Litterfall and nitrogen-use efficiency of plantations and primary forest in the eastern Brazilian Amazon

Smith, Kristin; Gholz, Henry L.; Oliveira, Francisco de Assis

doi:10.1016/s0378-1127(98)00247-3

Cited by 67 publications

(53 citation statements)

References 25 publications

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“…v. pallaciana (1.3 Mg C ha -1 year -1 ), but the contribution of no-needle litterfall was surprisingly low (less than 5%). Thus, upon the scarce information of genus Pinus in Mediterranean areas, litterfall rates seems to be in a range between 1.5-2 Mg C ha -1 , (with our data fitting in this threshold) far away from values of 3 Mg C ha -1 year -1 found in semi-arid areas (Pérez-Suárez et al, 2009) or up to 5 Mg C ha -1 year -1 in tropical areas (Smith et al, 1998). Regarding oak litterfall rates, information is even more limited.…”

Section: Discussioncontrasting

confidence: 49%

Aboveground soil C inputs in the ecotone between Scots pine

Díaz-Pinés¹,

Sánchez²,

Montes

2011

For. syst.

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Aboveground litterfall from Pyrenean oak (Quercus pyrenaica Willd. a semi-deciduous species), mixed Pyrenean oak-pine and pine (Pinus sylvestris L.) forest stands was surveyed in two sites in a Mediterranean mountain area during a period of 36 and 29 months, respectively. Separation in different litterfall fractions was performed, and C content of each fraction was measured to calculate the C flux to the soil due to litterfall. Our results showed that litterfall input was higher in pine stands than in Pyrenean oak stands (1.8-2.4 Mg C ha -1 year -1 at pine plots and 0.9-1.4 Mg C ha -1 year -1 at oak plots) and mixed plots showed intermediate values. Needles or leaves contributed about 50% to total litterfall, underpinning the importance of the rest of materials in the soil C input. The seasonal pattern showed a maximum in Pyrenean oak stands in autumn-early winter, while the pine stands had the maximum in summer, which is in consonance with the physiology of fall of broadleaves and coniferous trees in these latitudes , but clearly differs from needle-shed in Central and Northern Europe. A dry-spring year corresponded to a lower leaf fall during the following autumn, and leaf abscission came some weeks earlier than a year with a rainy spring.Key words: litterfall; Pinus sylvestris; Quercus pyrenaica; ecotone; Mediterranean mountain. ResumenCaída de hojarasca en un ecotono Pinus sylvestris L.-Quercus pyrenaica Willd. en la Sierra de Guadarrama La tasa de caída de hojarasca en parcelas puras de rebollo (Quercus pyrenaica Willd.), parcelas mixtas de rebollo y pino silvestre y parcelas puras de pino (Pinus sylvestris L.) fue estudiada en dos localizaciones de montaña mediterránea durante 36 y 29 meses, respectivamente. Se llevó a cabo una separación de los componentes de la hojarasca, y se determinó el porcentaje de C en cada una de las fracciones, para calcular un flujo de entrada de C al suelo debido al desfronde. Nuestros resultados muestras que la tasa de caída de hojarasca fue más alta en parcelas de pino que de rebollo, alrededor del doble (1.8-2.4 Mg C ha -1 año -1 en pino frente a 0.9-1.4 Mg C ha -1 año -1 en rebollo); las parcelas mixtas mostraron valores intermedios. Las acículas u hojas contribuyeron alrededor del 50% al total de caída de hojarasca. El patrón estacional mostró un máximo de caída de hojarasca de rebollo en otoño y comienzos de invierno, mientras que en las parcelas de pino, dicho máximo se produjo en verano, lo que es congruente con la fisiología de la caída de hojas o acículas en frondosas y coníferas en estas latitudes, pero desmarcándose de los valores obtenidos en Europa Central y del Norte. Un año con primavera seca coincidió con un desfronde de hojas de rebollo menor; asimismo, la caída de la hoja se adelantó algunas semanas con respecto al año con una primavera lluviosa.

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Section: Discussioncontrasting

confidence: 49%

Aboveground soil C inputs in the ecotone between Scots pine

Díaz-Pinés¹,

Sánchez²,

Montes

2011

For. syst.

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“…Although data were limited to one area in the basin, it is important to note that litterfall deposition was of the same order as those reported in many other studies in the Amazonian region. 30,40,41 The Hg concentrations in the litter were also on the same order than those reported by Mélières et al 30 (64 ng g -1…”

Section: Soil and Soil Cover Roles In The Mercury Cyclesupporting

confidence: 75%

Major aspects of the mercury cycle in the Negro River Basin, Amazon

Silva¹,

Bisinoti²,

Fadini³

et al. 2009

J. Braz. Chem. Soc.

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Embora com pouca atividade humana, as concentrações de Hg na bacia do Rio Negro são relativamente altas. A presença natural de Hg em solos e a deposição atmosférica são as principais fontes deste metal. O balanço entre fluxos invasivos e evasivos sugerem o seu acúmulo no interior da bacia em 39.9 t ano -1. O tipo de solo, fonte de metal para os rios, e o ciclo hidrológico com períodos de cheia e seca atuam sobre a química redox das águas. A conjunção sazonal de fatores como a natureza da matéria orgânica, pH ácido e radiação solar permitem que as águas pretas oscilem de redutora a oxidante, onde, por sua vez, ocorre o consumo de Hg 0 e degradação do metilmercúrio. Deste modo, o fluxo do mercúrio pode ser invasivo ou evasivo. Embora a metilação seja mais favorecida em águas pretas, a fotodegradação do metilmercúrio se contrapõe ao seu acúmulo, contribuindo para regular o estoque deste composto na coluna água.Despite the low level of industrial activity and human density, Hg concentration in the Negro River basin is relatively high. Soil enriched with naturally high Hg concentrations and atmospheric deposition are the main sources of the metal in this watershed. Differences between invasive and evasive fluxes at the water/air and soil/air interfaces indicate Hg accumulation in the basin at a rate of 39.9 t y -1 . The type of soil, which is the main source of mercury for the water bodies, the hydrological cycle with floods and dry periods, act markedly on the water redox chemistry. A complex interaction between many seasonable variables such as solar intensity, water pH, age of the naturally occurring organic matter and the hydrological cycle alter the redox characteristics of these black water bodies, thus markedly affecting the consumption of Hg 0 and the degradation of methylmercury present in the water. Although methylation is favored in black waters, photodegradation counterpoints this formation, thus regulating the methylmercury burden in the water column.

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“…Assuming this soil flux leads to an average within-canopy daytime NO 2 concentration of 0.40-2.00 ppbv, average leaf NO 2 uptake and emission rates would be 13.56 and 3.63 pmol m -2 s -1 , respectively (Table 2). Multiplying these uptake rates by a range of reported LAI values (Jipp et al 1998;Larcher 1995;Smith et al 1998), the canopy is estimated to assimilate and emit 11.5-19.6 and 12.2-19.5% of the soil-emitted NO as NO 2 , respectively, dependent on LAI.…”

Section: Discussionmentioning

confidence: 99%

“…Given the central role that NO 2 plays in the regulation of tropospheric O 3 formation, high priority should be given to elucidating the magnitude of canopy NO 2 uptake in a variety of ecosystems and the significance of such uptake to inventories of soil NO y emissions to the atmosphere. (Bakwin et al 1990), leaf area index (LAI) (Jipp et al 1998;Larcher 1995;Smith et al 1998) …”

Section: Discussionmentioning

confidence: 99%

Leaf uptake of nitrogen dioxide (NO2) in a tropical wet forest: implications for tropospheric chemistry

et al. 2001

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Tropical forest soils are known to emit large amounts of reactive nitrogen oxide compounds, often referred to collectively as NO y (NO y = NO + NO 2 + HNO 3 + organic nitrates). Plants are known to assimilate and emit NO y and it is therefore likely that plant canopies affect the atmospheric concentration of reactive nitrogen compounds by assimilating or emitting some fraction of the soil-emitted NO y . It is crucial to understand the magnitude of the canopy effects and the primary environmental and physiological controls over NO y exchange in order to accurately quantify regional NO y inventories and parameterize models of tropospheric photochemistry. In this study we focused on nitrogen dioxide (NO 2 ), which is the component of NO y that most directly catalyzes the chemistry of O 3 dynamics, one of the most abundant oxidative species in the troposphere, and which has been reported as the NO y species that is most readily exchanged between plants and the atmosphere. Leaf chamber measurements of NO 2 flux were measured in 25 tree species growing in a wet tropical forest in the Republic of Panama. NO 2 was emitted to the atmosphere at ambient NO 2 concentrations below 0.53-1.60 ppbv (the NO 2 compensation point) depending on species, with the highest rate of emission being 50 pmol m -2 s -1 at <0.1 ppbv. NO 2 was assimilated by leaves at ambient NO 2 concentrations above the compensation point, with the maximum observed uptake rate being 1,550 pmol m -2 s -1 at 5 ppbv. No seasonal variation in leaf NO 2 flux was observed in this study and leaf emission and uptake appeared to be primarily controlled by leaf nitrogen and stomatal conductance, respectively. When scaled to the entire canopy, soil NO emission rates to the atmosphere were estimated to be maximally altered ±19% by the overlying canopy.

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Litterfall and nitrogen-use efficiency of plantations and primary forest in the eastern Brazilian Amazon

Cited by 67 publications

References 25 publications

Aboveground soil C inputs in the ecotone between Scots pine

Aboveground soil C inputs in the ecotone between Scots pine

Major aspects of the mercury cycle in the Negro River Basin, Amazon

Leaf uptake of nitrogen dioxide (NO2) in a tropical wet forest: implications for tropospheric chemistry

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