TREE rings are Mother Nature's history books.

年轮是大自然书。

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

然而就和所有书一样，年轮也并不怎么靠谱。

This light blue section is data from tree ring observations.

浅蓝色部是树木年轮观测数据。

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

年轮基本上为两部，光明和黑暗。

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

然后弗莱决定数树年轮来了解它年龄。

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白色带，很像树木年轮。

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

但尚不清楚新年轮是每年出现一圈，还是每六个月出现一圈。

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

我们无法通过读取年轮来得知这些颤杨年龄。

Thin rings show years when there wasn't.

而这些细年轮则显不充足。

Scientists at NASA recently studied tree rings in the region.

美国宇航局科学家们最近对这个地区树木年轮进行了研究。

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

然后，科学家就可以读取这些记录，就像读取树上年轮一样。

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

首先，树上有年轮。

For example, narrow tree rings suggest dry conditions.

例如，狭窄年轮意味着干燥条件。

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，看起来有点像树年轮。

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，就很像探索树木年轮。

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

树木年轮可以显树龄，并提供随时间变化环境信息。

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

我们可以在古老红杉树年轮上看到火。

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

我们知道这一点，是根据鲨鱼脊椎骨显出它们生长环，就像树木年轮一样。

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

哇，数那种树年轮都算得上是个差事了。

Tree rings are made of tissue called xylem.

构成年轮组织被称为木质部。