Most estimates of P export from natural or disturbed humid tropical ecosystems by streams have been based only on export of dissolved P, even though P often is limiting and can be expected to be strongly associated to particles. Therefore loss of ignition (LOI) and particulate P (Ppart) analyses were made on organic and inorganic detritus resulting from surface erosion and on stream-suspended sediments in an undisturbed rain forest (control), as well as during and after conversion of rain forest into forest plantation. Control forest surface erosion and stream sediments consisted mainly of organics, and dissolved P (Pdiss) dominated over Ppart in stream water. The same relation was found after conversion, with a maximum mean Pdiss/Ppart ratio of up to 10 after burning, compared with 2--2.5 for control forests. This larger difference was assumed to depend on PO4 dissolved from ashes to larger concentrations than could be adsorbed during the short time (<1 hour) to reach peak flow during rainstorms. ¿ American Geophysical Union 1996