What’s In A Tree? A Lot!

Jan 28, 2011 By Vibeka
Vibeka Sisodiya's picture

Did climate change bring about the fall of the Roman Empire?

Yes, according to a latest scientific study of 9,000 wooden objects from the last 2,500 years. Researchers studied what are known as tree-growth rings on these objects, and came to the interesting conclusion.

They observed that extremely dry weather conditions in the 3rd Century coincided with a period of serious crisis in the western Roman empire such as barbarian invasions, political turmoil and population movement. They also found that increased humidity was a perfect breeding ground for rodents during the bubonic plague.

Record Rings

So, what are tree-growth rings, and what do they have to do with climate change, and the Roman Empire?

Tree-growth rings are circles that form every year inside the trunk of a tree and can be seen when the trunk is cut horizontally across. They look like concentric circles, or a circle within a circle, and reflect the climate conditions under which a tree grew from year to year.

During good seasons, when water and nutrients are abundant, trees form broad and spaced-out rings, while in dry seasons, the rings are much tighter. Researchers used this pattern of tree rings in ancient wooden objects from Germany, France, Italy and Austria to calculate weather changes in Central Europe, going back 2,500 years. Then they matched those patterns with historic facts known about the region.

They discovered that periods of warm and wet weather actually lined up with periods of prosperity in the region. On the other hand, droughts and other harsh weather conditions coincided with political and economic disturbance and invasions, ultimately resulting in the downfall of the Roman Empire. The scientists concluded that there is a strong link between climate change and most major events in human history, like the rise and fall of empires.

The researchers were also able to tell how many trees had been cut down at a certain time. A smaller number of trees were cut down in times of political and economic unrest, while more trees were cut down during prosperous times when there was more construction of buildings.

Looks like every tree tells a story, the story of mankind.