Robusta was planted in Halawa during reforestation efforts in the 1930s. Hawaii’s sugar plantations knew that sugar’s survival depended on the health of the forests. They were aware that their intensive agriculture, coupled to logging, and the presence of cattle, pigs and invasive plant species, had been causing extensive damage to the watershed.

At least 5 million eucalyptus robusta trees were planted in Hawaii between 1910 and 1960 in total, for the sake of the forests, but also as a source for sustainable timber, delivering a hardwood that’s gorgeous and deep-red.

Marked by deeply furrowed dark gray-brown bark, eucalyptus robusta grows well in Halawa. Most of the zip line’s platforms are built into specimens of this tree. Bridge materials, wood hardware, and cable backings are also made of eucalyptus robusta, from trees harvested in the gulch.