Can tree planting alone lead to zero carbon emissions?

Tree planting and carbon sequestration

To offset its projected emissions of 3.62 billion tonnes of CO2 for 2023-24 through tree planting, Kerala would need to plant at least six billion trees, which would require 55 million acres of land (or five times the state’s geographical area). This is an impossible task, considering that the total land available for non-agricultural use, land under mixed crops, wetlands and community forestry is less than 1.16 million acres.

The recommended spacing for agroforestry systems is 20 feet x 20 feet, which allows for 109 plants per acre, as they need sunlight, water, and nutrients from the soil. Young trees absorb about 5.9 kilograms of CO2 per year, and mature trees can absorb about 22 kg per year.

We also need to consider that when trees die, the carbon stored in their biomass is released back into the atmosphere through decomposition, combustion (in the case of forest fires) or harvesting. However, soil can continue to store carbon long after the trees have died, contributing to long-term sequestration, provided the trees or leaves are not burned.

In addition, not all regions are suitable for large-scale tree planting due to potential negative impacts, such as loss of native species. Ensuring the survival and growth of planted trees over time requires proper species selection, effective planting methods, and ongoing maintenance.

Better options

The Draft Kerala Blueprint, prepared by the Confederation of Indian Industry with support from the Kerala Energy Management Centre, under an initiative of the Bureau of Energy Efficiency, indicates a potential reduction of CO2 emissions by 470 million tonnes per annum by 2031 through various energy efficiency initiatives at an estimated capital expenditure of Rs 4,453 crores.

Considering the growth observed in the Pachathuruthu project, which has expanded to 856 acres in five years, it is projected that the current project could cover a maximum of 5,000 acres by 2050. The estimated annual absorption of CO2 by 2050 through the Pachathuruthu project is between 12,000 and 20,000 tonnes, assuming that trees are planted on 5,000 acres and mature to absorb CO2 at the rate of 22 kg per year. Therefore, it is obvious that reducing the carbon footprint of the power sector should be a primary focus.