It’s high time our urban tree management policies were revamped, says arborist Vaibhav H Raje

An arborist is someone who is trained, qualified and experienced in the scientific management of individual urban trees. Mumbai-based Vaibhav H Raje, however, is certified by the International Society of Arboriculture. A partner at Treecoach, a city-based arboriculture consultancy, he is often called upon by organizations for advice. At a time when the civic body undertakes tree cutting before the monsoon, he tells the Free Press Journal how the structural and physiological integrity of a tree is truly important to its growth, and ultimately that of the city.

Arborists are also called arborists, what is the science behind pruning/trimming trees?

Our job is to precisely prune a tree according to its needs, without compromising its integrity. A good arborist is someone who understands the level of pruning required, based on the initial detailed assessment. The equipment and tools used are highly specialized, which allows the work to be carried out in a safe, scientific and efficient manner. An arborist has the knowledge and skills to make the right cuts in the right places, minimizing damage to a tree’s living tissue, helping it recover with minimal complications.

Tree pruning is a practical task in which some branches may be removed for various reasons such as improving the structure of the tree, minimizing the risk of falling branches by removing dead or dangerous parts, providing clearance and increasing the penetration of light and air into the canopy. In short, tree pruning is a combination of science and aesthetics.

Having trees in urban areas is very valuable as they provide much needed ecological, environmental and social benefits. It is therefore imperative that our trees are maintained in a technically sound and sensible manner.

What special training underlies the training of an arborist?

Unfortunately, there are currently no colleges or university courses in India for arboriculture, but that shouldn’t stop you from pursuing your career. There are specialized organizations in other countries that provide credentials and training. Some of the basic theory courses could also be taken online. For example, the International Society of Arboriculture in the United States or the Arboricultural Association in the United Kingdom are industry leaders. Also, there are several courses, degrees, and college degrees available in the UK, New Zealand, Singapore, Australia, and the United States.

Can improper pruning lead to fatal tree falls?

Yes, improper pruning can lead to a range of issues that can lead to poor tree health or death over time. Excessive pruning (more than 25% of the canopy at a time) or “topping” of trees is one of the major factors in the failure and death of urban trees around the world. Excessive or improper pruning results in poor structure and health of a tree, as the majority of the tree’s foliage is removed. Removing several large branches larger than 15 to 20 cm in diameter from a tree at a time can create several large wounds and increase the risk of disease or rot. The tree is sometimes unable to cope with this sudden loss of branches and foliage, and so it produces excessive new weak branches (epicormic branches or water shoots) due to the stress response mechanism. This epicormic new growth is not always beneficial to the tree and may fail to sustain itself structurally due to weak attachment. Additionally, a tree’s ability to produce food through leaves using photosynthesis is greatly reduced due to excessive pruning, sometimes causing the tree to fail or die prematurely.

What are the other reasons?

Unwanted root damage caused by construction activities, soil compaction due to concreting around a larger root zone, limited root zone availability for healthy root growth, stem or root rot due to to poor growing conditions and pathogens. In some cases, planting the wrong tree in the wrong place or even planting poor quality trees could contribute to instances of tree failure in the city.

How to prevent falling trees?

With the help of appropriate technical and scientific assessment methods, 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 minimize these incidents to a certain level. It should also be noted that all shafts have the potential for failure and inherently present some degree of hazard and risk of failure or other causes and conditions. Natural failure can occur even without defects; there can be no absolute guarantee of safety for a tree at any given point.

What can citizens do at the local level to save the trees?

They could learn and raise awareness about basic tree management. They might consult or take advice from an arborist before planting trees in a particular area to check its viability. They must also be vigilant and prevent lawless or unscientific pruning from occurring in our city. With the help of social media, it is now easy to contact the authorities and report any mistreatment.

Pre-monsoon tree pruning started by BMC. Comments ?

I believe the BMC are the right people to comment on this issue. But I firmly believe that it is high time that our policies regarding the management of urban trees were revamped and updated in line with international best management practices. Appropriate technical standards and guidelines for tree protection, tree assessment and tree pruning should be drafted by competent experts and introduced soon for the benefit of our city’s green blanket.

Posted: Sunday, April 24, 2022, 07:00 IST