Manual de boas práticas de gestão dos espaços florestais na bacia drenante da Albufeira de Castelo do Bode

No âmbito do Projecto “Nascentes para a Vida” foram concluídas tarefas que se encontram sintetizadas neste documento, em particular no que se refere às seguintes tarefas: • Tarefa 3.1: Medidas a implementar ao nível das linhas de água afluentes à Albufeira de Castelo do Bode; • Tarefa 3.2: Implementação de um programa de gestão de matos e promoção da biodiversidade na envolvente da Albufeira de Castelo do Bode; • Tarefa 4.2: Monitorização das áreas submetidas às técnicas de gestão florestal e desenvolvimento de um conjunto de indicadores para uma gestão florestal sustentável. Diagnosticados os incêndios florestais como um dos maiores factores de perturbação na área de estudo, é sobre este tema que incide essencialmente o exposto neste trabalho

On the projection of future fire danger conditions with various instantaneous/mean-daily data sources

Fire danger indices are descriptors of fire potential in a large area, and combine a few variables that affect the initiation, spread and control of forest fires. The Canadian Fire Weather Index (FWI) is one of the most widely used fire danger indices in the world, and it is built upon instantaneous values of temperature, relative humidity and wind velocity at noon, together with 24 hourly accumulated precipitation. However, the scarcity of appropriate data has motivated the use of daily mean values as surrogates of the instantaneous ones in several studies that aimed to assess the impact of global warming on fire. In this paper we test the sensitivity of FWI values to both instantaneous and daily mean values, analyzing their effect on mean seasonal fire danger (seasonal severity rating, SSR) and extreme fire danger conditions (90th percentile, FWI90, and FWI>30, FOT30), with a special focus on its influence in climate change impact studies. To this aim, we analyzed reanalysis and regional climate model (RCM) simulations, and compared the resulting instantaneous and daily mean versions both in the present climate and in a future scenario. In particular, we were interested in determining the effect of these datasets on the projected changes obtained for the mean and extreme seasonal fire danger conditions in future climate scenarios, as given by a RCM. Overall, our results warn against the use of daily mean data for the computation of present and future fire danger conditions. Daily mean data lead to systematic negative biases of fire danger calculations. Although the mean seasonal fire danger indices might be corrected to compensate for this bias, fire danger extremes (FWI90 and specially FOT30) cannot be reliably transformed to accommodate the spatial pattern and magnitude of their respective instantaneous versions, leading to inconsistent results when projected into the future. As a result, we advocate caution when using daily mean data and strongly recommend the application of the standard definition for its calculation as closely as possible. Threshold-dependent indices derived from FWI are not reliably represented by the daily mean version and thus can neither be applied for the estimation of future fire danger season length and severity, nor for the estimation of future extreme events.The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement 243888 (FUME Project). J.F. acknowledges nancial support from the Spanish R&D&I programme through grant CGL2010-22158-C02 (CORWES project). The ESCENA project (200800050084265) of the Spanish \Strategic action on energy and climate change" provided the WRF RCM simulation used in this study. We acknowledge three anonymous referees for their useful comments that helped to improve the original manuscript

Fire-severity mitigation by prescribed burning assessed from fire-treatment encounters in maritime pine stands

Maritime pine (Pinus pinaster Ait.) stands are prone to high-intensity fire. Fuel treatments lessen potential fire behaviour and severity, but evidence of their effectiveness when tested by wildfire is extremely scarce in Europe. We assess the longevity of prescribed burning in maritime pine plantations in decreasing fire severity. Heights of crown scorch and stem-bark char were measured in treated and untreated adjacent areas after fire-treatment encounters in Portugal, Italy, and Australia. Treatment effect was quantified as the log-transformed ratio between prescribed-burned and untreated fire-severity data. Linear mixed modelling indicated that for typical wildfire conditions, the effect of prescribed burning in crown scorch height lasts 2-6 years. The persistence of prescribed burning benefits is higher for fire control operations than for fire-severity mitigation. Regression tree analysis of data from one wildfire highlighted the roles of wind direction, topography, and stand height in explaining variability in fire severity. A 4-year interval between prescribed burning treatments in maritime pine stands is recommended in general, depending on site quality and stand age and structure. Improved fuel-consumption prescriptions and monitoring procedures are advisable to foster prescribed-burning effectiveness and its evaluation

Using PiroPinus to assess fuel reduction effectiveness of prescribed burning in a Pinus halepensis plantation in Southern Italy

PiroPinus was developed in Portugal as a decision support-tool to prescribed burning use in Pinus pinaster. Although tailored for site-specific conditions, it is empirically-based and so its performance outside the environmental range of development is uncertain. The objective of the present study is to test PiroPinus 2.2 utilities to define prescriptions, implement and evaluate prescribed burning for fire hazard reduction in Pinus halepensis plantations. The study site was located in the Cilento and Vallo di Diano National Park, one of the most fire-prone areas of Southern Italy. The experimental design consisted of 3 burn plots (BU), 0.2 ha in size, and 2 controls (CO). In all plots the plantation presented high fire risk. Pre-burn surface fuels (5.2±1.3 t ha-1 of litter, and flammable Ampelodesmos mauritanicus) and elevated fuels (dominated by Erica arborea) presented horizontal and vertical continuity. Objectives for the burn were: (1) reduce surface fuels; (2) create vertical discontinuity. PiroPinus was used as a reference guide to define burning windows. All plots were burned in May 2009. Most of burning parameters fell within the PiroPinus prescriptions. Fire behaviour was assessed with a microplot scale approach. Observed average surface litter moisture was 17%; rate of spread 0.22±0.06 m min-1; flame length range 0.2- 1.0 m; fireline intensity 52±10 kW m-1. PiroPinus provided an accurate estimate of observed values: 17%, 0.25 m min-1, 0.5 m and 48 kW m-1 respectively. Prescribed burning objectives were achieved to some extent. According to the PiroPinus fire interpretation table the burn was conducted at the upper limit of moisture conditions. In fact, in summer 2009 surface fuels in BU were reduced only in part. Major changes were observed in elevated fuels whose cover decreased from 58% to 3%; the vertical continuity was remarkably reduced. Finally, PiroPinus was used to model post-treatment fire behaviour under different weather conditions. It predicted a remarkable mitigation of fire behaviour in BU vs. CO for all weather scenarios. Under the 97.5th scenario, simulated rate of spread, flame length and intensity in BU were respectively 75%, 31% and 12% of the CO values. PiroPinus resulted a useful tool to support prescribed burning in Pinus halepensis plantations of the Cilento Park. Despite constraints (research issues to address are outlined), this study showed that experimental data can be used to improve the performance of PiroPinus, extending its use as a reference guide for Mediterranean pine forests other than Pinus pinaster

Experimental prescribed burning in Turkey oak forest of Cilento and Vallo di Diano National Park (Southern Italy): effects on vegetation and soil

An experimental prescribed burn was conducted in February 2011 in a Quercus cerris forest in the Cilento e Vallo di Diano National Park (Southern Italy) to analyze fire effects on vegetation and soil. Fuel fire behavior characteristics and were assessed to define the burning conditions that allowed a rate of fire spread between 0.10 and 0.22 m min-1, fireline intensity never below 50 kW m-1 and maximum flame temperatures in the litter of 600°C but the average residence time above 60°C and 300°C were 198 and 12 seconds, respectively. Litter fuel consumption ranged between 80% and 90%. The effect of fire on vegetation was evaluated in terms of floristic composition and structure by means of phytosociological and dendrometric samplings randomly located in burned and unburned plots two years after fire. The effect of fire on soil was evaluated by determining soil chemical (pH, water content, total and extractable organic C content, total and mineral N) and microbial properties (microbial biomass, soil potential respiration) in the 0-5 cm soil at different time since fire (3 hours, 30, 94, 209 and 394 days). Moreover, water holding capacity and bulk density were measured in burned and unburned plots at first sampling. Results on vegetation evidenced no significant differences in species richness and diversity, in both burned and unburned plots. No changes have been found in frequency and cover values of endemic species (Digitalis micrantha, Echinops ritro subsp. siculus, Lathyrus jordanii, Teucrium siculum). Woody species showed a great resilience with very low tree mortality. Sapling persistence by high sprouting rootstocks evidenced no significant difference in the abundance of some species (Quercus cerris, Acer campestre, Carpinus betulus, Crataegus monogyna) or an increase for few species (Ruscus aculeatus, Ilex aquifolium, Erica arborea, Fraxinus ornus, Sorbus torminalis, Carpinus orientalis) in burned plots. Results on soil showed that prescribed burning did not affect soil chemical and microbial properties, so indirect effects on plants deriving on effect of fire on soil may be excluded. Our findings highlight the sustainability of prescribed burning in Quercus cerris forests and support its future use as a management tool of fire risk reduction without significant impact on vegetation and soil. Keywords: Quercus cerris forest, prescribed burning