Fine litterfall and leaf decomposition in a montane koa-ohia rain forest

Author:

Scowcroft, Paul G.

Title:

Fine litterfall and leaf decomposition in a montane koa-ohia rain forest

Periodical:

Proceedings, sixth Conference in Natural Sciences, Hawaii Volcanoes National Park : held at Hawaii Field Research Center, Hawaii Volcanoes National Park on June 10-13, 1986

Year:

1986

Pages:

p. 66-82

Subject:

Biology congresses Natural history congresses Hawaii Volcanoes National Park congresses Ecology Acacia koa

Summary:

Nutrients returned to the forest floor in litterfall and release of nutrients during decomposition are important nutrient cycling processes. Both of these ecosystem level processes may be changed by establishment of alien (introduced) plant species in predominantly native communities. Preliminary studies of litterfall and decomposition were done in a montane rainforest on the island of Hawaii to get indications of rates and to refine sampling procedures. Fine litterfall dry mass and nutrient mass were estimated from litter trap collections in two young koa (Acacia koa) stands and one old koa-ohia (Metrosideros polymorpha) stand in which the alien vine, banana poka (Passiflora mollisima), was established. Annual litterfall averaged from 6,300 to 12,200 kg/ha. Litter fall for the two upper elevation stands lies within the range of values reported for several other tropical montane rainforests . Return of nitrogen and phosphorus per unit of leaf litter dry mass were greater in pole-size koa stands than in the mature koa-ohia stand. Decomposition of koa, ohia, and banana poka foliage was studied using litter bags. Sclerophyllous foliage of koa and ohia, the native species, decayed more slowly than the non-sclerophyllous foliage of the alien , banana poka. High nutrient concentrations and low lignin concentrations in poka litter probably account for its rapid decay. Decomposition of the three species of leaf litter was correlated with initial nitrogen concentration. Banana poka litter may speed decomposition of recalcitrant native leaf litter when they occur in mixture.

Collection:

Monographs