An arborist is someone who is trained, qualified and experienced in managing individual urban trees in a scientific manner. Mumbai-based Vaibhav H Raje, though, has certification from the International Society of Arboriculture. A partner at Treecotech, a city-based arboriculture consultancy, he is often called by organisations for advice. At a time when the civic body is undertaking pre-monsoon tree-cutting, he tells the Free Press Journal how the structural and physiological integrity of a tree is really important for its growth, and ultimately the city’s.
Arborists are also called tree surgeons, what is the science behind tree trimming/cutting?
Our job is to precisely prune a tree as per its need, without compromising its integrity. A good tree surgeon is someone who understands the level of pruning required, based on the initial detailed assessment. The equipment and tools used are highly specialised, which helps to carry out the job in a safe, scientific and efficient manner. An arborist has the knowledge and skills to make the right cuts at the right places, thus minimising the damage caused to the living tissues of a tree, helping it recover with minimum complications.
Tree pruning is a practical task in which certain branches may be removed for various reasons like improving tree structure, minimising risks of branches falling by removing dead or dangerous parts, providing clearance and increasing light and air penetration within the canopy. In short, tree pruning is a combination of science and aesthetics.
Having trees in urban areas is highly valuable as they provide the much needed ecological, environmental and social benefits. So, it’s imperative that our trees are maintained in a technically sound and judicious manner.
What special training goes behind making an arborist?
Unfortunately, there aren’t any colleges or university courses at the moment in India for arboriculture but that shouldn’t stop one from pursuing it as a career. There are dedicated organisations in other countries that provide credentials and training. Some of the basic theory courses could be undertaken online as well. For example, the International Society of Arboriculture in the USA or the Arboricultural Association in the UK are industry leaders. Besides, there are several college courses, diplomas and degrees available in the UK, New Zealand, Singapore, Australia, the US.
Can improper pruning result in fatal tree falls?
Yes, improper pruning can lead to a range of problems that may cause trees to become unhealthy or die over a period of time. Excessive pruning (more than 25 per cent of the canopy at a time) or ‘topping’ in trees is one of the biggest contributors to urban tree failures and deaths globally. Excessive or improper pruning causes poor structure and health condition in a tree as majority foliage from the tree gets removed. Removal of multiple large branches of more than 15-20 cm diameter from a tree at a time can create several large wounds and increases the risk of disease or decay. The tree is sometimes unable to cope up with this sudden loss of branches and foliage, and so it puts out excessive new weak branches (epicormic branches or water sprouts) as a result of stress response mechanism. This new epicormic growth is not always beneficial to the tree and may fail to structurally sustain itself due to its weak attachment. Also the ability of a tree to produce food through leaves using photosynthesis gets highly reduced due to excessive pruning, causing the tree to fail or die prematurely at times.
What are the other reasons?
Unwanted root damage from construction activities, soil compaction due to concretisation around larger rooting area, limited root zone availability for healthy root growth, stem or root rot due to poor growing conditions and pathogens. In some instances, planting a wrong tree at a wrong place or even planting poor quality tree-stock could contribute to tree failure cases in the city.
How can one prevent tree-falling incidents?
With the help of proper technical and scientific methods of assessment, an arborist can help identify the likelihood of failure or the level of risk associated with trees. Timely inspections, risk assessments, strict maintenance regimes and timely interventions can help minimise these incidents up to a certain level. It must also be noted that all trees have a potential for failure and they inherently pose a certain degree of hazard and risk from breakage or other causes and conditions. Natural failure can occur even without defects; there can be no absolute guarantee of safety for any tree at any given point.
What can citizens do at the local level to save trees?
They could educate themselves and create awareness about basic tree management. They could consult or take advice from an arborist before planting trees in a particular area to check its viability. They should also be vigilant and stop haphazard or unscientific pruning work from happening in our city. With the help of social media, it is now easy to reach out to the authorities and report any mistreatment.
Pre-monsoon trimming of trees has begun by the BMC. Any comments?
I believe the BMC are the right people to comment on this issue. But I strongly feel that it is high time that our policies regarding urban tree management are revamped and upgraded as per international best management practices. Proper technical standards and guidelines in tree protection, tree assessment and tree pruning needs to be drafted by right experts and introduced soon for the benefit of our city’s green cover.