Manuka_State_Wayside_Park Manuka State Wayside Park (13.4 acres) is state park with arboretum located approximately west of Naalehu, on the Mamalahoa Highway (Route 11) section of the Hawaii Belt Road, Hawaii (island), Hawaii, coordinates The name means "blundering" in the Hawaiian Language, and was the name of the ancient land division (ahupaa) that ran from a bay on the southwest side of the island up the slopes of the Mauna Loa volcano.Manuka Forest Reserve.