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Why We Need Trees in Our Cities

Trees improve the livability of our cities for countless reasons. However, for many years tree canopy in our urban areas has been decreasing. Large mature trees which reach the end of their lives are often replaced with smaller species - if at all. These replanted trees then struggle to establish and reach maturity due to the demands of paved surrounds around them. 

Let's go over nine of the main reasons why we need trees in our urban environments, and touch briefly on the systems available to specifiers and designers to help ensure the new tree plantings that are done have the best opportunity to thrive. Landscape architects, urban planners, developers, and local authorities - this is for you! 

Research over the years has confirmed the immense value and benefits that mature urban trees offer our cities. Organizations such as American Forests andTrees Forever actively campaign in support of trees in urban areas. And the more mature the tree, the greater the benefits - so it's critical that trees are planted with mature establishment in mind. 

Below are a few facts to help validate the importance of urban trees and why professionals need to put the right systems in place to nurture them. 

Visual Appeal

Few things can compare with the aesthetic impact and seasonal interest that trees offer the urban setting. They provide huge visual appeal to any area and can significantly enhance the design of a streetscape. 

Air Quality

For every 10% increase in urban tree canopy, ozone is reduced by 3-7%. 

Trees are also proven to remove carbon from the air, getting absorbed and stored as cellulose in their trunks, branches, and leaves (a process known as sequestration). Planting trees remains one of the most cost-effective ways of drawing carbon dioxide from the atmosphere. A single mature tree can absorb CO2 at a rate of 21.6 KG/year and release enough oxygen back into the atmosphere to support 2 humans - those are numbers to be paid attention to. 

Research has also shown a 60% reduction in particulates from car exhaust fumes on streets lined with trees. 

Health & Well-Being

Trees have also been proven to have a positive impact on skin cancer, asthma, hypertension, and other stress related illness by filtering out polluted air, reducing smog formation, providing shade from solar radiation, and providing an attractive, calming setting for recreation. 

Sulphur dioxide, nitrogen oxides and particulates, carbon monoxide, cadmium, nickel, and lead are all pollutants that trees work constantly to remove from the air. 

Trees also form an effective sound absorbing barrier to help reduce unwanted urban noise pollution. 

The biodiversity of trees in providing natural habitats for birds, squirrels, and other fauna are considered to some as incalculable. 

Cost Savings

For every $1 spent on trees, a return of $2.70 in benefits is received; according to the United States Forest Service. A similar study performed in the U.K. byNatural England calculated that every £1 spent on tree planting yielded £7 savings, or a potential £2.1 billion if taken nationally. 

Managing Stormwater

For every 5% of tree cover in a community, stormwater runoff is reduced by 2%. Trees prevent stormwater runoff from reaching water courses with harmful chemicals collected from roads and sidewalks. 

Property Values

Independent studies have shown a consistent 5-15% increase in property values on tree lined streets, proving that trees increase commercial and residential real estate values. 

Crime Reduction

Researchers have discovered reductions in both violent and petty crime, including domestic violence through the therapeutic, calming influence of mature tree planting. 

Cooling Effects

Trees reduce temperatures by shade and transpiring water. This helps reduce air conditioning bills and energy use. Studies have even proven that one mature tree can produce the same cooling effect as 10 room-sized air conditioners. This becomes an effective tool in reducing urban heat islands and hot spots in cities. 

Trees can also save up to 10% of local energy consumption through their moderation of the local climate. 

Adverse Wind Speed

Buildings increase wind speed as wind is forced to travel further around them. Trees significantly reduce wind speed up to a distance of 10 times their height. 

Helping New Urban Trees Thrive

Trees in urban areas face a difficult environment. Paved hardscapes limit access to rainfall irrigation and the engineered requirements of pavement is completely opposite to what a tree needs to grow. GreenBlue systems help provide optimal conditions to give trees a fighting chance to reach mature in otherwise harsh urban conditions. Soil support cells allow for generous root growth while also providing the structural stability needed for paved surfaces. 

ArborSystem helps in all this by bringing together the key elements of successful tree pit design and simplifying the design and installation process for specifiers and contractors. 

It's important to understand however that a large portion of urban trees that are planted do not reach maturity, therefore not providing the extent of the benefits that they could. With all these benefits in mind, we must ensure that new urban tree plantings receive what they need. 

To learn more about the benefits of urban trees, download the FREE eBook, or view the GreenBlue blog post here