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Density-dependent mortality occurs in the evolution of even-aged populations when these approach crown closure age. This density-dependent mortality is regulated by the so-called "3/2 power law of self-thinning" that assumes a constant slope for the line relating the log of stand density with the log of the average tree size, the self-thinning line or maximum size–density relationship, MSDR. A good estimate of the self-thinning line is therefore an essential component to any forest growth model. Two concepts for the MSDR have emerged: (1) a static upper limit for the species; and (2) a dynamic self-thinning line influenced by several factors (e.g., management techniques, site quality and/or genetics). The objective of this study was to estimate a new static self-thinning line based on the quadratic mean diameter at breast height (Reineke's self-thinning line) for the generalized use in maritime pine growth models in Portugal. Data from 41 observations obtained in nine long-term permanent experimental trials of maritime pine species were carefully selected from a data set of 186 plots as being under self-thinning. Two methods were used: OLS and mixed linear models. An exploratory analysis on the impact of each environmental variable on the slope and intercept of the self-thinning line led to the selection of a subset of environmental variables later used in an all possible regressions algorithm to find the subsets leading to the lowest values of Akaike information criterion (AIC). The OLS procedure showed that the differences between the plots could be explained by site index, by climate variables (e.g., evaporation or climatic indices) and the use of more than one covariable slightly improved the fit. Nevertheless, the best MSDR line fitted with mixed linear models (ln N = 12.97158 − 1.83926 ln dg) having the plot random effect in the intercept, largely outperformed the best OLS model and is therefore recommended for generalized use in forest growth models. [ABSTRACT FROM AUTHOR]

Abstract: Modelling growth of trees or stands when age is not available is often necessary. This is the case in national forest inventories or when age is not a main [...]

For forest sustainability and vulnerability assessment, the landscape scale is considered to be more and more relevant as the stand level approaches its known limitations. This review, which describes the main forest landscape simulation tools used in the 20 European case studies of the European project "Future-oriented integrated management of European forest landscapes" (INTEGRAL), gives an update on existing decision support tools to run landscape simulation from Mediterranean to boreal ecosystems. The main growth models and software available in Europe are described, and the strengths and weaknesses of different approaches are discussed. Trades-offs between input efforts and output are illustrated. Recommendations for the selection of a forest landscape simulator are given. The paper concludes by describing the need to have tools that are able to cope with climate change and the need to build more robust indicators for assessment of forest landscape sustainability and vulnerability. [ABSTRACT FROM AUTHOR]

While sustainable forestry in Europe is characterized by the provision of a multitude of forest ecosystem services, there exists no comprehensive study that scrutinizes their sensitivity to forest management on a pan-European scale, so far. We compile scenario runs from regionally tailored forest growth models and Decision Support Systems (DSS) from 20 case studies throughout Europe and analyze whether the ecosystem service provision depends on management intensity and other co-variables, comprising regional affiliation, social environment, and tree species composition. The simulation runs provide information about the case-specifically most important ecosystem services in terms of appropriate indicators. We found a strong positive correlation between management intensity and wood production, but only weak correlation with protective and socioeconomic forest functions. Interestingly, depending on the forest region, we found that biodiversity can react in both ways, positively and negatively, to increased management intensity. Thus, it may be in tradeoff or in synergy with wood production and forest resource maintenance. The covariables species composition and social environment are of punctual interest only, while the affiliation to a certain region often makes an important difference in terms of an ecosystem service's treatment sensitivity. [ABSTRACT FROM AUTHOR]

The wildfire regime in Portugal has been responsible for millions of hectares of burnt area, and Alvares parish is no exception. In 2017, a severe wildfire burnt 60% of its area. Land abandonment has been increasing since the mid 20th century, and a large fraction of the forest area belongs to quasi-absent landowners. This has given rise to large, almost unbroken expanses of undermanaged forests that, in combination with rugged topography, originates a landscape prone to large, intense wildfires. Thus, a change in landscape composition and structure capable of reducing flammability and promoting fuel discontinuity is urgently needed. A fire spread simulator and a forest growth simulator were combined to show the impact of improving management at landscape level. It was assumed that the probability of large wildfires may be reduced by setting aside forest area for the implementation of a fuel break network (FBN) and increasing the area under sustainable forest management. Three levels of management intensity were simulated by restricting the area of Quasi-absent non-industrial owners to 34.5%, 20.1%, and 8.5% of the Alvares forest area, in favor of increasing the area of active and semi-active non-industrial owners (current, moderate, and high management scenarios). Different FBN extents, representing four levels of network implementation priority were combined with the management levels, resulting in 12 scenarios. To evaluate the impact of fire, simulations assuming no-fire, no-FBN, and current management intensity were performed, whereas the impact of operation costs was assessed assuming reduced costs for silvicultural operations. Per hectare simulations were then scaled up to the parish level and volume harvested and net present values were used to compare the management improvement scenarios. Results showed that fire has major repercussions on forest income, but these impacts can be minimized. Intensifying forest management and implementing the first priority FBN segments originated substantial improvements in financial outcome from timber production, close to those obtained for the full FBN implementation. Results also evidenced contrasting contributions from industrial and non-industrial owners with the later evidencing unbalanced cash-flows derailing the possibility for interesting forest incomes. The coupling of fire and forest growth simulations can be an interesting approach to assess the impact of different management and policy scenarios and inform policies. [ABSTRACT FROM AUTHOR]

Most European countries have signed the United Nations Framework Convention on climate change and its Kyoto Protocol. Because the European Union is a party to the convention just like the individual countries, there is a need for harmonizing emissions reporting. This specifically applies to the Land Use, Land-Use Change, and Forestry sector, for which harmonized reporting is complex and generally challenging. For example, parties use a variety of different methods for estimating emissions and removals, ranging from application of default factors to advanced methods adapted to national circumstances, such as ongoing field inventories. In this study, we demonstrate that without harmonization, national definitions and methods lead to inconsistent estimates. Based on case studies in Finland, Germany, Norway, Portugal, Slovenia, and Sweden, we conclude that common reference definitions and country-specific bridges are means to harmonize the estimates and make greenhouse gas reporting from forests comparable across countries. [ABSTRACT FROM AUTHOR]

Abstract: SIMPLOT is a forest simulator for eucalyptus mainly driven by wood demand. It was developed to predict the evolution of the eucalyptus plantations in Portugal by combining forest inventory data with growth models taking into account the effect of different drivers such as wood demand, hazards occurrence and percentage of land use changes. The use of simulators for scenario analysis can be a powerful tool to explore policy options and to illustrate the consequences of different management alternatives. In the past years Portugal has been marked by extremely severe forest fires of great environmental impact. This paper shows simulation runs for two main scenario lines: the wood demand line and the wildfires line. In the first one, the simulator is used to identify a reasonable wood demand out of three different wood demands combined with a low/medium intensity fire scenario. The selected wood demand combined with three fire scenarios of increasing severity and a fourth one disregarding the existence of recent severe wildfires builds the second scenario line. The purpose of this study is to evaluate the impact of different magnitudes of forest fires occurrence on the sustainability of eucalyptus plantations starting with NFI data gathered in 1997 during a horizon of 28 years. The simulations reflect a constant level of afforestation and deforestation and assume that no changes took place between different management alternatives. These simulations provide some insight on the impact of different wood demand and different magnitudes/frequency of severe wildfires: it is not only the number and magnitude of severe wildfires that make a difference, but it is also the number and magnitude of medium wildfires that follow an extremely severe one. Furthermore, the inter-annual variability of wildfire occurrence affects carbon stock and carbon sequestration in a different way. The occurrence of severe wildfires has an immediate effect on carbon sequestration. The lower values are registered in the same year in which the most severe wildfires occur. On the other hand, the occurrence of severe wildfires has more permanent consequences on carbon stocks than on carbon sequestration. The more severe and numerous are the wildfires the more difficult and at long-term will be to recover the carbon stocks in the forest. Results have also shown that if a higher wood demand compatible with the expected increase of pulp industry capacity would have been considered this would have had drastic impacts on eucalyptus forest sustainability due to overharvesting in order to meet the desired wood demand. [Copyright &y& Elsevier]

• Modeling the impact of defoliation on tree growth is an important tool for Integrated Pest Management (IPM). • A 3-PG based simulator was developed to integrate a Gonipterus platensis species-specific defoliation module. • Different scenarios of defoliation intensity under varying site conditions were simulated. • Wood volume losses of 74% and 85% were predicted for defoliations of the upper third of canopy of 75% and 100%, respectively. Growth losses due to insect defoliations are difficult to estimate. The lack of appropriate tools that account for defoliations in growth simulations makes difficult the task of forest managers to project growth, and thus, the expected economic income. The present work integrates defoliations in the 3-PG forest growth model in order to provide a tool that allows forest managers to estimate Eucalyptus globulus stands growth losses under a set of defoliation scenarios by simulating attacks of the Eucalyptus snout beetle Gonipterus platensis. To mimic these attacks, different amounts of the upper third of the canopy were removed, from 0 to 100%, depending on the scenario intensity, and considering only spring season attacks or both spring and autumn attacks in the same year. A set of E. globulus virtual stands, representing a range of site productivities, were submitted to constant yearly consecutive defoliations since age 2 up to 10. Simulation results showed that, for scenarios that removed 50, 75 and 100% of the upper third of the canopy, volume losses averaged 54, 74 and 83%, respectively, at age 10 with just the spring attack, reaching 69, 82 and 88%, respectively, with also the autumn attack. Removing only 25% of the upper third of the canopy produced relevant losses only if the stands were attacked in both seasons. Lighter defoliations tested seemed to have a marginal effect on stand growth regardless of site quality. The tool was also used to evaluate a field assessment methodology of G. platensis defoliation attacks on a set of real stands by comparing observed and estimated volumes at age 10. Estimations showed increasing volume losses with increasing defoliation intensities. When evaluating the field assessment methodology, results suggest that a single field visit to assess the G. platensis attack level in the whole lifetime of a stand is insufficient to make reliable growth loss estimations. The integration of the impact of defoliations in the 3-PG growth model revealed to be potentially useful as a forest management decision tool. [ABSTRACT FROM AUTHOR]

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 difficult 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 plans. [ABSTRACT FROM AUTHOR]

In this paper, we present a web-based decision support system (DSS)—wSADfLOR—to facilitate the access of stakeholders to tools that may contribute to enhancing forest management planning. The emphasis is on a web-based architecture and a web graphic user interface (wGUI) that may effectively support the analysis of trade-offs between ecosystem services in order to address participatory and sustainable forest management objectives. For that purpose, the wGUI provides remote access to a management information system, enabling users to analyze environmental and biometric data and topological information as well. Moreover, the wGUI provides remote access to forest simulators so that users may define and simulate prescriptions such as chronological sequences of management options and the corresponding forest ecosystem services outcomes. Remote access to management planning methods is further provided so that users may input their objectives and constraints. The wGUI delivers information about tradeoffs between ecosystem services in the form of decision maps so that users in different locations may negotiate bundles of ecosystem services as well as the plan needed to provide them. The multiple criteria programming routines provide proposals for management plans that may be assessed further, using geographical and alphanumeric information provided by the wGUI. Results for an application to a forested landscape extending to 14,388 ha are presented and discussed. This landscape provides several ecosystem services and the development of its management plan involves multiple stakeholders. Results show that the web-based architecture and the wGUI provide effective access for stakeholders to information about the forest management planning area and to decision support tools that may contribute to addressing complex multi-objective and multiple-decision-maker management planning contexts. They also highlight that the involvement and participation of stakeholders in the design of the web-based architecture contributes to assuring the quality and the usability of the system. [ABSTRACT FROM AUTHOR]