Bamboo forests need large emergent trees to provide shade if they are to survive.
(they; are; to survive) (they; to survive; ) (Bamboo forests; need; large emergent trees; to provide shade if they are to survive) Context(Bamboo forests need,List([0, 19))):(Bamboo forests; need large emergent trees to provide; shade)
Bamboo forests need,List([0, 19))
they they Bamboo forests Bamboo forests
are to survive need need large emergent trees to provide
to survive
large emergent trees to provide shade if they are to survive
shade