ASK YOUR SCIENCE TEACHER by Larry Scheckel
This week’s question was asked by a fourth grade lad at Wyeville Elementary
School, Tomah, Wisconsin
Where did the first tree come from?
The Earth’s earliest plants were believed to be ferns and mosses that were only a
few inches tall. About 400 million years ago, during the Devonian Period,
plants formed stems, grew taller, competed for air, developed root systems,
vascular growth, and secondary growth. So scientists believe that there was no
single moment when trees started, but rather a slow developing process over
millions of years.
Trees are really quite sneaky. Most have no branches at the lowest levels. The object
of the trunk is to raise the height of the branches that grow the leaf canopy.
Any plant that has leaves sticking way up there can get more sunlight than its
And by branching, a tree can spread its leaves to cover more area, hence gather more sun. A tree also spaces its leaves to prevent the leaves from shading each other. Further, the tree shades its root area to suppress any competition.
Sunlight is everything to a tree. Through the process of photosynthesis, the tree uses
energy from the sun, plus water and carbon dioxide and chlorophyll to
manufacture sugars. Here’s the chemistry: Six molecules of water plus six
molecules of carbon dioxide produce one molecule of sugar plus six molecules of
You just got to love trees. They provide shade, of course. They hold the soil in
place, preventing erosion. Trees provide sap for maple syrup. (There’s some little
sap in every family tree!!). Plus nests for birds. Trees provide wood for
burning, for building houses, and providing paper and fruit.
Trees are marvels of engineering. They are able to transport water up hundreds of
feet to the top of the tree by the process of capillary action.
One third of the United States is covered by trees. And one third of that is set
aside as our National Parks and National Forests. We have more trees today than
70 years ago.
Trees were not evenly distributed across the United States in the past and it is the
same situation today. New England states are covered with forests. But Lewis
and Clark “observed a vast treeless prairie” in the present day Dakotas. So few trees in parts of the Dakota states that the pioneers built their houses out of sod.
Do visit Redwoods National Forest or Muir Woods in California and Sequoia and
Kings Canyon National Parks. Stand in awe of the largest tree on Earth, the
General Sherman tree.
Who cannot love and be moved by the poem “Trees”, written by Joyce Kilmer,
who was killed by a German sniper at the Second Battle of the Marne in 1918 at
the age of 31 ? “I think that I shall never see, A poem as lovely as a tree. A tree whose hungry mouth is prest, Against the Earth’s sweet flowing
breast; A tree that looks at God all day, And lifts her leafy arms to pray.”