Ranger Rick or Landscape Larry? Last century and 5 decades ago when I was a senior in high school my recommended career paths (based on an aptitude evaluation) were Landscape Architecture or Forestry. I chose Landscape Architecture, but have always been a tree hugger at heart. In an Urban Environment, Trees and Water are intertwined mutually beneficial to each other as well as the Environment as a whole. Here are some of the amazing beneficial qualities of trees.

Air Quality

As noted in ASLA’s Sustainable Landscapes, a single large healthy tree can remove more than 300 pounds of carbon dioxide from the atmosphere every year. In fact U.S. trees remove some 784,000 tons of pollution annually, providing a value in excess of $3.8 Billion.

Water Quality

Trees are nature’s pollution filters. The canopies, trunks, roots, and associated soil and other natural elements of the landscape filter polluted particulate matter out of the flow toward the storm sewers and waterways. Trees also reduce topsoil erosion, slow down water run-off and help replenish groundwater supplies. (PDF)

Storm Water Management

When it rains, most of the raindrops hit a leaf or branch surface and remain there a while in “temporary storage” before they are released by evaporation into the atmosphere or by drops falling to the ground. Mature deciduous tree (i.e. maples, birch and most oaks lose leaves during the winter) can intercept 500–700 gallons of water per year, which equates to over 3 Water Butts every week. Mature evergreen trees (i.e. magnolias or pines, retain their leaves year round) can intercept more than 4,000 gallons per year. In fact for every 5% of tree cover added to a community, storm water runoff is reduced by approximately 2%.

Reduced Heat Island Effect

Most everyone appreciates the shade of a tree especially on a hot summer day. Large areas of asphalt and concrete trap the heat of the sun and reflect it back into the environment resulting in higher temperatures in the surrounding areas. This process also contributes to smog and higher energy costs associated with the need for more air conditioning in buildings. The strategic placement of trees in and around parking lots and similar areas provide shade and reduces the heat island effect.

Increased Rainfall

One acre of vegetation transpires as much as 1600 gallons of water on sunny summer days. (PDF) Transpiration means more water vapor in the atmosphere and in the spirit of “What goes up must come down” water vapor condenses and becomes rainfall somewhere.

So where did the 10,000,000 gallons of rainwater go?

Found: 10 Million Gallons of Rainwater

According to the USDA Forest Service a typical Urban Forest with 10,000 trees will retain 10 million gallons of rainwater per year.

Extreme Drought

So when a city, a region and a state has an extreme drought and loses millions of trees the economic and environmental impact will likely have ripple effects the size of a small tsunami.

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