Finding a Needle in a Leaf Pile,

Feature Writer: Denny Teichow

Grumps hate leaves; all that mess, all that raking. Serious grumps have been known to cut down a beautiful tree so they wouldn’t have to rake all those damned leaves. The rest of us are willing to pay for that refreshing summer shade with a few hours of raking. And all of us, probably even the grumps, take a lingering look and smile at a gorgeous crimson maple in the autumn. Walk down a street in a mature neighborhood and millions of leaves present a banquet of color that goes on for three or four weeks. And then they’re gone.   Except for the evergreens. Which raises an interesting question: Why don’t pine needles turn some beautiful color in the autumn? Are they grumps? Actually an individual pine needle does die, turn brown and fall off the tree. (I will use “pine” as the generic name for all evergreens.) Anyone who has a pine tree knows this. But those pesky little needles are individualistic. They won’t organize and drop off the tree all at once like lemmings jumping into the sea. A few drop today, a few tomorrow, and whenever they feel like it, all year long.

Pine trees are conifers, which, as their name implies, means they bear their seeds in cones. Conifers are Pine conessexual, but not in a promiscuous way, although that might depend on your definition of promiscuous. Sexual, in this case, meaning there are male cones and female cones. You know, the kind of sex where the sperm must get to the egg and all that. There are two unusual things about tree sex that distinguishes it from human sex. The first is that most trees have both male and female private parts; earthworms, too, in case you didn’t know. I don’t mean the tree has worms; but worms are also hermaphroditic (isn’t that a cool word?).

There’s another unusual thing about conifer sex parts. In almost all animal species, the male is the bigger, stronger, and more colorful of the two sexes. But in conifer trees those big fist-size cones that you find on the ground, those are the female cones. The male cones are pathetically small, fragile and inconspicuous. Most people have never noticed one. They are like soft blossoms about the size of the end of your little finger. There is no penis envy in the conifer world. After they do their biological duty, the male cones fall to the ground and disintegrate or get blown away. It’s kind of sad; they get no respect.

Leaves on a tree have two jobs: 1. Produce food. 2. Exchange gases; namely, take in the carbon dioxide needed by the tree and give off oxygen, which, from the tree’s viewpoint, is a waste product. Larger leaves can produce food faster than smaller ones. But the larger leaf has some disadvantages. Water escapes from the leaves, and it can be a lot. A large oak tree can give off 400 or 500 gallons of water a day. The small needle shaped leaf of a pine does not allow much water to evaporate from it, compared to large flat leaves. The compact needle is also less susceptible to freezing. So needles are well adapted for drier, colder climates.

The food that tree leaves produce is sugar. That’s right; trees eat sugar all day, every day. Don’t try it; you’re not a tree.   In autumn, as the weather gets colder and there is less sunshine, the food factory in large leaves shuts down. The green chlorophyll in the leaves isn’t needed any more and decomposes taking the green color out of the leaf and allowing the yellow or brown color in there to be seen. In some trees a little sugar is left in the leaf that reacts with other leaf parts to produce those wonderful red and crimson colors. And then the tree goes to sleep for the winter. But pine needles are real troopers. They may not produce food as fast as large leaves, but they keep producing it all winter long. Because they don’t lose their chlorophyll, they stay green year round. Pine needles live about three to five years before falling off.

There, now you know all about the wondrous beauty of trees.


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