Carbon Estimation Tools: A Primer

Scale
Scale is perhaps the most important factor to consider when selecting the appropriate tool for carbon estimation. The tool's scale may range from global, national, or regional on down to stand or tree-level. As you may guess, a tool's scale defines its purpose and potential applications. Table 1 provides more detail on the appropriate scale for each tool, while a specific tool's "landing page" here on the CCRC can give you much more specific information about that tool's purpose and potential applications.

Required Input Data
The issue of required input data is very closely related to the issue of scale. Some decision support tools are BYOD (bring your own data), while others draw FIA (Forest Inventory and Analysis) or other data that the Forest Service has been collecting for decades. Typically, the smaller or more precise the scale, the more likely you'll need to provide your own data. That's because FIA data are collected at a larger scale, using both remote sensing and field plots that are spaced at one plot per every 6,000 acres of forest. Statistics gives us many ways to determine an accurate sample size, but you don't need to be a statistics whiz to see why creating a stand- or even small county-level estimate using FIA data would lead to a very small sample size and inaccurate results! That's why most carbon estimation tools designed for smaller scales require more data – data which the user must often supply.

Accessibility and Ease of Use
Are you looking for outputs this afternoon or next month? Different tools require varying levels of user expertise and investments of time. Generally speaking, tools that don't require you to BYOD (bring your own data), tend to be easier to learn and use. On the other hand, models that yield spatially explicit and temporally dynamic results may need to be paramatized, or "tuned", a process that generally involves a certain degree of expertise. Among other things, table 2 provides a subjective ranking of ease-of-use for each carbon estimation tool.

Potential Applications
This topic is closely related to the issue of scale, but is more specific and personalized. It gets to the question of "what do you want to know and why?" Are you trying to inform national policy, decipher appropriate management actions, or communicate to the public about the benefits of local street trees? It's important to have some idea of what you'd like to accomplish when deciding what tool is appropriate. On the other hand, if you're completely new to the world of carbon estimation tools, merely browsing through the options offered will help you gain a better perspective of what information and options may be available.