54 Ancient Trees

What is the oldest living thing on earth? If you said “the sequoia tree,” you are very right. If you said “the redwood tree,” you would be right too. But let’s take it from the botanists. The redwood is in the Sequoia family. So sequoia is more correct. The tree is named to honor a Cherokee Indian who invented a system of writing.

There are two kinds of sequoia trees. First is the redwood. Second is the giant sequoia. The redwoods are the tallest. The giant sequoia is the biggest.

Redwoods grow to more than 300 feet. The trunks of many are more than 10 feet across. Giant sequoias are not so tall as redwoods. But their trunks are much larger. The world’s largest tree overall is the General Sherman tree. It is about 275 feet tall. The trunk’s diameter is 36.5 feet. But its seeds are only ¼ inch long. About 50,000 seeds weigh one pound. So big from so small!

The redwood and the giant sequoia live long. They have no known enemies. None has died from old age. Disease and insects have no effect. Though lightning has hit most tops, the trees just keep on growing. The General Sherman is about 3,500 years old. It dates back to 1500 B.C. The tree started to grow at the time of the pyramids of Egypt.

Numerous fires have swept through forests where redwoods and sequoias grow. Why weren’t these trees burned like the rest? This is probably the answer. Their bark is from 6 to 12 inches thick. The fires have charred the bark over and over again. But the flames cannot reach deep enough to burn the live wood. What a coat of armor! Nature thought of everything.

你知道地球上最古老的生物是什么吗？如果你说是“巨杉树”，那你非常正确。如果你说是“红杉树”，你也没错。但让我们听听植物学家的说法。红杉属于巨杉科，所以巨杉这个名称更准确。这种树是为了纪念一位发明了文字系统的切罗基印第安人而命名的。

有两种巨杉树，第一种是红杉，第二种是巨杉（giant sequoia）。红杉是最高的，巨杉是最大的。

红杉可以长到300多英尺高，许多红杉的树干直径超过10英尺。巨杉没有红杉那么高，但它们的树干要大得多。世界上整体最大的树是谢尔曼将军树，它大约有275英尺高，树干直径36.5英尺。但它的种子只有四分之一英寸长，大约5万颗种子才重一磅。如此小的种子却能长成这么大的树！

红杉和巨杉寿命很长，它们没有已知的天敌，没有一棵是因年老而死亡的。疾病和昆虫对它们没有影响。尽管大多数树顶都被闪电击中过，但这些树还是继续生长。谢尔曼将军树大约有3500年的树龄，可以追溯到公元前1500年，它开始生长的时间正值埃及金字塔建造的时期。

许多火灾席卷了红杉和巨杉生长的森林。为什么这些树没有像其他树木一样被烧毁呢？答案可能是这样的：它们的树皮有6到12英寸厚，火灾一次又一次地烧焦了树皮，但火焰无法深入到足以烧毁活木材的程度。多么坚固的一层盔甲啊！大自然考虑得真周到。