tropical rainforests are under threat with more and more of them being cleared to make（使） room for rubber plantations. Because rubber is a key component of car tires. If we don't change our mobility（ 可动性）, the demand for rubber will strongly increase. Could the rise of electric vehicles help turn the tide（潮）? Tires are getting larger and larger. What are tire manufacturers doing to help stop deforestation for the sake（缘故） of plantations?

  And are there viable（能养活的） alternatives to natural rubber from the tropics（热带）? Thailand（泰国）'s tropical climate is perfect for growing a raw material coveted the world over. It's 5 a.m. and farmer Satit Pramraksa is already at work harvesting（收割） natural rubber. Seven years after being planted, a rubber tree has an annual yield（屈服） of 1.5 kilograms. People have been making use of this tree sap（树液） for over 3,000 years, beginning with indigenous（本土的） peoples like the Maya（玛雅人） in Central America.

  At the end of the 19th century, the British began planting the trees in their Asian colonies. Scraping rubber makes me happy. It's a tradition passed down from one generation to the next. My grandparents harvested rubber. I love my job. I can feed my family with the money I earn.

  The milky（乳白色的） white sap（树液） is also known as latex. The resulting solid material has a number of unbeatable properties, such as tear resistance（阻力）. Rubber trees thrive（兴旺） in tropical climates. They require lots of water and warm, humid conditions. Over 90 percent of the annual global rubber harvest, 15 million tonnes, is cultivated（培养） in Southeast Asia. The top producers are Thailand, Indonesia（印度尼西亚（东南亚岛国））, Vietnam and India.

  In 1993 and 2016, some 4 million hectares（公顷） of rainforest were destroyed to make（使） way for rubber plantations. That's an area the size of Switzerland. 85 percent of production comes from small holders, most on fewer than two hectares. Even ancient rainforests have been destroyed to make room for rubber plantations. Gone forever is the unique flora（[罗神]花神） and fauna（动物群）, as well as the tree's carbon-storing potential. Without rainforests, the Earth's atmosphere will heat up even more rapidly.

  But some people are taking action to prevent further deforestation. We accompany Mai Loyan in southern Thailand. She's fighting for the preservation（保存） of these precious ecosystems. It's the gift that generations have passed to us. We enjoy it, we maintenance（维护） it, and we put four out of it, and then after that we have to give（做） back. And we would like the next generations to do the same, and this tree is giving them the same benefit that is the benefit to a generation before and forward after.

  Mai Loyan is a conservationist and entrepreneur. She worked（使工作） in the rubber industry for over 20 years and witnessed both the terrible working（工作） conditions for farmers and the destruction of rainforests. Together with a friend, she founded Agriac in 2019, a cooperative（合作的） uniting some 4,000 rubber farmers. They're committed to a common goal. No more rainforests being sacrificed（牺牲） to cultivate（培养） rubber. Mai Loyan has dropped by to visit Satit Pomeraksa, one of the farmers who Agriac helps by negotiating better deals for them.

  The small holders are working toward transforming existing monocultures in an eco-friendly and responsible way, without pesticides（杀虫剂） or artificial fertilizers. Our approach is to have the most biodiversity（生物多样性） in the monoculture plantations. For example, the plant like this is not only fixing the carbons inside, but it's also being a source of food as well. Besides rubber, the farmers harvest mushrooms for their own use. Satit Pomeraksa also keeps bees, then sells the honey at markets. The Agriac farmers are utilizing（利用） the land's full potential, supporting greater biodiversity than in a monoculture, which centers（居中） solely（单独地） on yield（屈服）.

  The global demand for rubber remains high due in large part to the material's versatility（多功能性）. Rubber is integrated into our everyday lives. It's found in our backyards and hoses（软管） and gardening gloves. It's used as flooring in hospitals and sports facilities. And it's also found in everything from condoms to sponges and rain boots. All told, some 50,000 products contain rubber.

  But most of the global harvest, a whopping 70%, goes toward making tires. There are now some 1.4 billion cars on the world's roads. Demand is increasing, and with it, the need for more tires. The Netherlands（荷兰（西欧国家））. A research team at Amsterdam（阿姆斯特丹（荷兰首都））'s Freya Universität is examining land use in the tropics（热带）. Peter Fairbaug is a professor of environmental geography and a leading expert on how the global demand for cars impacts rainforests.

  We drive more kilometers, and we don't see a transformation（变化） to less mobility（ 可动性）. If we look at countries like China（瓷器）, India and other upcoming（即将来临的） economies, we see that their mobility is still far below the European level, and people also buying bigger cars with bigger tires needing more rubber. So if we don't change our mobility, the demand for rubber will strongly increase, leading to more and more deforestation. In Germany, new car registrations are on the rise after a slump during the COVID pandemic. Accordingly（因此）, the demand for tires is increasing too. The German Automobile Club, or ADAC, tests car tires at its technical center in Landsberg.

  The team here considers all manner of environmental issues, because when it comes to tires, rubber is far from the only cause for concern. Rubber constitutes（组成） about 40% of the tire. There's natural rubber from trees and rainforests, and synthetic（合成的） rubber derived from fossil（化石的） fuels like crude（天然的） oil. Another 30% is fillers, including the harmful powder carbon black. 13% is steel for reinforcing the tire. Then there are toxic（有毒的） plasticizers.

  As the tire gets wear and tear, it releases environmentally harmful microplastics. Despite all that, billions of euros worth of tires are sold annually. Worldwide, an average of 1 in 4 people buy a tire every year. Stacked one on top of the other, the resulting tower would reach all the way to the moon. Many car drivers aren't well versed on what tires are made of, but manufacturers can't plead（辩护） ignorance（无知）. Are they serious about protecting the climate?

  Tires are getting larger and larger. This may stem（起源） from stricter requirements in terms of load index and speed rating, but it's also because car manufacturers are purposely（故意地） offering the option of larger tires, which customers can buy at a considerable premium（额外费用）. The safety gains are negligible（可以忽略的）. For mid-sized cars like the Volkswagen Golf, car makers actually sell tires that are far too big. 15 or 16-inch tires are perfectly suitable, compromising（妥协） neither safety nor drivability, the VW Golf is also sold with 17, 18 and 19-inch tires. For every additional inch, the weight of the tire increases by 400 to 500 grams, and that means more rubber from the tropics.

  Consumers who value protecting the rainforest should opt（选择） for smaller tires, which need less rubber. But they're not the only party involved. If we look at SUVs and other large vehicles, 22 or 23-inch tires are not uncommon these days, and there's no technical justification（理由） for that tire size. Even these larger vehicles that have an unladen weight of 2 or 2.5 tons drive just fine with smaller tires. Looking at ads from major German automakers, small e-cars with small tires are nowhere to be found. Whether Audi, BMW or Mercedes, the top manufacturers all want to sell the biggest and most expensive vehicles with maximum power.