Where necessary foresters control the grasses and shrubs that use up the water, plant food and sunlight needed by the trees.
(necessary foresters; control; the grasses and shrubs that use up) (the grasses and shrubs; use up; ) (plant food and sunlight; needed; by the trees)
necessary foresters the grasses and shrubs plant food and sunlight
control use up needed
the grasses and shrubs that use up
by the trees