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. 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 neighbors.
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 oxygen.
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 can 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. There were so few trees in parts of the Dakotas 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.”