Disturbance regimes, vegetation, and ecological processes occur at many different spatial scales. We can generally define these spatial scales into three groups.

The macro-level ecosystems are major units and are typically composed of seas or continents (Barnes et al. 1998). For example we could study carbon release rates across North America. Within the continents, we have the meso-level ecosystems. These ecosystems are typically identified as mountain ranges or large plains, for example the Rocky Mountains (Barnes et al. 1998). The meso-level ecosystems are further broken down into the micro level. Micro-level ecosystems are local areas such a specific mountain or valley (Barnes et al. 1998).

As one moves from the macro-level ecosystems to the micro-level ecosystems we reduce the amount of complexity. That is to say that the micro-level ecosystems are more homogenous than the macro- and meso-level ecosystems.