Dadar-Mahim tops Mumbai’s hazardous tree list

The June 25 survey, which covered 1,115 roadside trees, also found that 684 trees required scientific de-concretisation. Four wards recorded 100% concretisation of the trees inspected, highlighting what the report describes as systemic shortcomings in the city’s urban tree management.

MUMBAI: Dadar-Mahim in G North ward has emerged as Mumbai’s biggest tree safety concern, accounting for 22 of the 50 dead or dangerous trees identified during a joint inspection across 12 municipal wards. The June 25 survey, which covered 1,115 roadside trees, also found that 684 trees required scientific de-concretisation. Four wards recorded 100% concretisation of the trees inspected, highlighting what the report describes as systemic shortcomings in the city’s urban tree management.

Dadar-Mahim tops Mumbai’s hazardous tree list

The detailed report, prepared after an order by the Bombay high court in response to a 2023 PIL, is based on joint inspections carried out by environmental activist Rohit Joshi with 20 volunteers and BMC officials from the garden and roads and maintenance departments, junior tree officers, municipal engineers, the petitioner and citizen volunteers.

In a legal notice issued to the BMC on July 14, Joshi demanded immediate inspection and scientific treatment of identified dangerous trees, a city-wide survey of roadside trees affected by concretisation, and a scientifically guided de-concretisation policy. He also sought a standard operating procedure for urban tree maintenance, technical assistance for dangerous trees on private properties and a compliance report within seven days.

The notice warned that failure to act would prompt him to seek further directions from the high court, including action against officials for failing to discharge their statutory duties. The June 25 findings of 12 wards (see graphic) will be submitted to the court next week.

The inspection found widespread concretisation around tree bases. Every single tree surveyed in Bandra West in H West ward, Andheri-Juhu in K West ward, Borivali in R Central ward and Mulund in T ward will require scientific de-concretisation, indicating severe obstruction of their basal root zones. These were followed by other wards with choked trees, the highest being Parel in F South ward (78.6%) and the lowest being Bhandup in S ward (32.6%) (see graphic).

The joint inspections assessed tree concretisation, basal root zone conditions, adequacy of tree basins, visibility of root flares, soil availability and permeability, utility conflicts, construction debris, encroachments, and dead or dangerous trees. The findings were supported by field notes, ward-wise inspection reports and photographic documentation.

Inspectors found concrete, paving blocks and masonry extending right up to tree trunks in many locations, leaving little exposed soil for water infiltration and oxygen exchange. Many trees were confined to undersized masonry planters that provided inadequate permeable soil, while numerous mature trees had buried root flares, a condition associated with chronic physiological stress, reduced oxygen availability and increased susceptibility to decay.

The report also documented utility chambers, underground cables, drainage infrastructure and signposts constructed within tree root zones, along with construction debris and compacted fill inside tree basins. According to the report, these recurring deficiencies were observed across geographically separate wards, indicating systemic implementation issues rather than isolated engineering failures.

Photographic evidence included in the report showed advanced butt rot, root collar decay, hollow trunks and deterioration of structural roots in several mature trees. It cautions that a healthy green canopy should not be interpreted as evidence that a tree is structurally sound, as serious internal defects may remain hidden until failure occurs.

The report also points to governance challenges, including poor coordination between engineering works and tree protection, repeated encroachment of root zones during civil projects, inconsistent maintenance of tree basins, utility installations within rooting areas, limited post-construction monitoring and variations in implementation across wards.

The inspection was confined to roadside and publicly accessible trees, with the report claiming that protected trees within private residential, commercial and institutional premises could not be assessed. Joshi also told HT that the BMC’s claim that it was not responsible for trees within housing societies was legally untenable. “The Maharashtra Tree Act clearly mandates the Tree Authority to protect, preserve and scientifically maintain trees on all lands, including private properties,” he said. “Denying technical assistance to societies seeking help for dangerous trees violates the law. The civic body must provide scientific maintenance and support for all urban trees, irrespective of ownership, to ensure public safety.”

Concluding that tree concretisation is a citywide problem requiring coordinated intervention, the report recommends that the BMC adopt a science-based framework for urban tree management. It calls for preventive management and phased scientific de-concretisation, restoration of degraded root zones, periodic health and structural risk assessments, species-specific arboricultural standards, integration of tree protection into infrastructure planning and stronger institutional accountability.