While it is difficult to define a baseline for an &#147;undisturbed&#148; native California forest ecosystem, it is clear that both of these practices have interfered with normal forest succession, and engendered a long-term build-up of biomass in excess of the levels that would exist in the native, undisturbed forest ecosystem.
(the levels; would exist; L:in the native, undisturbed forest ecosystem) (both of these practices; engendered; a long-term build-up of biomass in excess of the levels)
the levels both of these practices
would exist engendered
L:in the native, undisturbed forest ecosystem
a long-term build-up of biomass in excess of the levels