Science Diaries: Tree Rings Millennia

Ambiance: Dawn chorus

JM: If you want to know what the weather was like, say, 50 or 100 years ago, you can search the archives of the National Weather Service. But what if you want to go back further? Much further? Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside.

EC: If we’re interested in past climate, which is my main interest in science, we want to reconstruct climate back as far as we can into the past. That means that we need to find trees that live a long time.

JM: Edward Cook is director of the Tree Ring Laboratory at Lamont Doherty Earth Observatory in Palisades, New York. Cook’s lab consults with trees that have been silently recording climactic data, in some cases for thousands of years.

EC: It turns out that in general, conifers, evergreen trees that we know, pines, spruce, hemlocks, live longer than broadleaf deciduous trees or hardwoods. So to find the oldest trees we’ll frequently look for conifers. They can live up to almost 5000 years of age in some cases. Hardwoods are typically more limited to several hundred years. Tree rings that we find in trees in temperate environments such as we have here around New York, reflect the annual growth variations of the tree’s life history. Each ring represents one year of growth, and variations in the widths of these rings from year to year reflect changes in the tree’s environment that might be due to climate, might be due to insects, might be due to any one of a number of things. The critical thing about tree ring analysis is that it provides us with the best history of growth variations and climate variations that we know of over the past several centuries.

JM: We’ll hear more about trees and climate in future programs. Pulse of the Planet’s Science Diaries are made possible by the National Science Foundation. I’m Jim Metzner.

Science Diaries: Tree Rings Millennia

For meteorological data preceding our own recordkeeping, just ask a tree!

Air Date:05/31/2012

Scientist:

Transcript:

Science Diaries: Tree Rings Millennia

Ambiance: Dawn chorus

JM: If you want to know what the weather was like, say, 50 or 100 years ago, you can search the archives of the National Weather Service. But what if you want to go back further? Much further? Welcome to Pulse of the Planet's Science Diaries, a glimpse of the world of science from the inside.

EC: If we're interested in past climate, which is my main interest in science, we want to reconstruct climate back as far as we can into the past. That means that we need to find trees that live a long time.

JM: Edward Cook is director of the Tree Ring Laboratory at Lamont Doherty Earth Observatory in Palisades, New York. Cook's lab consults with trees that have been silently recording climactic data, in some cases for thousands of years.

EC: It turns out that in general, conifers, evergreen trees that we know, pines, spruce, hemlocks, live longer than broadleaf deciduous trees or hardwoods. So to find the oldest trees we'll frequently look for conifers. They can live up to almost 5000 years of age in some cases. Hardwoods are typically more limited to several hundred years. Tree rings that we find in trees in temperate environments such as we have here around New York, reflect the annual growth variations of the tree's life history. Each ring represents one year of growth, and variations in the widths of these rings from year to year reflect changes in the tree's environment that might be due to climate, might be due to insects, might be due to any one of a number of things. The critical thing about tree ring analysis is that it provides us with the best history of growth variations and climate variations that we know of over the past several centuries.

JM: We'll hear more about trees and climate in future programs. Pulse of the Planet's Science Diaries are made possible by the National Science Foundation. I'm Jim Metzner.