Such immense plants require an extremely large leaf area in order to harness enough sunlight for photosynthesis, and the combined crowns of these enormous trees form an almost continuous canopy.
(Such immense plants; require; an extremely large leaf area) (the combined crowns of these enormous trees; form; an almost continuous canopy)
Such immense plants the combined crowns of these enormous trees
require form
an extremely large leaf area
an almost continuous canopy