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Why Plant Trees in the Desert?
As our communities grow, development means more streets, roof tops, parking lots, etc. All these hard,
paved surfaces cause “the heat island effect” warming our cities by as much as 10 degrees. Trees are a great
natural tool to help mitigate the heat island effect, and keep our cities clean, beautiful and healthy!
How Trees Function and Save Energy
Trees are a key factor in reducing consumer energy costs, avoided energy purchase and production costs and
overall water savings. Trees use water to grow but produce clean water for the environment through evapotranspiration
and they absorb and filter stormwater run-off which in turn recharges the aquifer. Tree shade helps lower energy
needs in the summer while allowing winter sun access. Trees also absorb atmospheric carbon which reduces the
greenhouse effect, and in turn lowers temperatures city-wide. Well placed, mature trees can save consumers up
to 30% of annual cooling costs and save 10-25% of energy used for heating. It is estimated that an additional
1 million trees strategically planted could save $10 million in energy savings in a city of similar size and
climate as Albuquerque. (Source: Center for Urban Forestry Research – UC Davis)
- Cooling: Shade resulting in cooling is what a tree is best known for. Shade from trees reduces the
need for air conditioning in summer. In winter, trees break the force of winter winds, lowering heating costs.
Trees and other vegetation also reduce reflected and absorbed heat from concrete, glass, brick asphalt and rock.
Studies have shown that parts of cities without cooling shade from trees can literally be "heat islands" with
temperatures as much as 12 degrees Fahrenheit higher than surrounding areas.
- Water and Evapo-transpiration: (the sum of evaporation and plant transpiration): Evaporation accounts for the
movement of water to the air from sources such as the soil, canopy interception, and waterbodies. Transpiration
accounts for the movement of water within a plant and the subsequent loss of water as vapour through the leaves.
A fully grown tree may release several hundred gallons of water through its leaves on a hot, dry summer day. About 90%
of the water that enters a plant's roots is used for this process. When the tree gives off vapor through
evapotranspiration through their leaves and the vapor cools, it falls to earth as rain, snow, or sleet.
- Water Savings: Trees significantly reduce and clean stormwater run-off by holding rainfall on the leaves,
branches and bark, and by absorbing surface runoff, making the threats of flooding less likely. Trees also save water
when there are trees shading the lawns and other plants that we water. Statistically, 100 mature trees catch about
250,000 gallons of rainwater per year, decreasing polluted runoff and decrease soil erosion.
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