“…This is because within the Amazon forest domain itself, there are many occurrences of savanna vegetation despite high rainfall (>2000 mm) with unusually adverse physical and/or chemical conditions for tree growth apparently responsible [Beard, 1953;Anderson, 1981;Brown, 1987]. Examples of this include the savannas of the relict sandstone cover that once made up much of the land portion of the Guyanas [van Donselaar, 1969]; these include the savannas of Roraima (Brazil) as well as the Rupunini savannas of Guyana [Myers, 1936] and the Sipalwini savanna of southern Suriname [van Donselaar, 1968], the Grand Sabana area of Venezuela [Dezzeo et al, 2004] as well as scattered "islands" across the northeast of Brazilian Amazonia [Andreae Lima, 1959;Egler, 1960;Ratter et al, 2003]. Although in some cases the presence of such "Amazonian savannas" can clearly be attributed to water-logging [e.g., Huber, 2006], in other cases, the generally poor nutrient status of the sandy soils seems to be the primary cause [Beard, 1953;Anderson, 1981;Brown, 1987].…”