Now that most people agree that the Earth is warming, the question has shifted to what can be done to reverse the process. But many people do not realize that trees can impact the climate, and in a positive way. In fact, trees have multiple ways to affect our climate. The one of most interest is the slowing of global warming. And, as polar caps melt with the sea level rise associated with the event, trees offer one way anyone can make a positive impact. I am referring to a reduction of global warming and making the situation better, not just not making things worse.
Trees Role in the Environment
Trees can impact the environment, and in a positive way. Planting trees and preserving those that are already there can be a start at reversing global warming.
The Way the Energy from the Sun Works
The energy from the sun that is absorbed by the Earth is shared molecule to molecule. So, light energy which is not heat is converted to molecular movement, which is heat. The earth normally would emit this energy back to space as inferred rays, and cool back down. But, some gases in the atmosphere absorb the inferred rays, and prevent the energy from leaving the earth, thus building up a hotter planet.
Trees Remove a Greenhouse Gas
Carbon Dioxide Reduction
Trees take in carbon dioxide, use the carbon to build the tree, and give back the oxygen. The reduction of carbon dioxide reduces one significant greenhouse gas from the atmosphere, thus making the situation better. In fact, as carbon dioxide levels go up trees may take in more carbon, and in the process eliminate carbon dioxide from the atmosphere at a greater rate.
The Albedo of the Earth
The albedo of the Earth is its ability to reflect light. Fresh snow reflects most of the incoming light, so the Earth does not heat as much when there is a fresh snow cover. Bare ground absorbs much of the incoming energy, and green trees operate at a reflectivity in between. So, trees can reflect quite a bit of light back to space before it is converted to heat.
A Short Term Gas
Water vapor is the tricky part. Trees take moisture from the ground, and give it back out through the leaves. But, water vapor is itself a greenhouse gas. Fortunately, this effect is not as great as the carbon dioxide removal. Also, the water is then available to condense into clouds, which reflect light before it reaches the ground. So, water has both a positive and a native effect on global warming, although more transient than carbon dioxide does.
Types of Trees
Trees are grouped in two types, deciduous and evergreen. Deciduous trees lose their leaves during the winter, while evergreen trees remain green year round.
Choosing a Tree
Another positive impact of a tree is to shade homes, which reduces air conditioning in the summer. But, allowing sunlight to heat the home in the winter may be important. Deciduous trees allow sunlight to be blocked in the summer, and pass in the winter. So, a tree on the side of a home that gets the sun might be best if a deciduous tree is chosen, whereas a tree opposite the sunlit side might be better as an evergreen.
Fruit Trees Can Also Provide
|The Homeowner's Complete Tree & Shrub Handbook: The Essential Guide...|
|Fruit Trees: An Introduction to Growing Backyard Fruit Trees (orang...|
In the tropics land is often cleared completely to get to certain trees for lumber. The problem is in the jungle the canopy of leaves is so thick that nether sunlight nor rain fall to the jungle floor. Once cleared the organic material that has been layering on the floor is subjected to sunlight and rain, and increases in decomposition. Decomposition releases greenhouse gases to the atmosphere.
Also associated with deforestation is that the albedo of the Earth changes, and the result is less reflected sunlight. More sunlight is absorbed by the cleared ground.
Still another problem is the unwanted trees and other plants are usually burned, converting the carbon the trees have taken from the atmosphere over years of growth, and releasing it in a short period as carbon dioxide.
Where Sunlight Is Needed
If shading your home with trees, do not interfere with the solar panels if you have them. This means you may have to use shorter trees on the sunlit side of your home. Even if you plan future solar panels, take that into consideration when selecting trees.