Natural Regeneration of Maritime Pine: A Review of the Influencing Factors and Proposals for Management

ReviewThe main objective of the present work was to review the current knowledge about the factors that influence the different phases of the natural regeneration of maritime pine (Pinus pinaster Aiton) and propose scientifically based management schedules. The review focused on the natural regeneration of maritime pine within its most representative areas (Portugal, Spain, and France). First, a brief characterisation of the main phases of the natural regeneration of maritime pine is described. Next, information on the factors affecting the natural regeneration of the species is provided, highlighting its positive and negative effects. Finally, management proposals are presented to promote the natural regeneration of maritime pine species. Numerous factors influencing the natural regeneration of maritime pine were identified. Fires and climatic factors can intervene in all three regeneration phases (seeding, germination, and seedling survival and development). The natural regeneration failure of maritime pine species can be aggravated in drier scenarios. Forest management plays an important role as it can promote the natural regeneration of the speciesinfo:eu-repo/semantics/publishedVersio

Solving a harvest scheduling optimization problem with constraints on clearcut area and clearcut proximity

This study aims at solving a harvesting scheduling optimization problem with constraints on the clearcut area with additional constraints on clearcut proximity. The objective function is defined as the net present value generated by harvesting discounted by a penalty for each clearcut. This problem arises to reduce the negative environmental impact of excessive harvesting. We propose the connected-bucket model, the so-called bucket model with additional constraints on bucket connectivity and two definitions of stand adjacency, and a Dantzig–Wolfe decomposition. The decomposed model is solved by branch-and-price and the connected-bucket model by a general-purpose mixed integer programming solver (CPLEX). We compare the quality of the solutions obtained with both approaches for real instances. The branch-and-price approach found better solutions for the majority of the instances.This research was supported by the Center of Mathematics, Fundamental Applications and Operations Research - project UIDB/04561/2020, the INESC TEC - Institute for Systems and Computer, Engineering, Technology and Science - project LA/P/0063/2020, and also by the R&D project entitled “An Optimization Framework to reduce Forest Fire” - PCIF/GRF/0141/2019, all funded by FCT - Fundação para a Ciência e Tecnologia

Size–density trajectory in regenerated maritime pine stands after fire.

Research Highlights: This study bridges a gap of knowledge about the maximum size–density trajectory for juvenile stands of maritime pine. The continuity of the trajectory along the development stages to maturity is assured with a straightforward approach providing support to determine optimum density along all the revolution periods for the species. Background and Objectives: Forest fire is a significant threat to forests in the Mediterranean regions, but also a natural disturbance that plays a vital role in the perpetuation of forest stands. In recent decades, there has been an increase of burnt area in maritime forests in Portugal, followed by an increased interest in managing the natural and usually abundant regeneration occurring after the fires. The gap in the knowledge of growth dynamics for juvenile stages, for these forest systems, currently constrains their correct management, for forest planning, particularly in determining the optimal densities. The study aims to identify the maximum attainable density trajectory at the early stages of development of the species that could support a non-empirical definition of silvicultural prescriptions and thinning decisions, along the revolution. Materials and Methods: A representative data set collected in stands regenerated after fire supports the analysis of the maximum size–density trajectory for the species. Results: The maximum size–density trajectory for the juvenile stands deviates from the expected trajectory defined in the self-thinning line published for the species. Significant deviation occurs at the lower end of the line, indicating the need for a reevaluation of the existing self-thinning line. We propose a new self-thinning model for the species that explicitly considers the behavior of size–density for juvenile stands. The new model assures a logical continuity for the trajectory from the young stages of development to maturity. Conclusions: The proposed model based on the maximum attainable size–density trajectory provides ecological-based support to define silvicultural guidelines for management of the species.info:eu-repo/semantics/publishedVersio

Impact of fire recurrence and induced water stress on seed germination and root mitotic cell cycle of Pinus pinaster aiton

Climate change will increase the frequency of drought, heat waves, and wildfires. We intended to analyse how fire recurrence and/or induced water stress can affect seed germination and root cell division in Pinus pinaster Aiton. Seeds from stands with no prior fire history and from post-fire regeneration (in areas burnt once, twice, and thrice) in northern Portugal were germinated in distilled water (control) and polyethylene glycol (PEG) to simulate water stress for four weeks, followed by a recovery period. Roots were analysed cytogenetically. The germination index of the Pinus pinaster seeds was not statistically influenced by the induction of osmotic stress, nor by the fire recurrence of the stands. The mean germination time (MGT) was 10–29 days and 1–36 days for the stress and recovery periods, respectively, and increased with PEG concentration. The 20% PEG treatment inhibited root growth after germination. The 10% PEG treatment induced a high frequency of cytogenetic anomalies, mostly in the sites which experienced fire exposure. While fire recurrence did not affect the germination rate, it seemed to reduce the water stress response, negatively impacting cell division and impair root growthinfo:eu-repo/semantics/publishedVersio

Optimization of Production Planning

The challenge proposed by PRIMAVERA BSS software company was to find an effective scheduling algorithm that can add new features to their production planning software, with a good performance (being able to run in less than 10 minutes), and that can be su�ciently generic and adaptable to be used by different industries (metal, furniture, wood, textile, and food industry). The requirements configured a NP-hard problem known in the literature as the Flexible Job Shop Scheduling Problem (FJSSP), for which sophisticated mathematical models and heuristic methods are widely available. The wherein proposed approaches consider sequence dependent setup times and different priorities for the operations. Two approaches are considered in the present report. First, two mathematical models were created to address this problem and give insight to the structure of the problem and its constraints. A second approach proposed the use of heuristics. A constructive heuristic used to find initial solutions is followed by the use of an improvement heuristic, which allows to obtain better solutions at reasonable computational costs. The solutions obtained by the heuristics can be used to warm start the optimal solving procedure using mathematical models with commercial solvers

Self-Sustainability Assessment for a High Building Based on Linear Programming and Computational Fluid Dynamics

With excess energy use from non-renewable sources, new energy generation solutions must be adopted to make up for this excess. In this sense, the integration of renewable energy sources in high-rise buildings reduces the need for energy from the national power grid to maximize the self-sustainability of common services. Moreover, self-consumption in low-voltage and medium-voltage networks strongly facilitates a reduction in external energy dependence. For consumers, the benefits of installing small wind turbines and energy storage systems include tax benefits and reduced electricity bills as well as a profitable system after the payback period. This paper focuses on assessing the wind potential in a high-rise building through computational fluid dynamics (CFD) simulations, quantifying the potential for wind energy production by small wind turbines (WT) at the installation site. Furthermore, a mathematical model is proposed to optimize wind energy production for a self-consumption system to minimize the total cost of energy purchased from the grid, maximizing the return on investment. The potential of a CFD-based project practice that has wide application in developing the most varied processes and equipment results in a huge reduction in the time and costs spent compared to conventional practices. Furthermore, the optimization model guarantees a significant decrease in the energy purchased at peak hours through the energy stored in energy storage systems (ESS). The results show that the efficiency of the proposed model leads to an investment amortization period of 7 years for a lifetime of 20 years

Self-thinning dynamics in cork oak woodlands: providing a baseline for managing density

Aim of study: The study aims to evaluate the maximum potential stocking level in cork oak (Quercus suber L.) woodlands, using the ecologically-based size-density relationship of the self-thinning law.Area of study: The study area refers to cork oak forests in mainland Portugal, distributed along its 18 districts from north to south.Material and Methods: A dataset with a total of 2181 observations regarding pure cork oak stands was collected from the Portuguese Forest Inventory (NFI) databases and from research plots. The dataset was subjected to two filtering procedures, one more restrictive than the other, to select the stands presenting the higher stocking values. The two resulting subsets, with 116 and 36 observations, from 16 and 10 districts of mainland Portugal, respectively, were then used to assess and describe the allometric relationship between tree number and their mean diameter.Main results: The allometric relationship was analysed and modelled using the log transformed variables. A slightly curvilinear trend was identified. Thus, a straight line and a curve were both fitted for comparison purposes. Goodness-of-fit statistics point out for a good performance when the data is set to the uppermost observed stocking values. A self-thinning line for cork oak was projected from the estimated relationship.Research highlights: The self-thinning model can be used as an ecological approach to develop density guidelines for oak woodlands in a scenario of increasing cork demands. The results indicate that the recommendations being applied in Portugal are far below the maximal potential stocking values for the species. It is therefore of the utmost importance to review the traditional silvicultural guidelines and endorse new ones

Wind Farm Cable Connection Layout Optimization with Several Substations

Green energy has become a media issue due to climate changes, and consequently, the population has become more aware of pollution. Wind farms are an essential energy production alternative to fossil energy. The incentive to produce wind energy was a government policy some decades ago to decrease carbon emissions. In recent decades, wind farms were formed by a substation and a couple of turbines. Nowadays, wind farms are designed with hundreds of turbines requiring more than one substation. This paper formulates an integer linear programming model to design wind farms’ cable layout with several turbines. The proposed model obtains the optimal solution considering different cable types, infrastructure costs, and energy losses. An additional constraint was considered to limit the number of cables that cross a walkway, i.e., the number of connections between a set of wind turbines and the remaining wind farm. Furthermore, considering a discrete set of possible turbine locations, the model allows identifying those that should be present in the optimal solution, thereby addressing the optimal location of the substation(s) in the wind farm. The paper illustrates solutions and the associated costs of two wind farms, with up to 102 turbines and three substations in the optimal solution, selected among sixteen possible places. The optimal solutions are obtained in a short time

A climate index proposal for the wine sector: a descriptive statistical approach

Understanding the role of the climate on the wine production is one of the major concerns of this sector since the environment usually determines the output of this industry. There are only a few previous studies that attempted to compile these environmental effects as an index, usually considering the temperature and the precipitation as their core variables. The present study suggests a new climate index which is based on descriptive statistics. Our index tries to mimic the target region characteristics and avoid the past studies premise of imposing previously conceived restrictions such as a fixed optimal climate. We then used yearly production and daily temperature data (1950-2016) from the Portuguese Minho wine region to test our proposed index and compare it with Ribéreau-Gayon and Peynaud (RGP, Ribéreau-Gayon et al., 2003) and Growing Degree-Days (GDD, Winkler et al., 1974) indexes. Our results showed that the newly proposed index may outperform the explanatory power of the other indexes and, in addition, may output interesting and unknown characteristics such as the different ideal temperatures regarding the studied region

Influência do preço da mão de obra na sustentabilidade das explorações vitícolas durienses: uma aplicação de modelos baseados em agentes

In Portugal, labour availability has been revealed as a key factor for the activity, particularly in mountain viticulture. The latest statistics present worrying values that could undermine the production of quality wine and the attractive set of wine landscapes considered as a potential resource for tourism development. The Douro Region is one of the main Portuguese wine regions, characterized by a prominent and accentuated mountain viticulture. This paper aims to simulate the behaviour of its farms about the changes in the price of labour, through Agent-Based Models (ABM). The MATLAB software was used to obtain periodic functions adjusted to the data that characterize the relevant variables, obtained from face-to-face surveys of 110 farms, and taking into account the data provided by PTFADN. Subsequently, the ABM software (NETLOGO) was selected to simulate the next 100 years, familiarizing the real dynamics based on the previously considered data. Depending on the price of labour at the end of the simulation horizon, with a grape price of 0,77 €/kg, from the 300 initially existing farms survive between 127 and 231 (42,3 - 77%). In a more optimistic scenario, with a grape price of 1,17 €/kg, the survival rate ranges between 72.1 and 93.2%