Forest Burning Research Articles

Disturbance can slow down litter decomposition, depending on severity of disturbance and season: an example from Mount Kilimanjaro

Abstract. Deforestation and land-use change affect ecosystem processes such as carbon cycling. Here, we present results from a litter decomposition experiment in six natural and six disturbed vegetation types along an elevation gradient of 3600 m on the southern slopes of Mount Kilimanjaro, Tanzania. We exposed litter bags with a standard material for up to 12 weeks each in two seasons. In the cold wet season we sampled the full elevation gradient and in the warm wet season we repeated the sampling in the lower part of the elevation gradient. Though we found significantly negative effects of disturbance in forest ecosystems, this was only due to differences between natural and burned Podocarpus forests. Disturbance characterized by a more open vegetation structure in many of the studied vegetation types had no general effect when we studied the full elevation gradient; this also included non-forest vegetation types. Land-use intensity had a significant negative effect on decomposition rates but only in the warm wet season, not in the cold wet season. Temperature and humidity were the most important drivers of decomposition overall and for all subsets of vegetation types and seasons. Our study shows that negative effects of disturbance or land-use intensity on decomposition depended on the severity of disturbance and on the season. Nevertheless, climate was generally the most relevant driver of decomposition. Therefore, vegetation types with moderate levels of disturbance can retain high functionality in regards to carbon cycling over short periods of time. More and longer decomposition studies are necessary to better predict consequences of land-use change for carbon cycling in the Afrotropics.

Heterogeneity in post-fire thermal responses across Pacific Northwest streams: A multi-site study

Over the past century, water temperatures in many streams across the Pacific Northwest (PNW) have steadily risen, shrinking endangered salmonid habitats. The warming of PNW stream reaches can be further accelerated by wildfires burning forest stands that provide shade to streams. However, previous research on the effect of wildfires on stream water temperatures has focused on individual streams or burn events, limiting our understanding of the diversity in post-fire thermal responses across PNW streams. To bridge this knowledge gap, we assessed the impact of wildfires on daily summer water temperatures across 31 PNW stream sites, where 10–100% of their riparian area burned. To ensure robustness of our results, we employed multiple approaches to characterize and quantify fire effects on post-fire stream water temperature changes.Averaged across the 31 burned sites, wildfires corresponded to a 0.3 – 1°C increase in daily summer water temperatures over the subsequent three years. Nonetheless, post-fire summer thermal responses displayed extensive heterogeneity across burned sites where the likelihood and rate of a post-fire summer water temperature warming was higher for stream sites with greater proportion of their riparian area burned under high severity. Also, watershed features such as basin area, post-fire weather, bedrock permeability, pre-fire riparian forest cover, and winter snowpack depth were identified as strong predictors of the post-fire summer water temperature responses across burned sites. Our study offers a multi-site perspective on the effect of wildfires on summer stream temperatures in the PNW, providing insights that can inform freshwater management efforts beyond individual streams and basins.

Fire effect on bamboo-dominated forests in Southwestern Amazon: impacts on tree diversity and forest structure

Severe droughts increase the forest flammability, especially if fires are recurrent. Considering that fires tend to alter the forest structure and reduce biological diversity, we analyzed the fire effect on the tree plant community and forest structure over a 10-year post-fire period. The study was carried out in two tropical forest fragments located in the eastern Acre State in southwestern Brazilian Amazon. In each fragment, we established three plots of 250 × 10 m2 in an unburned forest and three in a burned forest. In these plots, we collected all tree individuals with DBH≥10 following the RAINFOR protocol, with censuses made in 2011, 2014, 2016, 2017, 2019, 2020 and 2021. The fire significantly reduced the abundance, basal area, and aboveground biomass of tree species, and altered the species composition along the post-fire temporal gradient. The absence of differences in the species richness and species diversity between unburned and burned forests is probably related to the life cycle of bamboo. The results suggest that, 10 years after the fire, the structure and phytosociology of the forest have not yet fully recovered.

Modification of the Rothermel model parameters – the rate of surface fire spread of Pinus koraiensis needles under no-wind and various slope conditions

Background The prediction accuracy for the rate of surface fire spread varies in different regions; thus, increasing the prediction accuracy for local fuel types to reduce the destructive consequences of fire is critically needed. Aims The objective of this study is to improve the Rothermel model’s accuracy in predicting the ROS for surface fuel burning in planted forests of Pinus koraiensis in the eastern mountains of north-east China. Methods Fuel beds with various fuel loads and moisture content was constructed on a laboratory burning bed, 276 combustion experiments were performed under multiple slope conditions, and the ROS data from the combustion experiments were used to modify the related parameters in the Rothermel model. Results The surface fire spread rate in Pinus koraiensis plantations was directly predicted using the Rothermel model but had significant errors. The Rothermel model after modification predicted the following: MRE = 25.09%, MAE = 0.46 m min−1, and R2 = 0.80. Conclusion The prediction accuracy of the Rothermel model was greatly enhanced through parameter tuning based on in-lab combustion experiments Implications This study provides a method for the local application of the Rothermel model in China and helps with forest fire fighting and management in China.

Listening to tropical forest soils

Acoustic monitoring has proven to be an effective tool for monitoring biotic soundscapes in the marine, terrestrial, and aquatic realms. Recently it has been suggested that it could also be an effective method for monitoring soil soundscapes, but has been used in very few studies, primarily in temperate and polar regions.We present the first study of soil soundscapes using passive acoustic monitoring in tropical forests, using a novel analytical pipeline allowing for the use of in-situ recording of soundscapes with minimal soil disturbance. We found significant differences in acoustic index values between burnt and unburnt forests and the first indications of a diel cycle in soil soundscapes.These promising results and methodological advances highlight the potential of passive acoustic monitoring for large-scale and long-term monitoring of soil biodiversity. We use the results to discuss research priorities, including relating soil biophony to community structure and ecosystem function, and the use of appropriate hardware and analytical techniques.

Study of the conditions of ignition of forest combustible material for anthropogenic reasons

Study of the conditions of ignition of forest combustible material for anthropogenic reasons

One Step Before Disaster: Determining Individuals’ Perceptions of Global Warming and Climate Change in Terms of Different Demographic Variables

Aim of study: The friendship between humankind and nature ended with the mechanization process initiated by the Industrial Revolution. Today, we are faced with the problems of global warming and climate change due to human factors such as fossil fuel consumption and the destruction of vegetation. These two problems promise us a warmer world, melting glaciers, burning forests, and thousands of dead people in the future. Research indicates that people’s awareness is the most important factor in combating the disastrous consequences of global warming and climate change. Based on this fact, this study aims to examine individuals’ perceptions of global warming and climate change in terms of various variables. 
 Material and methods: The research was conducted with 2022 participants in line with the screening model. A perception scale on global warming and climate change was used as a data collection tool. The obtained data were analyzed with descriptive statistics, Mann Whitney U, and Kruskal Wallis Tests.
 Main results: As a result of the research, it has been determined that female participants have a positive attitude towards global warming and climate change compared to male participants, and as the age level of individuals increases, their perceptions of global warming and climate change increase. 
 Research highlights: Awareness of people is the most important factor in the fight against the consequences of global warming and climate change. As a result of the data collected from 2022 participants, it was determined that female participants' perceptions of global warming and climate change were more positive than male participants

Analisis Efek Rumah Kaca serta Teknologi Penanggulangan Efek Rumah Kaca yang Terbarukan

Global warming is an increase in global temperature at the Earth's surface (within several thousand kilometers) compared to the normal/average value recorded over a standard period (World Meteorological Organization/WMO measurements: at least 30 years). Global warming is one of the impacts caused by the greenhouse effect. The greenhouse effect is a condition where the surface temperature of a celestial body, such as a planet or star, increases rapidly. This increase in temperature is caused by changes in the composition and conditions of the atmosphere around the object. The greenhouse effect can be caused by human activities and can occur naturally due to natural events such as forest burning due to a prolonged dry season. Basically, the greenhouse effect is very difficult to overcome, but we can reduce the greenhouse effect by using environmentally friendly energy such as renewable energy. With the rapid development of technology in this modern era, there are many renewable technologies that can be developed and utilized. This analysis aims to determine the process, causes and consequences of the greenhouse effect as well as the development and use of renewable energy technology to overcome the greenhouse effect.

Criminal Sanctions Against Corporations Committing Forest Burning: A Perspective of Environmental Law in Indonesia

Criminal Sanctions Against Corporations Committing Forest Burning: A Perspective of Environmental Law in Indonesia

Prescribed fire promotes regeneration in a mature eastern white pine forest

Although evidence indicates that fire exclusion may result in substantial short- and long-term changes to forest stand structure and composition, the long-term effects on eastern white pine (Pinus strobus L.) stands remain largely unknown. We investigated the response of trees and understory vegetation after prescribed burning in a mature white pine stand in northern Ontario, Canada. Results indicate that a single prescribed burning treatment improved regeneration of white pine and other mid-shade tolerant species compared to controls whereas repeated burning favoured shade intolerant species such as trembling aspen (Populus tremuloides Michx.). Unburned control plots had a substantial understory component of shade tolerant balsam fir (Abies balsamea [L.] Mill.). We simulated stand compositions after 70 years post-treatment and found that prescribed burn plots had much higher volume of white pine compared to unburned plots. Overall, the results highlight fire severity as a driving influence on the successional trajectory of white pine stands. The findings support low to moderate prescribed burning of mature white pine-dominated forests as an effective means to retain a white pine component within areas of the Great Lakes-St. Lawrence forest region.

The Potential of Carbon-Offset as an Integrative Ecocide Prevention Instrument with Climate Change Mitigation

This research is built from the concept that crimes against the environment also have implications for climate change. In this case, ecocides in the form of forest burning that cause Transboundary Haze to contribute positively in increasing carbon emissions in the atmosphere. Therefore, an integrated prevention instrument is needed to simultaneously mitigate forest fires and climate change. Thus, this study aims to examine the potential of Carbon Offset, or what in the regime of Presidential Regulation Number 98 of 2021 concerning the Economic Value of Carbon calls it Greenhouse Gas Emission Offsetting, as an alternative instrument in modern environmental restoration. The research method uses normative juridical with a conceptual approach and legislation. The novelty of this research is to find a correlation between the impact of environmental destruction and climate change, as well as an analysis of carbon trading as an alternative solution. The results of the study indicate that the market mechanism-based carbon offset scheme is expected to be able to change the behavior of the extractive industry in forest land use, so that forest burning is no longer a profitable business option.

Delayed application of straw mulching increases soil erosion in Mediterranean pine forests burned by wildfires

Several studies have explored the effectiveness of straw mulching against soil erosion in wildfire-affected forests as post-fire management technique. In contrast, scarce literature exists about the application time of the mulch cover, although this factor - beside climate patterns of the application site - is essential to increase mulching effectiveness. To fill this gap, this study has evaluated the soil loss in two forest sites of Castilla La Mancha (Spain), in which straw mulching was applied in two burned forests immediately after the wildfire or four months after the fire event. These sites show similar characteristics (soil burn severity, soil type, and vegetation), and thus the difference in soil erosion can be attributed to the treatments. The mulching effectiveness has been measured as the difference between the soil loss per unit of erodibility comparing unburned and untreated, and burned and mulched plots. At a comparable rainfall erosivity (difference in EI30 between the two sites lower than 40 %), soil loss decreased by 67 % (in the case of timely distribution) and 33 % (when the action is delayed) in mulched sites compared to the untreated areas. After a rainstorm with very high erosivity (+600 % of EI30), soil loss reduction was equal to 85 % in the case of early mulching application. This higher effectiveness of early mulching compared to the delayed application was due to the quicker post-fire regrowth of vegetation, and the increased level of incorporation of vegetal residues into the soil. This result suggests to land managers that straw mulching should be applied immediately after a wildfire in burned forests, in order to achieve the highest anti-erosive effects. Further research is suggested to validate these results in other environments and after application of other mulches.

Aspects of Forest and Forestry Management Laws on the Rate of Deforestation in Indonesia

The thick smoke resulting from forest fires in Indonesia has caught the attention of foreign countries. Through their news channels, foreign nations have commented on the frequent occurrences of forest fires in Indonesia. The phenomenon of forest fires remains an unresolved issue for Indonesia. Deforestation resulting from forest burning continues to persist, especially when carried out deliberately by human activities. While Indonesia has regulations prohibiting land and forest fires, the author will analyze the issues surrounding why land and forest fires incidents persist in Indonesia and how to address them. The researcher employs a descriptive research method with a literature review in data collection, drawing from primary and secondary legal materials. The author s observes inconsistencies in norms regarding the prohibition of land and forest burning. Sanctions for land and forest fires outlined in related regulations vary, lack consistency and lead to overlapping rules. Therefore, there is a need for reformulation of regulations with loopholes. Additionally, regulations concerning indigenous communities should be established to ensure clear recognition and legal certainty for these communities.

Criminal Liability for Forest Burning in Indonesia

Degradation of the forest environment has a huge negative effect on the environment, economy, institutions, as well as society, especially in terms of accessibility of forest resources and biodiversity. Forest and land fires (“Karhutla”) in Indonesia have increased drastically this year during the dry season, according to the non-profit organization Madani Sustainable. Based on their monitoring findings, an area of 152,678 hectares is an indicative area for land fires and forest and land fires in Indonesia in August 2023 alone. This study aims to determine criminal liability for forest burning in Indonesia. This research uses normative legal methods which are supported by literature reviews from various scientific journal sources published in 2019-2023. The research results show that criminal liability has been regulated in Article 108 of Law Number 32 of 2009 concerning Environmental Management.

Potential of paleoecology and paleolandscape modeling to identify pre-Colonial cultural burning in montane forests: case studies in California

Paleoecology and paleolandscape modeling have the potential to differentiate cultural burning from climatic fires, improving interpretations of past fire histories and vegetation resource management practices. People have conducted variations of traditional fire management to increase terrestrial resources for hundreds of millennia, commonly in fire-prone areas where vegetation is adapted to frequent fire events. Over time, these cultural fires influenced regrowth and led to an anthropogenically-modified landscape. For some non-agrarian, semi-nomadic societies, such as the pre-Colonial groups within what is now known as California, identifying anthropogenic landscapes is difficult because of a lack of domesticated plant remains in the environmental record to indicate where human impacts occurred. This paper uses case studies from the central and southern Sierra Nevada range in California to explore the potential of paleoecology, specifically pollen and sedimentary charcoal, and spatially-explicit paleolandscape modeling to identify and distinguish periods of cultural burning in mountainous forests to improve archaeological interpretations of human-fire dynamics. Specifically, I use climate-vegetation dynamics and cluster analysis to look at temporal relationships of change between sites. These case studies are ideal because (1) the region is naturally fire-prone, (2) study sites are typically well-dated and analyzed at a sub-centennial resolution, (3) study sites are associated with archaeological sites, and (4) indigenous groups were proto-agricultural, balanophagy societies known to practice cultural burning. These case study sites show a strong potential to identify periods of cultural burning that help better inform archaeological interpretations and show synchronous evidence for cultural burning during the Little Ice Age (1250-1850). Furthermore, these studies provide better dated timelines of human influence at each site than nearby archaeological studies, indicating that in certain locales, paleoecological studies with high temporal resolutions could be used to inform the timing of archaeological activities and shifts.

Empirical Modelling of Stem Cambium Heating Caused by Prescribed Burning in Mediterranean Pine Forest

Little is known about the interactions between the variables involved in the post-fire response of Mediterranean pine species to prescribed burning (PB). Thus, it is essential to develop an empirical model in order to assess the influence of tree and stand attributes, burn season, and fire severity on the probability of stem cambium damage occurring. Prescribed burnings were conducted in different seasons and areas covering a wide climatic and ecological range. Potential explanatory variables were measured. A random effects hurdle model framework was used to evaluate the temperature duration above 60 °C as a proxy for stem cambium damage at tree scale. The results showed significant differences in cambium damage between the PB seasons. Pinus nigra was more resistant than other pine species. Bark thickness was critical for protecting cambium. Volume of crown scorch, percentage of stem scorch, and maximum outer bark temperature were directly related to temperature duration above 60 °C in the cambium. Prescribed burning conducted under tree canopy in Mediterranean pine species generally results in a low level of cambium damage. Empirical models could help managers to predict the effects of PB and thus select the most suitable prescriptions.

The influence of seed functional traits and anthropogenic disturbances on persistence and size of the soil seed bank from dry subtropical forest species

Soil seed banks (SSB) are reservoirs of viable mature seeds that play a crucial role in the dynamics and recovery of vegetation following disturbances. Despite its importance, there is still limited understanding of their characteristics of SSB in semiarid subtropical ecosystems. Our objective was to evaluate the effects of wildfire and roller-chopping on the size and persistence of the SSB of six native woody species, considering the influence of seed functional traits (FT). This study was conducted in dry subtropical forests of the western Argentine Chaco region. We evaluated SSB of six woody species: Aspidosperma quebracho-blanco (Aqb); Schinopsis lorentzii (Sl); Sarcomphalus mistol (Sm); Senegalia gilliesii (Sg) and Vachellia aroma (Va) in experimental plots located in two sites (forest plots of ca. 5 ha): forests without disturbance within the last four decades (conserved forest - CF) and forests subjected to fires and mechanical treatments for the partial removal of the shrub layer (roller-chopping and burned forest -RBF). Samples of the SSB were taken under the canopy of six focal individuals of each species in two reproductive seasons between 2016 and 2018. Seeds from ten mature trees of each species were collected to characterize their functional traits (shape and seed mass) related to their aptitude to form the SSB. Three groups of species were identified based on FT analysis: I-large, compressed seeds (Sl, Aqb and Sg); II- medium-size subspherical seeds (Va and Nn); and III- large spherical seeds (Sm). Aqb, Sl, Nn, and Va presented significant differences in the size of their SSB when comparing between sites and sampling years (p = 0.0013; p = 0.0006; p = 0.0020; p = 0.0151, respectively), but no clear patterns emerged among them. The SSB from Aqb and Va were greater in RBF than in CF, only during the second sampling season (105.3 ± 35.2; 352.6 ± 133.4 seeds.m−2, respectively). Sl also exhibited the highest SSB (97.7 ± 30.5) in the second year of sampling, while Nn showed the largest SSB in the first year, (1569.0 ± 847.0 seeds.m−2), both within CF. Finally, Sm and Sg did not present significant differences in their SBB between sites and years. We concluded that all studied species form transient SSB and that the shape index type II favors seed burial, so increasing SSB size and viability. Forest disturbances differentially affect the SSB of woody species in the dry subtropical Chaco because some species decreased, increased or showed no effects during different reproductive seasons. Thus, the potential long-term influence on the dynamics and resilience of dry forests in the subtropics needs to be monitored in the long term.

Thinning and prescribed burning increase shade-tolerant conifer regeneration in a fire excluded mixed-conifer forest

Fire exclusion and past management have altered the composition, structure, and function of frequent-fire forests throughout western North America. In mixed-conifer forests of the California Sierra Nevada, fire exclusion has exacerbated the effects of drought and endemic bark beetles, resulting in extensive mortality of fire-adapted pine species. Thinning and prescribed fire are widely used in these forests to reduce fuels, moderate fire behavior, and restore ecosystems. Tree regeneration influences future forest composition and structure, and therefore future resilience to disturbances, but long-term effects of thinning and prescribed burning on tree regeneration after prolonged fire exclusion are poorly understood. We measured tree regeneration one year prior to, and periodically for 16 years following thinning and prescribed burning in a mixed-conifer forest in the Sierra Nevada, California, USA. We asked three questions. How did the composition and density of tree regeneration change after thinning and prescribed burning? Did pretreatment vegetation types influence conifer regeneration density after treatments? Did planting after overstory thinning increase regeneration density of native pine species?Sixteen years after treatments, combined natural regeneration of shade-tolerant white fir (Abies concolor) and incense-cedar (Calocedrus decurrens) averaged 2,032 trees per hectare (tph) after understory thinning, and 7,745 tph after understory thinning combined with prescribed burning, increases of 37 % and 146 % from pretreatment densities. In contrast, combined natural regeneration of white fir and incense-cedar averaged 497 tph after overstory thinning, 780 tph after overstory thinning with prescribed burning, 113 tph after prescribed burning alone, and 807 tph in untreated controls, all of which were declines from pretreatment densities. Natural regeneration of white fir and incense-cedar was consistently an order of magnitude greater than Jeffrey pine (Pinus jeffreyi) and sugar pine (Pinus lambertiana), whose combined densities 16 years after treatments averaged 37 tph across treatments and did not significantly respond to thinning and/or prescribed burning. Natural conifer regeneration after treatments varied by pre-treatment vegetation type (closed canopy, Ceanothus cordulatus shrub dominated, and open sparse), with large increases of natural regeneration after understory thinning in closed canopy and Ceanothus shrub vegetation types. Planting increased sugar pine regeneration density after overstory thinning, marginally increased Jeffrey pine regeneration after overstory thinning combined with prescribed burning, and increased white fir regeneration after overstory thinning with and without burning. No treatments reduced white fir and incense-cedar natural regeneration while simultaneously increasing natural pine regeneration, suggesting new thinning, burning, and planting approaches may be required to meet regeneration restoration objectives.

Accounting for forest fire risks: global insights for climate change mitigation

Fire is an important risk in global forest loss and contributed 20% to 25% of the global anthropogenic greenhouse gas emissions between 1997 and 2016. Forest fire risks will increase with climate change in some locations, but existing estimates of the costs of using forests for climate mitigation do not yet fully account for these risks or how these risks change inter-temporally. To quantify the importance of forest fire risks, we undertook a global study of individual country fire risks, combining economic datasets and global remote sensing data from 2001 to 2020. Our estimates of forest fire risk premia better account for the risk of forest burning that would be additional to the risk-free and break-even price of credits or offsets to promote carbon sequestration and storage in forests. Our results show the following: (1) forest fire risk premia can be much larger than the historical forest area burned; (2) for some countries, forest fire risk premia have a large impact on the relative country-level break-even price of carbon credits or offsets; (3) a large spatial and inter-temporal heterogeneity of forest fires across countries between 2001 and 2020; and (4) the importance of properly incorporating forest fire risk premia into carbon credits/offset programs. As part of our analysis, and to emphasise the possible sub-national scale differences, our results highlight the heterogeneity in fire risk premia across 10 Canadian provinces.

Spatio-Temporal Characteristics of Ice–Snow Freezing and Its Impact on Subtropical Forest Fires in China

Ice–snow freezing may disrupt the growth condition and structure of forest vegetation, increasing combustible loads and thus triggering forest fires. China’s subtropical regions are rich in forest resources, but are often disturbed by ice–snow freezing, especially due to climate change. Clarifying the responsive areas and times of forest fires to ice-snow freezing in this region is of vital importance for local forest fire management. In this study, meteorological data from 2001 to 2019 were used to extract the precipitation and its duration during the freezing period in order to analyze the freezing condition of forest vegetation in subtropical China. To improve the accuracy of identifying forest fires, we extracted forest fire information year-by-year and month-by-month based on the moderate resolution imaging spectroradiometer (MODIS) active fire data (MOD14A2) using the enhanced vegetation index (EVI), and analyzed the forest fire clustering characteristics in the region using the Moran’s Index. Then, correlation analysis between forest fires and freezing precipitation was utilized to explore the responsive areas and periods of forest fires caused by ice–snow freezing. Our analysis shows the following: (1) during the period of 2001–2019, the ice–snow freezing of forest vegetation was more serious in Hunan, Jiangxi, Hubei, and Anhui provinces; (2) forest fires in subtropical China have shown a significant downward trend since 2008 and their degree of clustering has been reduced from 0.44 to 0.29; (3) forest fires in Hunan, Jiangxi, and Fujian provinces are greatly affected by ice–snow freezing, and their correlation coefficients are as high as 0.25, 0.25, and 0.32, respectively; and (4) heavy ice–snow freezing can increase forest combustibles and affect forest fire behavior in February and March. This research is valuable for forest fire management in subtropical China and could also provide a reference for other regions.