Tamil Nadu Plans Scientific System to Measure Climate Benefits of Urban Tree Plantation

Chennai — The Tamil Nadu government is preparing to introduce a scientific framework to evaluate the environmental and climate benefits of tree-planting efforts in urban areas. The initiative aims to systematically measure how expanding green cover in cities contributes to climate mitigation and strengthens ecological resilience.

A detailed roadmap has been developed to create a structured method for tracking the environmental gains from urban forestry programmes. Officials say the framework will help quantify benefits that go far beyond beautification and biodiversity conservation. These include carbon sequestration, reduction in urban temperatures, improved groundwater recharge, better flood management and stronger ecological balance in rapidly expanding cities.

The plan has been formulated under the Indo-German Support Project for Climate Action in India. It seeks to integrate climate-focused monitoring into the state’s urban greening initiatives so that the outcomes of such programmes can be incorporated into broader climate strategies and sustainability planning.

Experts associated with the project have highlighted the need for measurable indicators that can demonstrate the environmental value of large-scale plantation drives. Until now, urban forestry projects in the state have mainly focused on expanding green cover and restoring ecological balance, but their wider climate benefits have not been systematically assessed.

The lack of reliable data has also limited the ability of policymakers to include urban forestry achievements in climate reporting, policy planning and investment decisions.

In recent years, Tamil Nadu has undertaken large plantation drives through the Green Tamil Nadu Mission. Between 2022-23 and 2025-26, the programme planted more than 14.16 crore seedlings across the state, covering a potential area of about 1.28 lakh hectares.

Initial estimates suggest these plantations could help absorb between two and three lakh tonnes of carbon dioxide every year. While detailed data on urban plantations is still being compiled, officials estimate that about 25 lakh seedlings have already been planted in city areas. Plans are also in place to add another seven lakh seedlings in urban centres during the current year.

Despite the scale of the plantation drives, authorities acknowledge several challenges in urban forestry efforts, including limited availability of land in cities and the need for consistent maintenance of planted trees.

The proposed monitoring framework will evaluate both climate mitigation and adaptation benefits. Carbon capture will be calculated through biomass growth using field measurements such as trunk diameter or standard carbon sequestration models.

Alongside carbon absorption, the framework will track four key adaptation indicators: reduction in the urban heat island effect, improved groundwater recharge, better stormwater and flood management, and enhanced biodiversity within city ecosystems.

Trees help reduce temperatures through shade and evapotranspiration, while vegetation also improves soil infiltration and limits surface runoff during heavy rainfall.

However, the implementation of the monitoring system faces several institutional and technical hurdles. These include the absence of baseline environmental data, limited technical training for field staff and inadequate use of advanced tools such as remote sensing and environmental sensors.

To address these issues, the roadmap recommends a phased rollout of the system through pilot projects, policy support and capacity-building programmes. Authorities believe that integrating climate impact assessments into urban forestry initiatives will help strengthen environmental planning and allow the government to measure the long-term climate value of tree-planting programmes.

With inputs from IANS