TREE rings are Mother Nature's history books.

轮是大自的史书。

Like all history books, though, they can be unreliable.

而就和所有的史书一样，轮也并不怎么靠谱。

This light blue section is data from tree ring observations.

浅蓝色的部分是树木轮观测的数据。

Essentially divided into two halves, the light and the dark.

轮基本上分为两部分，光明和黑暗。

Fry then decided to count the tree's rings to learn its age.

后弗莱决定数树的轮来了解它的龄。

There they form regular white bands amid the sediments, much like age rings in trees.

它们在沉积中形成规则的白色带，很像树木的轮。

But it was unclear whether new rings appeared yearly or every six months.

但尚不清楚新轮是每出现一圈，还是每六个出现一圈。

We can't read the rings to know how old these aspens are.

我们无法通过读取轮来得知这些颤杨的龄。

Thin rings show years when there wasn't.

而这些细的轮则显示水分不充足。

Scientists at NASA recently studied tree rings in the region.

美国宇航局的学家们最近对这个地区的树木轮进行了研究。

Scientists can then read these records, similar to reading the rings on a tree.

后，学家就可以读取这些记录，就像读取树上的轮一样。

First, there are the yearly growth rings in the trees.

首先，树上有轮。

For example, narrow tree rings suggest dry conditions.

例如，狭窄的轮意味着干燥的条件。

Around the Haversian canals, there are concentric lamellae, which look a bit like tree rings.

在哈弗斯管周围有许多同心薄片，看起来有点像树的轮。

When we look at words this way, it is much like exploring tree rings.

当我们以这种方式看待单词时，就很像探索树木的轮。

Tree rings can show age and give information about the environment over time.

树木轮可以显示树龄，并提供随时间变化的环境信息。

We see it in the tree rings of the ancient redwoods.

我们可以在古老的红杉树的轮上看到火。

We know this because shark vertebrae show rings of their growth, just like tree rings.

我们知道这一点，是根据鲨鱼的脊椎骨显示出它们生长的环，就像树木的轮一样。

Wow, it'd be a job to count the rings on those trees!

哇，数那种树的轮都算得上是个差事了。

Tree rings are made of tissue called xylem.

构成轮的组织被称为木质部。