We have all driven down the road and seen nicely planted yards and neighborhoods that invite us in and yards that seem barren, with nothing but grass and a house. But a tree does more than add “curb appeal” to a house. They have very real value providing environmental services around your house as well as increasing your home’s value.
“In one study, 83% of Realtors believe mature trees have a
‘strong or moderate impact’ on the salability of homes listed for under $150,000; on homes over $250,000, this perception increases to 98%” (American Forests, Arbor National Mortgage). This is a tangible indication of the value of trees in a home landscape.
Trees can moderate temperatures around your home. Paving and concrete buildings refl ect heat causing “heat islands,” while a mature tree canopy reduces air temperature, cooling nearby buildings. Just one healthy tree produces a net cooling effect equivalent to ten roomsize air conditioners operating twenty hours a day!
Stormwater falling on paved surfaces washes oils, metals, salts, and other chemicals into nearby streams and rivers. Riparian forest buffers fi lter sediments from water before it enters streams during
storm events, intercept nutrients and pollutants from runoff, stabilize stream banks, provide shade and modify stream temperatures, and create aquatic and wildlife habitat.
Trees absorb and use large amounts of water for growth. The benefi ts of a tree canopy in reducing stormwater peak fl ows can mean real reductions in design, installation, and management costs as they allow smaller stormwater drainage systems to be used by municipalities. Just imagine, a single mature oak tree can transpire over 40,000 gallons of water each year.
A good tree canopy cover reduces the amount of water that would run off paved surfaces to nearby streams and rivers, reducing fl ash fl ooding in a community. Trees work like large umbrellas, capturing rainfall in their canopies. In one year, a deciduous tree can intercept up to 1,000 gallons of rainfall, while an evergreen can intercept over 4,000 gallons, and each allows this water to evaporate, never allowing it to reach the ground. This can help reduce drainage problems that cause ponding in yards and water in basements.
Trees, especially forests, allow rain to infi ltrate into the soil and recharge groundwater, which is then fi ltered as it slowly works its way beneath the surface to streams. Private and municipal water supplies both rely on this service to provide us suffi cient clean water. Trees are very good at removing nutrients and contaminants from soil. One study documented how a single sugar maple growing along a road in one growing season removed signifi cant amounts of cadmium, chromium, nickel, and lead. Two healthy trees produce enough oxygen to supply one person with their oxygen for one year. Air pollutants such as nitrogen-, sulfur-, and carbon dioxide produced by automobiles, power plants, and factories are absorbed by trees, which also sequester carbon dioxide by converting and storing it in the form of wood.
USDA Forest Service’s Center for Urban Forest Research shows that it pays to care for trees. Landscape trees provide benefi ts in excess of the costs of planting and care over their lifetime. Properly cared for,
they are valuable growing assets worth three times the investment. Data collected from a tree project in Minneapolis, Minnesota used a cost benefi ts analysis of community street trees to demonstrate that:
• One healthy street tree, in its 20th year after planting, provided $96 in benefi ts annually versus $36 in annual maintenance costs, yielding a net benefi t of $60 per year.
• One hundred healthy street trees provide a net benefi t of $232,000 over a 40-year period.
• One hundred healthy yard trees provided $272,000 in net benefi ts over a 40-year period.
• One hundred trees removed fi fty-three tons of carbon dioxide per year and 430 pounds of other air pollutants per year.
• One hundred mature trees intercepted about 139,000 gallons of rainwater per year that would have become stormwater, potentially polluting and eroding our streams.