Wood Production and Native Vegetation Conservation in Hawaii's Uplands

Stand basal area, a stochastic growth model (KOA), and GIS were used to simulate and spatially integrate potential timber production of the native koa (Acacia koa) in uplands on the island of Hawaii. Vegetation patterns were examined to estimate potential impacts on the ecosystem from increased forest activities and to select suitable areas for wood production and ecological preservation. The KOA model predicted a production of 82,200 m3 of merchantable koa wood at age 30 from nonmanaged, naturally regenerated stands. The spatial analysis revealed four corridors with high wood production. Mean vegetation patch size was 69 ha, with a greater frequency of small patches than of large patches. An index of patch shape and complexity was similar for patches from different categories, but it was inversely correlated to patch size, indicating different processes affecting landscape structure. A shape diversity index was greater for savannah patches than for closed canopy units, implying higher complexity in more disturbed areas. Patches within the same category were highly aggregated, and the core of the area with lower degree of disturbance matched low-productivity sites for koa.