We now know that to sustain forest productivity it is important to protect soils, to maintain forest cover, and to preserve the links among living and nonliving components of a forest.
(We; know; that; T:now) Context(We know,List([0, 11))):(We; know that to sustain; forest productivity)
We know,List([0, 11))
We We
know know that to sustain
that T:now
forest productivity