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Today I attended a council meeting in Sheffield which included a debate regarding a petition that received over 10000 signatures. It was concerning the policies and framework in place to remove and replace trees along the roads in Sheffield. I am an arboriculturist. I was curious to witness the meeting even if I don’t believe that this sort of debate can happen verbally as too many factors are involved. In the end, all it came down to was the councillors voting on the two choices: one was to carry on as usual and the other was to scrutinise the methods in place to ascertain that the work was carried out in the best possible way. I was astonished at how 10 or so people could overrule over 10000, as the majority of councillors voted to keep things as they are. In some ways it is understandable; stopping the work would cause financial losses to the parties involved (perhaps breaching the contract), a study into the most appropriate strategies to manage the trees would require funding (which is unavailable), not all the facts are known and finally, emotion is believed to be responsible for certain people’s response and therefore secondary (fine in my opinion). There was talk of creating a forum for decisions regarding Sheffield’s trees. What is really needed is a plan that is not only approved by residents but also by experts. A plan that takes into consideration the many beneficial factors that trees bring to people whilst still retaining a view of their limitations. Trees do a lot of things but like us humans, have limitations.

Here are some aspects of trees:

Environmental

Values:

• Trees can help with water management in the sense that they can reduce the speed at which water reaches drainage pipes by catching and retaining water on their leaves.
• Trees can reduce noise pollution by screening the area where noise is coming from.
• They can reduce the amount of wind flowing in an area by dampening it with their leaves.
• They create shade with their leaves and branches reducing heat and evaporation from the ground.
• Trees improve air quality by releasing oxygen into the atmosphere through photosynthesis.
• Trees can intercept pollution and particulates on their leaves and their bark.

Drawbacks:

• Trees may block light by being very dense.
• May break sidewalks or structures over time with the growth of their roots.
• May drop fruits or leaves creating a messy area.
• May create noise when the wind blows amongst their leaves such as on some poplars.

Ecological

Values:

• Trees can build up humus through the shedding of their leaves which improves the soil through the addition of organic matter.
• They can associate with nitrogen fixing bacteria which also improves soil but in a different way.
• They can provide food for birds and insects with their fruit, leaves or pollen.
• Trees can provide homes for squirrels and other small animals.
• They can provide nesting materials for various animals, not least birds.
• They can provide green corridors which can extend the amount of space animals, such as squirrels, can utilize in urban settings.

Drawbacks:

• Trees can provide food for fungi which may help them colonize new areas and decay other things such as shrubs.
• Some trees make the ground around them toxic by allelopathy, the exuding of chemicals, preventing other plants from growing.
• Some trees may require so much water that they deprive nearby plants of it.
• Some trees can attract large quantities of certain insects, such as stink bugs, which may then start feeding on other plants.

Social/Economic

Values:

• Trees provide work for people that maintain them.
• Trees can help in the recovery rates of medical patients through their calming effect.
• Trees provide timber and many other products required today such as toys, picture frames, paper etc...
• Trees can increase property values as they are seen as beneficial or they might be rare specimens offering a type of status symbol.
• They provide educational material in the form of habitats for other species or just in themselves.
• They provide a meeting/recreational area or a place where one can hang a hammock or a swing.

Drawbacks:

• Trees may fail causing injury or damage or both.
• They can shed multitudes of leaves making a mess which requires sweeping and therefore expenses or maintenance.
• They can host insects such as aphids which coat everything under them with a sticky residue.
• They can encourage anti-social behavior by creating areas where people can hide or are not easily seen.
• They can reduce the value of a property if they require expensive work to make them safe or if they are simply too imposing or just create a lot of shade.

Amenity/Landscape:

Values:

• Trees can be beautiful by their leaves, bark or flowers in form or color.
• Trees can attract pretty birds/wildlife with their fruits.
• They soften the landscape with their leaves and swaying branches in areas containing multitudes of angular structures.
• They can conceal entirely or partially things that may not be pleasing to the eye.
• They can frame views or create avenues when rows of trees are present.
• They can be the centerpiece in a garden defining its theme.
• They can provide welcome shade on a hot, sunny, day.

Drawbacks:

• Trees can obstruct views whether panoramic or otherwise, simply due to their location.
• Trees can block street lights and CCTVs with their leaves and branches making areas unsafe.
• They can grow roots which protrude from the ground creating a trip hazard or that may impede people in wheelchairs from accessing certain areas.
• Trees with low branches may tempt children into climbing them which may deter their parents from living nearby or visiting to avoid the risk of their children hurting themselves.
• Trees may impede the construction of access for motorists through the campaign of people that know better, or the opposite, preventing their removal.