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Estimating Your Potential Credits

by mhowell last modified 2007-12-06 11:23

How are C pools estimated?

            Each registry has guidelines regarding methodologies that must be utilized for estimating each specific C pool.  Many of the registries also allow land owners to choose between a number of methods.  There is actually a fair bit of convergence in estimation methodologies between the registries, although all registries do not accept all methods. The available approaches are:

1)      Direct in-field measurements of carbon

2)      Mathematical models of forest carbon

3)      Look-up tables of carbon contents

Method Approach Costs  Uncertainty 
 Direct in-field measurements

Inventories and/or sample collections are utilized to estimate carbon contents.  Repeated measurements are required over many years. Sample plots must be established, measurements made for required and optional carbon pools, and methods must be developed to translate field measurements into carbon mass estimates for the entire forest area.   

High cost (up to $5/acre), requires skilled professionals <10%
 Mathematical models Using factors such as timber volume, forest type, stand size class, etc, models estimate the amount of carbon.  These might be growth and yield models for tree carbon or soil simulation models for soil carbon estimation. The specificity of the model will depend on the detail of the inventory data that it receives.  All models require some knowledge of forest site conditions and often some forest stand information. Medium cost, requires computer model 10-30%
Look-up tables

Tables with average carbon contents for forest stands similar to the forest stand of interest are utilized.  The data are from earlier forest carbon models or formal forest inventories.   The look-up tables can be general (e.g., based on regional forest types such as northern mixed hardwood) or  locally specific information (e.g., loblolly pine of site index 52).


Low cost, limited knowledge required 20-40%

What are the units for C accounting?

By agreement C credits (or C trading offsets) are sold in units of metric tons of CO2 equivalents.  This means that every metric dry ton of  forest C sequestration is equal to 3.67 metric tons of CO2 equivalents (i.e., the atomic weight of C is 12 g, that of Oxygen is 16 g, as such C is 12/44 of a CO2 molecule so we divide C by this fraction to get CO2 equivalents). 

                             1 metric dry ton of C = 3.67 metric tons of CO2 equivalents

How much money can you make trading C credits?

A landowners ability to earn money trading carbon credits depends on many factors including where they own land, how much land they own, what are the forest conditions, management activities they practice, the availability of buyers, and the price per ton of carbon.

Current prices for Carbon per ton can be found here

What tools are available for estimating your C credits?

As a first approximation, however, a landowner can use a few tools available here to estimate the amount of carbon currently on their land and the potential rate of accumulation of carbon on their land.  

The simplest tool is INFORM (INteractive Fast Online Report Maps).  INFORM provides estimates of the standing stock of carbon in coniferous or deciduous forests for any county in the the Southeastern USA.  (Unfortunately, maps for other regions are not presently available.)

    • Using your cursor simple choose your state, direct the cursor to the county of your forest lands, be sure to toggle to AC from TOT if necessary, and the table on the right will present the average tons of C per acre for coniferous or deciduous forest types.  If you know the acres of each forest type on your land you can multiply to get a first estimate of the total C available on your land.

The next tool, the carbon calculator, is available nationally and includes all forest carbon pools. 

    • In this case you are required to step through a series of dropdown menus to identify your region, forest type, and age.
    • After doing so, a table will appear the has estimate on a per hectare basis of the average amount of carbon in each forest carbon pool.
    • To estimate the potential accumulation of carbon on your lands over time you can select a second older age to generate another table.  Using the difference between these two tables can provide an average expected rate of carbon accumulation.
    • Data in this carbon calculator come from the US Forest Service General Technical Report NE-343 (Smith et al., 2006).

The final tool is one developed by the USDA Forest Service called COLE (Carbon OnLine Estimator).  COLE produces similar data as the carbon calculator but can take you to the county level similar to that in INFORM.  To utilized COLE access the weblink provided and follow the tutorial.

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