Tree-Nation's CO2 offset methodology

Tree-Nation is committed to making reforestation accessible, measurable, and impactful. Our CO₂ offset methodology provides a consistent, transparent way to calculate the carbon captured by the trees we plant—based on 10-year carbon models, specific to each species.

Unlike traditional offset standards (e.g. VCS, CCB, Plan Vivo), which are designed primarily for large-scale, verified carbon markets, Tree-Nation focuses on practical offsetting solutions that are easy to use, diverse in scope, and tailored to reforestation projects of all sizes.

🌱 Key Differences: Traditional vs Tree-Nation Methodology

📊 How our methodology works 

Our CO₂ offset calculations are continuously updated to incorporate additional parameters and increasingly accurate data, collected from our projects during regular site visits. The Tree-Nation methodology, now in its fifth version*, is conducted in three steps:

Calculating tree volume
For each tree species, we use a large set of data, including height, trunk diameter, branch/root volume, dry mass, wood density, growth pattern (slow to fast), growth region climate, and average lifespan to estimate a reasonable species dimension average.

The carbon equation
Dry wood is composed of about 50% carbon, 6% hydrogen, 44% oxygen, and trace amounts of inorganics. Once we have a tree species' average dimensions, we determine its average mass, and then derive the amount of carbon that the tree species typically holds.

From carbon to CO₂
We utilize a conversion ratio of 3.667, representing the mass of carbon to that of CO₂, to translate the average carbon content of a tree of a specific species into its corresponding CO₂ value. We cap all species' measurements at ten years old, ensuring that they take place during peak absorption periods (between 10 and 35 years, on average) for swift impact in combating climate change.

We take a conservative approach in our estimations. Although trees will continue to absorb CO₂ beyond our measurement period, the offset figures we provide are guaranteed. This means you can confidently claim the impact listed on your Tree-Nation certificates.

🔟 10-Year CO₂ modeling & upfront accounting

Tree-Nation’s methodology estimates how much CO₂ each tree will capture over its first 10 years—a period when growth and absorption are typically at their peak.

We credit this 10-year value upfront, at the moment the tree is planted. This allows you to see your expected environmental impact right away, while remaining transparent that:

⚠️ The carbon is not absorbed instantly — trees capture CO₂ gradually over time.

This ex-ante approach aligns with widely accepted environmental reporting practices and ensures clarity when presenting your impact to stakeholders.

Why use 10-year estimates?

• Reliable & conservative: We base our values on conservative assumptions, and cap all species’ CO₂ values to reflect only their first 10 years of growth.

• Transparent & standardized: You can compare tree impact across species and projects with confidence.

• Visible & motivating: Displaying estimated CO₂ capture helps you, and your audience, track progress, stay engaged, and celebrate milestones.

*Our newest methodology versions update species' CO₂ absorption rates only at the time of
implementation, not retroactively