637 research outputs found

    Contributo da Silvicultura para o combate à desertificação: Valorização de espécies adaptadas

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    No quadro das mudanças climáticas previsíveis (Projecto SIAM II) espera-se uma redução na produtividade e no sequestro de carbono nas áreas sujeitas a períodos de secura. Por outro lado, prevê-se que os períodos de secura aumentem e que as chuvas se concentrem cada vez mais no período invernal. As variações climáticas previsíveis acarretam, naturalmente, mudanças quanto ao domínio de algumas espécies e nas áreas de distribuição dos diversos tipos de floresta bem como um aumento do risco de desertificação. Assim, no geral, verifica-se uma tendência de migração das espécies de Sul para Norte e do Interior para o Litoral. Estas variações climáticas terão também influência nos incêndios e ataque de pragas e doenças. Nesta perspectiva, a silvicultura a propor para as áreas susceptíveis à desertificação terá de ser uma silvicultura multifuncional, em que a principal preocupação seja a protecção do solo e dos recursos hídricos e, como complemento, uma oferta diversificada de valores de uso directo e/ ou indirecto que permita obter contrapartidas económicas, resultantes de uma gestão sustentável dos recursos, promovendo a fixação das populações uma vez que à desertificação está associado o despovoamento. Todavia, em floresta, o processo de produção lenhosa é relativamente longo, tornando-se, por isso, indispensável fazer uma selecção criteriosa das espécies a instalar tendo por base os cenários das alterações climáticas. Assim, deve-se optar, desde já, pela selecção e instalação de espécies resistentes à secura como a azinheira, o sobreiro, o pinheiro manso, os carvalhos negral e faginea e o zimbro. No combate à desertificação a principal preocupação, como já se referiu, deve ser a protecção do solo e dos recursos hídricos pelo que se deve privilegiar as espécies adaptadas e a mobilização mínima do solo. Deve-se assegurar uma melhoria produtiva dos povoamentos através de uma gestão sustentável, quer se trate de produtos lenhosos ou não lenhosos resultantes da multifuncionalidade do espaço florestal. Assim, torna-se fundamental diversificar as actividades nas explorações florestais e agro-florestais e potenciar a exploração de recursos associados como a cinegética, a apicultura, os cogumelos, a silvopastorícia, o artesanato, a valorização paisagística e eco-turismo, entre outros. Outro aspecto a ter em consideração é a utilização dos resíduos resultantes das limpezas da floresta para produção de bioenergia no quadro do aproveitamento das energias renováveis.No quadro das mudanças climáticas previsíveis (Projecto SIAM II) espera-se uma redução na produtividade e no sequestro de carbono nas áreas sujeitas a períodos de secura. Por outro lado, prevê-se que os períodos de secura aumentem e que as chuvas se concentrem cada vez mais no período invernal. As variações climáticas previsíveis acarretam, naturalmente, mudanças quanto ao domínio de algumas espécies e nas áreas de distribuição dos diversos tipos de floresta bem como um aumento do risco de desertificação. Assim, no geral, verifica-se uma tendência de migração das espécies de Sul para Norte e do Interior para o Litoral. Estas variações climáticas terão também influência nos incêndios e ataque de pragas e doenças. Nesta perspectiva, a silvicultura a propor para as áreas susceptíveis à desertificação terá de ser uma silvicultura multifuncional, em que a principal preocupação seja a protecção do solo e dos recursos hídricos e, como complemento, uma oferta diversificada de valores de uso directo e/ ou indirecto que permita obter contrapartidas económicas, resultantes de uma gestão sustentável dos recursos, promovendo a fixação das populações uma vez que à desertificação está associado o despovoamento

    BEZOARI U KOLEKCIJI TÁVORA SEQUEIRA PINTO U OPORTU (PORTUGAL)

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    Bezoar stones, once used as universal antidotes and panaceas, but currently regarded as costly and useless medicines of the past, are a major milestone in the history of toxicology. Arabic physicians had been using bezoars in medicine from the 8th century onwards. In the 16th century, the Portuguese controlled bezoar trade from India, and the Portuguese doctors Garcia de Orta, Amatus Lusitanus, and Cristobal Acosta introduced the medicinal use of Oriental bezoars to European medical literature. Some criticism aside, leading European doctors prescribed bezoars mainly as powerful antidotes. Five bezoars that now adorn the Távora Sequeira Pinto Collection in Oporto testify to the allure and glory of bezoars at the height of their golden age, when they equalled the splendour of gems and noble minerals that dominated the Eastern and Western lithotherapy. The end of the 18th century marked the end of ancient panaceas. This article focuses on the therapeutic and apotropaic use of bezoars.Bezoari – nekad univerzalni protuotrov i panaceja, a danas smatrani skupim i beskorisnim lijekom iz prošlosti – imaju su značajno mjesto u povijesti toksikologije. Arapski su liječnici rabili bezoare u medicinske svrhe još od 8. stoljeća. U 16. stoljeću, kad su trgovinu bezoarima držali Portugalci, liječnici Garcia de Orta, Amatus Lusitanus i Cristobal Acosta predstavili su europskoj medicini primjenu istočnjačkih bezoara u terapeutske svrhe. Zanemare li se određene kritike, vodeći su europski liječnici bezoare mahom propisivali kao snažne protuotrove. Pet izložaka iz kolekcije Távora Sequeira Pinto u Oportu svjedoči o privlačnosti i slavi bezoara na vrhuncu njihova zlatnog doba, kada su po cijenjenosti bili izjednačeni s dragim kamenjem i mineralima rabljenim u istočnjačkoj i zapadnoj litoterapiji. Kraj XVIII. stoljeća donio je i kraj primjene antičkih panaceja. Ovaj je članak posvećen terapijskim i apotropaičnim primjenama bezoara

    Density management diagrams for sweet chestnut high-forest stands in Portugal

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    This study aims to develop stand density management diagrams (SDMDs) for pure even-aged high-forest stands of sweet chestnut in Portugal, defining the appropriate upper and lower limits of growing stock while considering the biological, technological and economic objectives that are expected for these stands. The SDMDs were developed with data collected from high-forest stands in northern Portugal, which is the main representative area of these stands in the country. Data were collected from 23 pure even-aged permanent plots with re-measurement intervals of 4-10 years, 43 semi-permanent plots and 18 even-aged temporary plots; all plots were established in chestnut high-forest stands with a broad range of ages. SDMDs were constructed by simultaneously fitting four nonlinear equations relating stand variables using the full information likelihood technique. SDMDs for the estimation of stand total volume, stand stem biomass, stand total aboveground biomass, and carbon content in aboveground biomass are presented as bivariate graphs with dominant height on the x-axis and the number of trees per hectare on the y-axis (using logarithmic scale). A tool is made available to define an optimal range of stand density for a silviculture oriented to single-stem selection on a tree-by-tree basis, focusing management on the most valuable trees. This tool is aimed to support forest managers in the decision-making process, enabling them to schedule thinnings on the basis of the dominant height growth of the trees with the greatest potential (frame trees), maintaining an adequate growing stock and assessing the corresponding aboveground wood volume, biomass, carbon, and mean diameter breast height.Conception of the study, data analysis, drafting of the manuscript and critical revision: MSP and LN. Contributed materials: MSP. Data used in this study were collected under financial support of AGRO Program, Project 267: Sustainable Management of Chestnut Forested Areas in High-Forest and Coppice Systems, and Project PTDC/AGRCFL/68186/ “Mixed forests: Modeling, dynamics and geographical distribution of productivity and carbon storage in mixed forest ecosystems in Portugal”, funded by the Portuguese Science Foundation (FCT) and FEDER - COMPETE Program.info:eu-repo/semantics/publishedVersio

    Comparative growth and yield performance of sweet chestnut in high forest and coppice systems in young plantations

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    In Portugal, sweet chestnut Castanea sativa Mill is predominantly found in inland mountain areas in the North and Center of the country Patrício et al 2022 covering an estimated area of over 48 000 hectares (ICNF, 2015), including orchards and forest woodlands. Chestnut forests have been managed for wood production in both coppice and high forest systems, with coppice offering flexibility in producing wood of various calibers to meet market demands. However, extensive areas of healthy coppices remain unmanaged or lack clear technical and economic objectives, resulting in reduced forest health and productivity. Comparing the growth patterns of coppice and high forest systems during the juvenile phase is essential, as coppice shows higher initial productivity but faces limited market demand for small sized chestnut material. Exploring management alternatives to enhance long term rotation and utilize juvenile biomass can incentivize the recovery of abandoned areas and improve the quality and value of chestnut timber for long lived products for a more sustainable management. Main Objective: compare growth and yield of young chestnut stands, up to 24 years of age, in coppice and high forest systems from mountain areas of Northern PortugalFinancial support FCT/MCTES to CIMO (00690 2020 AGRO Program); Project AGRO 267; Project PTDC/AGRCFL/68186/; Project PDR 2020 101 031671 GO_FTAN/

    Stem volume ratio equations to variable merchantable limits for sweet chestnut in Portugal

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    Having reliable estimates of wood volume categorized by classes of use is crucial for effective wood utilization. Accurate estimations enable better planning and allocation of resources, ensuring wood is utilized efficiently and appropriately for various purposes. In turn, this leads to informed decisions regarding wood allocation, optimal utilization, and waste minimization, ultimately contributing to maximizing profitability in forest management. However, tools for estimating wood volume are scarce, particularly for sweet chestnut (Castanea sativa Mill.) stands in North Portugal. Sweet chestnut is a species with great potential for producing high-quality timber that serves diverse purposes. The wood obtained from sweet chestnut is known for its durability, strength, and appealing aesthetics, making it suitable for construction, furniture making, flooring, and joinery. Furthermore, chestnut can play a significant and renewed role in engineered wood products like Glulam beams and pillars used in sustainable construction practices. Objective: By utilizing data from high-forest sweet chestnut stands in North Portugal as a baseline, this research aims to fill the gap in tools for estimating wood volume in sweet chestnut and contribute to the sustainable management and utilization of this valuable timber resource.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020); This work was supported by the AGRO Program, Project 267: Sustainable Management of Chestnut Woodlands in High-forest and Coppice Systems.info:eu-repo/semantics/publishedVersio

    Allometric equations for predicting mineralomass in high-forest chestnut stands in Portugal

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    The evaluation of nutrients in biomass tree-components is a process time consuming and expensive, often involving tree felling, not always possible or desirable. Thus, mineralomass prediction equations are an important tool for the quantification of the nutrients exported in management and harvesting activities towards to its replacement and sustainable management as well as to evaluate the effect of other disturbances in the balance of ecosystems. Thus, given the importance of the relationship of biomass and nutrients (mineralomass) for dynamic and sustainable management of chestnut woodlands, aboveground mineralomass was studied in sweet chestnut (Castanea sativa Mill.) high forest stands located in Northern Portugal. Nutrient specific prediction equations that allow estimating the mineralomass (N, P, K, Ca, Mg, S, B and C) above the ground, total and by components: stem-wood, stem-bark, branches, leaves and flowers, based on tree dendrometric variables, DBH (diameter breast height) and total height, were developed. Linear and non-linear regression estimation methods were used. Data analysis is based on information collected in destructive analysis of thirty-four felled trees, distributed by the existing diameter classes (10-65 cm) in three adult chestnut stands. Several linear and nonlinear equations were fitted by the least squares method to select models. A simultaneous fit by SUR method using iterative seemingly unrelated regression (ITSUR) was used for the final selected models. The best fitting models are presented.info:eu-repo/semantics/publishedVersio

    BEZOARI U KOLEKCIJI TÁVORA SEQUEIRA PINTO U OPORTU (PORTUGAL)

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    Bezoar stones, once used as universal antidotes and panaceas, but currently regarded as costly and useless medicines of the past, are a major milestone in the history of toxicology. Arabic physicians had been using bezoars in medicine from the 8th century onwards. In the 16th century, the Portuguese controlled bezoar trade from India, and the Portuguese doctors Garcia de Orta, Amatus Lusitanus, and Cristobal Acosta introduced the medicinal use of Oriental bezoars to European medical literature. Some criticism aside, leading European doctors prescribed bezoars mainly as powerful antidotes. Five bezoars that now adorn the Távora Sequeira Pinto Collection in Oporto testify to the allure and glory of bezoars at the height of their golden age, when they equalled the splendour of gems and noble minerals that dominated the Eastern and Western lithotherapy. The end of the 18th century marked the end of ancient panaceas. This article focuses on the therapeutic and apotropaic use of bezoars.Bezoari – nekad univerzalni protuotrov i panaceja, a danas smatrani skupim i beskorisnim lijekom iz prošlosti – imaju su značajno mjesto u povijesti toksikologije. Arapski su liječnici rabili bezoare u medicinske svrhe još od 8. stoljeća. U 16. stoljeću, kad su trgovinu bezoarima držali Portugalci, liječnici Garcia de Orta, Amatus Lusitanus i Cristobal Acosta predstavili su europskoj medicini primjenu istočnjačkih bezoara u terapeutske svrhe. Zanemare li se određene kritike, vodeći su europski liječnici bezoare mahom propisivali kao snažne protuotrove. Pet izložaka iz kolekcije Távora Sequeira Pinto u Oportu svjedoči o privlačnosti i slavi bezoara na vrhuncu njihova zlatnog doba, kada su po cijenjenosti bili izjednačeni s dragim kamenjem i mineralima rabljenim u istočnjačkoj i zapadnoj litoterapiji. Kraj XVIII. stoljeća donio je i kraj primjene antičkih panaceja. Ovaj je članak posvećen terapijskim i apotropaičnim primjenama bezoara

    Sensory Entrainment Mechanisms in Auditory Perception: Neural Synchronization Cortico-Striatal Activation.

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    The auditory system displays modulations in sensitivity that can align with the temporal structure of the acoustic environment. This sensory entrainment can facilitate sensory perception and is particularly relevant for audition. Systems neuroscience is slowly uncovering the neural mechanisms underlying the behaviorally observed sensory entrainment effects in the human sensory system. The present article summarizes the prominent behavioral effects of sensory entrainment and reviews our current understanding of the neural basis of sensory entrainment, such as synchronized neural oscillations, and potentially, neural activation in the cortico-striatal system

    Conservação, regeneração e exploração do castanheiro

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    O castanheiro é uma árvore que apresenta dupla vocação, podendo ser explorado para produção de fruto e madeira (sistema agro-florestal), ou para produção de madeira (sistema florestal). Os espaços florestados com castanheiro para produção de madeira são, habitualmente, designados por castinçais enquanto os espaços, essencialmente, produtores de fruto se designam por soutos ou pomares. Esta essência pode ser explorada segundo dois regimes ou processos: talhadia e alto fuste ou ainda sob a forma de talhadia composta. Os regimes caracterizam-se pelo tipo de regeneração (via seminal ou vegetativa) a que podem submeter-se as espécies florestais para a reprodução de novos povoamentos, ou seja, formas de continuidade dos espaços florestados
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