Street trees offer so much to our local environment and the people who live in urban areas, from providing homes for wildlife to increasing property values. However, these amazing benefits can only be enjoyed by planting the right tree in the right place, and this requires specialist knowledge.
We talked to Dr Matthew Ling, Project Lead of the Cambridge Canopy Project at Cambridge City Council to learn about all the things that need to be considered when deciding what trees to plant to achieve the best outcome for each area.
The right tree, in the right place…
…for the right reason and at the right time is a commonly used phrase in arboriculture. When deciding what species of tree to plant, arboriculturists use their expert knowledge to work out the best tree for each specific environment.
While the shade provided by tree cover is essential as our climate heats up, the position of individual trees is critical, as an ill-placed tree could completely block the light to a property.
Roots uplifting pavements is another common concern when it comes to street trees. Some trees have demanding root systems that can damage paving in crowded urban areas. The mature trees that people often see causing these kinds of problems were actually planted up to 80 years ago, when the landscape and needs of our streets were very different.
Council tree teams survey each location chosen by one of our sponsors before deciding if it's a suitable spot to plant a street tree. A lot of considerations are taken into account at this stage, including:
- ground conditions - e.g. is there already a tree pit, or a grass verge to plant into
- the existing mix of trees in the road
- proximity to buildings
- pavement width
- presence of underground services (gas, electricity, water and broadband)
- street furniture (telephone/lamp-posts, drop-kerbs, crossing points)
- overall tree strategy for that area
With any tree planting scheme, the aim is that the trees will be there for as long as possible, so expert knowledge and forward planning is essential. This is especially true when it comes to planting street trees.
“In old cities and towns, affluent areas were built with wider streets and often have mature trees today. But in poorer areas, streets were narrower and gardens were smaller. Today, there is less tree coverage in less affluent areas.”
Dr Matthew Ling, Project Lead of the Cambridge Canopy Project
Technology lends a helping hand
Tree specialists have access to some clever technology to help them plan tree planting. Innovations have been developed to solve all kinds of tree management challenges, from locating roots to detecting signs of decay or disease. More on this in another post...
A GIS (Geographic Information System) is one of the most useful pieces of tech, which creates a detailed digital map of an area with features such as utilities marked on it, to help identify the best locations for planting. Tree coverage can be shown in the maps too, helping tree specialists to plan a more uniform distribution of trees across an urban area.
The leaves and fruits that drop from some tree varieties can make the ground slippery or block drainage and in some cases can even cause property damage. There are also other considerations - it can be unwise to plant certain tree types near to schools, for example, as the temptation for children to use fruit and any other debris as missiles is just too great!
Experts also know what tree varieties should be avoided, no matter what the location is. For example, Ash trees are prone to a disease called Ash dieback, and Oak trees can suffer from a condition known as ‘sudden oak death’ – both of which are caused by parasitic fungi.
Climate vs Biodiversity
There is a fine balance between doing what’s best for local biodiversity and what’s best for the climate. Our climate continues to get warmer, and many of our native tree species are not adapted to survive in these higher temperatures and extreme periods of wet and dryness we’re experiencing.
Species from the Mediterranean and Asia may actually be more suitable for our new conditions, and be more likely to survive in the future. These non-native species still provide a suitable home for the pollinators that are so essential to our local ecology, and are enjoyed and inhabited by other wildlife.
Timing is essential
Just like animals that hibernate in winter, trees like to store nutrients for winter to prepare them for surviving the year of growth ahead. If you condense a year in the life of a tree into one day, summer is like the daytime when the tree grows new leaves, spreads its roots, and maximises its growth, while winter is like bed time.
The best time to plant a tree is therefore between November to March, when trees are dormant and aren’t producing sap - December and January are ideal. This means that growing roots won’t be disturbed, and the tree stands the best chance of survival and giving us years of benefits.
An army of local helpers
Any tree planting scheme depends on the support of local people to be successful. After planting, trees need careful maintenance during their first 3 years of life on a street. Some of this is done by council tree specialists, but there are plenty of things the public can do to help.
Watering is the main task that people can help out with during the summer months, as it costs councils thousands of pounds to keep street trees watered in hot weather. Help is therefore encouraged from local ‘tree superheroes’ to ensure that young trees get enough water to survive during their early years. Take a look at our watering tips if you want to do your bit andhelp care for the trees in your neighbourhood.
Planting trees takes time, money, and energy, but the benefits for our environment and wider society are enormous. That’s why it is so essential that we use the expert knowledge arboriculturalists can provide to ensure that we get the best, most sustainable results for our efforts.