Fire Disturbance Research Articles

Fire severity as a key determinant of aboveground and belowground biological community recovery in managed even-aged boreal forests.

Changes in fire regime of boreal forests in response to climate warming are expected to impact postfire recovery. However, quantitative data on how managed forests sustain and recover from recent fire disturbance are limited.Two years after a large wildfire in managed even-aged boreal forests in Sweden, we investigated how recovery of aboveground and belowground communities, that is, understory vegetation and soil microbial and faunal communities, responded to variation in the severity of soil (i.e., consumption of soil organic matter) and canopy fires (i.e., tree mortality).While fire overall enhanced diversity of understory vegetation through colonization of fire adapted plant species, it reduced the abundance and diversity of soil biota. We observed contrasting effects of tree- and soil-related fire severity on survival and recovery of understory vegetation and soil biological communities. Severe fires that killed overstory Pinus sylvestris promoted a successional stage dominated by the mosses Ceratodon purpureus and Polytrichum juniperinum, but reduced regeneration of tree seedlings and disfavored the ericaceous dwarf-shrub Vaccinium vitis-idaea and the grass Deschampsia flexuosa. Moreover, high tree mortality from fire reduced fungal biomass and changed fungal community composition, in particular that of ectomycorrhizal fungi, and reduced the fungivorous soil Oribatida. In contrast, soil-related fire severity had little impact on vegetation composition, fungal communities, and soil animals. Bacterial communities responded to both tree- and soil-related fire severity. Synthesis: Our results 2 years postfire suggest that a change in fire regime from a historically low-severity ground fire regime, with fires that mainly burns into the soil organic layer, to a stand-replacing fire regime with a high degree of tree mortality, as may be expected with climate change, is likely to impact the short-term recovery of stand structure and above- and belowground species composition of even-aged P. sylvestris boreal forests.

The post-fire shift of temperate white pine-birch forest to boreal balsam fir forest in eastern Canada: climate-fire implications

Extensive 14C dating and botanical identification of charcoal fragments located in the organic surface soil layer and buried in the mineral podzolic solum were used to reconstruct the successional pathways of a balsam fir forest site. The studied forest site developed in a context of continuous fire disturbance over the last 9000 years with at least 26 fires occurring at a mean interval of 330 years. Tree vegetation of the site followed a four-step trajectory consisting of an early-Holocene spruce forest and a late-Holocene mixedwood balsam fir forest. Boreal-like spruce-birch and temperate-like white pine-birch forests dominated the site between 7900 and 5900 cal. B.P. and 5600 and 1275 cal. B.P., respectively. Because all forest types developed repeatedly after fire since early deglaciation, changes in forest composition, in particular the shift of white pine forest to balsam fir forest, and concurrent decline of birch (yellow birch and/or paper birch) and pine populations were most likely related to progressive cooler and wetter conditions from mid- to late Holocene. Fire disturbance on this part of the southern boreal biome has been a continuous, positive regenerative process over the Holocene, allowing the successional turnover of boreal and temperate trees under the influence of climatic change.

Impact of Native Quercus robur and Non-Native Quercus rubra on Soil Properties during Post-Fire Ecosystem Regeneration

Following disturbances, ecosystems are more susceptible to invasion by non-native species. Furthermore, it is important to determine the impact of alien tree species on soil regeneration processes during secondary succession. In this study, we analyzed the effect of native and late successional common oak (Quercus robur) and non-native red oak (Q. rubra) on soil physicochemical (pH, carbon, and nutrient content) and microbial properties (microbial biomass [Cmic] and respiration [RESP]) nearly 30 years after severe fire disturbance. Post-fire soils under Q. rubra had organic horizons with a greater mass, lower pH values, and depleted nutrient (N, Ca, K, Mg, and P) contents than soils under Q. robur. The impact of Q. robur as a late successional species on soil properties 30 years after a disturbance was similar to that of pioneer species (Scots pine, European larch, common birch, and black alder), as is indicated in previous studies. Most of the studied physicochemical (bulk density, soil organic carbon, N, Ca, K, and P content) and microbial (RESP and Cmic) soil parameters under Q. robur were within the ranges found for post-fire soils under pioneer tree species. Only the pH and Mg and Na contents in organic horizons were higher under Q. robur than under pioneer species. Our results indicate that Q. robur could be a valuable addition to reforestation sites after fire disturbance, especially in more fertile microhabitats. Due to the depletion of soil nutrients, care should be taken when introducing Q. rubra during the reforestation of post-fire sites, especially in larger groups.

The role of fire disturbances, human activities and climate change for long-term forest dynamics in upper-montane forests of the central Dinaric Alps

We present the first high-resolution Holocene pollen, plant-macrofossil, and charcoal records from the upper-montane zone in the central Dinaric Alps. Drawing on these new records from well-dated lacustrine sediments of Zminje Jezero (ca. 1500 m a.s.l.; Montenegro) and on independent chironomid-inferred summer temperatures, we explore long-term ecosystem responses to variations in climate, fire disturbances and land use, as well as legacy effects of past environmental changes. A mixed spruce-fir forest established in the upper-montane zone around 9500 cal BP, and Fagus sylvatica became co-dominant with the two conifers after 5000 cal BP. Prehistoric land-use pressure was overall remarkably low, but increased since 2000 cal BP and was highest after the Middle Ages. We found a significant positive relationship between biomass burning and summer temperature, indicating that fires were mostly climate driven. Picea abies was insensitive to summer temperature, biomass burning and human impact, which supports the view that spruce forests may not be significantly impacted by fire. In contrast, Abies alba and other disturbance-sensitive trees ( Tilia, Ulmus, Fraxinus excelsior-type) show significant negative responses to land-use pressure and positive responses to summer temperature. This supports the notion that these species may be well-adapted to warmer-than present summer temperatures and that their populations declined in recent millennia due to land-use activities. Conversely, F. sylvatica was sensitive to summer temperatures but was promoted by low biomass burning, indicating that its expansion in the spruce-fir dominated forest was enhanced by the onset of cooler and possibly also moister climatic conditions as well as by fire disturbances.

Population dynamics and individual growth dynamics of Larix gmelinii under non-stand replacing fire

The population dynamics and individual growth dynamics of dominant tree species in boreal forests are associated with fire regimes. Fire regimes in the boreal forests of eastern Siberia are dominated by non-stand replacing (NSR) fire types. Fire drives population demographics by triggering tree mortality and births, and affects the post-fire growth dynamics of surviving individuals. When a non-stand replacing fire occurs, population dynamics fluctuate and individual growth changes occur simultaneously. The Great Xing’an Mountains is located at the southern edge of the eastern Siberia boreal forest and research on fire regimes and stand dynamics in this region are scarce. Understanding the effect of fire on the population structure and individual growth of the dominant species in the stand and the disturbance mechanisms are essential to understand the develop of boreal forests in the context of climate warming. In this study, three Larix gmelinii stands disturbed by NSR fire in the Great Xing’an Mountains were selected and established plots, and control stand plots were established at similar site conditions. We conducted a forest inventory and used dendrochronological methods to reveal the short- and long-term effects of NSR fire disturbance on the population dynamics and individual growth of the dominant species of L. gmelinii. Specifically, the effects of NSR fire on stand structure, the relationship between L. gmelinii demographics and disturbance, and the response of growth dynamics to disturbance were analyzed. Finally, the history of potential disturbance at stand level was reconstructed. The study found that common NSR fire affect the biomass and species composition of L. gmelinii forests. Fire disturbance contributes to the younger age structure of L. gmelinii populations. However, The NSR fire may limit the size of L. gmelinii populations but does not necessarily destroy population resilience depending on stand conditions. Irregular fluctuations in population survival and mortality curves are directly related to historical disturbance events. The NSR fire can inhibit the growth of surviving trees for 1–2 years, resulting in temporary growth asynchrony. The population dynamics fluctuations and temporal patterns of growth release signals can reconstruct historical disturbance events at the stand level. For example, the MH intra-group (Mohe Luogu River Nature Reserve burned stand&Mohe Luogu River Nature Reserve unburned stand) probably experienced a high-severity fire in 1880–1900, the TH intra-group (Tahe Nature Reserve burned stand&Tahe Nature Reserve unburned stand) experienced a high-severity fire around 1930, and THB (Tahe Nature Reserve burned stand) suffered stand-replacing. Overall, irregular fluctuations in population survival and mortality curves have been directly related to historical disturbance events. These findings provide direct evidence of the short- and long-term effects of fire on the survival and growth of L. gmelinii populations.

Long-Term Dynamics of Forest Fires in Southern Siberia

The research focus. Wildfire is a critical environmental disturbance affecting forest dynamics, succession, and the carbon cycle in Siberian forests. Forests of southern Siberia experienced an increase of fire rate. We analyzed spatial and temporal dynamics of burned area in the southern Central Siberian Mountains. We considered burning rate within different forest types: dark needle conifers (DNC) composed by Siberian pine, spruce and fir, light-needle composed by Scotch pine and larch, and mix wood (composed by birch, aspen and conifers). Methods. We used long-term (1982–2021) climatic variables from the ERA5-Land database. Satellite observations included MODIS wildfire data (2002–2021) and gravimetric (GRACE) data (2002–2021) for estimation soil moisture content. We analyzed the spatial distribution of burned areas considering dominant forest stands and terrain (elevation, slope aspect and steepness). Results. We found a significant decreasing trend in burned area. On average, about 978.7 ± 447.5 thousand ha including 257.1 ± 154.3 thousand ha of forests are disturbed by fire annually. Light coniferous forests are characterized by the highest degree of the fire disturbance (relative burned area, RBA, was ca. 0.83% per year); whereas DNC stands have the lowest RBA (ca. 0.15% per year). The spatial distribution of fires in light coniferous forests showed predominance of fires on the southern slopes comparing to northern slopes (by 15–20%). We found a decreasing logarithmic trend in burned area between plains and low mountains and high mountains due to lower forest fuel loads and increased amount of precipitation on higher elevations. We also observed lower RBA values (by 300–400%) on steep slopes for light coniferous forests and mixed forests comparing to gentle slopes due to lower available forest fuels. The long-term dynamics of burned area in the region was related to the variation of climatic variables, such as soil moisture (r2 = 0.70, p < 0.01), moisture content (r2 = 0.63, p < 0.01) and drought index (r2 = 0.3, p < 0.05).

Disturbance and Succession in Early to Mid-Holocene Northern English Forests: Palaeoecological Evidence for Disturbance of Woodland Ecosystems by Mesolithic Hunter-Gatherers

Forest succession can be monitored in the present, modelled for the future, but also reconstructed in the past on the records of forest history, including through the use of palaeo-ecological techniques. Longer-term records from pollen data can show changes over centennial and millennial timescales that are impacted by climate, migration or soil development. Having knowledge of previous phases of post-disturbance seral stages of woodland regeneration however, as after fire, can provide insights regarding successional process and function over short-term decadal timescales. The aim of this paper is to test the high-resolution pollen record as a source of new insights into processes of succession, assisted by the supplementary data of microscopic charcoal analyses. On short-term timescales, multiple phases of forest disturbance and then recovery have been identified in early to mid-Holocene peat records in northern England, many from the uplands but also from lowland areas. We identify and describe a typology of recovery patterns, including the composition and rate of recovery, and then test the processes and factors that impacted on different seral trajectories, concentrating on fire disturbance which might have had a natural origin, or might have been caused by pre-agricultural Mesolithic hunter-gatherers. Factors considered include the spatial location and intensity of the fire event, the duration of the disturbance phase, the structure and dynamics of the successional regeneration vegetation communities and the pre-disturbance tree cover. Data from examples of fire disturbance of woodland have been examined from both upland and lowland sites in northern England and indicate that they had different successional pathways after disturbance. Fire disturbances in the denser lowland forests were mostly single burn events followed by natural successions and regeneration to forest, whereas fire disturbances in the upland woods usually showed continued or repetitive fire pressure after the initial burning, arresting succession so that vegetation was maintained in a shrub phase, often dominated by Corylus, for an extended period of time until disturbance ceased. This creation of a kind of prolonged, almost plagioclimax, ‘fire-coppice’ hazel stage suggests controlled rather than natural successional pathways, and strongly suggests that Mesolithic foragers were the fire starters in the upland English woodlands where hazel was naturally common and could be maintained in abundance in later-stage successions, along with other edible plants, for human use. All post-fire seral stages would have been attractive to game animals, providing a reliable food source that would have been of great benefit to hunter-gatherer populations.

Oak savanna vegetation response to layered restoration approaches: Thinning, burning, and grazing

Temperate savannas are unique, biodiverse ecosystems that have undergone extensive habitat conversion globally. In the midwestern United States, 99% of historic oak savanna area has been lost. Most remaining patches of savanna are degraded due to woody encroachment following the removal of both fire and large herbivore disturbances from the landscape. Restoring degraded savanna remnants is challenging because we lack an understanding of how to best apply contemporary restoration tools to mimic historic disturbance dynamics. To that end, we evaluated the outcomes of ongoing oak savanna restorations that have received a gradient of restoration actions: 1) no management, 2) tree thinning, 3) thinning + burning, and 4) thinning + burning + cattle grazing. We assessed several metrics of restoration success including canopy, shrub, herbaceous, and non-native cover, herbaceous diversity, and plant community composition. We found that layering restoration approaches achieved certain, but not all, structural vegetation goals. Compared to no management, thinning and fire successfully increased canopy openness, herbaceous cover, and herbaceous diversity, but had the unwanted effect of increased shrub cover. The addition of low-intensity cattle grazing did not improve structural outcomes. We also found that each restoration treatment left a unique signature on understory plant community composition. Unmanaged and thin-only treatments were characterized by tree saplings and woodland herbs, while burned and grazed treatments were defined by shrubs and savanna-associate species. We conclude that reintroducing multiple disturbances does not guarantee the successful restoration of disturbance-dependent ecosystems such as oak savannas. Restoration outcomes are not dictated by how many management approaches are applied, but rather, the nuances of how they are applied such as burn season and livestock density.

Natural disturbances as drivers of tipping points in forest ecosystems under climate change – implications for adaptive management

AbstractAs climate continues to change, disturbances may increasingly navigate forest ecosystems towards tipping points, causing irreversible state shifts and a loss of biodiversity and ecosystem services. In this review, I elaborate the Special Issue topic ‘Natural disturbances as tipping points of forest ecosystems under climate change’ featured by Forestry and suggest a suit of adaptive measures to mitigate increasing disturbances and their impacts on forest ecosystems. The Special Issue contains seven case studies assessing drought, fire, wind and bark beetle disturbances in Europe, North America and Africa. Despite high severities and/or frequencies, disturbances have not yet induced a shift of the investigated forest ecosystems towards an alternative state. Instead, forests have shown high resistance, resilience or both. For instance, one case study reveals that short-interval fires in European beech forests may not even significantly alter tree species composition due to the high resprouting ability of beech. Yet, other case studies identify distinct differences in resilience amongst ecoregions, and indicate that climate change and disturbance interactions might tip the future carbon balance of forests from sink to source. Many forest ecosystems are likely able to cope with future increases in disturbance activity to some degree. However, tipping points might vary across ecosystems dominated by different disturbance agents. While wind and bark beetles mainly affect canopy trees, fire and drought also directly impair tree regeneration, thus reducing the capacity of ecosystems to recover and reorganize. Hence, forest ecosystems in which fire and drought are the dominant disturbance agents might approach tipping points earlier than forests dominated by other agents if disturbance activity continues to increase. Several proactive and reactive adaptive measures are available to mitigate increasing disturbances, but more research is needed to develop robust and region-specific strategies to prevent tipping points in forest ecosystems.

Functional traits and climate drive interspecific differences in disturbance-induced tree mortality.

With climate change, natural disturbances such as storm or fire are reshuffled, inducing pervasive shifts in forest dynamics. To predict how it will impact forest structure and composition, it is crucial to understand how tree species differ in their sensitivity to disturbances. In this study, we investigated how functional traits and species mean climate affect their sensitivity to disturbances while controlling for tree size and stand structure. With data on 130,594 trees located on 7617 plots that were disturbed by storm, fire, snow, biotic or other disturbances from the French, Spanish, and Finnish National Forest Inventory, we modeled annual mortality probability for 40 European tree species as a function of tree size, dominance status, disturbance type, and intensity. We tested the correlation of our estimated species probability of disturbance mortality with their traits and their mean climate niches. We found that different trait combinations controlled species sensitivity to disturbances. Storm-sensitive species had a high height-dbh ratio, low wood density and high maximum growth, while fire-sensitive species had low bark thickness and high P50. Species from warmer and drier climates, where fires are more frequent, were more resistant to fire. The ranking in disturbance sensitivity between species was overall consistent across disturbance types. Productive conifer species were the most disturbance sensitive, while Mediterranean oaks were the least disturbance sensitive. Our study identified key relations between species functional traits and disturbance sensitivity, that allows more reliable predictions of how changing climate and disturbance regimes will impact future forest structure and species composition at large spatial scales.

Peatland fire regime across Riau peat hydrological unit, Indonesia

Peatland stretches across approximately 8% of Indonesia’s land area. Peat fire disturbance, which affects the carbon dynamics of the ecosystem, will determine the country's vision for a long-term strategy for low carbon development. While the impact of excessive draining on peatland fire is well-known to the scientific community, much less is known about peatland fire regimes in distinctive land management systems. We examined the effect of land use, land management, and climatic factors in peatland fires. The examination was performed at the Peat Hydrological Unit at Gaung–Batang Tuaka, Riau, Indonesia. We used a semi-automatic approach to determine the area of burned peatland and used a spatial analysis tool to analyze the spatio-temporal pattern of peatland fire in the region. Our results demonstrate an increasing trend of peatland fires between 2001 and 2020, with 33% of the burned peatland undergoing multiple fires. The bulk of the burned land was covered by either wet shrubs or estate crops, with the area of burned wet shrub-land cover was two times higher than the burned estate crop-land cover. Concerning peatland draining, this study found a positive correlation between draining intensity, as represented by canal density, and burned area in peatland forests. In managed and unmanaged land, canal density had no apparent correlation with the area of peatland burned; however, we found that the weighted area of burned peatland was, on average, seven times higher in the unmanaged area compared to the managed area. These findings urgently demand an increase in community participation in the utilization of unmanaged land and prompt execution of peatland rewetting in drained peat forests. While the government of Indonesia has developed a social forestry and agrarian reform scheme to enable the legal utilization of unproductive land in forest areas, we argue that greater impacts can only be achieved if environmental services incentive schemes escalate non-party actors' participation.

Could biological soil crusts act as natural fire fuel breaks in the sagebrush steppe?

Could biological soil crusts act as natural fire fuel breaks in the sagebrush steppe?

Bark characteristics of Betula platyphylla at different heights and their environmental interpretation under fire disturbance

Betula platyphylla is a pioneer tree species after fire disturbance in forest communities in the Daxing'an Mountains of China. Bark, as an external structure of vascular cambium, plays an important role in protection and transport. To understand the survival strategy of B. platyphylla under fire disturbance, we analyzed the functional traits of inner and outer bark of B. platyphylla at different heights (0.3, 0.8 and 1.3 m) in natural secondary forest of the Daxing'an Mountains. We further quantified the explanation of three environmental factors (stand, topography and soil) and identified the key factors driving the changes in those traits. The results showed that the relative inner bark thickness of B. platyphylla in burned plot followed an order of 0.3 m (4.7%) > 0.8 m (3.8%) > 1.3 m (3.3%), which was 28.6%, 14.4% and 3.1% higher than that in the unburned plot (30-35 years without fire disturbance), respectively. The relative outer bark thickness and the relative total bark thickness showed similar pattern with tree height. Fire had different effects on other bark functional traits of B. platyphylla. The inner bark density of B. platyphylla in burned plot was significantly decreased by 3.8%-5.6% and water content was significantly increased by 11.0%-12.2%, compared with that in unburned plot across the three heights. However, the contents of carbon, nitrogen, and phosphorus in inner (or outer) bark were not significantly affected by fire. Further, the mean inner bark nitrogen content at 0.3 m in burned plot (5.24 g·kg-1) was significantly higher than that at the other two heights (4.56-4.76 g·kg-1). Environmental factors explained 49.6% and 28.1% of the total variation in inner and outer bark functional traits, respectively, with the highest single explanation (18.9% or 9.9%) of soil factors. Diameter at breast height was the most important factor affecting the growth of inner and outer barks. In summary, fire affected survival strategies of B. platyphylla (e.g., increased the resource allocation to the base bark) via changing the environment factors, which would help improve their defense ability under fire disturbance.

Independence Effects of Heat and Ash on Forest Soil Nematode-Trapping Fungi Communities

Heat input and ash residues are main components of vegetation fire disturbances. Understanding the distinct impacts of heat and ash on soil microorganisms is crucial to comprehend and predict the induced changes in soil ecosystem composition and dynamics following different types of fire disturbances. This study’s main goal was to track the dynamic shifts in the community of soil nematode-trapping fungi (NTF) following the separate disturbances of heat and ash by means of a specifically designed experiment conducted in the field. Four simulated fire treatments, one treatment reproducing natural burning, and one control treatment were taken into account. Every ten days following the disturbance, soil samples from each treatment were collected, and soil NTF and physicochemical characteristics were measured. The results showed that: (1) Heat drastically decreased the number of strains and heavily altered the NTF community, but it also encouraged the emergence of new NTF species. Instead, no overt changes were observed in the treatment that just experienced the addition of ash on the soil. (2) When compared to treatments that received only heat input, the lower strain count of NTF recovered more quickly in the natural burning treatment which was affected by both heat and ash input. These findings suggest that the disruptive effect of fire heat on soil NTF biomass may be counterbalanced by the emergence of new species and the repairing capabilities of new nutrients introduced by ash residue. In the future, both conventional and cutting-edge techniques should be considered in research designs to better understand the ecological role of fire disturbances occurring at different intensities, as well as the mechanisms that make soil ecosystems resilient to fire, in particular the role of new species.

A New Method for the Rapid Determination of Fire Disturbance Events Using GEE and the VCT Algorithm—A Case Study in Southwestern and Northeastern China

Forest fires are major disturbances in forest ecosystems. The rapid detection of the spatial and temporal characteristics of fires is essential for formulating targeted post-fire vegetation restoration measures and assessing fire-induced carbon emissions. We propose an accurate and efficient framework for extracting the spatiotemporal characteristics of fires using vegetation change tracker (VCT) products and the Google Earth Engine (GEE) platform. The VCT was used to extract areas of persistent forest and forest disturbance patches from Landsat images of Xichang and Muli, Liangshan prefecture, Sichuan province in southwestern China and Huma, Heilongjiang province, in northeastern China. All available Landsat images in the GEE platform in a year were normalized using the VCT-derived persisting forest mask to derive three standardized vegetation indices (normalized burn ratio (NBRr), normalized difference moisture index (NDMIr), and normalized difference vegetation index (NDVIr)). Historical forest disturbance events in Xichang were used to train two decision trees using the C4.5 data mining tool. The differenced NBRr, NDMIr, and NDVIr (dNBRr, dNDMIr, and dNDVIr) were obtained by calculating the difference in the index values between two temporally adjacent images. The occurrence time of disturbance events were extracted using the thresholds identified by decision tree 1. The use of all available images in GEE narrowed the disturbance occurrence time down to 16 days. This period was extended if images were not available or had cloud cover. Fire disturbances were distinguished from other disturbances by comparing the dNBRr, dNDMIr, and dNDVIr values with the thresholds identified by decision tree 2. The results showed that the proposed framework performed well in three study areas. The temporal accuracy for detecting disturbances in the three areas was 94.33%, 90.33%, and 89.67%, the classification accuracy of fire and non-fire disturbances was 85.33%, 89.67%, and 83.67%, and the Kappa coefficients were 0.71, 0.74, and 0.67, respectively. The proposed framework enables the efficient and rapid extraction of the spatiotemporal characteristics of forest fire disturbances using frequent Landsat time-series data, GEE, and VCT products. The results can be used in forest fire disturbance databases and to implement targeted post-disturbance vegetation restoration practices.

变化环境下火干扰研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 变化环境下火干扰研究进展 DOI: 10.5846/stxb202210142923 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41991230） Research progress on fire disturbance in a changing environment Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:火是地球系统的重要过程，也是一种剧烈的环境干扰因素。火是生态系统变化的驱动力和催化剂，调节着生态系统的结构和功能，同时反馈给气候系统。近年来，世界多个国家相继爆发了历史上罕见的极端火事件，使得火干扰、气候变化和人类活动之间的相互作用关系得到了空前的关注。主要从3个方面回顾了变化环境下火干扰研究的进展，包括（1）火干扰的时空格局；（2）火干扰的驱动机制；（3）火干扰的生态效应。概括起来，遥感技术的发展使得火监测精度不断提高，对火时空格局的刻画由过去侧重火燃烧面积单一因素转向具有多重属性的火干扰体系。气候变化和人类活动共同决定着火干扰的分布格局、频率和强度，考虑气候的季节性能够提高火干扰的预测能力。火干扰调节着生态系统的草木平衡，对于生物多样性和生境的维持非常重要。此外，火干扰通过生物质燃烧释放的大量温室气体影响大气组成和空气质量，同时通过改变地表状况和陆-气相互作用来影响气候系统。正确理解气候-植被-火之间的相互作用和反馈机制有助于未来火干扰体系的预测。随着高温、大风、干旱等极端气候事件增多，未来全球大部分区域火发生的风险增加，但是人类活动可能会使火和气候之间的关系发生解耦。可持续的火管理应充分结合生态学知识和土著居民火文化，以保护生物多样性、维持重要生态系统服务和减缓气候变化为目标，减少极端火灾的风险。 Abstract:Fire is an essential component of the Earth system and a severe environmental disturbance factor. Fire is an important driver and catalyst for ecosystem changes, which regulates the structure and function of the ecosystem and provides feedback to regional and global climate systems. In recent years, extreme fire events that are rare in history have erupted in many countries around the world, drawing unprecedented attention to the interaction between fire disturbance, climate change, and human activities. This paper mainly reviews the progress of fire disturbance research in a changing environment from three aspects, including (1) spatiotemporal patterns of fire disturbance; (2) driving mechanisms of fire disturbance; (3) ecological effects of fire disturbance. In summary, state-of-the-art remote sensing technology has greatly improved the accuracy of fire monitoring, and the portrayal of the spatiotemporal pattern of fire has shifted from focusing on a single factor of fire burned area to the fire regime with multiple attributes. Climate change and human activities jointly determine the pattern, frequency, and intensity of fire disturbance. Taking into account the seasonality of climate can improve the prediction ability of the global fire system. Fires play an important role in regulating the competition between herbaceous and woody vegetation and thus are very important for biodiversity and habitat maintenance. In addition, fire disturbance affects the atmospheric composition and air quality through the release of large amounts of greenhouse gases from biomass burning, while impacting the climate system by altering land surface conditions and affecting land-atmosphere interactions. A better understanding of the interactions and feedback of climate-vegetation-fire can facilitate the prediction of fire regimes. In the future climate scenario, increases in extreme climate events, such as high temperatures, strong winds, and droughts, create a fire-prone environment. Although an increased risk of fire disturbances in most parts of the world, human activity may decouple the relationship between fire and climate. Sustainable fire management should fully integrate ecological knowledge and indigenous fire culture to reduce the risk of extreme fires, with the goal of protecting biodiversity, maintaining vital ecosystem services, and mitigating climate change. 参考文献 相似文献 引证文献

林火干扰对广东木荷林生态系统碳库的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 林火干扰对广东木荷林生态系统碳库的影响 DOI: 10.5846/stxb202004240980 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划重点专项(2018YFE0207800);广东省自然科学基金项目(2021A1515010946);广东省林业科技创新项目(2020KJCX003);广西自然科学基金项目(2014GXNSFBA118108) Effects of forest fire disturbance on carbon pools of Schima superba forest ecosystem in Guangdong Province Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:森林碳库在调节CO2浓度及减缓温室效应中发挥重要作用。选择广东木荷林为研究对象,通过相邻样地法,进行植被生物量、凋落物生物量和土壤样品的采样与分析,研究不同林火干扰强度对生态系统各碳库(植被、凋落物和土壤有机碳)及生态系统碳库产生的变化规律和空间分布格局及其影响因素。结果表明:(1)植被碳密度随着林火干扰强度增强而减少,但不同组分的植被碳密度表现不同,乔木碳密度在不同林火干扰强度下变化与植被碳密度变化一致,而草本碳密度则呈现相反的变化趋势。相同林火干扰强度下,植被各组分碳密度均以乔木层降低幅度最大。林火干扰均显著降低了凋落物碳密度(P<0.05),并随林火干扰强度的增加其降低幅度增大,但不同林火干扰强度对凋落物碳密度的影响有所差异。林火干扰降低了土壤有机碳密度,且降低幅度随土层深度增加而逐渐变小。(2)林火干扰有效改变了生态系统碳库的空间分布格局。对照样地木荷林土壤有机碳库占比为61.59%,重度林火干扰后,土壤有机碳库占比为70.96%呈上升趋势,占生态系统碳库的优势地位,而植被和凋落物碳库占比呈下降趋势,处于生态系统碳库的次要地位。(3)双因素方差分析表明,林火干扰强度和土层深度及其交互作用均对土壤有机碳密度有显著影响。林火干扰强度解释了土壤有机碳密度变异的8.78%,土层深度解释了土壤有机碳密度变异的70.29%,林火干扰强度和土层深度之间的交互作用解释了土壤有机碳密度变异的8.16%。研究发现:林火干扰降低了生态系统碳库,且随林火干扰强度增加,生态系统碳库减少幅度增大。轻度林火干扰对森林生态系统碳库的影响差异不显著,而中度和重度林火干扰对森林生态系统碳库的影响差异显著。研究结果对深化亚热带森林固碳效应的影响机制提供理论支撑。 Abstract:Forest carbon pools play an important role in regulating CO2 concentration and mitigating the greenhouse effect. In this study, the Schima superba forest in Guangdong was selected as the research object. Through the adjacent plot method, the sampling and analysis of vegetation biomass, litter biomass and soil samples were conducted to study the impact of different forest fire disturbance intensities on the various carbon pools (vegetation, vegetation, litter and soil organic carbon) and the change law and spatial distribution pattern of ecosystem carbon pool and its influencing factors. The results showed that the vegetation carbon density decreased with the increase of forest fire disturbance intensity, but the vegetation carbon densities of different components were different. The change of tree carbon density under different forest fire disturbance intensities was consistent with the change of vegetation carbon density. The carbon density showed the opposite trend. Under the same fire disturbance intensity, the arbor layer had the largest decrease in the carbon density of each component of vegetation. The forest fire disturbance significantly reduced the litter carbon density (P<0.05), and the decrease range increased with the increase of the forest fire disturbance intensity, but the effects of different forest fire disturbance intensities on the litter carbon density were different. The forest fire disturbance reduced soil organic carbon density, and the reduction range gradually became smaller with the increase of soil depth. Forest fire disturbance has effectively changed the spatial distribution pattern of the ecosystem carbon pool. The proportion of soil organic carbon reservoir in the control plot was 61.59%. After severe forest fire disturbance, the proportion of soil organic carbon pool was 70.96%, showing an upward trend, accounting for the dominant position of ecosystem carbon pool, while the proportion of vegetation and litter carbon pool showed a downward trend, which was in the secondary position of ecosystem carbon pool. ANOVA showed that the intensity of forest fire disturbance and the depth of soil layer and its interaction had a significant impact on soil organic carbon density. The intensity of forest fire interference explained 8.78% of the soil organic carbon density variation, the soil layer depth explained 70.29% of the soil organic carbon density variation, and the interaction between the forest fire interference intensity and the soil layer depth explained 8.16% of the soil organic carbon density variation. The study found that forest fire disturbance reduced the ecosystem carbon pool, and as the intensity of forest fire disturbance increased, the reduction in ecosystem carbon pool increased. The impact of low forest fire disturbance on forest ecosystem carbon pool was not significant, while the impact of moderate and high forest fire disturbance on forest ecosystem carbon pool was significant. The research results provide theoretical support for the impact mechanism of deepening the carbon sequestration effect of subtropical forests. 参考文献 相似文献 引证文献

Distribution and habitat requirements of the Bahama Warbler Setophaga flavescens on Grand Bahama in 2018

Summary The Bahama Warbler Setophaga flavescens is restricted to Grand Bahama and Abaco in the Bahamas Islands, where in recent decades its pine forest habitat has been seriously affected by hurricanes. To assess its conservation status and determine its habitat requirements, we conducted point transects with playback and simultaneously took measurements at 464 locations in pine forest across Grand Bahama from April to June 2018. Warbler presence was predicted by taller Thatch Palms Thrinax radiata and some fire disturbance, and its absence by a higher number of needleless pines. A comparison of these habitat predictors between the combined regions where warblers were detected (Lucayan Estates and East End) vs. where they were not (West End and Freeport) also revealed that Bahama Warblers showed a marked preference for taller Thatch Palms (&gt;140 cm) and habitat plots within the middle fire disturbance category. These findings suggest that the species is adapted to a climax pine forest habitat maintained under a standard fire regime. Our research was intended to provide a first baseline study of the warbler’s distribution and ecology on Grand Bahama, but the distribution may have radically changed following Hurricane Dorian’s devastation of the island in 2019, and the species may now only survive on Abaco. Nevertheless, ecological insights from Grand Bahama seem likely to help conservation management on Abaco, but both islands now need to be surveyed.

Soil seed bank development of smoke‐responsive plant species in a 23‐year restoration chronosequence and implications for resilience to fire

AbstractAimsResponses of ecological restoration projects to disturbances are rarely explored, yet their capacity to withstand and recover from disturbance (resilience) is a critical measure of restoration success. In many plant communities, the soil seed bank (SSB) provides an important source of propagules for species persistence and community resilience to disturbance. Understanding how SSBs develop with time can inform restoration of resilient ecosystems. Here, in fire‐prone Banksia woodland restoration following sand mining, we ask: (a) how does the smoke‐responsive (dormancy broken by smoke) SSB develop over time; (b) what plant‐trait and climate factors influence its development; and (c) what do the data suggest for the resilience of these restored woodlands to fire?LocationEllenbrook, Swan Coastal Plain, Western Australia (latitude −31.76, longitude 115.95).MethodsWe used smoke, a key germination cue associated with fire disturbance, to trigger germination of the SSB in Banksia woodland restoration. Using a chronosequence of nine ages between 3 and 26 years since initiation of restoration, we tested how the SSB develops using counts and richness of germinating native and invasive annuals, and native perennial obligate seeding and resprouting species. To understand the contribution of above‐ground restored vegetation to SSB development, we compared Sørensen's similarity of the smoke germinable SSB (smoked SSB) and untreated germinable SSB (control SSB) with above‐ground vegetation.ResultsSmoked SSB germinant density decreased with restoration age for both native and invasive annuals, but was stable for native perennials. Similarity between smoked SSB and above‐ground vegetation was higher for perennial obligate seeders than for resprouters and peaked for perennials at 23 years.ConclusionsPost‐fire regeneration potential of the SSB was evident across the chronosequence, with restoration age influencing the density of native annuals and overall composition of the SSB. The findings for perennial species suggest an increase in resilience to fire with restoration age.

不同烈度林火对油松林潜在地表火行为的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 不同烈度林火对油松林潜在地表火行为的影响 DOI: 10.5846/stxb202111223283 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划项目（2020YFC1511601） Effects of wildfire of different severities on potential surface fire behavior of Pinus tabuliformis forest Author: Affiliation: Fund Project: the Key Project of National Key Research and Development Plan 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:油松是我国华北地区代表性树种之一，含有丰富油脂，容易引发大面积高烈度森林火灾。阐明不同烈度林火对油松林地表可燃物负荷量和潜在地表火行为的影响，对于油松林林火管理具有重要意义。以辽河源自然保护区2014年不同烈度林火干扰后油松林分为研究对象，根据不同烈度（重度、中度、轻度）和对照（未过火）分别设置3块20 m×20 m样地，共12块样地，调查地表可燃物和林分结构指标，结合室内实验，利用BehavePlus 5.0软件进行潜在火行为模拟，探讨不同烈度林火5年后油松林地表可燃物负荷量和潜在地表火行为特点，并分析影响潜在地表火行为的主要因素。研究结果表明：（1）不同烈度林火之间，细小可燃物负荷量和地表可燃物总负荷量均不存在显著性差异（P>0.05）。（2）不同烈度林火后，在不同风速和可燃物含水率条件下，油松林潜在地表火蔓延速度、火线强度不存在显著性差异（P>0.05），单位面积发热量、火焰高度、反应强度存在显著性差异（P<0.05）。（3）不同烈度林火后油松林潜在地表火行为主要受油松更新幼苗基径、灌木负荷量、油松平均冠幅、上层枯叶负荷量、油松更新幼苗密度的影响。研究结果表明不同烈度林火均可以降低再次燃烧的火烈度和风险。 Abstract:Pinus tabuliformis is one of the representative tree species in North China, which is rich in oil and easy to cause large area and high severity wildfire. It is of great significance for wildfire management of Pinus tabuliformis forest to elucidate the influence of wildfire of different severities on the surface fuel load and potential surface fire behavior of Pinus tabuliformis forest. In this study, Pinus tabuliformis forests with different severities of wildfire disturbance in Liaoheyuan Nature Reserve in 2014 were taken as the research object. According to different severities (high, moderate, low) and control (unburned), three 20 m×20 m sample plots were set, and a total of 12 plots were set. Based on the investigation of surface fuel and stand structure index, combined with indoor experiments, the potential fire behavior was simulated by BehavePlus 5.0 software. The characteristics of surface fuel load and potential surface fire behavior of Pinus tabuliformis forest after 5 years of fire with different severities were discussed, and the main factors affecting the potential surface fire behavior were analyzed. The results indicated that (1) there was no significant difference in the fine fuel load and the total surface fuel load between different severities wildfire disturbance (P>0.05). (2) Under the conditions of different wind speeds and fuel moisture content, there were no significant differences in the potential surface fire spread rate and fireline intensity (P>0.05), but there were significant differences in the calorific value per unit area, flame height and reaction intensity (P<0.05) after forest fire disturbance with different severities. (3) The potential surface fire behavior of Pinus tabuliformis forest with different severities was mainly affected by the regeneration seedling base diameter of Pinus tabuliformis, shrub load, average canopy width of Pinus tabuliformis, load of upper dead leaves, and the regeneration seedling density of Pinus tabuliformis. The results showed that forest fires with different severities could reduce the severity and risk of reburning. 参考文献 相似文献 引证文献