Influência da precipitação pluviométrica na regeneração natural em trecho de uma floresta ombrófila densa aluvial (Influence of rainfall in natural regeneration in a dense ombrophylous forest alluvial in eastern amazona, Pará, Brasil

R E S U M OO objetivo do presente estudo foi avaliar a influência da precipitação interna sobre a composição e estrutura da regeneração natural em um trecho de floresta ombrófila densa aluvial no estuário amazônico. Os dados foram coletados de fevereiro a julho de 2016, em quatro parcelas de 20 x 20m, subdivididas em subparcelas de 1 x 1m para análise da composição florística e estrutural da regeneração e instalados 11 pluviômetros para amostragem da precipitação. Houve pouca variação na quantidade de indivíduos, famílias, gêneros e espécies entre o período chuvoso e o menos chuvoso. Pariana campestris Aubl., Anthurium sinuatum Benth. ex, Schott, Costus arabicus L. e Costus spicatus (Jacq.) Sw. foram mais representativas devido aos impactos antrópicos na área. Conclui-se que não houve influência da precipitação interna na abundância e na riqueza de espécies da regeneração natural.Palavras-chave: Floresta de várzea; florística; estrutura. A B S T R A C T The objective of the present study was to evaluate the influence of internal precipitation on the composition and structure of natural regeneration in an alluvial dense ombrophilous forest in the Amazonian estuary. The data were collected from february to july 2016, in four 20 x 20m plots, subdivided into 1x1m subplots to analyze the floristic and structural composition of the regeneration and using 11 pluviometers to sample the precipitation. There was little variation in the number of individuals, families, genera and species between the rainy season and the less rainy season. Pariana campestris Aubl., Anthurium sinuatum Benth. Schott, Costus arabicus L. and Costus spicatus (Jacq.) Sw. were more representative due to anthropic impacts on the area. It was concluded that there was no influence of internal precipitation on the abundance and richness of natural regeneration species.Keywords: Floodplain forest, Floristic, Structure.

Determining forest litter interception in an area of the Cerrado sensu stricto

ABSTRACT Mainly due to the difficulty of directly measuring forest litter interception, many empirical studies on water balance in forests have disregarded this component. In order to assess the magnitude of forest litter interception in an area of the Cerrado s.s. , an estimate of the intercepted volume was made based on equations from two forest litter parameters (Cmax and Cmin) obtained from laboratory assays and monitoring the forest litter quantity. The estimates obtained from the litter interception for 2015 and 2016 were compared with the calculated values of evapotranspiration and internal precipitation of the study area. The total volume of litter interception corresponded on average to 13.4% of the internal precipitation and 8.5% of the total rainfall. Regarding the total annual evapotranspiration, the evaporation from the forest litter interception volume corresponded on average to 10.3% (122 mm) of this total. Forest litter interception for areas such as the Cerrado sensu stricto can have a significant impact on the water balance. This shows the need for directly measuring the forest litter interception, providing more accurate determinations of the rainfall partitioning in these forest areas.

CARACTERÍSTICAS DAS CHUVAS E INTERCEPTAÇÃO VEGETAL NO BIOMA CAATINGA

CARACTERÍSTICAS DAS CHUVAS E INTERCEPTAÇÃO VEGETAL NO BIOMA CAATINGA JOSÉ BANDEIRA BRASIL1; HELBA ARAÚJO DE QUEIROZ PALÁCIO2; JOSÉ RIBEIRO DE ARAÚJO NETO2; JACQUES CARVALHO RIBEIRO FILHO3 E EUNICE MAIA DE ANDRADE1 1 Departamento de Engenharia Agrícola, Universidade Federal do Ceará-UFC, Campus do PICI, Bloco 804, Fortaleza-CE, Brasil. E-mail: [email protected]; [email protected] Instituto Federal de Educação, Ciência e Tecnologia do Ceará-IFCE, Campus Iguatu, rodovia Iguatu-Várzea Alegre, Km 05, s/n, Iguatu-CE, Brasil. E-mail: [email protected]; [email protected] Departamento de Ciências Ambientais e Tecnológicas, Universidade Federal Rural do Semi-Árido-UFERSA, Mossoró-RN, Brasil; [email protected]. 1 RESUMO A dinâmica da interceptação vegetal depende principalmente das características das chuvas e estrutura do dossel das árvores. Objetivou-se com este estudo analisar o efeito das características das chuvas (classes de precipitação (CP) - CP < 15 mm, 15 ≤ CP < 30 mm, 30 ≤ CP < 60 mm e CP ≥ 60 mm e classes de intensidade (CI) - 1,1 mm h-1 ≤ CI < 5 mm h-1, 5,1 mm h-1 ≤ CI < 25 mm h-1, 25,1 mm h-1 ≤ CI < 50 mm h-1 e CI ≥ 50,1 mm h-1) e as variações sazonais na interceptação em área de caatinga em regeneração. O experimento foi conduzido em uma microbacia experimental no município de Iguatu-Ceará, em seis anos consecutivos, de 2010 a 2015, totalizando 212 eventos. Foram monitorados a precipitação interna, escoamento pelos caules das árvores e perda por interceptação em uma área de 10 x 10 m. A precipitação total foi medida com o auxílio de um pluviômetro do tipo “Ville de Paris” instalado em área aberta. Constatou-se que não houve diferenças sazonais (período chuvoso - janeiro a junho e período seco - julho a dezembro) entre os percentuais médios de Precipitação interna (Pint), Escoamento pelo caule (Esc) e Perda por interceptação (I), em função das características das chuvas e da vegetação. Os resultados demonstram que as menores perdas relativas por interceptação foram observadas nas classes de precipitação > 60 mm e nos eventos mais intensos os percentuais médios de perda por interceptação são menores. Palavras-chave: Classes de chuva, intensidades pluviométricas, variabilidade sazonal. BRASIL, J. B.; PALÁCIO, H. A. de Q.; ARAÚJO NETO, J. R. de; RIBEIRO FILHO, J. C.; ANDRADE, E. M. deRAINFALL CHARACTERISTICS AND VEGETATION INTERCEPTION IN THE CAATINGA BIOME 2 ABSTRACT The mechanism of vegetation interception depends largely on the rainfall characteristics and canopy of the trees. The main objective of this study was to analyze the effects of the rainfall characteristics (precipitation classes (RC) - RC < 15 mm, 15 mm ≤ RC < 30 mm, 30 mm ≤ RC < 60 mm and RC ≥ 60 mm and intensity classes (IC) - 1,1 mm h-1 ≤ IC < 5 mm h-1, 5,1 mm h-1 ≤ IC < 25 mm h-1, 25,1 mm h-1 ≤ IC < 50 mm h-1 and IC ≥ 50,1 mm h-1) and the seasonal variations of the interception in an area with regenerating caatinga. The experiment was conducted on an experimental catchment in the municipality of Iguatu, Ceará, during six consecutive years, from 2010 to 2015, with a total of 212 events. Internal precipitation, tree trunk runoff and loss by interception in areas of 10 x 10 m were monitored. The total rainfall was measured with a “Ville de Paris” rain gage, installed in an open area. No seasonal changes were observed (wet season – January through June – and dry season – July through December) among the average percentages of internal precipitation (Pint), tree trunk runoff (Esc) and loss by interception (I), due to the rainfall and vegetation characteristics. The results show that the smallest relative losses by interception were observed in the precipitation classes over 60 mm and, among the most intense events, the average loss percentages by interception are smaller. Keywords: Rainfall classes, rainfall intensities, seasonal variability.

Predicting Internal Oxidation: Building on the Wagner Model

Wagner’s 1959 diffusion model of the internal oxidation process provided a method of predicting the rate at which a binary alloy was penetrated by dissolved oxygen as it precipitated the more reactive (but dilute) alloy component. Parabolic kinetics were predicted to depend on oxygen permeability in the unreacted alloy solvent and also, in cases where the reactive component was sufficiently mobile, the diffusion coefficient of the latter. The model has proven very successful, but is restricted to single oxidant-binary alloy systems, in which the precipitated oxide has extremely low solubility. This paper reviews recent results on a number of internal precipitation processes which cannot be described with the Wagner theory. These include formation of low stability carbides and nitrades; internal precipitation driven by multiple oxidants; the templating effects of prior precipitates on subsequently formed corrosion products; cellular precipitation morphologies; internal interface diffusion effects; volume changes in the reaction zone and the effects upon them of simultaneous external scaling.