Dynamics of organic matter and nutrient return from litterfall in stands of ten tropical tree plantation species

Abstract

We studied the rates and patterns of carbon and nutrient¯uxes in litterfall in ten tropical tree plantation species grown at the USDA Forest Service Arboretum in the Luquillo Experimental Forest, Puerto Rico. The stands were 26-years old and grew under similar climatic and edaphic conditions. Individual plantation species ranked differently in terms of their capacity to return mass and speci®c nutrients to the forest¯oor, and with respect to their ef®ciency of nutrient use. The species that returned the most mass did not return the most P, N, or cations. Moreover, species differed according to the amount of N and P resorption before leaf fall. These differences re¯ect the variation in the ecophysiological response of each species to edaphic and climatic conditions. The difference between average and minimum resorption values of the species studied indicate that other environmental factors, such as heavy winds or the physical effects of heavy rains, can force the shedding of nonsenesced leaves. This higher quality material, although not very much in quantity, can provide a small pulse of available nutrients to the forest¯oor community. The same holds true for other high nutrient/low mass fractions of litterfall such as reproductive parts and miscellaneous materials.In areas with no prevalent or strongly seasonal water limitations, temporal variations of leaf litter on the forest¯oor are the combined result of the rate of fall and decomposition of the falling material, and the diverse responses of species to different environmental cues. Leaf fall was inversely correlated to reduced water availability in three of the species studied. Leaf fall of the other species was correlated either to daylight duration or minimum temperatures. The results highlight the importance of understanding species performance relative to nutrient and mass metabolism before selection for plantation use, or for rehabilitation of degraded lands. #

Seasonal changes in soil organic matter after a decade of nutrient addition in a lowland tropical forest

“…In contrast, the 7 % increase in leaf litter N after a decade of fertilization is identical to the increase observed in the first six years (Kaspari et al 2008), suggesting that continued N addition does not further increase leaf litter N. Leaf litter N concentrations varied seasonally, with highest concentrations in the late wet season, but there were no seasonal differences for P. Greater N concentrations in wet season leaf litter were also reported for a nearby forest on Barro Colorado Island (Yavitt et al 2004), as well as in a variety of other tropical forests (e.g., Chuyong et al 2000;Cuevas and Lugo 1998), suggsting that it is a widespread phenomenon. Seasonal variation in leaf litter P appears to be slightly more muted compared to the variation in N, as was also reported for an African forest dominated by ectomycorrhizal trees (Chuyong et al 2000).…”

“…(Cuevas and Lugo 1998). Indeed, only four species out of the hundreds at the site occur in all plots, and those four species vary markedly in their litter nutrient concentrations (Mayor et al 2014).…”

“…Indeed, only four species out of the hundreds at the site occur in all plots, and those four species vary markedly in their litter nutrient concentrations (Mayor et al 2014). However, the change in leaf litter N might indicate reduced resorption of N during leaf senescence in the late wet season, or the contribution of non-senesced leaves (with higher N and a lower C:N ratio) in this period of greatest rainfall and frequent storms (Cuevas and Lugo 1998). This latter possibility seems unlikely, however, given the absence of parallel variation in leaf litter P.…”

Alocação de nutrientes em plantios de eucalipto no Brasil

“…Esta imobilização pode evitar perda por erosão e lixiviação (Cuevas & Lugo, 1998) e contribui para aumentar o teor de nutrientes das suas camadas superficiais, visto que o sistema radicular do eucalipto explora camadas profundas do seu perfil e pode realocar os nutrientes para as camadas superficiais. A intensidade da colheita florestal adotada determina a quantidade de nutrientes exportados do sítio.…”

Litterfall dynamics in Boter-Becho Forest: Moist evergreen montane forest of Southwestern Ethiopia

“…It has been suggested that rainfall may have a two-fold influence on litter production as it may induce water stress in dry periods which increases shedding of senescent leaves whereas heavy rainfall at some time of a year force the shedding of non-senescent leaves. This cycle of events provides a nutrient pulse through higher qualities of leaf litter (Cuevas and Lugo, 1998;Johansson 1995;Morrison, 1991;Parker, 1983;Gosz et al, 1976).…”