In most soils of the humid tropics, kaolinitic topsoil horizons overlie more gibbsitic horizons. This arrangement cannot be produced simply by leaching. Quantitative measurement of the turnover of chemical elements in the litterfall in an Amazonian ecosystem indicates that the forest cycles a significant amount of elements, particularly silicon. As a result, fluids that percolate through topsoi...

Published by the College of Tropical Agriculture and Human Resources (CTAHR) and issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Andrew G. Hashimoto, Director/Dean, Cooperative Extension Service/CTAHR, University of Hawai‘i at Mänoa, Honolulu, Hawai‘i 96822. An equal opportunity/affirmative action inst...

1 Nitrification is an important microbial process in humid tropical ecosystems because of its effects on potentials for nitrogen loss via nitrate leaching and denitrification and on the hydrogen ion cycle. Nitrification rates in humid tropical soils vary markedly among different forest types but in general appear to increase following disturbance. Proximal controls on nitrifiers include ammoniu...

Chromoblastomycosis is a mutilating infection of the skin and subcutaneous tissues caused by melanized fungi belonging to the order Chaetothyriales. Proven cases of the main agent, Fonsecaea pedrosoi are mainly limited to (sub)tropical, humid climates of Latin and Central America and the Caribbean. Fonsecaea monophora has a global distribution along the equator. Cases outside the (sub)tropics h...

[1] The enhancement of infiltration capacity in the presence of vegetation is well documented in arid ecosystems where it can significantly impact the water balance and vegetation spatial organization. To begin progress toward developing a theory of vegetation‐infiltration interactions across a wide spectrum of climate regimes, three key questions are addressed: (1) Does vegetation also enhance...

Forest loss and degradation in the tropics contribute 6–17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world’s humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the em...