109 research outputs found
Modelo de crescimento para árvores em povoamentos juvenis de sobreiro em Portugal
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
Carbon sequestration of modern Quercus suber L. silvoarable agroforestry systems in Portugal: a YeldSAFE-based estimation
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
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
Using quantile regression to evaluate the impact of different factors in the cork caliper of cork oak trees in montado agroforestry ecosystem
Published in: https://
link.springer.com/article/10.1007/s1034
2 021 01379 8N/
Carbon balance estimation for agroforestry land use alternatives in Portugal
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
- …