based food and each plant-based food.

By using this method, the study found that red meats were the most unfriendly foods to the environment. Keeping farm animals produces a large number of methane (甲烷) that keeps 30 times more heat than CO2. As well as making the earth warmer, eating too much red meat is known to increase the risk of a few illnesses, such as heart trouble.

Plant-based diets can give us the same health benefits in a much greener way. According to the study, without eating or using meat and milk products, global farmland use could be cut down by more than 75% and still feed the world.

Speaking to the Guardian (英国卫报), Tim Benton of Chatham House (英国皇家国际事务研究所) said, “If we can give people reasonable official (官方的) advice of what a healthy and green diet is, the world and its people would be in a much better place.”