Harvesting the surplus is the principle, from Ethan Roland and Gregory Landua's 📝Regenerative Enterprise, that an enterprise may take only the excess a healthy system produces, never the core pools of capital that produce it.
Healthy systems with abundant 📝edges and connections "begin to generate capital surpluses," the authors write (p. 20). In living capital, a tree yields more fruit and seeds than could ever grow into new trees; in intellectual capital, a collaborative team generates more ideas than it can act on. Those emergent surpluses are what may be harvested and exchanged in a regenerative economy. The extractive economy instead "forcibly steals from the core pools of different forms of capital, reducing the ability of the system to maintain itself, much less produce a surplus" (p. 20) — a pattern that shows financial profit while mining living, cultural, social, and spiritual capital.
The principle sets a limit on markets. Roland and Landua warn that pricing ecosystem services through carbon markets or mitigation banking "has the potential to go horribly awry": living capital "should only be valued and exchanged on the marketplace to the extent that the capital being traded is a surplus," and "enterprises must never extract more value than can be regenerated within the capacity of the living system itself" (p. 21).
Their example is Windhorse Farm in Nova Scotia, which harvests a fixed share of its forest's annual growth and culls the weakest trees. Harvested every year since 1840, it has yielded over 7.5 million board feet of timber with 2.0 million still standing and growing (p. 21). In the book's shorthand, a regenerative enterprise "does not harvest the root of the tree of production, only its fruit" (p. 24).