Science Diary: Mims – Tree Rings

music; ambience: sanding wood

“People hate these trees, but I love them, because their rings are so nice. And the advantage of people not liking them is that I get to cut them.”

Count the tree rings in the trunk of a tree, and you’ll discover the tree’s age. It’s a well-known bit of science. But tree rings can be found in branches, too, and they shed light on the conditions in which that tree grew. Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside.

“The trunk of a tree has a lot less data than the branches, and the tree ring specialists just haven’t discovered that yet. They need to add to their collections the branch rings, as well as the tree rings.”

Forrest Mims is a citizen scientist in Texas who studies hackberries and other trees. And by examining their rings, he’s able to gather data about the sunlight conditions in a corresponding year. Tree branches see more sunlight than the trunk, and so branch rings can yield more information.

“This branch is not much bigger than an inch across. So it’s very small. (sound of sanding wood) And then I can take my magnifier and look at it and count the rings. This branch began in 1994, and it’s only an inch across, so it’s got lots of data.”

Forrest Mims has been collecting atmospheric data since 1990. He believes there is a relationship between the color of one year’s tree ring and sunlight exposure during that timeframe. Tree ring color is influenced by tannins, astringent compounds found in plants.

“There appears to be an interesting relationship between tannin deposited in some tree rings and sunlight changes. Some of the rings are much darker than others in certain areas, and that shows the shading of the branch based on my sunlight hypothesis.”

We’ll hear more about Forrest Mims’ research in future programs.

Pulse of the Planet’s Science Diaries are made possible by the National Science Foundation.

Science Diary: Mims - Tree Rings

Counting tree rings is a great way to determine that tree's age. But what can variations in tree ring colors tell us about sunlight conditions?
Air Date:04/21/2008
Scientist:
Transcript:

music; ambience: sanding wood

"People hate these trees, but I love them, because their rings are so nice. And the advantage of people not liking them is that I get to cut them."

Count the tree rings in the trunk of a tree, and you'll discover the tree's age. It's a well-known bit of science. But tree rings can be found in branches, too, and they shed light on the conditions in which that tree grew. Welcome to Pulse of the Planet's Science Diaries, a glimpse of the world of science from the inside.

"The trunk of a tree has a lot less data than the branches, and the tree ring specialists just haven't discovered that yet. They need to add to their collections the branch rings, as well as the tree rings."

Forrest Mims is a citizen scientist in Texas who studies hackberries and other trees. And by examining their rings, he's able to gather data about the sunlight conditions in a corresponding year. Tree branches see more sunlight than the trunk, and so branch rings can yield more information.

"This branch is not much bigger than an inch across. So it's very small. (sound of sanding wood) And then I can take my magnifier and look at it and count the rings. This branch began in 1994, and it's only an inch across, so it's got lots of data."

Forrest Mims has been collecting atmospheric data since 1990. He believes there is a relationship between the color of one year's tree ring and sunlight exposure during that timeframe. Tree ring color is influenced by tannins, astringent compounds found in plants.

"There appears to be an interesting relationship between tannin deposited in some tree rings and sunlight changes. Some of the rings are much darker than others in certain areas, and that shows the shading of the branch based on my sunlight hypothesis."

We'll hear more about Forrest Mims' research in future programs.

Pulse of the Planet's Science Diaries are made possible by the National Science Foundation.