The number of trees in our cities is decreasing. Photo / File
Trees remove carbon from the atmosphere, filter air, produce oxygen and prevent soil erosion.
Our Government is moving with the Zero Carbon Bill and tree planting programmes in the right direction, but Hastings council and probably many other communities have a different understanding of trees.
In 2017, the Government announced the goal of having one billion trees planted by 2028. The One Billion Trees programme also encompasses changes to the regulatory settings to drive an increase in new tree planting in our communities.
Unfortunately the number of trees in our cities is decreasing. Havelock North shows a typical situation.
Under the pressure of new housing developments, an apple orchard with hundreds of trees has to give space to a new subdivision. On the Napier Rd about 30 healthy trees were chopped down to install new pipe work and only a few young trees were replanted.
European countries have binding community requirements to compensate the loss of trees and other valuable vegetation.
Germany developed the so-called ECO ACCOUNT for communities. Trees, shrubs and open land, which has to give way to new developments will be documented with its assessed environmental value using a simple point system.
Depending on the number of lost environmental points through a new development the community or developer has to plant trees or shrubs in the community. Even the loss of single trees - if they have a certain environmental value - have to be offset.
Our Government developed a Biodiversity Strategy to offset the loss of valuable natural elements of our communities.
Unfortunately, it is not more than a non-binding recommendation. The result: nobody is controlling the loss of trees or shrubs. Biodiversity is essential for all life.
It is the variability among living organism including diversity within and between species. It is a form of natural wealth that provides the resources on which human life depends.
Looking a bit closer on the value of trees. A single tree can absorb 10 to 20kg of CO2 per year and up to 5kg of other greenhouse gases. On the other hand trees are producing oxygen. It can be between 100 to 130kg per tree and year.
The loss of the 30 trees on the Napier Rd means we have about 350 to 400kg CO2 emission more, because this is the amount the trees are capable of absorbing each year. In other words our trees absorbed during one year the CO2 emission of 2000 to 2200 kilometres driven by a petrol car.
Beside the CO2 absorption the trees are filtering and absorbing other nasty emissions like carbon monoxide (CO), sulphur dioxide (SO2), nitrogen oxides (NOx) and particulates emitted from burning diesel fuel.
Our 30 trees absorbed about 120 to 150kg of these greenhouse gases. The probably most important contribution from trees in our communities is that they deliver fresh air in form of oxygen.
About 3000kg oxygen per year were produced by our 30 trees, the annual oxygen demand of three to four Hastings citizens.
After the trees were chopped down and the groundwork was finished only a few trees were replanted.
I discussed this issue with the Hastings District Council last year. First I receive a promising answer that at least a few native shrubs could be planted on the eastern end.
Last month I received a phone call that it would be too expensive and dangerous to maintain the shrubs. A week later this middle strip was sealed with concrete. On my request to replant the missing trees I was told that more trees would interfere with the street lights. I was shocked by this answer.
Before this conversation I was pleased to read in our newspaper that our mayor is committed to fight against the loss of biodiversity in our community.
Obviously the goals of our political leaders and the operational decisions of the council are two different pairs of shows.
Last week I have spoken with locals and business owners at the Napier Rd who are interested to replant the missing trees and probably a few more.
In 20 to 30 years time when trees are really interfering with the street lights the council may cut one or two branches to solve the issue. I hope that I can report in a few months time a more promising emission balance for the Napier Rd.
Walter Breustedt, director of ECO Management Group Ltd, Havelock North. Before Walter came to New Zealand he worked as independent adviser for the German government.