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Energy Savings from Planting Trees
The term 'climate change' doesn't have to mean global warming or some inevitable environmental force. Local climates are highly sensitive to changes in topographical features; in city areas these are often called urban microclimates. Planting trees is one way to influence a local urban microclimate, in order to change temperatures and manipulate winds.
Trees provide shade and also have an active cooling mechanism in the form of evapotranspiration. Cool air tends to collect beneath their canopies while they also influence temperatures in the immediate vicinity. The US Department of Energy believes that strategic planting of trees can reduce local summer air temperatures by around 5°C.
Secondly, wind chill can be a major energy loss factor during the winter. A wind of 20 mph can create a wind chill factor of over -10°C. Trees can reduce leeward wind speeds for a distance of around 30 times their height; strategic planting to block cold north winds can significantly reduce heat loss during the winter.
The right configuration of trees depends on the local climate, however when the above principles are applied correctly they can significantly reduce central heating and air conditioning costs.
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Ecological Benefits of Trees
As well as reducing energy costs for local households, trees have a great ecological benefit for society as a whole. Many of these benefits save money for governments in the long run.
Planting trees can mitigate the urban heat island effect. Cities generate additional heat due to the thermal properties of construction materials but trees can help increase daytime cooling, provide shade and reduce urban temperatures. The urban heat island effect is estimated to cost Los Angeles alone around $100 million a year in energy costs.
Trees also help to improve air quality and reduce pollution. Tackling pollution costs money, while increased pollution itself results in increased health care costs. Scientists estimate that a 12% reduction in pollution in L.A. could save the city $350 million a year.
Floods are less likely in areas with lots of trees. Trees intercept rain water, while their roots take up water from the soil. Urban areas are prone to flooding because the hard surfaces used for construction transport water quickly to rivers and tributaries; trees slow this process down. Flood damage can cost millions when it happens so mitigation of flash floods is another money saver in the long run.
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Uses for Dead Trees
Trees can be also be useful when they're dead. Wood is particularly versatile. Dead tree limbs can be used for firewood in the winter, with can help to further reduce household energy costs, or they can be repurposed in the garden as fence posts, stakes, borders or just plain mulch. For those feeling particularly creative they can even be used for woodworking projects and building household furniture and tree limbs or wood chippings are excellent for arts and crafts projects for children.
Deciduous trees also produce dead leaves at fall which can be recycled as compost or mulch. Leaves are excellent at retaining soil moisture and as they decompose they provide the soil with nutrients while maintaining an excellent structure for soil aeration. They are an essential ingredient for organic mulch which can be a great help in boosting the health and productivity of garden ecosystems.
Finally, trees can also produce fruit. Planting apple or pear trees for example will provide annual returns of fruit that can be incorporated into jams, chutneys, desserts or just eaten raw.
Planting trees is a great and environmentally friendly way of saving money, through improved energy efficiency and long term ecological benefits. Dead wood, leaves and fruit produce by trees can all be used in other projects around the house and garden. Some local governments, such as that in Los Angeles, are actively promoting tree planting as a benefit both for individuals and wider society. Adding trees to a garden now could result in long term savings for you and your family.
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US Department of Energy, “Energy Efficiency and Renewable Energy", http://www.energysavers.gov/your_home/landscaping/index.cfm/mytopic=11910
DIY Life, “Avant Yard: 30 Uses for a dead tree", http://www.diylife.com/2008/02/18/avant-yard-30-uses-for-a-dead-tree/
Trees Are Good, “Benefits of Trees", http://www.treesaregood.com/treecare/tree_benefits.aspx
Heat Island Group, “Energy Use", http://eetd.lbl.gov/HeatIsland/EnergyUse/