21 Giant Sequoias-Mid

Giant Sequoias FOCUS Question Why do giant sequoias grow so large and live for so long?

巨红杉为什么长得这么大，寿命这么长?

The Largest Living Things Giant sequoias (suh-KWOY-uhs) are big trees. Very big! In fact, they are some of the largest living things on Earth. Some trees are taller. Some are wider. But a giant sequoia takes up more space than most other living things.

巨型红杉(suh-KWOY-uhs)是一种大树。 非常大的!事实上，它们是地球上最大的生物之一。 有些树更高。有些更宽。 但巨型红杉比大多数其他生物占据更多的空间。

How Do They Get So Big? Giant sequoias keep growing as long as they live. And they can live for more than 3,000 years! Trees add a ring around their trunk every year. One sequoia has more than 3,500 rings. That means it is more than 3,500 years old!

它们是怎么变得这么大的?巨红杉只要活着就会一直生长。 它们可以活3000多年!树木每年都会在树干上长出一圈。 一棵红杉有3500多个环。 这意味着它有3500多年的历史了!

How Do They Live So Long? Few things can kill a giant sequoia. Chemicals in the bark keep the tree from getting sick. The chemicals also keep insects away. The bark is thick at the bottom. Thick bark helps the tree live through fires.

它们是怎么活这么久的?很少有东西能杀死一棵巨大的红杉。 树皮中的化学物质可以防止树木生病。 这些化学物质还能驱走昆虫。 树皮底部很厚。 厚厚的树皮有助于树在火灾中生存。

Giant sequoias only grow in parts of California. The soil is just right for the trees. There is not too much or too little rain It is not too hot or too cold. But giant sequoias need one more thing.

巨红杉只生长在加州的部分地区。 这里的土壤适合树木生长。 没有太多或太少的雨水。它不是太热或太冷。 但巨型红杉还需要一件事。

Fire and the Forest Giant sequoias need fire. They have small, hard pinecones. The cones hold the seeds. The cones only open when they get hot in a fire. Then the seeds can fall out. Wowser! A giant sequoia can release 400,000 seeds in one year!

火与森林巨杉需要火。 它们有又小又硬的松果。 球果里装着种子。球果只有在火中变热时才会打开。 然后种子就会掉出来。 老古板!一棵巨大的红杉一年可以释放40万颗种子!