The influence of SO2 fuming on the vegetation surrounding the Kahe power plant on Oahu, Hawaii

Abstract

The study relates to an investigation of the vegetation around Kahe power station, a recently established electricity generating plant at Kahe Point on SW Oahu. A vegetation map was prepared from aerial photographs at 1:5,000 and a search was made for possible S02 damage manifestations from the fumes emitted by the plant. Three major communities were identified, (1) closed forest of Prosopis pallida, (2) open forest-scrub dominated by Leucaena leucocephala and Acacia farnesiana and 3) open scrub-grassland dominated by the native pili grass (Heteropogon contortus). Within each of these major units, two to three floristic and structural subunits were mapped. No S02 damage was noted in the vascular plants. A separate survey of rock-lichens on identically sea-breeze-exposed ridges, north and south of the power plant, showed a considerably lower abundance of foliose rock-lichens in the southern area which receives much of the S02 plume. It was concluded that a beginning influence is shown by the lower abundance of lichens and that S02 damage in the vascular plants may show up only during the rainy season when the vegetation is actively growing. The investigation was done during the dry season in September.