109 research outputs found

    Modelo de crescimento para árvores em povoamentos juvenis de sobreiro em Portugal

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    The juvenile and adult stages in cork oak are distinct because of the periodic debarking of the stem and branches that characterizes the adult stage. This fact implies the use of diameter under bark for the adult stage while diameter over bark is the natural variable for juvenile stands in growth and yield studies. Tree growth in the adult stage may also be affected by the periodic debarking. The differences between the two stages justify the development of different models for each of them. The objective of this paper is to develop an individual tree growth and yield model for juvenile cork oak stands for general application on the cork oak distribution area in Southern Portugal. The most important modules of this growth model were developed using data collected from a large number of trees in the juvenile stage, from several plots distributed around the South of Portugal. These modules were: an individual tree diameter growth model, a height-diameter model and a model for crown diameter prediction

    Assessment of cork production in new Quercus suber plantations under future climate

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    Carbon sequestration of modern Quercus suber L. silvoarable agroforestry systems in Portugal: a YeldSAFE-based estimation

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    Modern alley cropping designs, with trees aligned in rows and adapted to operating farming machinery, have been suggested for Europe. This paper explores the potential for adoption of cork oak (Quercus suber L.) agroforestry in Portugal and estimates the potential carbon sequestration. Spatial modeling and Portuguese datasets were used to estimate target areas where cork oak could grow on farmland. Different implementation scenarios were then modeled for this area assuming a modern silvoarable agroforestry system (113 trees ha-1 thinned at year 20 for establishing 50 trees ha-1). The YieldSAFE process-based model was used to predict the biomass and carbon yield of cork oak under low and high soil water holding capacity levels. Approximately 353,000 ha are available in Portugal for new cork oak alley cropping. Assuming implementation rates between 10 % of the area with low soil water capacity (60 mm: 15 cm depth, coarse texture) and 70 %of the areawith high soilwater holding capacity (1,228 mm: 200 cm depth, very fine texture), then carbon sequestration could be 5 9 106 and 123 9 106 Mg CO2 respectively. Due to higher yields on more productive land, scenarios of limited implementation in high productivity locations can sequester similar amounts of carbon as wide implementation on low productivity land, suggesting that a priori land classification assessments can improve the targeting of land and financial incentives for carbon sequestratio

    Drivers for annual cork growth under two understory management alternatives on a podzolic cork oak stand

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    ArticleUnderstory management practices and stand density characteristics allow one to distinguish a cork oak traditional silvopastoral system (known as a montado) from a cork oak forest system. Although understanding the manner in which different management practices affect cork growth is imperative, there are still only a few outputs from experimental research that contribute to this knowledge. The effect of potential drivers on annual cork growth was analyzed using a linear mixed model approach. Two dimensions of drivers were considered: intraspecific competition, assessed by tree level distance-dependent indices; and interspecific competition, assessed by variables characterizing understory management. The present dataset was collected from an experimental trial established on a cork oak stand in Podzolic soil on the Tagus river basin, covering two different cork growth cycles over the period from 2003 to 2015. The adjusted models considered two understory management alternatives: spontaneous shrubs maintenance and forage application. In both models, annual precipitation displayed a positive effect on annual cork growth, as expected. However, no significant effect of intraspecific competition was found. Additionally, there was a positive effect on annual cork growth associated with the spontaneous shrubs growth and a negative effect associated with lupine presence; both effects linked to different cork ring ages’ thresholds. The study main contributions are the following: (i) the introduction of the interaction between cork growth cycle stage and understory management practices, only possible with cork sample collections from different cork rotation cycles; (ii) the finding that there was no significant effect of intraspecific competition on cork growthinfo:eu-repo/semantics/publishedVersio

    Carbon balance estimation for agroforestry land use alternatives in Portugal

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    PosterIn 2005, 11% of the anthropogenic greenhouse gases emissions (GHG) were originated from agricultural activities and this value is expected to increase in the future. Besides the contribution for the restoration of soil productivity and for the improvement of conditions in degraded land, Agroforestry is also proposed as one of the main solutions for the mitigation of the GHG emissions and their effect on Climate Change. With European Union’s legislation supporting and promoting the conversion of land into low-carbon-integrated agriculture, new opportunities arise for the implementation of this type of land use in Europe. In Portugal, this type of agriculture is well represented by a traditional Agroforestry system called montado, combining low density cork oak trees (Quercus suber L) with pastoral activities occupying an area of 715,922 ha, with recent studies showing an extra area suitable for its implementation of around 353,000ha. Considering the new policies established by the EU in regard to the measures to be considered in agriculture for the Climate Change mitigation, and the capacity of the Agroforestry systems to act as a low-carbon and highly productive agriculture, two main objectives are proposed for this work: 1) Compare the potential capacity of the montado to mitigate the GHG emissions by quantifying the net carbon balance of activities in comparison to two other land-use alternatives occurring in the same area: dense cork oak forestry and wheat monoculture; 2) Quantify the benefits/consequences in terms of net carbon balance if new areas are converted into Agroforestry systems, as an alternative to current activities and management models. The methodology for the net carbon balance estimation includes the use of the Yield-SAFE model, calibrated for crop components and cork oak and current most used management practices concerning the three land use types and associated activities.AGFORWARD FP7 (contract nº 613520); FCT CorkCarbon Footprint (PTDC/AGR-FOR/4360/2012
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