Trees decrease air temperature and help to offset
the "heat island" effect of
hardscapes by providing
shade and by transpiration (the release of water vapor
into the air). By properly selecting and planting trees,
energy savings can exceed 40%. Three mature trees placed
strategically around a house can cut air conditioning
bills by 10% to 40%!
Dallas area neighborhoods with mature trees can be
up to 11 degrees cooler than new neighborhoods without
trees. A one-degree rise in temperature equals a 2%
increase in peak electricity consumption.
A single large tree can release up to 400 gallons of
water into the atmosphere each day. Water from roots is
drawn up to the leaves where it evaporates. The
conversion from water to gas absorbs huge amounts of
heat, cooling hot city air.
Cities are 5 to 9 degrees warmer than rural areas,
and 3% to 8% of summer electric use goes to compensate
for this urban "heat island" effect.
