字幕列表 影片播放 列印英文字幕 It's winter where I live… ...and a lot of trees have lost their leaves! The leaves turned brown, or yellow, red, and even purple and then they fell off the trees. But some trees are still green! In fact, it seems like these trees don't ever turn brown -- they stay green all of the time! That's why we have a special name for these kinds of trees … evergreens! Depending on where you live, you might have some well-known evergreens in your neighborhood. These include pine, fir, and spruce. These trees are easiest to recognize by their leaves. And yes! Those thin, pointy, things on these trees are actually their leaves! We usually call them needles, because that's what these leaves look like! Some needles are long and soft, and others are short and sharp. When needles get old, they do fall from the tree, but usually just a few at a time, and the tree grows new ones very quickly. So the trees stay green all year round. Now, even though needles don't look like the leaves on other trees, they have the same job — to catch sunlight. The tree then uses the sunlight to make energy. And energy helps the tree grow! Of course, evergreen trees also need lots of water, just like most other plants. But in many places, rain doesn't fall very often during the winter. And trees can't use the water that's frozen into ice and snow. So a tree needs to hold on to the water inside it, for as long as it can. And the thin needles you find on evergreens help keep the water inside those trees, because they're covered with a thin layer of stuff that's kind of like wax. This waxy layer helps trap water inside the needles, so the tree doesn't dry out. Another thing you might know about pine, spruce, and fir trees is that they make these neat little things called cones. Cones can be big...or very small...and even colorful! A cone's job is to make the seeds that will someday grow into new trees! In fact, if you look deep inside a pine cone, you'll see the seeds inside. These seeds are a tasty snack for animals like squirrels, chipmunks, and birds. And evergreens that have cones also have a special name. This group of plants is called conifers. The name has the word “cone” right in it! And pine, spruce, and fir aren't the only conifers out there! Some of the biggest conifers in the world are known as giant sequoia trees. Giant Sequoias live in the Western United States, and they live up to their name -- because they can grow to be enormous. Many of these trees are wide enough to drive a car through. One of these trees is almost eighty four meters tall, and about eleven meters wide. It even has a name: General Sherman. And scientists say that, while it's not the tallest tree in the world, it's the biggest, heaviest tree overall. Trees like General Sherman grow to be so big, because they live for a really long time. Some sequoias can live for over three thousand years, making them some of the oldest living things on the planet. Now, you might see lots of pictures or drawings of conifers in cold and snowy places. But they don't only grow where it's cold! Some of the most common plants in hot, dry places are conifers, too -- like the cedar and the cypress. And many evergreens in these places have a different kind of leaf. Instead of being thin and pointy like a needle, cedar leaves are thin and flat. This kind of leaf is called a scale, and they do seem a little like the thin and flat scales of a fish. Just like needles, scales help the evergreen save water, so it can stay green even when it's very dry. Okay, let's talk about one more evergreen. This one is known for its broad, flat leaves and brightly colored berries. Right you are Squeaks! It's holly! Holly is an evergreen with leaves that are often dark green and prickly around the edges. And just like needles, holly leaves have a shiny coating on them that helps them save water when it's dry. Holly is not a conifer, so it doesn't make cones. Instead, the seeds of holly plants are found inside the berries. Although the most famous kinds of holly have red berries, some holly plants make berries that are white, orange, or even black. So even when it's wintertime, many kinds of trees keep their green! Here's hoping you get outside and have a chance to see some of these excellent evergreens this winter! Thanks for joining us on SciShow Kids! Do you have a question about something in the world around you? If so, ask a grownup to help you leave a comment down below, or send us an e-mail to firstname.lastname@example.org! Thanks! See ya next time.