Belowground carbon cycling in a humid tropical forest decreases with fertilization.

Only a small fraction of the carbon (C) allocated belowground by trees is retained by soils in long-lived, decay-resistant forms, yet because of the large magnitude of terrestrial primary productivity, even small changes in C allocation or retention can alter terrestrial C storage. The humid tropics exert a disproportionately large influence over terrestrial C storage, but C allocation and belowground retention in these ecosystems remain poorly quantified. Using mass balance and 13C isotope methods, we examined the effects of afforestation and fertilization, two land-use changes of large-scale importance, on belowground C cycling at a humid tropical site in Hawaii.

Transpiration and forest structure in relation to soil waterlogging in a Hawaiian montane cloud forest.

Transpiration, leaf characteristics and forest structure in Metrosideros polymorpha Gaud. stands growing in East Maui, Hawaii were investigated to assess physiological limitations associated with flooding as a mechanism of reduced canopy leaf area in waterlogged sites. Whole-tree sap flow, stomatal conductance, microclimate, soil oxidation-reduction potential, stand basal area and leaf area index (LAI) were measured on moderately sloped, drained sites with closed canopies (90%) and on level, waterlogged sites with open canopies (50-60%).

Forest growth along a rainfall gradient in Hawaii: Acacia koa stand structure, productivity, foliar nutrients, and water- and nutrient-use efficiencies.

We tested whether variation in growth of native koa (Acacia koa) forest along a rainfall gradient was attributable to differences in leaf area index (LAI) or to differences in physiological performance per unit of leaf area. Koa stands were studied on western Kauai prior to Hurricane Iniki, and ranged from 500 to 1130 m elevation and from 850 to 1800 mm annual precipitation. Koa stands along the gradient had basal area ranging from 8 to 42 m/ha, LAI ranging from 1.

Ecophysiology of exotic and native shrubs in Southern Wisconsin : II. Annual growth and carbon gain.

In this study we compared the aboveground growth rates of two exotic shrubs (Rhamnus cathartica and Lonicera X bella) and two native shrubs (Cornus racemosa and Prunus serotina) that are important in southern Wisconsin hardwood forests. For all species except P. serotina, aboveground growth rates in an open habitat were greater than in an understory environment.