Looking remarkably like grass, this is actually a field of sugar cane. What's lacking is a size perspective because these canes are about 3 meter(10 ft) tall.
The central region of Maui, between the two large volcanoes of that island, has thousands of acres of sugar cane and is the last of the Hawaiian islands to grow sugar to any degree. A thirsty crop, rainwater is diverted from the northern slopes of Haleakala (Road to Hana region) to irrigate these cane fields.
It's often quite windy in Maui the breeze makes these fields come alive, moving and swaying in the wind like a crazed hula dancer!