An ESW Spotlight on Trees

Trees are some of the best defences against climate change and are the foundation a sustainable ecological system. Surprisingly, trees can help in a number of ways we don’t often think about! In cities, trees can help reduce the heat island effect and improve stormwater management. But what good are they really?

Reducing Temperature

Australian summers can be brutal and the shade from trees can lower temperatures by up to a whopping 8°C, which can reduce air conditioner use by 12-15% and also decreases carbon emissions from our largely brown coal generated electricity.
Two medium sized trees, planted in the right position (usually to the north or west) can save up to $180 per year off a domestic electricity bill through lower air conditioner use.

Moderating Wind
It is difficult to place a value on the role trees play in reducing wind speeds of up to 10% during storms and protecting property from hail damage. However, we do know that under climate change winds will be stronger and that severe storms will be more frequent, and that trees filter and deflect wind in they are planted in appropriate places. Indeed, it is often forgotten that properly planted and positioned trees can reduce the swirling of the wind during major fire events, making fire fighting safer.

Reducing Water Runoff
Trees are very good at holding and absorbing water during heavy rainfall events. This is now being recognized as an important part of storm water run-off management as it can reduce localized flooding. In many parts of Australia, while annual rainfall is likely to fall under climate change scenarios, the rain that does fall is likely to occur in heavier downpours. In many places, the storm water pipes are not large enough to cope with the extra volume of water and so water is now being diverted to open space and tree pits to ease the flow, which will reduce local flooding and save the cost of retro-fitting bigger pipes.

Increasing real estate value
Determining a monetary value that appropriate trees add to real estate can be difficult, but a conservative estimate of 5% of the total value has been used in the USA and a figure of about 5.4% has merged from research undertaken in Brisbane. Real estate agents have recognized the value of a good tree in a front garden at about $5,000 for a suburban property and earlier work had estimated that a tree-lined nature strip added 30% to properties. There is also an indirect but significant financial benefit for a local council in increased house prices, which are reflected in higher council property rates.
Excessive tree removal in part of a council’s area of control could impact on its income when properties are next valued for rating purposes. Given that these are significant financial considerations, it is not difficult to envisage a situation where the unnecessary removal of a safe and healthy tree from a streetscape could precipitate legal action by a resident for the loss of property value. I am often amazed at how seldom the effects of tree removal on real estate value are considered until after the tree is gone and the loss is realized

Improving Health
Treed open spaces improve human heath, extend life spans, reduce violence and vandalism, and lower blood pressure. It is not for aesthetic reasons that hospitals now have gardens, even if they are many floors up. Their presence and visits by patients speed recover and shortens time until discharge, which reduce the costs of hospitalization. The vegetation also humidifies the air which can ease breathing and reduce the need for medication in those with respiratory difficulties.

Tree cover in many Australian cities is declining, particularly with the loss of private open space. While the damage and nuisance values attributed to trees are well-known, the benefits they provide are often under-appreciated. Cities are biodiversity hot spots due to the variety of habitats available in front and back yards. For most people planting the right tree in the right place at the right time for the benefit of future generations is a significant legacy. What else delivers so many benefits immediately: benefits that last centuries into the future, which prolong healthy lives and make cities both sustainable and liveable?
The value of trees in our cities in clear, dollar value or not.

Stats & Information Courtesy Of:

Economic Value of Trees