Carbon storage and fixation, and evaluation of environmental services in agroforestry systems in Costa Rica

2 ilus. 3 tab. 9 ref.Se evalu? el almacenamiento y fijaci?n de carbono (C) en: 1) los sistemas agroforestales caf? (Coffea arabica) + eucalipto (Eucalyptus deglupta) de cuatro, seis u ocho a?os de edad, caf? + por? (Erythrina poeppigiana), pasto brachiaria (Brachiaria brizantha) + mangium (Acacia mangium) y pasto brachiaria + eucalipto y en 2) los monocultivos de caf?, brachiaria o pasto ratana (Ischaemun indicum) a pleno sol. M?s del 89 por ciento del C almacenado en los sistemas correspondi? al C del suelo. La fijaci?n de C del componente arb?reo estuvo entre 0.4 y 2.2 t ha-1 a?o-1. El aporte del componente arb?reo al total de C almacenado por el sistema vari? entre 1 por ciento, para eucalipto de seis a?os en caf?, y 7 por ciento para mangium en potreros de brachiaria. El monto pagado en la actualidad en Costa Rica por el servicio ambiental de almacenamiento de C (US d?lares 10-13 ha-1) no es suficiente para tener una influencia significativa en el uso de la tierra. Carbon storage and fixation were studied in: 1) agroforestry systems of Coffea arabica (coffee) associated with Eucalyptus deglupta (eucalyptus) aged four, six or eight years, C. arabica associated with Erythrina poeppigiana (mountain immortelle) and Brachiaria brizantha (brachiaria) pasture associated with Acacia mangium (mangium) or with E. deglupta and in 2) monocultures of coffee, B. brizantha or Ischaemun indicum (ratana) pasture in full sun. More than 89 percent of the C stored in the systems was soil C. Carbon fixation in the trees was between 0.4 and 2.2 t ha-1 year-1. The contribution of the tree component to the total C stored by the system varied from 1 percent, for six year old eucalyptus in coffee, to 7 percent for mangium in brachiaria pastures. In Costa Rica, the amount presently paid for the environmental service of C storage (US dollars 10-13 ha-1) is inadequate to have a significant impact on land use