Severe Forest Fires Research Articles

Forest fires in Northern region of Portugal: Impact on PM levels

Every year European citizens become victims of devastating fires, which are especially disastrous for Southern European countries. Apart from the numerous health and economic consequences, fires generate hazardous pollutants that are introduced into the environment, thus representing serious risks for public health. In that regard, particulate matter (PM) is of a major concern. Thus, the objectives of this work were to characterize the trend of forest fire occurrences and burnt area during the period of 2005 and 2010 and to study the influence of forest fires on levels of particulate matter PM10 and PM2.5. In 2010, 22,026 forest fires occurred in Portugal. The northern region was the most affected by forest fires, with 27% of occurrences in Oporto district. The annual means of PM10 and PM2.5 concentrations at two urban background sites were 25±14μgm−3 and 8.2±4.9μgm−3, and 17±13μgm−3 and 7.3±5.9μgm−3, respectively. At both sites the highest levels of PM fractions were observed during July and August of 2010, corresponding to the periods when majority (66%) of forest fires occurred. Furthermore, PM10 daily limit at the two sites was exceeded during 20 and 5days, respectively; 56%, and respectively 60% of those exceedances occurred during the forest fire season. Considering that the risks of forest fire ignition and severity are enhanced with elevated temperatures, the climate change might increase the environmental impacts of forest fires.

The influence of fire history on selection of foraging sites by barren-ground caribou

We used an information-theoretic model comparison approach to investigate the influence of forest stand attributes resulting from wildfire on the occupancy of winter habitats by barren-ground caribou (Rangifer tarandus groenlandicus) in the Northwest Territories, Canada. We used field data describing forest stand and understory attributes to develop multinomial regression models. These analyses identified a combination of ground cover type and tree volume (i.e., stand basal area) as best able to describe the observed selection of feeding sites. An observed increase in the percent ground cover of lichen had a positive influence on site selection, while an increase in the percent rock cover and basal area of conifer trees had a negative influence on selection of feeding sites by caribou. The most parsimonious regression model predicted site use with an accuracy of 87%. Lastly, we used published equations to determine the biomass of fruticose lichens on experimental and control sites classified as unburned. Our data indicated that fruticose lichen biomass on the winter range of the Bathurst herd of barren-ground caribou was high compared to winter habitats of caribou in Alaska and the Yukon Territory, and falls in the general range of lichen values reported for winter habitats of the more easterly Beverly herd, as well as portions of Saskatchewan, Manitoba, and Ungava. Overall, the analyses of feeding-site selection suggest that Bathurst caribou forage in areas with a high percentage cover and biomass of lichen, and that future increased incidence and severity of forest fires could cause a temporary decrease in the quality of winter habitat available to the Bathurst herd.

Woody debris and tree regeneration dynamics following severe wildfires in Arizona ponderosa pine forests

Severe forest fires worldwide leave behind large quantities of dead woody debris and regenerating trees that can affect future ecosystem trajectories. We studied a chronosequence of severe fires in Arizona, USA, spanning 1 to 18 years after burning to investigate postfire woody debris and regeneration dynamics. Snag densities varied over time, with predominantly recent snags in recent fires and broken or fallen snags in older fires. Coarse woody debris peaked at > 60 Mg/ha in the time period 6–12 years after fire, a value higher than previously reported in postfire fuel assessments in this region. However, debris loadings on fires older than 12 years were within the range of recommended management values (11.2–44.8 Mg/ha). Overstory and regeneration were most commonly dominated by sprouting deciduous species. Ponderosa pine ( Pinus ponderosa C. Lawson var. scopulorum Engelm.) overstory and regeneration were completely lacking in 50% and 57% of the sites, respectively, indicating that many sites were likely to experience extended periods as shrublands or grasslands rather than returning rapidly to pine forest. More time is needed to see whether these patterns will remain stable, but there are substantial obstacles to pine forest recovery: competition with sprouting species and (or) grasses, lack of seed sources, and the forecast of warmer, drier climatic conditions for coming decades.

Analysis of the seasonal characteristics of forest fires in South Korea using the multivariate analysis approach

For efficient forest fire management, special precautions are required in dry and strong-wind seasons vulnerable to severe forest fires. To extract the seasonal characteristics of forest fires in South Korea, the statistics over the past 16 years, 1991 through 2005, were investigated. The daily records of the number of fire occurrences, the total area burned and the average burned area per occurrence were examined to identify the seasonal patterns of forest fires using cluster analysis and principal component analysis; the risk of daily fires was also assessed using the ordered logit model. As a result, the fire patterns were classified into five clusters and a general danger index for forest fires was derived from the first principal component, showing relatively large-scaled fire regimes in spring, and frequent small-scaled fire regimes in autumn and winter. In connection with the ordered logit model, the probability for the five ranks of forest fire risk was calculated and the threshold for high-risk fires was detected. As an implementation of the results above, the proper forest fire precautionary period in South Korea was estimated, and consequently October 21 through May 17 was recognized as a dry season at a high risk of forest fires. This period began 10 days earlier in autumn and extended into midwinter (late December and January) as opposed to the existing precautionary period, indicating the need of more cautious forest fire management earlier in autumn and continuing through midwinter.

The efficacy of salvage logging in reducing subsequent fire severity in conifer-dominated forests of Minnesota, USA

Although primarily used to mitigate economic losses following disturbance, salvage logging has also been justified on the basis of reducing fire risk and fire severity; however, its ability to achieve these secondary objectives remains unclear. The patchiness resulting from a sequence of recent disturbances-blowdown, salvage logging, and wildfire-provided an excellent opportunity to assess the impacts of blowdown and salvage logging on wildfire severity. We used two fire-severity assessments (tree-crown and forest-floor characteristics) to compare post-wildfire conditions among three treatment combinations (Blowdown-Salvage-Fire, Blowdown-Fire, and Fire only). Our results suggest that salvage logging reduced the intensity (heat released) of the subsequent fire. However, its effect on severity (impact to the system) differed between the tree crowns and forest floor: tree-crown indices suggest that salvage logging decreased fire severity (albeit with modest statistical support), while forest-floor indices suggest that salvage logging increased fire severity. We attribute the latter finding to the greater exposure of mineral soil caused by logging operations; once exposed, soils are more likely to register the damaging effects of fire, even if fire intensity is not extreme. These results highlight the important distinction between fire intensity and severity when formulating post-disturbance management prescriptions.

Pre-fire forest conditions and fire severity as determinants of the quality of burned forests for deadwood-dependent species: the case of the black-backed woodpecker

Burned forests represent high-quality habitats for many deadwood-dependent species. Yet, post-fire conditions may vary greatly within and among burns and thereby may affect habitat suitability for these species. We studied habitat selection of nesting black-backed woodpeckers ( Picoides arcticus Swainson) in recently burned spruce-dominated boreal forests. Our objectives were to (i) identify factors involved in snag selection for both nesting and foraging and (ii) examine selection of nest sites within the burned landscape. A total of 92 nests and 1612 foraging observations were used to investigate snag selection. Our results show that both pre-fire forest conditions and fire severity are important in determining the quality of burned forests for black-backed woodpeckers. This species selected large snags for both nesting (>20 cm DBH) and foraging (>15 cm DBH). Woodpeckers selected deciduous and degraded “pre-fire” snags for nesting whereas black spruce snags that had been created by fire and that were moderately burned were preferred for foraging. Nest sites were concentrated in burned mature stands and supported higher densities of large snags (e.g., >15 cm DBH). Our results suggest that burned forest patches of at least 20 ha and composed mainly of burned mature and old-growth forests should be maintained during post-fire harvesting. The decrease in the amount of late seral stands in managed forest landscapes raises concerns about the future availability of high-quality burned forests for this species.

Investing in Natural Capital: Using Economic Incentives to Overcome Barriers to Forest Restoration

A legacy of fire suppression and the impacts of climate change have induced a worsening pattern of large and severe forest fires across the western United States. This has spurred action to jump‐start wildfire risk mitigation initiatives. Despite an increase in resources and attention, the persistence of economic impediments has forestalled the successful expansion of forest restoration to a landscape level. The failure to properly account for the full range of costs and benefits from restoration treatments has contributed to the asymmetry between needed action and actual implementation. The valuation of non‐market ecosystem services such as carbon sequestration, along with the ability of ecological restoration to act as an agent of economic stimulus, should be incorporated into the policymaking process. We demonstrate how institutionalizing the economic benefits from both the process and products of forest restoration can strengthen policies for advancing long‐term forest health.

Prediction of Seasonal Forest Fire Severity in Canada from Large-Scale Climate Patterns

AbstractAn empirical scheme for predicting the meteorological conditions that lead to summer forest fire severity for Canada using the multivariate singular value decomposition (SVD) has been developed for the 1953–2007 period. The levels and sources of predictive skill have been estimated using a cross-validation design. The predictor fields are global sea surface temperatures (SST) and Palmer drought severity index. Two consecutive 3-month predictor periods are used to detect evolving conditions in the predictor fields. Correlation, mean absolute error, and percent correct verification statistics are used to assess forecast model performance. Nationally averaged skills are shown to be statistically significant, which suggests that they are suitable for application to forest fire prediction and for management purposes. These forecasts average a 0.33 correlation skill across Canada and greater than 0.6 in the forested regions from the Yukon, through northern Prairie Provinces, northern Ontario, and central Quebec into Newfoundland. SVD forecasts generally outperform persistence forecasts. The importance of the leading two SVD modes to Canadian summer forest fire severity, accounting for approximately 95% of the squared covariance, is emphasized. The first mode relates strongly to interdecadal trend in global SST. Between 1953 and 2007 the western tropical Pacific, the Indian, and the North Atlantic Oceans have tended to warm while the northeastern Pacific and the extreme Southern Hemisphere oceans have shown a cooling trend. During the same period, summer forest fire exhibited increased severity across the large boreal forest region of Canada. The SVD diagnostics also indicate that the El Niño–Southern Oscillation and the Pacific decadal oscillation play a significant role in Canadian fire severity. Warm episodes (El Niño) tend to be associated with severe fire conditions over the Yukon, parts of the northern Prairie Provinces, and central Quebec. The linearity of the SVD manifests opposite response during the cold (La Niña) events.

A comparison of effects from prescribed fires and wildfires managed for resource objectives in Sequoia and Kings Canyon National Parks

Current goals for prescription burning are focused on measures of fuel consumption and changes in forest density. These benchmarks, however, do not address the extent to which prescription burning meets perceived ecosystem needs of heterogeneity in burning, both for overstory trees and understory herbs and shrubs. There are still questions about how closely prescribed fires mimic these patterns compared to natural wildfires. This study compared burn patterns of prescribed fires and managed unplanned wildfires to understand how the differing burning regimes affect ecosystem properties. Measures of forest structure and fire severity were sampled in three recent prescribed fires and three wildfires managed for resource objectives in Sequoia and Kings Canyon National Parks. Fine scale patterns of fire severity and heterogeneity were compared between fire types using ground-based measures of fire effects on fuels and overstory and understory vegetation. Prescribed fires and wildfires managed for resource objectives displayed similar patterns of overstory and understory fire severity, heterogeneity, and seedling and sapling survival. Variation among plots within the same fire was always greater than between fire types. Prescribed fires can provide burned landscapes that approximate natural fires in many ways. It is recognized that constraints placed on when wildfires managed for resource objectives are allowed to burn freely may bias the range of conditions that might have been experienced under more natural conditions. Therefore they may not exactly mimic natural wildfires. Overall, the similarity in fire effects that we observed between prescribed fires and managed wildfires indicate that despite the restrictions that are often placed on prescribed fires, they appear to be creating post-fire conditions that approximate natural fires when assessed on a fine spatial scale.

Impact of Climate Change on Forest Fire Severity and Consequences for Carbon Stocks in Boreal Forest Stands of Quebec, Canada: a Synthesis

The global boreal forests comprise large stocks of organic carbon that vary with climate and fire regimes. Global warming is likely to influence several aspects of fire and cause shifts in carbon sequestration patterns. Fire severity or forest floor depth of burn is one important aspect that influences both carbon emission during combustion as well as post-fire ecosystem regeneration. Numerous publications on projections of future area burned exist, whereas scenarios on twenty-first century fire severity are more scarce, and the stand-typical response to severe fire weather is rarely taken into account. This paper aims to synthesize knowledge on boreal forest carbon stocks in relation to changes in fire severity for Quebec, Canada. Besides warming, this region may be subjected to an important increase in future precipitation. Future fire severity and area burned may well increase as fire weather will be drier, especially near the end of the twenty-first century. Moreover, the fire season peak may shift towards the late summer. Intense burning will favour tree cover development while the forest floor carbon stock may become less important. As a result, total Quebec boreal carbon sequestration may diminish. The development of dynamic vegetation models may improve scenarios on twenty-first century changes in carbon sequestration driven by climate change and fire severity and frequency effects.

Modeling of multi-strata forest fire severity using Landsat TM Data

Most of fire severity studies use field measures of composite burn index (CBI) to represent forest fire severity and fit the relationships between CBI and Landsat imagery derived differenced normalized burn ratio (dNBR) to predict and map fire severity at unsampled locations. However, less attention has been paid on the multi-strata forest fire severity, which represents fire activities and ecological responses at different forest layers. In this study, using field measured fire severity across five forest strata of dominant tree, intermediate-sized tree, shrub, herb, substrate layers, and the aggregated measure of CBI as response variables, we fit statistical models with predictors of Landsat TM bands, Landsat derived NBR or dNBR, image differencing, and image ratioing data. We model multi-strata forest fire in the historical recorded largest wildfire in California, the Big Sur Basin Complex fire. We explore the potential contributions of the post-fire Landsat bands, image differencing, image ratioing to fire severity modeling and compare with the widely used NBR and dNBR. Models using combinations of post-fire Landsat bands perform much better than NBR, dNBR, image differencing, and image ratioing. We predict and map multi-strata forest fire severity across the whole Big Sur fire areas, and find that the overall measure CBI is not optimal to represent multi-strata forest fire severity.

Quantifying fire severity, carbon, and nitrogen emissions in Alaska's boreal forest

The boreal region stores a large proportion of the world's terrestrial carbon (C) and is subject to high-intensity, stand-replacing wildfires that release C and nitrogen (N) stored in biomass and soils through combustion. While severity and extent of fires drives overall emissions, methods for accurately estimating fire severity are poorly tested in this unique region where organic soil combustion is responsible for a large proportion of total emissions. We tested a method using adventitious roots on black spruce trees (Picea mariana) in combination with canopy allometry to reconstruct prefire organic soil layers and canopy biomass in boreal black spruce forests of Alaska (USA), thus providing a basis for more accurately quantifying fire severity levels. We calibrated this adventitious-root-height method in unburned spruce stands and then tested it by comparing our biomass and soils estimates reconstructed in burned stands with actual prefire stand measurements. We applied this approach to 38 black spruce stands burned in 2004 in Alaska, where we measured organic soil and stand characteristics and estimated the amount of soil and canopy biomass, as well as C and N pools, consumed by fire. These high-intensity quantitative estimates of severity were significantly correlated to a semiquantitative visual rapid assessment tool, the composite burn index (CBI). This index has proved useful for assessing fire severity in forests in the western United States but has not yet been widely tested in the boreal forest. From our study, we conclude that using postfire measurements of adventitious roots on black spruce trees in combination with soils and tree data can be used to reconstruct prefire organic soil depths and biomass pools, providing accurate estimates of fire severity and emissions. Furthermore, using our quantitative reconstruction we show that CBI is a reasonably good predictor of biomass and soil C loss at these sites, and it shows promise for rapidly estimating fire severity across a wide range of boreal black spruce forest types, especially where the use of high-intensity measurements may be limited by cost and time.

Forest fire hazard rating assessment in peat swamp forest using Landsat thematic mapper image

Forest fires are one of the major causes of the deforestation of tropical peat swamps in Malaysia. One way of trying to identify which peat swamp forests are vulnerable to forest fire is to develop a forest fire risk index. The objectives of this study were to develop both a fuel-type map and a forest fire hazard rating assessment for the peat swamp forests. The study was conducted in a peat swamp forest located at Batu Enam, Penor/Kuantan District of Pahang. This area suffered a severe forest fire on 12 March 1998 which degraded the peat swamp area. Digitally processed Landsat Thematic Mapper (TM) satellite image were integrated with geographic information layer of fuel type, roads and canal layer to derive a fire hazard rating map of the area. Using the superior spectral and temporal resolution of a Landsat TM, five fire hazard rating classifications were defined. A forest fire hazard rating map was produced showing that 49% of the area was 'low' fire hazard rating, 23% was 'high', 17% was 'moderate', 10% was 'extreme' and 1% was 'null'. Peat lands within 150 meters of roads and of a canal were identified as having an 'extreme' fire hazard rating. Both the fire hazard rating map and the forest fire hazard rating assessment can be used in future forest fire management planning.

Vegetation dynamics and exotic plant invasion following high severity crown fire in a southern California conifer forest

Early post-fire vegetation dynamics following large, severe forest fires are largely unknown for the southern California mountains owing to historic fire suppression. Vegetation in 38 forest stands was surveyed (2004, 2005, and 2007) following the 2003 Cedar Fire in the Cuyamaca Mountains, Peninsular Ranges, San Diego County, California, USA. Each stand was sampled using four 10-m radius plots for the tree stratum, and 20 1-m2 quadrats for shrub and herb strata. Changes in canopy cover by species, origin (native and exotic) and life form were analyzed. 2007 data were subjected to clustering to examine the divergence in species composition of the stands with time. Shrub cover increased from 3 to 31%, and exotic herbaceous cover increased from 3 to 40%. Cover of native annuals had increased from 2004 (17%) to 2005 (33%), but then dropped to 15% in 2007. Forty percent of the stands were dominated by the shrub species Ceanothus palmeri, and associated with higher pre-fire conifer cover and fire severity. More than 50% of the stands were dominated by exotic annuals and associated with lower fire severity and less steep slopes. The remaining stands (<10%) were dominated by chaparral shrubs and occurred on lower elevation, steep west-facing slopes. Species traits predict their dynamics following disturbance, as environmental conditions change. Establishment and increasing abundance of species dependent on dispersal to reach a site, including exotic and native herbaceous species, occurred in years 2–4. Differences among stands in species composition 4 years post-fire were associated with topographic and fire severity gradients.

SIMPLOT: Simulating the impacts of fire severity on sustainability of eucalyptus forests in Portugal

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.

Laboratory Study of Leaching Properties of Mediterranean Forest Species Ashes

Heavy metal content of high load ashes applied on the ground during severe forest fires may be released into rainwater, and through it, they can either penetrate into the ground water or be washed out into water receivers, causing a severe environmental problem. The chemical composition of two dominant Greek forest species (Pinus halepensis, Quercus coccifera) ashes was determined before and after leaching. The ash samples were similar to those obtained in actual forest fires and two leaching tests (column and shake leaching test) were employed using aqueous solutions of pH = 6 and 1. For the analysis of ashes (prior to and after leaching), the following analytical techniques were used: X-ray diffraction and scanning electron microscopy with energy dispersive X-ray analysis. For the analysis of leachates ion chromatography and inductively coupled plasma emission spectrometry were used. At pH = 6 (rainwater conditions) some elements were released (i.e., 95% Cr, 70% Pb). The release of Cr is up to 95% for P. halepensis and 76% for Q. coccifera. The total amount of some toxic elements recovered (i.e., Cd) was up to 99%. As expected, at pH = 1 the majority of metallic elements were almost completely recovered. Knowledge of the leaching properties of Mediterranean forest species ashes is very important for evaluating their impact on the environment (soil and ground and underground water streams).

Quantitative Evidence for Increasing Forest Fire Severity in the Sierra Nevada and Southern Cascade Mountains, California and Nevada, USA

Recent research has concluded that forest wildfires in the western United States are becoming larger and more frequent. A more significant question may be whether the ecosystem impacts of wildfire are also increasing. We show that a large area (approximately 120000 km2) of California and western Nevada experienced a notable increase in the extent of forest stand-replacing (“high severity”) fire between 1984 and 2006. High severity forest fire is closely linked to forest fragmentation, wildlife habitat availability, erosion rates and sedimentation, post-fire seedling recruitment, carbon sequestration, and various other ecosystem properties and processes. Mean and maximum fire size, and the area burned annually have also all risen substantially since the beginning of the 1980s, and are now at or above values from the decades preceding the 1940s, when fire suppression became national policy. These trends are occurring in concert with a regional rise in temperature and a long-term increase in annual precipitation. A close examination of the climate–fire relationship and other evidence suggests that forest fuels are no longer limiting fire occurrence and behavior across much of the study region. We conclude that current trends in forest fire severity necessitate a re-examination of the implications of all-out fire suppression and its ecological impacts.

Inhabitants of Landscape Scars: Succession of Woody Plants After Large, Severe Forest Fires in Arizona and New Mexico

Understanding consequences of changes in climate and fire regimes for succession in plant communities is critical for conservation planning at broad spatial and temporal scales. We selected two sites that burned in high-severity fire decades ago and studied succession in the woody plant community and its variations across two environmental gradients; elevation and distance from a lower- severity/unburned edge. By overlaying an ordination of data for woody species on the modeled environmental gradient most closely related to variation in communities, we analyzed the interaction of life-history traits of species and landscape heterogeneity at each study site. Species that resprout from surviving roots were widespread across the distance gradient 28 years after the La Mesa fire in New Mexico. Species that reproduce from off-site seed, including Pinus ponderosa, were more prevalent where resprouters (e.g., Quercus) were less important in defining communities. At Saddle Mountain, Arizona, 45 years post-fire, we observed neighborhood interactions across the elevation gradient, for example, where shade-tolerant conifers (e.g., Abies concolor) occurred in understories of Populus tremuloides .A t both sites, greater cover of woody plants that reproduce from off-site seed at shorter distances from a lower-severity/unburned edge suggested migration of these species following the model of wave-form succession. In contrast to studies that emphasize undesirable effects when forest transitions to openings and alternative habitats, our research elucidates the need for further consideration of both young forest communities and the persistent species and communities described as landscape scars in conservation plans for forest systems of the southwestern United States.

Seed Invasion Filters and Forest Fire Severity

Forest seed dispersal is altered after fire. Using seed traps, we studied impacts of fire severity on timing of seed dispersal, total seed rain, and seed rain richness in patches of high and low severity fire and unburned Douglas-fir (Pseudotsuga menziesii) forests in the Fischer and Tyee fire complexes in the eastern Washington Cascades. Unburned plots had the lowest average seed production. The high severity fire patches in the Fischer Fire Complex had a higher total seed production than low severity fire patches of the same complex. At the Tyee Fire Complex, the total seed production for each of the two fire severities was similar, but the period of maximum seed dispersal was later for high severity than low severity fire. Seed rain at the Fischer Fire patches (sampled one year after the fire) was predominantly composed of annual species, while that of the Tyee Fire patches (sampled nine years after fire) was predominantly perennial species. Seed rain richness was greater in Tyee high severity patches than paired low severity fire patches. In these paired Tyee patches the average number of new seed species (species not found in the extant plot vegetation) was greater for high severity than low severity fire. Our results suggest that high severity fire plots are more porous to seed rain than low severity plots. Intact forest canopies may filter seed rain and reduce seed influx, while high severity fires are more open to invasion by seed dispersal.

Abundance of soil microarthropods associated with forest fire severity in Samcheok, Korea

This study investigated the association of soil arthropod abundance from mountain sites where differential forest fire severities had been influenced since April 2000. The post-fire study was conducted from 2005 to 2007 at mountain sites in Imwon-ri and Yang-ri, Samcheok, Korea. Study sites were arranged based on the burn severity and subsequent recovery rate in a year after the fire; ranging from unburned control to severely burned site: Con, T3, C2, T2 and T1. Results from soil sampling revealed that abundance of soil microarthropods was highest in unburned control site, and lowest in most severely burned site, T1. Among the microarthropod groups, abundances of Gamasida, Oribatida and Collembola were significantly different among the sites and showed the abundance ranking of Control > C2 = T3 > T2 > T1. The soil moisture contents and organic matter contents were lower in sites with higher burn severities. But, soil pH values were in reverse trend. The abundances of oribatid mites and collembolans were positively correlated with the soil moisture contents and the organic matter contents but negatively to the soil pH. Abundance of gamasid mites, which are the predators in microarthropod food web was positively correlated to those of their potential preys, oribatid mites and collembolans.