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This paper presents a model to predict annual wildfire risk in pure and evenaged eucalypt stands in Portugal. Emphasis was in developing a management- oriented model, i.e., a model that might both: (a) help assess wildfire occurrence probability as a function of readily available forest inventory data; and (b) help predict the effects of management options (e.g., silvicultural treatments) on the risk of fire in eucalypt stands. Data from both the 1995/1998 and the 2005/2006 Portuguese National Forest Inventories as well as wildfire perimeters' data were used for modeling purposes. Specifically, this research considered 1122 inventory plots with approximately 1.2 million trees and 85 wildfire perimeters. The model to predict the probability of wildfire occurrence is a logistic function of measurable and controllable biometric and environmental variables. Results showed that wildfire occurrence probability in a stand increases with the ratio basal area/quadratic mean diameter and with the shrubs biomass load, while it decreases with stand dominant height. They further showed that the probability of wildfire occurrence is higher in stands that are over 1 Km distant from roads. These results are instrumental for assessing the impact of forest management options on wildfire risk levels thus helping forest managers develop plans that may mitigate wildfire impacts. [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]

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]

Umbrella pine (Pinus pinea L.) cones take three years to develop. With the increasing frequency of extreme droughts, water available for trees has decreased—climate change is a reality. The cone's survival in its first two years of development and the average cone weight during its last year of maturation is affected, thus, reducing kernel quantity and quality. Climate change has resulted in forest fires becoming an inescapable issue in forest management planning. A literature review was carried out, focusing, on one hand, the predicted climatic changes for the Mediterranean basin and, on the other hand, the umbrella pine silvicultural mechanisms at tree, stand, and landscape levels that may help to face these constraints. Finally, the Portuguese case was focused, describing the management practices that are being adopted to achieve, even when the period of cone formation and growth include dry years, one to six tons of cones per hectare per year in adult stands. [ABSTRACT FROM AUTHOR]