“It is well that you should celebrate your Arbor Day thoughtfully, for within your lifetime the nation's need of trees will become serious. We of an older generation can get along with what we have, though with growing hardship; but… you will want what nature once so bountifully supplied and man so thoughtlessly destroyed; and because of that want you will reproach us, not for what we have used, but for what we have wasted.”
Theodore Roosevelt, 1907 Arbor Day Message
National Arbor Day, Last Friday of April
In much the same way that we tend to judge people by their appearance, we tend to focus on superficial qualities in our appreciation of landscapes—their form, color, visual appeal. As in all other things, looks can be deceiving. Some of the gardens most attractive to us may in reality be the most demanding and the least beneficial.
Reaping the Rewards of Diversity
We want beauty from our yards, all of us do, and rightly so. We want them to be appealing places to retreat to, want them to offer characteristics that draw us outdoors or make us stop and pay attention. But their purposes and benefits go far beyond physical appeal.
Trees are the largest and longest-lived elements in our gardens, and the benefits they offer are far more complex, varied and invisible than our shortsighted use of them would imply. Aiming solely at seasonal beauty tends to limit us to a very limited group of trees, ones with spring blossoms, fall color, winter form.
A mass planting of a few species might be dramatic for a few weeks of the year but it doesn’t provide them, or us, with the diversity needed when difficult weather, pests or diseases come along. And if we want wildlife in our yard—from birds to butterflies to other wildlife—a limited number of tree species is not likely to sustain them through the year.
Why do we, and all the creatures we share our landscapes with, need a diversity of trees and other landscape plants?
- Native trees, in particular, provide food sources at the right time and in the right form for pollinators and other wildlife they evolved with. With one third of the food we eat requiring pollination, feeding and sheltering the creatures that provide our food is essential.
- Trees save energy in both cold and hot weather by reducing winds and providing shade and shelter.
- Trees absorb carbon dioxide and release oxygen. They reduce noise, air and water pollution by reducing and filtering noise, air particles and rainwater by means of their leaves and roots.
- They help prevent soil erosion on slopes by slowing runoff and holding soil in place.
- Trees reduce ultraviolet rays by about 50 percent, and thereby the risk of skin cancer.
- Trees can increase property values by as much as 37 percent.
- Green spaces are restorative for all ages and in almost every setting. For children with attention deficit disorder, time outdoors can reduce the symptoms.
- People are more likely to spend time outdoors for exercise, relaxation and restoration in areas with trees.