13 Reasons to Plant Trees and the Psychology of Tree Planting

Beautiful Tree

Why plant a tree?

  1. Trees provide the oxygen that keeps us alive. One mature tree provides enough for 10 people to breathe per year.
  2. Trees absorb carbon dioxide, removing and storing the carbon as they grow. This should be reason enough as the global CO2 concentration surpasses 400 ppm.
  3. Strategically planted trees can reduce home energy use by as much as 30 % (Arbor Day Foundation). Planting deciduous trees on the east and west sides of the home provide shade in summer, while coniferous trees planted on the north and northwest sides can shield properties from cold winter winds.
  4. Trees raise property values for the entire neighbourhood: A 2010 US Forest Service study concluded that a tree planted “growing along the public right of way added an average of $12,828 (£8,500) to the combined value of all houses within 100 ft”.
  5. In 1985 the US Forest Service estimated the value of an individual tree at $273 annually (£180), well over $57,000 over its life time (£38,000). This value comes from its contribution to climate control, soil erosion, stormwater management, wildlife shelter and air pollution reduction.
  6. Trees improve biodiversity and improve habitat for local wildlife. Trees and large shrubs in your garden can make a real difference to butterflies, bees and birds.
  7. Trees cool the streets and the city, reducing the urban heat island and the evaporation of fuels within your car parked outside.
  8. They help the soil by reducing soil erosion by slowing run-off and holding soil in place with their roots, and also by remediating the soil and breaking down harmful chemicals.
  9. Trees help conserve water through reducing evaporation and run-off, allowing underground aquifers to recharge.
  10. Aesthetically, these organisms provide beauty to residential and urban areas and research has shown their presence decreases hospital stayover times of patients who had a view of them from their window.
  11. Socially and communally they provide a sense of identity and communities often band together to protect significant or historic trees.
  12. As playmates for children and places of rest and spiritual retreat for adults.
  13. Trees can form an effective sound barrier to noisy streets, providing more peace to one’s home.

    An oak tree in Wales (John Haynes)

    An oak tree in Wales (John Haynes)

The Psychological Motivation to Plant a Tree

If the above reasons are known and understood this should provide some rationale for planting a tree in your garden or local area. To summarise key motivations:

  1. Improving Your Living Space: The serenity of trees in one’s garden adds natural beauty
  2. Financial: A mature tree increases the value of your property
  3. Helping the Planet: Understanding the environmental condition of the Earth and why trees are needed
  4. The Feel Good Factor: The sense of satisfaction that comes from providing value or help

As seen, there are already powerful human drives present in these reasons. However, with the Teratrees project I hope to add to these motivations. This project shall be launched in the near future and updates shall follow!

Bohinj Lake, Slovenia (http://www.slovenijaturizem.com/)

Bohinj Lake, Slovenia (http://www.slovenijaturizem.com/)

Trees in the City

When humans have concentrated together in places of commerce and culture i.e. cities, the natural landscape has suffered. Woodlands have been cleared and fields have made way for concrete. Most cities, however, retain green spaces and parks though of small relative size. Trees are an essential part of maintaining a natural element in these spaces and they provide far more than aesthetic appeal while at some cost to their stoic selves.

Trees in our midst (Design for London)

Not only is carbon dioxide being absorbed through the leaf stomata of trees, but also carbon monoxide, sulphur dioxide, nitrogen dioxide and ozone.  And not only are these gases harmful to humans but also fine particulates (including cadmium, lead, chromium and nickel) which can be reduced by 60 % in tree-lined streets1. This gift from the trees comes at an expense to their health and leaves can often be discoloured and their growth stunted. Some like the plane tree are more adaptable through the shedding of their bark every year.

Ozone damage on prunus serotina (Swiss Federal Institute for Forest, Snow and Landscape Research)

Shade also has greater consequences than making your lunchtime sandwich more pleasant.  Cars in shaded parking lots (50 % cover) have an 8 % reduction in evaporation of their hydrocarbons. Roads also last longer as their surfaces are kept cooler. In summer, trees reduce the urban heat island effect through shade and the cooling effects of water evaporation from their leaves. In fact the evaporation from one large tree can produce the equivalent cooling of 10 room size air conditioners2.

Un dimanche après-midi à l’Ile de la Grande Jatte (George Seurat, 1884)

Trees attract life, and in higher tree density areas bird populations are also higher, while there is a correlation between expanses of manicured lawns and low bird diversity, suggesting that we could do with less frills and more substance. Psychologically, positive effects on human health have been explained with theories such as the biophilia hypothesis (Edward O. Wilson) and Attention Restoration Theory (Rachel and Stephen Kaplan) – these ideas will be explored in later blogs. Trees offer unconditional service to the whole environment, even in the unsuitable conditions found in cities, and for this we should be most grateful.

  1. Dr Rim Coder, University of Georgia , 1996
  2. USDA Forest Service