Loading...
71 results
Search Results
Now showing 1 - 10 of 71
- Using EcoYieldSAFE to compare soil carbon dynamics under future climate in two contrasting agroforestry systemsPublication . Palma, J.H.N.; Crous-Duran, J.; Graves, A.R.; Garcia de Jalon, S.; Upson, M.; Oliveira, T.S.; Paulo, Joana Amaral; Ferreiro-Dominguez, N.; Moreno, G.; Burgess, P.J.
- Recolha de dados de biomassa de azinheiras (Quercus ilex). Protocolo para a instalação de parcelas temporárias e medição de árvores amostraPublication . Paulo, Joana Amaral; Tomé, Margarida; Uva, José SousaObjectivo: Instalação e medição de parcelas temporárias de Azinheira, para calculo de volumes e biomassas totais e por componentes de árvores desta espécie. Os dados biométricos recolhidos, após serem armazenados numa base de dados em formato Access 2000, irão ser utilizados em estudos biométricos da Azinheira e ajustamento de equações de biomassa.
- Produtividade dos montados em Portugal no período 1984-2017Publication . Paulo, Joana Amaral; Aubard, Valentine; Silva, João
- Problemas de pragas em montado: o que sabemos e o que nos falta saberPublication . Branco, Manuela; Paulo, Joana Amaral; Sousa, Edmundo
- Using the SUBER model for assessing the impact of cork debarking rotation on equivalent annual annuity in Portuguese standsPublication . Paulo, Joana Amaral; Tomé, MargaridaAim of study: Use the SUBER model to evaluate the influence of the cork debarking rotation period (CDR) on equivalent annual annuity (EAA) value. Area of study: Nine simulated stands, varying in site index (14.4, 15.6, 17.1) and cork quality characteristics (high, medium, low). Material and methods: EAA values were computed considering CDR periods varying from 9 to 14 years, two contrasting structures of cork prices (high and low cork price scenarios), and three discount rate values (0.5%, 2% and 5%). Main results: For discount rates of 0.5% and 2% the impact of different CDR on the EAA is similar. In stands characterized by high to average site index values or high to medium cork quality characteristics, CDR of 9 and 11 years are associated with similar values of EAA. The variation of the CDR in stands characterized by low site index values and/or low cork quality characteristics did not have a relevant effect on the variation of EAA. For the simulations carried out with a discount rate of 5% the EAA decreases with the increase of CDR, indicating that the minimum legal value of 9 years for CDR should be applied. Research highlights: In stands characterized by high to average site index values or high to medium cork quality characteristics, a delay in the debarking may result in a significant increase of cork thickness and, as a result, of cork price. Detailed knowledge of cork and stand characteristics and updated information on cork prices structure and values are essential for the best usage of management tools such as the SUBER model, which can contribute to the decision-making process concerning the debarking operation
- Holistic agroforestry system in practice. Just an idea or is there a living model ?Publication . Palma, J.H.N.; Paulo, Joana Amaral; Sendim, A.In the last decades there has been a tendency to classify agroforestry systems to help focus on particular aspects of different practices with specific objectives. However, in practice, the management of land use at farm scale has a wide range of options and decisions to be made at operational level following a certain strategy. Farmers can adopt certain agroforestry practices to suit and enhance their business as usual. What if agroforestry is considered the central key for the farming system and the business as usual is built under the “agroforestry concept umbrella” to produce different farming activities? We introduce a holistic agroforestry business model running in practice in Herdade do Freixo do Meio (HFM), about 100 km east of Lisbon. This farm has 423 ha running a business which strategy is based on sustainability concepts. There are three pillars in the current sustainable management model: Deepening, Widening and Repositioning. The first one focus on a) diversification of income, b) organic agriculture, c) extensive production practices, d) autochthonous species and their certification, e) on-farm added value to products. The Widening strategy focus on f) recreational and environmental education, g) enabling visiting activities, h) organizing thematic pathways, i) eco-camping, j) catering and k) environmental services. The Repositioning strategy focus on l) energy production, m) organizing on-farm events and n) host “your nursery” projects (Auriault 2012). The farm has the social responsibility of employing about 20 local people. The cornerstone in the management strategy is the improvement of the soil quality as this is considered vital to surrounding around 300 satellite products and services coming from the farm. Trees under the Montado agroforestry system are vital in the management as they provide services such as improvement of soil organic matter, soil water management, fungus and bacteria host, erosion regulator, animal shelter, fodder, ecological niches, direct non wood forest products (e.g. cork, acorns) and indirect (e.g. mushrooms, honey), hunting services, aesthetic value and cultural heritage. According to the recent established EU project “Agroforestry that will advance rural development (AGFORWARD 2014-2017), agroforestry systems can be roughly focused in four types: 1) High Natural and Conservation Value, 2) High value tree systems, 3) Silvoarable systems and 4) Silvopastoral systems. Throughout the above brief description of HFM farm, it is not possible to frame HFM in a singular type due to its holistic management embracing all “types of agroforestry”. The AGFORWARD project is embracing the farm to be studied under a High Natural and Conservation Value system, but the farm is also a unique opportunity to improve existing farm-scale agroforestry models (e.g. Graves et al 2011) as it helps to understand the interactions between products and services of agroforestry systems in a multifunctional concept, a goal envisaged in “field and farm evaluation” work package (WP6). According to the farmer, “if I would do conventional farming practices, I would increase my income by almost double. This is due to the current payment scheme biased towards intensive agriculture”. This was partially studied in Palma et al (2007), and a more comprehensive evaluation is being strengthened through the improvement of models, where innovative farms, such as HFM, are of high importance.
- Quassia amara L. growth under different shading conditions: implications for the management of Costa Rica natural and planted forestsPublication . Paulo, Joana Amaral; Villalobos, R.
- An individual tree growth model for juvenile cork oak stands in southern PortugalPublication . Tomé, Margarida; Paulo, Joana AmaralThe 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 estimationPublication . Palma, J.H.N.; Paulo, Joana Amaral; Tomé, MargaridaModern 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 sequestration
- Identification of agroforestry systems and practices to modelPublication . Palma, J.H.N.; Graves, Anil; Crous-Duran, Josep; Paulo, Joana Amaral; Upson, Matthew; Dupraz, Christian; Gosme, Marie; Lecomte, Isabelle; Touhami, Haythem Ben; Mézière, Delphine; Burgess, PaulThis report is an output from work-package 6 which contributes to the third objective. Work-package 6 focuses on the field- and farm-scale evaluation of innovation research that have arisen from about 40 agroforestry stakeholder groups created across Europe. Some research, for example tree protection options, are best determined by technical evaluations in the field. However some research questions require a modelling approach to predict, for example, the financial and economic impact of a new practice over a number of years. This report seeks to identify those agroforestry systems and practices which could be usefully assessed using biophysical agroforestry models such as Yield-SAFE (van der Werf et al., 2007) and Hi-sAFe (Talbot, 2011), or bio-economic models such as Farm-SAFE (Graves et al., 2011).