Universidade de Trás-os-Montes e Alto Douro (UTAD) Escola de Ciências Agrárias & Veterinárias (ECAV) Dept. Ciências Florestais e Arquitectura Paisagista (CIFAP) & Centro de Investigação e de Tecnologias Agro-Ambientais e Biológicas (CITAB) Quinta de Prados, 5001-801 Vila Real, Portugal phone: +351 259350861
Forest Engineer (1991) and Ph.D. in Forest Sciences (2003) I do research and teach on wildland fire, being particularly interested in the interactions between the behaviour, ecology and management of fire. My main expertise and interests are on fuel characterization and modelling, empirical fire behaviour modelling (including its application to fire management), post-fire tree survival, the effects and effectiveness of prescribed burning and other fuel treatments, and the roles of fuels/pyrodiversity and weather on burn probability and fire size.
Bibliometry at http://www.researcherid.com/rid/A-6948-2008 (h-index = 11) and http://scholar.google.com/citations?hl=en&user=VEaRO9oAAAAJ
Abstract: Forest fires are an integral part of the ecology
of the Mediterranean Basin; however, fire incidence has
increased dramatically during the past decades and fire is
expected to become more prevalent in the future due to
climate change. Fuel modification by prescribed burning
reduces the spread and intensity potential of subsequent
wildfires. We used the most recently published data to
calculate the average annual wildfire CO2 emissions in
France, Greece, Italy, Portugal and Spain following the
IPCC guidelines. The effect of prescribed burning on
emissions was calculated for four scenarios of prescribed
burning effectiveness based on data from Portugal. Results
show that prescribed burning could have a considerable
effect on the carbon balance of the land use, land-use
change and forestry (LULUCF) sector in Mediterranean
countries. However, uncertainty in emission estimates
remains large, and more accurate data is needed, especially
regarding fuel load and fuel consumption in different
vegetation types and fuel layers and the total area protected
from wildfire per unit area treated by prescribed burning,
i.e. the leverage of prescribed burning.
Abstract: A dataset of 42 experimental fires in maritime pine ( Pinus pinaster Ait.) stands was used to develop fuel models to describe pine litter and understorey surface fuel complexes. A backtracking calibration procedure quantified the surface fuel bed characteristics that best explained the observed rate of fire spread. The study suggested the need for two distinct fuel models to adequately characterise the variability in fire behaviour in this fuel type. In these heterogeneous fuel beds the fuel models do not necessarily represent the inventoried average fuel conditions. Evaluation against the modelling data produced mean absolute errors of 0.8 and 0.6 m min(-1) in rate of spread, respectively, for the litter and understorey fuel models, with little evidence of bias. The fuel models predicted the rate of spread of a validation dataset with comparable error. Comparison of the behaviour and evaluation statistics produced by the study fuel models with fuel models developed from inventoried fuel data alone revealed an improvement on model performance for the current study approach for the litter fuel model and comparable behaviour for the understorey one. We examined model behaviour through comparative analysis with models used operationally to predict fire spread in pine stands. Large departures from model behaviour essentially occur when the models are exercised outside the range of the model development dataset. The discrepancies in predicted fire behaviour were hypothesised to arise not from differences in fuel complex structure but from the selected functional relationships that determine the effect of wind and fuel moisture on rate of spread.
Abstract: Thresholds for surface fire spread were examined in maritime pine (Pinus pinaster Ait.) stands in northern Portugal. Fire sustainability was assessed after ignition of 2 m fire lines or in larger burns conducted in 10-15am wide plots. The experiments were carried out from November to June in three fuel types: litter, litter plus shrubs, and litter with a nonwoody understorey. Moisture content of fine dead fuels, on-site weather variables, and descriptors of the fuel complex all had a highly significant influence on the probability of self-sustaining fire spread. A logistic model based solely on fuel moisture content correctly classified the fire sustainability status of 88% of the observations. Nonetheless, the subjectivity of the moisture of extinction concept was apparent, and further accuracy was achieved by the consecutive addition of fire spread direction (forward or backward), fuel type, and ambient temperature. Fully sustained fire spread, in opposition to marginal burns with broken fire fronts, was similarly dependent on fuel moisture but was affected also by fire spread direction and time since rain. The models can benefit fire research and fire management operations but can be made more practical if integrated in a fire danger rating system.
Abstract: Maritime pine (Pinus pinaster Ait.) is an important conifer from the western Mediterranean Basin. Fire is the most significant threat to maritime pine plantations but also a disturbance that plays a vital role in the perpetuation of natural stands. The species has physical characteristics that allow survival after low-intensity fire, namely thick bark, and reproduction processes that facilitate recovery after stand replacement fire from seeds stored in serotinous cones. These traits are consistent with the opposing strategies of fire resistance and fire evasion and can be interpreted as evolutionary adaptations to fire, but their development and coexistence are highly variable between populations, thus invalidating the classification of maritime pine in a general fire regime category. When the two strategies are concurrent the species should be able to persist under a variable or mixed fire regime. The quality, quantity and structural arrangement of fuels in maritime pine stands explain why they are so flammable. Thorough descriptions of the litter and understorey fuel complex are available in the literature, which makes custom fire behaviour prediction possible with software tools based on Rothermel's fire spread model; empirical fire behaviour models developed from experimental fire data are also available and are preferred to plan prescribed burning operations. There is ample evidence, although largely anecdotal, that surface, ladder and canopy fuel treatments mitigate wildfire intensity and burn severity and avoid crown fire in maritime pine stands. The optimization of fuel hazard management is nevertheless curtailed by the current state of knowledge about crown fire behaviour and fuel dynamics in relation to stand development and silviculture. The conservation and sustainable management of maritime pine in fire-prone landscapes should integrate the active use of fire and understand that effective protection from high-severity wildfire is not possible without sacrificing some stand volume.
Abstract: The ignition of low-intensity fires in the dormant season in the pine stands of north-western Portugal seeks to reduce the existing fuel hazard without compromising site quality. The purpose of this study is to characterise this practice and assess its effectiveness, based on information resulting from the normal monitoring process at the management level, and using operational guidelines, fire behaviour models and a newly developed method to classify prescribed fire severity. Although the region's humid climate strongly constrains the activity of prescribed fire, 87% of the fires analysed were undertaken under acceptable meteorological and fuel moisture conditions. In fact, most operations achieved satisfactory results. On average, prescribed fire reduces by 96% the potential intensity of a wildfire occurring under extreme weather conditions, but 36% of the treated sites would still require heavy fire fighting resources to suppress such fire, and 17% would still carry it in the tree canopy. Only 10% of the prescribed burns have an excessive impact on trees or the forest floor, while 89% (normal fire weather) or 59% (extreme fire weather) comply with both ecological integrity maintenance and wildfire protection needs. Improved planning and monitoring procedures are recommended in order to overcome the current deficiencies.
Abstract: An experimental fire was conducted in the summer in a 28-year old maritime pine ( Pinus pinaster) plantation in northeastern Portugal. Fuel conditions within the stand were age-dependent and comprised four situations: treated with prescribed fire at differing times, respectively 2, 3, and 13 years before the study, and undisturbed, where fuel accumulation time equalled stand age. The rate of fire spread did not respond to factors other than wind speed, in spite of the fuel-complex diversity. A high-intensity fire involving partially or totally the tree canopy and killing all trees was experienced in the older treatment area and in the untreated part of the stand, but the benefits of fuel management were still detectable in the former. Surface fire intensity, crown fire potential and fire severity ( including tree mortality) were drastically reduced where prescribed fire had been carried recently. Fuel and fire management implications are discussed.
Abstract: Wildfire hazard abatement is one of the major reasons to use prescribed burning. Computer simulation, case studies, and analysis of the fire regime in the presence of active prescribed burning programs in forest and shrubland generally indicate that this fuel management tool facilitates fire suppression efforts by reducing the intensity, size and damage of wildfires. However, the conclusions that can be drawn from the above approaches are limited, highlighting the need for more properly designed experiments addressing this question. Fuel accumulation rate frequently limits prescribed fire effectiveness to a short post-treatment period ( 2 - 4 years). Optimisation of the spatial pattern of fire application is critical but has been poorly addressed by research, and practical management guidelines are lacking to initiate this. Furthermore, adequate treatment efforts in terms of fire protection are constrained by operational, social and ecological issues. The best results of prescribed fire application are likely to be attained in heterogeneous landscapes and in climates where the likelihood of extreme weather conditions is low. Conclusive statements concerning the hazard-reduction potential of prescribed fire are not easily generalised, and will ultimately depend on the overall efficiency of the entire fire management process.
Abstract: Expertise and knowledge of forest fire behaviour provide a sound basis to fire management activities. This study examines the possibility of describing fire spread in shrubland by means of a simple empirical model. Rates of fire spread up to 20 m min(-1) and the associated weather and fuel conditions were measured on a set of experimental and prescribed bums in four different shrub fuel types in Portugal. Shrubland fire spread in flat terrain could be accurately predicted in terms of wind speed, aerial dead fuel moisture content and vegetation height. However, it was not possible to identify individual effects of the fuel-complex descriptors on fire propagation. Preliminary fire spread models are presented but their use should be restricted to mild to moderate burning conditions until more extensive experimentation is carried out. (C) 2001 Elsevier Science B.V. All rights reserved.
Abstract: Fire behaviour modelling has been based primarily on experiments involving the measurement of a certain number of fires, where each variable is represented by an average value per fire. The main objective of this study was to examine if data collected from a microplot sampling design could be used to derive meaningful fire behaviour models. Three burns were conducted in low shrubland of Erica umbellata Loefl., and Chamaespartium tridentatum (L.) P. Gibbs in northeastern Portugal. Wind speed and aerial dead fuel moisture content varied from 5 to 27 km/h and from 14 to 21%, respectively. Rate of spread and flame length ranged from 0.3 to 14.1 m/min and from 0.2 to 3.1 m, respectively. Rate of fire spread could be described effectively in terms of an empirical model with wind speed and fuel height as independent variables. The coefficients that describe the effects of wind speed and fuel height on fire propagation were consistent with published values for similar fuel types. Flame length was strongly related to Byram's fireline intensity. Microplot sampling is not free from methodological problems, which are discussed, but can be effectively used in field studies of fire behaviour.
Abstract: A fast, simple, low cost and general technique for estimating fuel surface area-to-volume ratio was developed. It requires the knowledge of particle density, the determination of fuel weight before and after immersion in water, and theoretical thickness of the adsorbed water pellicle that is assumed constant. Estimates by the technique were consistent and in good agreement with published surface area-to-volume ratios for the same fuels obtained through commonly used methods, and its performance is judged appropriate for the current fire behaviour modeling needs. The water immersion technique was applied to five common shrub species in Portugal. Limitations and possibilities for improvement of the newly developed technique are discussed.
