Phenology and growth of Hawaiian plants, a preliminary report

Abstract

Observations on phenology and growth of several Hawaiian plants between January 1971 and June 1972 are presented. Most species exhibit some seasonality in flowering, fruiting, flushing, and (at least in deciduous species) leaf fall. Most phenophases show single annual peaks, but durations of phenophases generally extend over periods of several months, and onset and cessation of most phenophases in gradual rather than sharply marked. In Acacia koa the flowering peak occurred between December 1971 and February 1972 in plots on the Mauna Loa Strip Road, and in October 1971 in the Kilauea Forest Reserve, but all plots showed considerable winter flowering. However, little or no flowering took place in the winter of 1970-71. At higher elevations peak flushing was during summer months, at lower elevations during winter and spring. In Sophora chrysophylla flowering and flushing took place throughout the year without pronounced peaks at Kipuka Nene. Plots at 6000 and 6700 feet on the Strip Road showed flowering throughout the year, but with pronounced winter peaks. At 4000 and 5150 feet on the Strip Road the flowering peak was during winter and no summer flowering was found. Peak flushing occurred during spring and summer in all Strip Road plots. Cheirodendron trigynum shows peak flowering in summer, peak flushing in winter and spring. Sapindus saponaria flushes in spring, flowers in summer, and loses its leaves in winter. Diospyros ferrea flushes throughout the year, but most heavily in fall and winter; peak flowering is during winter and spring. Erythrina sandwicensis loses its leaves in spring, flowers during summer, and flushes in the fall. Ilex anomala flushes in spring, shows peak flowering in summer with flowering extending into fall and winter. Coprosma ochracea has peak flushing and flowering simultaneously in spring. Myrsine lessertiana has peak flushing in spring, with a less pronounced flush in fall; the flowering peak is in the late winter, continuing through spring. Myoporum sandwicense shows peak flowering in summer and fall; flushing seems to occur throughout the year. Santalum ellipticum flowers and flushes throughout the year, with peaks for both extending from summer to fall. Dodonaea viscosa seems to flush throughout the year; peak flowering occurs in fall and extends into winter and spring. All species examined show cambial activity throughout the year, but growth rates vary from month to month. It has not been possible to demonstrate correlations between rainfall and growth rates.