Trees, Air, and Water
By: Steve Roark
When I ask kids why trees are important their number one answer is that they produce oxygen. Plant Leaves are solar collectors that take sun energy to produce food through the miracle of photosynthesis, a complex chemical process where carbon dioxide and water are converted to a glucose sugar. This sugar is used for food energy or converted to a starch called cellulose for building the plant body (stem, limbs, etc.). In trees we call this wood, something we use a lot of. It requires a lot of solar energy to sustain trees, and they must have huge canopies of branches to hold many thousands of leaves to the sun. If the leaves of one mature sugar maple tree were laid out flat, they would cover a half acre of ground.
A byproduct of photosynthesis is oxygen, crucial to all air breathers. A healthy, rapidly growing tree can produce 6-8 pounds of oxygen annually. As trees age they grow slower and contribute less oxygen. Old, over-mature trees produce only about as much oxygen as they themselves need to convert food to energy.
Trees take carbon dioxide from the atmosphere and convert it to wood. There’s a rule of thumb that to make a ton of wood, a tree takes in two tons of carbon dioxide and releases 1 ton of oxygen. Trees are important “carbon storage units”, taking up and storing huge amounts of carbon dioxide that is presently being overproduced by automobiles, factories, and coal burning. Excess carbon dioxide is helping fuel a warming climate, something with bad future consequences.
Trees also use a lot of water to run the photosynthesis process. Certain species can raise water high into the canopy at speeds of up to 150 feet per hour. A large leafy tree can take up 95 gallons of water each day, but only a small percentage of it is converted to glucose. The rest is released through the leaves into the atmosphere as water vapor, where it forms clouds and eventually returns to earth as rain.
There are concerned people who feel trees are so important to our environment that they should not be cut for lumber, fuel, or paper. The products derived from wood are many and a big part of our modern lifestyle. What is important to remember is that through sustainable management trees can grow back and replace trees cut and assures that there will be enough wood for human use while still allowing the important ecological benefits of trees to remain intact. For more information on trees, their management and benefits, contact your local state forestry office.