Trees in urban environment capturing carbon

Can Planting Trees Really Offset Carbon Emissions? A Realistic Look

Mira Elwood in Climate & Environment December 2025 • 4 min read.

"Explore the potential and limitations of using tree planting as a carbon offsetting strategy in urban environments."

In the face of escalating climate change, individuals and organizations are increasingly looking for ways to reduce their carbon footprint. One popular solution is participating in greening projects, particularly those involving tree planting. Trees, after all, are known to absorb carbon dioxide (CO2), a major greenhouse gas, from the atmosphere. But how effective is this strategy, especially in urban environments? Understanding the real impact of tree planting projects requires a closer look at the science behind carbon sequestration.

Carbon credits, which represent a certified reduction in greenhouse gas emissions, are designed to incentivize companies and countries to invest in projects that mitigate climate change. These credits can be earned through various activities, including renewable energy projects, energy conservation efforts, and, of course, forestry and tree planting initiatives. However, the process of quantifying the amount of carbon dioxide that trees actually absorb and converting that into tangible carbon credits is complex.

This article dives into the methodologies used to calculate CO2 absorption by tree planting projects, particularly in urban settings. By examining the formulas and data used in these calculations, we can gain a clearer understanding of the potential and limitations of tree planting as a carbon offsetting strategy. We'll also explore the challenges and opportunities associated with integrating these projects into carbon credit frameworks, ensuring that they contribute meaningfully to climate change mitigation.

The Methodology Behind Calculating CO2 Absorption

Trees in urban environment capturing carbon

Estimating the amount of carbon dioxide absorbed by trees involves a detailed calculation that takes into account several factors. One common formula considers the tree's growth rate, size, and survival probability over a specific period. This formula helps in determining the total CO2 absorbed by a tree, factoring in the likelihood that the tree will continue to thrive and contribute to carbon sequestration.

The basic formula to calculate CO2 absorption considers variables, including tree height, trunk diameter, and a constant that represents carbon absorption capacity. The formula looks like this:

CO2 absorption = ∫099(1-p)|pH(t)|(d(t))^2|c|dt + (1-p)100|H(100)|(d(100))^2|π / 2

Where:

p = likelihood that the tree will be removed during the year.
H(t) = height of the tree t years after it was first planted (in cm).
d(t) = diameter of the tree trunk (in cm).
c = constant for CO2 absorption (t-C/cm3).

This equation estimates the CO2 absorbed per tree over 100 years, considering the potential for tree removal. A crucial element in this calculation is determining the probability of tree removal. Factors such as tree felling due to construction, natural causes, or urban development must be considered to provide a realistic estimate of carbon sequestration.

The Future of Urban Greening and Carbon Credits

While there are challenges in accurately measuring and verifying carbon sequestration in urban tree planting projects, it's clear that these initiatives offer numerous environmental and social benefits. By refining our methodologies, addressing current limitations, and exploring innovative approaches, we can enhance the effectiveness of urban greening as a climate change mitigation strategy. Recognizing and supporting these efforts through carbon credit frameworks can provide significant incentives for businesses and communities to invest in a greener, healthier future.

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This article is based on research published under:

DOI-LINK: https://doi.org/10.48550/arXiv.2407.05596,

Title: Methodology For Calculating Co2 Absorption By Tree Planting For Greening Projects

Subject: econ.em

Authors: Kento Ichii, Toshiki Muraoka, Nobumichi Shinohara, Shunsuke Managi, Shutaro Takeda

Published: 08-07-2024

Everything You Need To Know

What are carbon credits, and how do they relate to tree planting projects?

Carbon credits represent a certified reduction in greenhouse gas emissions, designed to incentivize climate change mitigation efforts. They can be earned through various projects, including forestry and tree planting initiatives. These credits are crucial because they provide a financial incentive for companies and countries to invest in projects that reduce carbon emissions. In the context of tree planting, earning carbon credits involves accurately quantifying the CO2 absorbed by trees and converting that into tangible credits, which can be complex.

How is CO2 absorption calculated in tree planting projects, and what factors are considered?

Estimating CO2 absorption involves a detailed calculation that considers several factors, including the tree's growth rate, size, and survival probability. The calculation often uses a formula that incorporates variables such as tree height, trunk diameter, and a constant representing carbon absorption capacity. The formula is: CO2 absorption = ∫099(1-p)|pH(t)|(d(t))^2|c|dt + (1-p)100|H(100)|(d(100))^2|π / 2. It estimates the CO2 absorbed per tree over 100 years, considering the likelihood of tree removal (p), the tree's height (H(t)), trunk diameter (d(t)), and a constant (c) for CO2 absorption.

What are the key challenges in integrating urban tree planting projects into carbon credit frameworks?

One of the main challenges is accurately measuring and verifying carbon sequestration in urban environments. Factors such as tree removal, urban development, and the specific tree species can impact CO2 absorption. Furthermore, there are difficulties in quantifying the exact amount of CO2 absorbed by trees and converting that into tangible carbon credits. The probability of a tree's survival and the potential for it to be removed due to construction or other factors must be considered to provide a realistic estimate.

What is the significance of the 'p' variable in the CO2 absorption formula?

The 'p' variable, which represents the likelihood that the tree will be removed during the year, is a crucial element in calculating CO2 absorption. Tree removal can occur due to various reasons, including construction, natural causes, or urban development. Accurately assessing 'p' is essential because it directly impacts the estimated total CO2 absorbed over the tree's lifespan. A higher 'p' value indicates a greater probability of removal, which would reduce the estimated carbon sequestration.

Beyond carbon sequestration, what other benefits do urban tree planting projects offer, and what does the future hold for these initiatives?

Besides CO2 absorption, urban tree planting projects offer numerous environmental and social benefits, such as improved air quality, enhanced biodiversity, and aesthetic improvements to urban landscapes. The future of these initiatives involves refining methodologies, addressing current limitations, and exploring innovative approaches to enhance their effectiveness. Integrating these projects into carbon credit frameworks can provide significant incentives for businesses and communities to invest in a greener, healthier future, fostering meaningful climate change mitigation strategies.