Additionality: Forest project practices that exceed the baseline characterization, including any applicable mandatory land use laws and regulations. Additionality measurements constitute carbon credits for emissions reductions.

Baseline: The emission of greenhouse gases that would occur without the contemplated policy intervention or project activity.

Carbon/emissions reductions credits: A greenhouse gas "currency" that can be bought and sold within a carbon market system. One carbon credit generally equals one metric ton of carbon dioxide or carbon dioxide equivalent in emissions reductions.

Carbon dioxide equivalents: The emissions of a gas, by weight, multiplied by its "global warming potential." Enables different greenhouse gases to be compared on equal scale.

Carbon footprint: a measure of the impact human activities have on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide.

Carbon sink: Occurs where carbon sequestration is greater than carbon releases (emissions) over a period of time.

Emissions avoidance: Protection of carbon stocks in order to prevent the release of greenhouse gas emissions.

Emissions reductions: Removals or reductions of CO2 and prevented CO2 emissions resulting from Registry-approved forest projects. GHG reductions are calculated as gains in carbon stocks over time relative to the project baseline.

Greenhouse gases (GHG): Any gas that contributes to the "greenhouse effect," the insulating effect of atmospheric greenhouse gases (e.g., water vapor, carbon dioxide, methane, etc.) that keeps the Earth's temperature about 60ºF warmer than it would be otherwise.

Sequestration: Usually referred to as carbon sequestration, the process through which carbon dioxide (CO2) from the atmosphere is absorbed by trees and plants though photosynthesis and stored as carbon in biomass (tree trunks, branches, foliage and roots) and soils. New biomass growth increases carbon storage in terrestrial vegetation. Also referred to as terrestrial carbon sequestration.