Take a look outside, and you will be sure to find the beautiful colours of autumn and the figurative outline of tree limbs reaching towards the sky.

The science behind it: Daylight length decreases along with temperatures. Chlorophyll breaks down with the green of summer slowly disappearing and yellows and oranges appear. Meanwhile, the development of anthocyanin gives rise to the reds and purples.

Trees are wonderful things - they can provide a range of ecosystem services, including producing that useful gas oxygen!

Cooling down

Trees are well known for reducing the adverse effects of the urban environment, with its towering buildings, heat pockets, and impermeable surfaces. Cities and the urban heat island effect go hand-in-hand. Temps are comparably higher than the surrounding rural landscape. Summertime energy demands soar with demands for ventilation and air conditioning. Trees can help to mitigate these raised temperatures through the provision of shade and evapotranspiration. Air temperatures can be reduced by 2-8°C, whilst gound temperatures become 15-20°C lower (Saito, 1990-91, cited in Doick and Hutchings, 2013).

Pollutant trapping

It is well known that trees can remove carbon dioxide and nitrogen dioxide. They also act as bio-filters in urban environs. It is true that not all trees have the same ability to filter out pollutants, however, they have the capacity to benefit human health, in this manner, nevertheless. Dangerous microscopic particles can be linked to a range of health problems, including heart disease, asthma, strokes, diabetes, obesity, and dementia. Trees have tiny hairs and ridges on their leaves that can trap pollutants.

Reducing run-off and flooding

Run-off from the urban environment can result in the addition of artificially warm water into the aquatic ecosystem via storm drains. In addition to this and due to impermeable surfaces, water can enter the watercourses fast and in huge quantities. A healthy tree canopy can offer the relief of a natural umbrella to pedestrians caught in a downpour, whilst bark and leaves slow the progression of the water, and roots absorb groundwater, which is eventually released once again to cool the atmosphere. Xiao and McPherson mathematically calculated the interception of water, with seasonal variation, and rainfall ranging from 15.3% to 66.5% depending on the maturity of the tree.

Slowing airflow

Following the same logic they also influence airflow and turbulence. Trees can act as a wind-break causing a deceleration in wind. As the density of trees increases the flow of air slows as it moves through and around (it does however increase as it moves over the trees). In a similar vein, trees can act as a barrier to noise. For an in-depth review of the impacts of vegetation on urban air pollution check this out.

Green mosaic

The green utopia created by a mosaic of trees and Public Open Spaces across the urban environment helps to provide the above benefits to the immediate surroundings as well as seating towns and cities in the wider landscape. In a fragmented world caused by urban sprawl, green areas provide ecosystem services to wildlife. They can provide a diverse habitat, nesting or roosting opportunities, act as a pantry of food resources, and aid the movement of wildlife.


The facilitation of nature's movement makes for pleasant environs for the human populous who are made up of residents and commuters. It is now becoming clear that street trees can benefit people suffering from various degrees of mental health by increasing their sense of well being. Taylor et al found that increases in urban street tree density correlate with a decrease in prescription rates. The opportunity to alleviate stress and anxiety by taking a walk in a natural setting is far better in the long run for both an individual and the health service.


Trees are a part of the landscape that links us to the past. They can be an integral part of a community, providing people with a sense of identity. They can act as landmarks and a feature of a local area. I can personally distinctly remember the trees that were an important part of my childhood - the group of trees that my brother and I climbed, the tree that supported a swing, and the ever-present oak that underwent beautiful transformation throughout the seasons.

Planting trees can be beneficial in many ways. The importance of their presence needs to be acknowledged with the strategic planning of their placement being brought to the forefront. The aim should be to plant healthy and resilient trees so that they can be of service locally and as part of a wider green network.

How to plant a tree

When planting trees in an urban environment it is important to consider whether species choice is correct. Tree planting solutions should be employed as a method of making sure that root establishment and development can happen in a healthy manner. These roots should be protected from heavy loads of water and traffic, and also should be able to access water and a loose substrate rather than the highly compacted structure that is synonymous with roads. When planting in this environment it is worth noting the presence of existing utilities, with tree pits being designed so that these utilities can be integrated. Trees can often benefit from modular structural cell systems and load-bearing growing solutions.

When planting a tree:

  • Identify a good location. Make sure that the tree will be able to access light, water, nutrients, and an aerated substrate.
  • Locate underground and overhead utilities.
  • Find the point between the tree trunk and the roots (the trunk will visibly expand out).
  • A tree pit should be sufficiently big to be able to accommodate tree roots. Girdling of tree roots should be avoided to ensure the longevity of the tree - tree roots should be soaked and teased out. The format of the roots will depend upon the production system. They may be in a rootball, as a bare-root, container-grown, or containerised. Each is treated differently and received different forms of aftercare. A tree pit should be 2-3 times wider than the root ball and as deep as the root ball.
  • Get help from another to make sure that you are planting the tree in a position where it is straight. Your helper should walk around the tree. When you do backfill try not to compact the soil too much as it will squeeze out air pockets which are vital to the roots. Stake the tree if necessary.
  • Watering, mulching, and weed control are important. Bear in mind that transplanting a tree from the nursery into a new environment can be shocking.
  • Formative pruning should be undertaken in order to help develop the architecture of the crown.

Get tooled up!

Planting made easier: The treaded tree planter has been designed to help plant saplings! All you need to do is tread the spear firmly into the ground and gently manoeuver it back and forwards to create a perfect size transplanting hole.

Protect your tree: Tree shelter tubes protect young trees from rabbits, voles and other wildlife. Flat packed for economical transport and storage. Slips simply over the stake. The Spiral tree guard is traditional protection for young trees. Good ventilation and flexibility to expand. Alternatively, Tree Guard Mesh can be used to make 1m high tree guards which are ideal for tree or shrub protection guard against rabbits, hares, livestock, or deer.

Stabilise your tree: Tree Shelter Stakes (square, round, machined) combined with Tree Ties (buckle type) can be used to help keep the tree straight whilst the roots establish.

Identify your tree: Aluminium Tree Tags supplied with nails can be used to identify your trees in parkland, arboretum, formal settings, planned plantings, and landscaped gardens.

Enhance habitats

In addition to planting trees, you can also provide homes to a number of animals. Nest boxes are widely used in the ecology profession to provide additional habitat or mitigate habitat losses due to development work. Wildcare provides sturdy bat, bird, insect and mammal boxes tailored to specific species, times of year and situations.

Learn more

We always like to encourage people to learn more about the natural world around us. If you want to read more in-depth information about what we have been talking about today, take a look at these:

If you are a beginner in terms of trees you could always take yourself on a trail by using the FSC Guide to Tree Name which is a 12-page laminated fold-out chart that contains a full-colour illustrated key to the leaves, twigs, fruits and seeds, of the commonest broadleaved and coniferous trees of Britain and Ireland. Why not challenge yourself and see if you can identify trees that have senesced (lost their leaves) - if not give the conifers a go! You can also get a Guide to Common Urban Lichens - these are great little composite organisms that are an amalgamation of cyanobacteria and fungi.

How else can you help? Citizen science!

The OPAL Tree Health Survey came into being in 2013 and involves citizens examining trees in their local area - keeping an eye on trees that are particularly prone to pests and disease. All you have to do is identify trees, measure girth and height, and examine the tree for signs of poor health. The survey also asks people to keep an eye out for the key pests and diseases.