Aggregated Methods for Calculating Tree Carbon Stock and Sequestration Rate, and Soil Carbon Stock from Field Collected Fixed Radius Plot Data

This document summarizes methods for calculating living and dead tree carbon stock density (Mg C/ha-1), soil carbon stock density (Mg C/ha-1), and annual modeled live tree carbon sequestration rates (Mg C/ha-1/yr-1) in forests using stem data collected in forested natural areas using a fixed-area plot methodology. These methods were aggregated from various literature sources (cited in text), and are a modified form of the methods used in Pregitzer et al. 2021. Differences between those methods and what is outlined here are: 1) updated species coefficients for tree carbon stock; 2) use of measured instead of estimated soil bulk density for soil carbon estimates; 3) modified methods for standing dead tree carbon; 4) removal of by-vigor scaling for carbon sequestration estimates; and 5) correction of the stem bark reduction factor used for Equation 10.

In a nutshell, this resource offers:

• Methods for calculating tree and soil carbon stock. 
• Methods for calculating annual modeled live tree sequestration rates.
• Equations sourced from relevant literature, with some modifications for this use-case (as noted in the document).

How to use this resource:

• As an example of data required to calculate carbon storage. 
• As a way to calculate carbon storage in an urban context. 
• As a supplement to carbon fact sheets.

Author: Crystal Crown, Natural Areas Conservancy, Chloe Hanna, Yale School of the Environment, and Clara Pregitzer, Natural Areas Conservancy

Date published: 2023

Point of contact: Crystal Crown, crystal.crown@naturalareasnyc.org