Fall Leaves: Recipe For a Rainbow

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Fall’s brilliant colors are among nature’s most beautiful sights, and they’re actually the results of a very specific biological recipe. I’m Jim Metzner, and this is the Pulse of the Planet. The ingredients for creating a brilliant Fall include a dash of genetics and a slice of the right environment.

“People are always in what makes a great fall. And there are several factors that really determine how great the fall colors are going to be in any particular year.”

Nina Bassuk is Director of the Urban Horticultural Institute at Cornell University.

“The first thing of course is the genetics of the individual tree itself. Some trees just have the ability to produce these wonderful colors and others do not, regardless of environmental factors. That aside, there are environmental factors that cause the best color to occur, and first and foremost it is the intensity of the sunlight. The sunlight helps produce those red or purple colors — and the cool nights. We have to have both the cool nights and the sunlight to get the best color. Another factor which is important in how brilliant the fall color is in any particular year is how long the leaves actually stay on the trees. It’s not so much what happens in the previous summer, but it’s during the time of change. As long as there are leaves on the tree, the time when the leaves are walling off against the cold, and starting to batten down the hatches, so to speak — at that point you’ll get more reds if it’s warm sunny days and cool nights. If you have kind of warm wet weather, you’ll get more yellows and fewer reds. Other factors are soil and particularly the acidity or alkalinity of the soil. A more acid soil tends to give you more vibrant red colors. A more alkaline soil tends to give more yellow colors.”

If you’d like to hear about our new Pulse of the Planet CD, please visit our website at pulseplanet.com. Pulse of the Planet is presented with support provided by the National Science Foundation. I’m Jim Metzner.

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Fall Leaves: Recipe For a Rainbow

Nucleotides, sunny days, cool nights and soil Ph are some ingredients of the arboreal recipe for a terrestrial rainbow.
Air Date:10/14/2002
Scientist:
Transcript:


music

Fall’s brilliant colors are among nature’s most beautiful sights, and they’re actually the results of a very specific biological recipe. I’m Jim Metzner, and this is the Pulse of the Planet. The ingredients for creating a brilliant Fall include a dash of genetics and a slice of the right environment.

“People are always in what makes a great fall. And there are several factors that really determine how great the fall colors are going to be in any particular year.”

Nina Bassuk is Director of the Urban Horticultural Institute at Cornell University.

"The first thing of course is the genetics of the individual tree itself. Some trees just have the ability to produce these wonderful colors and others do not, regardless of environmental factors. That aside, there are environmental factors that cause the best color to occur, and first and foremost it is the intensity of the sunlight. The sunlight helps produce those red or purple colors -- and the cool nights. We have to have both the cool nights and the sunlight to get the best color. Another factor which is important in how brilliant the fall color is in any particular year is how long the leaves actually stay on the trees. It’s not so much what happens in the previous summer, but it’s during the time of change. As long as there are leaves on the tree, the time when the leaves are walling off against the cold, and starting to batten down the hatches, so to speak -- at that point you’ll get more reds if it’s warm sunny days and cool nights. If you have kind of warm wet weather, you’ll get more yellows and fewer reds. Other factors are soil and particularly the acidity or alkalinity of the soil. A more acid soil tends to give you more vibrant red colors. A more alkaline soil tends to give more yellow colors."

If you'd like to hear about our new Pulse of the Planet CD, please visit our website at pulseplanet.com. Pulse of the Planet is presented with support provided by the National Science Foundation. I’m Jim Metzner.

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