Physiological drought responses improve predictions of live fuel moisture dynamics in a Mediterranean forest.

The moisture content of live fuels is an important determinant of forest flammability. Current approaches for modelling live fuel moisture content typically focus on the use of drought indices. However, these have mixed success partly because of species-specific differences in drought responses. Here we seek to understand the physiological mechanisms driving changes in live fuel moisture content, and to investigate the potential for incorporating plant physiological traits into live fuel moisture models. We measured the dynamics of leaf moisture content, access to water resources (through stable isotope analyses) and physiological traits (including leaf water potential, stomatal conductance, and cellular osmotic and elastic adjustments) across a fire season in a Mediterranean mixed forest in Catalonia, NE Spain. We found that differences in both seasonal variation and minimum values of live fuel moisture content were a function of access to water resources and plant physiological traits. Specifically, those species with the lowest minimum moisture content and largest seasonal variation in moisture (Cistus albidus: 49–137% and Rosmarinus officinalis: 47–144%) were most reliant on shallow soil water and had the lowest values of predawn leaf water potential. Species with the smallest variation in live fuel moisture content (Pinus nigra: 96–116% and Quercus ilex: 56–91%) exhibited isohydric behaviour (little variation in midday leaf water potential, and relatively tight regulation of stomata in response to soil drying). Of the traits measured, predawn leaf water potential provided the strongest predictor of live fuel moisture content (R2 = 0.63, AIC = 249), outperforming two commonly used drought indices (both with R2 = 0.49, AIC = 258). This is the first study to explicitly link fuel moisture with plant physiology and our findings demonstrate the potential and importance of incorporating ecophysiological plant traits to investigating seasonal changes in fuel moisture and, more broadly, forest flammability.This study was made possible thanks to the collaboration of and the staff from the Natural Park of Poblet, P Sopeña, and the technical staff from MedForLab. This study was funded by the Spanish Government (RYC-2012-10970, AGL2015-69151-R). R. H. Nolan was supported with funding from the New South Wales Office of Environment and Heritage, via the Bushfire Risk Management Research Hub. We benefitted from critical comments from J Voltas, JM Moreno and L Serrano and instrument loans from R Savín

Diurnal surface fuel moisture prediction model for Calabrian pine stands in Turkey

We would like to extend our appreciation and thanks to Mugla and Antalya Regional Forest Directorate and its staff. This study was supported by The Scientific and Technological Research Council of Turkey, project no. TOVAG-112O809. We are grateful to two anonymous reviewers for their useful suggestions and comments that greatly improved the manuscript.This study presents a dynamic model for the prediction of diurnal changes in the moisture content of dead surface fuels in normally stocked Calabrian pine stands under varying weather conditions. The model was developed based on several empirical relationships between moisture contents of dead surface fuels and weather variables, and calibrated using field data collected from three Calabrian stands from three different regions of Turkey (Mugla, southwest; Antalya, south; Trabzon, north-east). The model was tested and validated with independent measurements of fuel moisture from two sets of field observations made during dry and rainy periods. Model predictions showed a mean absolute error (MAE) of 1.19% for litter and 0.90% for duff at Mugla, and 3.62% for litter and 14.38% for duff at Antalya. When two rainy periods were excluded from the analysis at Antalya site, the MAE decreased from 14.38% to 4.29% and R-2 increased from 0.25 to 0.83 for duff fuels. Graphical inspection and statistical validation of the model indicated that the diurnal litter and duff moisture dynamics could be predicted reasonably. The model can easily be adapted for other similar fuel types in the Mediterranean region

On the key role of droughts in the dynamics of summer fires in Mediterranean Europe

Summer fires frequently rage across Mediterranean Europe, often intensified by high temperatures and droughts. According to the state-of-the-art regional fire risk projections, in forthcoming decades climate effects are expected to become stronger and possibly overcome fire prevention efforts. However, significant uncertainties exist and the direct effect of climate change in regulating fuel moisture (e.g. warmer conditions increasing fuel dryness) could be counterbalanced by the indirect effects on fuel structure (e.g. warmer conditions limiting fuel amount), affecting the transition between climate-driven and fuel-limited fire regimes as temperatures increase. Here we analyse and model the impact of coincident drought and antecedent wet conditions (proxy for the climatic factor influencing total fuel and fine fuel structure) on the summer Burned Area (BA) across all eco-regions in Mediterranean Europe. This approach allows BA to be linked to the key drivers of fire in the region. We show a statistically significant relationship between fire and same-summer droughts in most regions, while antecedent climate conditions play a relatively minor role, except in few specific eco-regions. The presented models for individual eco-regions provide insights on the impacts of climate variability on BA, and appear to be promising for developing a seasonal forecast system supporting fire management strategies.We thank the European Forest Fire Information System-EFFIS (http://effis.jrc.ec.europa.eu) of the European Commission Joint Research Centre for the fire data. We acknowledge the SPEI data providers (http://sac.csic. es/spei/database.html). Special thanks to Joaquín Bedia, Esteve Canyameras, Xavier Castro and Andrej Ceglar for helpful discussions on the study. This work was partially funded by the Project of Interest “NextData” of the Italian Ministry for Education, University and Research and by the EU H2020 Project 641762 “ECOPOTENTIAL: Improving Future Ecosystem Benefits through Earth Observations”. Ricardo Trigo was supported by IMDROFLOOD funded by Portuguese FCT (WaterJPI/0004/2014).Peer ReviewedPostprint (published version

Characteristics and Spatial Heterogeneity of Prescribed Fire Behavior in North Dakota Grasslands

Fire is a critical physical and chemical process required to sustain many grassland ecosystems. In North America, observations of grassland fire behavior in warm-season, southern grasslands are commonly used in fire behavior modeling efforts across the Great Plains. However, grasslands of the northern Great Plains contain a greater component of cool-season vegetation that may generate different fire behavior. To further our understanding of prescribed fire behavior in North Dakota grasslands, we quantified fuel, weather, and fire behavior characteristics associated with 27 prescribed fires conducted across three sites in North Dakota. We sampled 27 points on each fire arranged into a Sierpinski triangle sampling scheme with three fractally nested spatial scales. Field station are climatologically and vegetatively different sites, yet fuel and weather characteristics associated with the fires were similar. Ultimately, fire behavior was similar between the stations having burned under similar fuel bed properties and weather conditions. Fire behavior averaged 227.26 ± 94.74 °C (maximum temperature), 0.4 ± 0.3 m (flame height), 4.47 ± 3.82 m/min (0.07 ± 0.064 m/s; rate of spread). Maximum temperature and flame height were best explained by fuel moisture, relative humidity, and quantity of the last rainfall event. Rate of spread was best explained by dew point, wind speed, and quantity of last rainfall. However, increased fuel moisture and relative humidity suppressed fire behavior. To quantify spatial heterogeneity, we assessed fuel bed properties (fuel load, soil and fuel moisture) prior to ignition and the resulting fire behavior (maximum temperature, flame height, and rate of fire spread) on 26 prescribed fires. We used a hierarchical Restricted Maximum Likelihood (REML) variance component analysis with the full 27-point dataset to assess how each sample scale (100 m, 10 m, 1 m) contributed to the variance in the fuel and fire behavior responses. Fuel loads (LAI) were most variable at higher scales (100 m, 10 m) but most similar at the 1 m scale. Fuel moisture contrasts fuel load in that it was the most variable at 1 m but similar at 100 m. Soil moisture variance was not dependent on the sample scale. Assessing relationships between fuel explanatory and fire response variables, we found similar effects of heterogeneity in fuel load and fuel moisture on maximum temperature and flame height. Maximum temperature and flame height exhibit the most variation when fuel load is most consistent and when fuel moisture variance is high. Rate of spread has a limited dataset and did not relate to the variation in fuel load and fuel moisture. Understanding the spatial variability within the fuel bed and its contribution to fire behavior will aid fire practitioners will better guide future planning efforts and provide a greater understanding of ecological fire effects

Forestry to Support Increased Agricultural Production: Focus on Employment Generation and Rural Development

India possesses several advantages due to its varied ecological range and agro-climates to cultivate several important and diverse commercial food commodities ranging from cereals, fruits and spices to medicinal plants. The country has abundance of human resource comprising skilled, educated, technical and scientific manpower on one hand and unskilled manpower on the other. Forests- and agriculture-based industries are a major source of employment in the primary, secondary and tertiary sectors all over the country. This article has presented a brief overview of the potential of forest and agriculture in generating employment, providing livelihood and environmental services, sequestration of green house gases, carbon trading, rehabilitation of degraded lands, production of fuel wood, etc. There are clear linkages and synergies between agricultural production and sustainable forest management. If the sustainability of the agriculture and forests can be assured, food security and employment generation would go in long-term perpetuity.Community/Rural/Urban Development, Resource /Energy Economics and Policy,

A review of wildland fire spread modelling, 1990-present 2: Empirical and quasi-empirical models

In recent years, advances in computational power and spatial data analysis (GIS, remote sensing, etc) have led to an increase in attempts to model the spread and behaviour of wildland fires across the landscape. This series of review papers endeavours to critically and comprehensively review all types of surface fire spread models developed since 1990. This paper reviews models of an empirical or quasi-empirical nature. These models are based solely on the statistical analysis of experimentally obtained data with or without some physical framework for the basis of the relations. Other papers in the series review models of a physical or quasi-physical nature, and mathematical analogues and simulation models. The main relations of empirical models are that of wind speed and fuel moisture content with rate of forward spread. Comparisons are made of the different functional relationships selected by various authors for these variables.Comment: 22 pages + 7 pages references + 2 pages tables + 2 pages figures. Submitted to International Journal of Wildland Fir

The Effects of Climatic Variations on Peat Swamp Forest Condition and Peat Combustibility

Studi tentang pengaruh variasi iklim terhadap kondisi hutan rawa gambut dan kemampuan terbakar gambut ini dilaksanakan di Hutan Simpan Sungai karang, Tanjong Karang, Selangor, Malaysia. Tujuan dari studi ini adalah untuk menentukan: 1) Variasi iklim di daerah penelitian , 2) Pengaruh variasi iklim terhadap kondisi hutan rawa gambut; 3) Kemampuan terbakar gambut dan faktor-faktor yang mempengaruhinya; dan 4) Pengaruh kebakaran hutan terhadap kondisi hutan rawa gambut. Studi ini dilakukan di kompartemen 127 selama dua periode, yaitu: Oktober 1999 sampai Januari 2000 dan Mei 2000 sampai Oktober 2000, sementara, studi tentang pengaruh kebakaran dilakukan di kompartemen 132 dari Oktober 1999 sampai dengan Januari 2000. Studi ini mengklasifikasikan musim kemarau dan musim penghujan sebagai periode dengan curah hujan bulanan berturut-turut kurang dari atau sama dengan 125 mm dan lebih besar dari 125 mm. Daerah penelitian memiliki dua periode kering, yaitu: Januari, Februari, dan Maret sebagai periode pertama dan Mei sampai Agustus sebagai periode kedua. Secara statistik, musim berpengaruh pada kadar air, bulk density, potassium, magnesium, sodium dan tinggi muka air. Dengan menggunakan prediksi curah hujan mingguan, kadar air kritis dari lahan gambut terhadap kebakaran adalah 355 %.Keywords:  climatic variations, peat swamp forest, forest fire, peat combustibilit