Date of Award

1988

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Harley J. Walker

Abstract

The composition of a forest of relicts of cultivation in four uninhabited valleys in Kohala, Hawaii, is documented. A general hypothesis is made that arboreal distribution patterns are a function of both historical land use and ecological interaction since abandonment. The physical and historical geography of the valleys was investigated. Climate varies little, but distinct geomorphic zones offer differing biological environments. Prehistoric land use consisted of taro patches with intercropped banks. Talus slope gardens supported the Polynesian tree crops 'ohi'a 'ai (Eugenia malaccensis), kukui (Aleurites moluccana), 'ulu, (Artocarpus incisus), ti (Cordyline terminalis), and noni (Morinda citrifolia), important in today's flora. Gathering took place on slopes. Western contact with Hawaii, initiated in 1778, brought new crops. Papaya (Carica papaya), mango (Mangifera indica), guava (Psidium guajava), and coffee (Coffea arabica) were important adoptions in Kohala. As land use changed, the region also suffered depopulation, losing half its numbers between 1830 and 1870. Chinese rice-growing forestalled complete abandonment, which finally occurred after 1920. Current vegetation was assessed by creating 15 sampling units containing 554 quadrats. Inside quadrats, the size-class and species of each tree was recorded, yielding measures of frequency, density, cover, importance, and richness. Four environmental conditions were also assessed. The resulting variables were mapped and inter-correlated. Guava, kukui, noni, 'ohi'a 'ai, ti, hala (Pandanus odoratissimus), and coffee proved the most numerous species. Rarer species were often localized, illuminating historical land use. The data were examined and reformatted into matrices suitable for cross-classification analysis. Consistent relationships included the association of guava with low-slope and 'ohi'a 'ai with high-slope. Richness showed association with high-slope and cliff proximity. The mark of Hawaiian cultivators is apparent. Polynesian species accounted for 48.2% of the importance value. Size-class histograms revealed a stable structure for most species. Certain Western exotics had spotty distributions or size-class structures that indicate impending extinction. Native species are rare except for hala. There are indications that they were probably scarce during prehistory as well. This study exemplifies historical biogeography. It synthesizes methods of geography, ecology, and archaeology for the purpose of better interpreting cultural vegetation.

Pages

409

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