Development of forest simulation tools for assessing the impact of different management strategies and climatic changes on wood production and carbon sequestration for Eucalyptus in Portugal

Doutoramento em Engenharia Florestal e dos Recursos Florestais - Instituto Superior de AgronomiaThe present work had as main objective developing tools capable of simulating the evolution of Eucalyptus globulus forests in Portugal taking into account disturbance factors, such as market demands, hazards occurrence, land use changes, forest management and/or climate changes. Some conceptual work was done concerning the definition of different forest management alternatives while at the same time the E. globulus current management was described. SIMPLOT, a regional simulator based on national forest inventory plots was developed and validated. This simulation tool, mainly driven by wood and biomass demands, takes into account the occurrence of hazards, land use changes and the changes between different forest management alternatives allowing accessing its long-term impacts, namely on wood production and carbon sequestration. Some of the empirical growth models available for this species in Portugal were integrated into this simulator. However, the need to forecast the growth of highly stocked stands managed for bioenergy lead to the development of a new model. In order to account for climate changes, a process-based model was required. Therefore, the applicability of 3PG process-based model at a regional scale was tested for planted and coppice stands. Two forest level simulators, 3PG-Out+ and GLOBULUS, were developed along this study

StandsSIM-MD: a management driven forest SIMulator

Resource CommunicationAim of the study: The existing stand level forest simulators available in Portugal were not developed with the aim of including up-to-date model versions and were limited in terms of accounting for forest management. The simulators’ platform, sIMfLOR was recently created to implement different growth models with a common philosophy. The objective was developing one easily-updatable, user-friendly, forest management and climate change sensitive simulator capable of projecting growth for the main tree species in Portugal. Area of the study: Portugal. Material and methods: The new simulator was programmed in a modular form consisting of several modules. The growth module integrates different forest growth and yield models (empirical and process-based) for the main wood production tree species in Portugal (eucalypt, stone pine and maritime pine), the management module drives the growth projections along the planning horizon according to a range of forest management approaches and climate (at present only available for eucalypt). Main results: The main result is the StandsSIM-MD Management Driven simulator that overcomes the limitations of the existing stand level simulators. It is a step forward when compared to the models currently available in the sIMfLOR platform covering more tree species, stand structures and stand compositions. It is focused on end-users and it is based on similar concepts regarding the creation of required inputs and generated outputs. Research highlights: — Forest Management Driven simulations approach — Multiple Prescriptions-Per-Stand functionality — StandsSIM-MD can be used to support landowners decisions on stand Forest management — StandsSIM-MD simulations at regional level can be combined with optimization routinesinfo:eu-repo/semantics/publishedVersio

EuMIXFOR Introduction: integrating scientific knowledge in sustainable management of mixed forests

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SIMPLOT - simulador regional de eucalipto baseado em parcelas de inventário

O objectivo deste trabalho é descrever o SIMPLOT, uma ferramenta (não espacializada) para simular a evolução de povoamentos de eucalipto em Portugal. Esta ferramenta foi desenvolvida para realizar análises de grandes áreas a longo prazo, nomeadamente para avaliar o estado futuro da floresta de acordo com diferentes cenários de procura de madeira, ocorrência de fogo e de alterações de uso do solo. Os potenciais utilizadores desta ferramenta passam pelas indústrias de pasta e papel, pelas associações de produtores florestais e pelos decisores políticos a nível central ou nos municípios que podem recorrer a ela como apoio à na tomada de decisões

A progressive hedging approach to solve harvest scheduling problem under climate change

Due to the long time horizon typically characterizing forest planning, uncertainty plays an important role when developing forest management plans. Especially important is the uncertainty related to recently human-induced global warming since it has a clear impact on forest capacity to contribute to biogenic and anthropogenic ecosystem services. If the forest manager ignores uncertainty, the resulting forest management plan may be sub-optimal, in the best case. This paper presents a methodology to incorporate uncertainty due to climate change into forest management planning. Specifically, this paper addresses the problem of harvest planning, i.e., defining which stands are to be cut in each planning period in order to maximize expected net revenues, considering several climate change scenarios. This study develops a solution approach for a planning problem for a eucalyptus forest with 1000 stands located in central Portugal where expected future conditions are anticipated by considering a set of climate scenarios. The model including all the constraints that link all the scenarios and spatial adjacency constraints leads to a very large problem that can only be solved by decomposing it into scenarios. For this purpose, we solve the problem using Progressive Hedging (PH) algorithm, which decomposes the problem into scenario sub-problems easier to solve. To analyze the performance of PH versus the use of the extensive form (EF), we solve several instances of the original problem using both approaches. Results show that PH outperforms the EF in both solving time and final optimality gap. In addition, the use of PH allows to solve the most di cult problems while the commercial solvers are not able to solve the EF. The approach presented allows the planner to develop more robust management plans that incorporate the uncertainty due to climate change in their plansinfo:eu-repo/semantics/publishedVersio

Effects of different soil management practices on soil mechanic resistance and seed depth placement in a maize crop in Alentejo, Portugal.

In Alentejo region, Portugal, maize crop field studies were conducted to compare the effect of different tillage systems and no tillage in seed depth placement. Seed depth placement was measured by maize mesocotyl length after crop emergence under conventional tillage (CT), minimum tillage (MT) and no-tillage conditions (NT). In no-tillage condition two work speeds, 4km-1 and 6 km-1, were tested

Evaluation of the influence of post-processing on the optical inspection accuracy of additively manufactured parts

[EN] Optical measurement systems are important techniques for rapid inspecting additively manufactured parts by techniques such as selective laser melting (SLM). Depending on their application, SLM parts require post-processes such as sandblasting or heat treatment, commonly applied in order to improve their surface finish or mechanical properties, respectively. These post-processes modify the parts surface characteristics, and therefore the suitability for optical inspection. This work evaluates the influence of these SLM post-processes on optical inspection. For this, a test part, manufactured in 17-4PH stainless steel using a 3DSystems ProX100 machine, was optically measured using a structured light scanner and compared to the values obtained from contact measurements (reference values). Both optical and contact measurements were performed under three conditions: as-built, post sandblasting, and post sandblasting and subsequent heat treatment. The analysis results show that applying the sandblasting postprocessing provides a surface finish to the SLM parts suitable for optical inspection. This postprocess allows precise inspection of this type of parts, reaching values close to those obtained by contact. Likewise, it is concluded that the used structured blue-light scanner is suitable for inspecting SLM parts.SIMinisterio de Ciencia, Innovación y UniversidadesInstituto Universitario de Tecnología Industrial (SV-18-1-GIJON-1-06 and SV-19-GIJON-1-14

Influence of 17-4 PH stainless steel powder recycling on properties of SLM additive manufactured parts

[EN] Metal Additive Manufacturing (AM) processes are developing quickly. These processes have several attractive qualities, however, the quality of manufactured parts still remains a major issue that needs to be addressed if it is to become a prevalent technology in the industry. In some powder bed fusion techniques, such as Selective Laser Melting (SLM), there is a portion of initial powder that does not melt and it can be recycled to ensure the economic and environmental viability of the process. In previous research, we demonstrated the morphological, chemical and microstructural change suffered by 17-4 PH stainless steel powder after reusing it in a SLM manufacturing process. In this work, the properties of 17-4 PH stainless steel parts, printed from powder in different recycling states (virgin powder (P0) and 20 times reused powder (P20)), were evaluated, in order to establish good recycling procedures and optimise the SLM process performance. Analyses of the properties revealed a slight decrease in roughness and pore size with powder recycling. The external porosity of the samples is similar in both powder states; however, internal porosity decreases by increasing the number of reuse cycles. Regarding the microstructural analysis, a slight increase in the γ-phase is observed with the powder recycling, which leads to a slight increase in ductility and decrease in hardness of the samples. Therefore, it is concluded that the 17-4 PH powder recycling process in SLM manufacturing is adequate and recommended to ensure the economic and environmental viability of the process without adversely affecting the properties of the parts.S

New procedure for qualification of structured light 3D scanners using an optical feature-based gauge

[EN] This work evaluates the performance and operative limits to the dimensional accuracy of 3D optical scanning based on blue-light fringe projection technology. This technology, also known as structured light 3D scanning, is widely used in many reverse engineering applications. It allows the user to quickly capture and create point-clouds, by using images taken at different orientations of white-or blue-light fringe projected patterns on the part. For the survey, a large and feature-based gauge has been used with specific optical properties. The gauge is endowed with canonical geometrical features made of matt white ceramic material. The gauge was calibrated using a coordinate measuring machine (CMM) by contact. Therefore, it is possible to compare the measurements obtained by the structured blue-light sensor with those obtained by the CMM, which are used as reference. In the experimentation, the influence of the scanner software in the measurement results was also analysed. Besides, different tests were carried out for the different fields of view (FOV) of the sensor. The survey offers some practical values and limits to the accuracy obtained in each configuration.SIMinisterio de Economía y Competitividad de EspañaJunta de Castilla y Leó

Direct seed and precision agriculture technologies

A importância da sementeira directa tanto do ponto de vista agronómico como ambiental tem sido evidenciada por diversos autores. A transição de técnicas convencionais de sementeira com mobilização do solo para sementeira directa pode ser mais ou menos facilitada pelo tipo de solo e época de realização da operação. Contudo nos primeiros anos de instalação de culturas em sementeira directa, a irregularidade de resistência à penetração do solo não mobilizado pelo semeador pode estar na origem de heterogeneidades de distribuição da semente, nomeadamente no que respeita à sua profundidade. A utilização de tecnologias de Agricultura de Precisão permitindo identificar in situ algumas destas situações podem contribuir para a correcção das mesmas. No I ensaio realizado na Herdade da comenda em Caia os resultados preliminares indicam correlação moderada entre 3 níveis de profundidade de sementeira relativamente força exercida na respectiva linha propondo o desenvolvimento de dispositivos dinâmicos de controlo de profundidade em semeadores de sementeira directa