Shifting cultivation is an agricultural system where forest land is cleared, cultivated for a few years, and then abandoned to allow forest regeneration, with the cultivators moving to a new plot. This system is intimately tied to the forest ecosystem cycle. While the term "ecosystem metric" is unusual phrasing in this context, shifting cultivation is often studied as a specific type of agro-ecosystem, and its characteristics (such as soil fertility decline, forest regeneration time, biodiversity changes) are inherently ecological "metrics" related to the sustainability and impact of the system on the environment. Among the given options, it is the system most fundamentally defined by its interaction with and reliance on natural ecological processes and succession.