Stereo Photo Series for Estimating Natural Fuels in The Netherlands, Volume I: Veluwe Region

The photo series are collections of photos and associated field data representing a region of The Netherlands. Volume I includes vegetation types in the Veluwe Region, including Heather, Grasslands, Beech/Hardwoods, Scots Pine, and Douglas-fir. Volume 2 includes dune vegetation types on the island of Texel, plus a site on the mainland near Haarlam. For each vegetation type, sites were sampled with varying fuel loads. The description of the sites consists of a wide-angle site photo, supplemented with field data on the various fuel loads and vegetative layers. The photo series is an important ecological tool to assess landscapes by analyzing both dead and living fuels, and thereby provides real-world data to predict potential wildland fire behavior. The data collected can also be used to evaluate these same areas for animal and insect habitat, among other uses. The field protocols utilized for this study were modified from Stereo Photo Series in the United States authored by Roger Ottmar and Robert Vihnanek

Effect of hydrofracking fluid on colloid transport in the unsaturated zone

Hydraulic fracturing is expanding rapidly in the US to meet increasing energy demand and requires high volumes of hydrofracking fluid to displace natural gas from shale. Accidental spills and deliberate land application of hydrofracking fluids, which return to the surface during hydrofracking, are common causes of environmental contamination. Since the chemistry of hydrofracking fluids favors transport of colloids and mineral particles through rock cracks, it may also facilitate transport of in situ colloids and associated pollutants in unsaturated soils. We investigated this by subsequently injecting deionized water and flowback fluid at increasing flow rates into unsaturated sand columns containing colloids. Colloid retention and mobilization was measured in the column effluent and visualized in situ with bright field microscopy. While <5% of initial colloids were released by flushing with deionized water, 32–36% were released by flushing with flowback fluid in two distinct breakthrough peaks. These peaks resulted from 1) surface tension reduction and steric repulsion and 2) slow kinetic disaggregation of colloid flocs. Increasing the flow rate of the flowback fluid mobilized an additional 36% of colloids, due to the expansion of water filled pore space. This study suggests that hydrofracking fluid may also indirectly contaminate groundwater by remobilizing existing colloidal pollutants

Preview Brief 2: Wildland Fire Management under COVID-19, Survey Results

Wildland fire management is impacted by COVID-19 as a result of strict hygiene and social distancing requirements. Here, we give a preview of the of our online survey (link) that aimed to clarify implications of COVID-19 restrictions on wildland fire management, map current thinking, and collate any plans, protocols or procedures to generate generic guidance for wildland fire professionals. The survey was completed by 443 individuals from over 38 countries, working at a large variety of organizations in terms of organization type, level of jurisdiction, primary function, and the size of the fire management and fire suppression work force. This preview includes the most important preliminary results. In short, the data indicates that people are worried about the effect of COVID-19 on wildland fire management and also expect this to impede management. Despite this, there is high confidence that operations can be continued during the pandemic. COVID-19 hygiene and distancing requirements are being widely adopted, which is being reflected by a reduced number of staff per vehicle. There is an expected reduction in support services being available. Notable to mention is furthermore the expected reduction in sharing and receiving of resources (from and to other countries, regions) in times of need. Finally, training and risk reduction activities are also impacted, suggesting a longer-term impact of the pandemic on fire management. Two main concerns highlighted by survey respondents are the lack of preventive COVID-19 testing amongst wildland fire fighters, and the increased risk of vehicle accidents if staff is spread across more vehicles. We are now analyzing the wealth of responses including over 30.000 words of comments shared, and plan to publish the full analysis mid Jun

Characterizing the rate of spread of large wildfires in emerging fire environments of northwestern Europe using visible infrared imaging radiometer suite active fire data

In recent years fires of greater magnitude have been documented throughout northwest Europe. With several climate projections indicating future increases in fire activity in this temperate area, it is imperative to identify the status of fire in this region. This study unravels unknowns about the state of the fire regime in northwest Europe by characterizing one of the key aspects of fire behavior, the rate of spread (ROS). Using an innovative approach to cluster Visible Infrared Imaging Radiometer Suite (VIIRS) hotspots into fire perimeter isochrones to derive ROS, we identify the effects of land cover and season on the rate of spread of 102 landscape fires that occurred between 2012 and 2022. Results reveal significant differences between land cover types, and there is a clear peak of ROS and burned area in the months of March and April. Median ROS within these peak months is approximately 0.09 km h−1 during a 12 h overpass, and 66 % of the burned area occurs in this spring period. Heightened ROS and burned area values persist in the bordering months of February and May, suggesting that these months may present the extent of the main fire season in northwest Europe. Accurate data on ROS among the represented land cover types, as well as periods of peak activity, are essential for determining periods of elevated fire risk, the effectiveness of available suppression techniques, and appropriate mitigation strategies (land and fuel management).This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 860787 (PyroLife Innovative Training Network; https://pyrolife.lessonsonfire.eu/, last access: January 2023), a project in which a new generation of experts is trained in integrated fire manageme

Climate teleconnections modulate global burned area

Climate teleconnections (CT) remotely influence weather conditions in many regions on Earth, entailing changes in primary drivers of fire activity such as vegetation biomass accumulation and moisture. We reveal significant relationships between the main global CTs and burned area that vary across and within continents and biomes according to both synchronous and lagged signals, and marked regional patterns. Overall, CTs modulate 52.9% of global burned area, the Tropical North Atlantic mode being the most relevant CT. Here, we summarized the CT-fire relationships into a set of six global CT domains that are discussed by continent, considering the underlying mechanisms relating weather patterns and vegetation types with burned area across the different world's biomes. Our findings highlight the regional CT-fire relationships worldwide, aiming to further support fire management and policy-making.We thank Lorea Garcia for her insights and useful suggestions in the interpretation of CT-fire relationships during the review process of the manuscript. This project received funding from the Spanish Ministry of Science and Innovation, project FIREPATHS (PID2020-116556RA-I00) (authors receiving funding: A.C. and M.R.) and the European Union’s Horizon 2020 research and innovation programme MSCA-ITN-2019— Innovative Training Networks under grant agreement No. 860787 (PyroLife) (authors receiving funding: A.C., M.T. and C.S.), and the European Horizon 2020 research and innovation programme under grant agreement No. 101037419 (FIRE-RES) (authors receiving funding: A.C., J.R., C.S. and S.d.M.)

Fire behavior modeling for operational decision-making

Simulation frameworks are necessary to facilitate decision-making to many fire agencies. An accurate estimation of fire behavior is required to analyze potential impact and risk. Applied research and technology together have improved the implementation of fire modeling, and decision-making in operational environments.Dr Cardil acknowledges the support of Technosylva USA and Wageningen University in his research stays in the USA and the Netherlands to develop this work. The authors of this paper acknowledges the support of the EUfunded PYROLIFE project (Reference: 860787; https://pyrolife.lessonsonfire.eu/), a project in which a new generation of experts will be trained in integrated wildfire management

Informed debate on the use of fire for peatland management means acknowledging the complexity of socio-ecological systems

The effects of fire and its use on European peatlands and heaths are the focus of considerable research and debate due to the important services these ecosystems provide and the threats they face from climatic and land-use change. Whilst in some countries ecologists are actively promoting the restoration of historic fire management regimes, in the UK the debate has become increasingly acrimonious. Positions seem entrenched between continuing the intensive form of management associated with grouse moors or ceasing burning and seeking to eliminate fire altogether. In a recent paper we argued that participants’ positions appeared influenced by political and philosophical beliefs associated with, for example, private land-ownership, hunting, and associated conservation conflicts such as raptor persecution. We also suggested there was inadequate engagement with key concepts and evidence from fire and peatland ecology. We argued that management debates should aim to be inclusive and evidence-based, and to understand the benefits and costs of different fire regimes. In a strongly-worded critique of our paper, George Monbiot (author of “Feral: Searching for Enchantment on the Frontiers of Rewilding”) suggested we: i) framed our research question too narrowly; ii) made the implicit assumption that moorlands were the “right” ecosystem for the UK countryside; and iii) failed to adequately engage with arguments put forward for cessation of managed burning. Here we critically examine each of these issues to provide further insight into how adaptive, participatory land-management could develop. We argue that a productive debate must acknowledge that complex trade-offs are inevitable during ecological management. Choosing the “right” ecosystem is difficult, especially in a landscape with a long history of human influence, and the answer depends on the values and ecosystem services we prioritize. Natural resource management decisions will be improved if based on an understanding and valuation of the multiple scales and levels of organization at which ecological diversity exists, the role of disturbance in controlling ecosystem composition and function, and the need for participatory action

Pore scale consideration in unstable gravity driven finger flow

To explain the dynamic behavior of the matric potential at the wetting front of gravity driven fingers, we take into account the pressure across the interface that is not continuous and depends on the radius of the meniscus, which is a function of pore size and the dynamic contact angle θ[subscript d] • θ[subscript d] depends on a number of factors including velocity of the water and can be found by the Hoffman-Jiang equation that was modified for gravity effects. By assuming that water at the wetting front imbibes one pore at a time, realistic velocities are obtained that can explain the capillary pressures observed in unstable flow experiments in wettable and water repellent sands.Keywords: overshoot, fingered flow, dynamic pressure, column flow, preferential flow, dynamic contact angl