Crescimento diamétrico de Blepharocalyx salicifolius em remanescente de Floresta Ombrófila Mista Aluvial, Paraná.

Buscou-se avaliar o incremento diamétrico de Blepharocalyx salicifolius (Kunth) O. Berg (Myrtaceae) a partir de cintas dendrométricas fixadas em 11 indivíduos de um remanescente de Floresta Ombrófila Mista Aluvial na Região Metropolitana de Curitiba-PR. Concomitantemente às leituras de incremento, foi avaliado o comportamento fenológico desses indivíduos, durante 24 meses. O incremento diamétrico médio mensal de B. salicifolius variou de 0,36 mm a praticamente nulo nos meses mais frios (de junho a agosto) e até 1,78 mm, durante os meses mais favoráveis (de novembro a março). A taxa média de incremento anual foi de 4,52 mm. O crescimento ainda pouco expressivo nos meses de setembro e outubro pode ser justificado pelo pico de floração e frutificação. A correlação do incremento mensal intraespécie foi alta (r = 0,55), indicando boa sincronia dos dados. A correlação entre o incremento médio, as variáveis meteorológicas e as fenofases apontou que a temperatura média responde por 42% da variação do incremento médio e da frutificação

Parâmetros climáticos e incremento diamétrico de espécies florestais em floresta aluvial no Sul do Brasil.

Objetiva-se com este estudo avaliar a periodicidade do incremento em diâmetro do tronco de Sebastiania commersoniana e das espécies arbóreas exóticas invasoras Hovenia dulcis e Ligustrum lucidum em remanescente de Floresta Ombrófila Mista Aluvial em Araucária, Paraná. Foram selecionados indivíduos presentes no dossel e sub-bosque. Cintas dendrométricas foram instaladas em todos os indivíduos selecionados, que foram monitorados mensalmente, de julho de 2009 a junho de 2012. Os incrementos correntes mensais e anuais foram correlacionados com precipitação e temperatura. As espécies exóticas e os indivíduos do dossel apresentaram incremento superior à espécie nativa, que teve pouca variação ao longo do ano, e aos indivíduos de sub-bosque. Correlações significativas do incremento foram obtidas com temperatura e precipitação, mostrando que o crescimento em diâmetro está, em grande parte, relacionado às condições meteorológicas

A decontamination approach altered the Gymnanthes klotzschiana Müll. Arg. Vessel anatomy in Southern Brazil.

Here we conducted an anatomical analysis of vessel elements from woody tissues of Gymnanthes klotzschiana individuals in a remnant of Alluvial Mixed Rain Forest in southern Brazil. This tree is among the species with the highest abundance within these forests. We sampled an area adjacent to a meadow highly impacted by an oil spill of four million liters from Petróleo Brasileiro S. A. The study was aimed at uncovering possible anatomical and structural changes in the wood of G. klotzschiana after an attempt at the decontamination of the area, which was performed by its flooding and extracting the oil that was deposited on the soil surface. Therefore, our sampling was performed in two environments with distinct water table characteristics: (1) with temporary water saturation, and (2) with permanent saturation. Radial samples were collected from an individual from both environments and analyzed through optical microscopy and dendroecological variables, which allowed us to reconstruct the wood development from 1997 to 2010. Our results demonstrated that no significant anatomic changes occurred in the condition with temporary saturation. Conversely, the environment with permanent saturation led to an increase in the frequency of the vessel elements, as a strategy to acclimate to the altered environment. Moreover, it altered the grouping pattern of the vessels, with a gradual increase in the percentage of solitary vessels, which is consistent with environments with more humidity. These results drive our attention for developing more efficient strategies to overcoming natural disasters and diminishing their impact on local biological communities

Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter productivity measurements), their associate canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonality in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rainfall is < 2000 mm.yr−1 (water-limited forests) and to radiation otherwise (light-limited forests); on the other hand, independent of climate limitations, wood productivity and litterfall are driven by seasonal variation in precipitation and evapotranspiration respectively. Consequently, light-limited forests present an asynchronism between canopy photosynthetic capacity and wood productivity. Precipitation first-order control indicates an overall decrease in tropical forest productivity in a drier climate.Peer reviewe

Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter productivity measurements), their associated canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonality in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rainfall is  < 2000 mm yr⁻¹ (water-limited forests) and to radiation otherwise (light-limited forests). On the other hand, independent of climate limitations, wood productivity and litterfall are driven by seasonal variation in precipitation and evapotranspiration, respectively. Consequently, light-limited forests present an asynchronism between canopy photosynthetic capacity and wood productivity. First-order control by precipitation likely indicates a decrease in tropical forest productivity in a drier climate in water-limited forest, and in current light-limited forest with future rainfall  < 2000 mm yr⁻¹