Eff ect of prescribed burning on the small-scale spatial heterogeneity of soil microbial biomass in Pinus koraiensis and Quercus mongolica forests of China

Prescribed burning can alter soil microbial activity and spatially redistribute soil nutrient elements.However,no systematic,in-depth studies have investigated the impact of prescribed burning on the spatial patterns of soil microbial biomass in temperate forest ecosystems in Northeast China.The present study investigated the impacts of prescribed burning on the small-scale spatial heterogeneity of microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN)in the upper(0–10 cm)and lower(10–20 cm)soil layers in Pinus koraiensis and Quercus mongolica forests and explored the factors that infl uence spatial variations of these variables after prescribed burning.Our results showed that,MBC declined by approximately 30%in the 10–20 cm soil layer in the Q.mongolica forest,where there were no signifi cant eff ects on the soil MBC and MBN contents of the P.koraiensis forest(p>0.05)after prescribed burning.Compared to the MBC of the Q.mongolica forest before the prescribed burn,MBC spatial dependence in the upper and lower soil layers was approximately 7%and 2%higher,respectively.After the prescribed burn,MBN spatial dependence in the upper and lower soil layers in the P.koraiensis forest was approximately 1%and 13%lower,respectively,than that before the burn,and the MBC spatial variability in the 0–10 cm soil layer in the two forest types was explained by the soil moisture content(SMC),whereas the MBN spatial variability in the 0–10 cm soil layer in the two forests was explained by the soil pH and nitrate nitrogen(NO_(3)^(–)-N),respectively.In the lower soil layer(10–20 cm)of the Q.mongolica forest,elevation and ammonium nitrogen(NH 4+-N)were the main factors aff ecting the spatial variability of MBC and MBN,respectively.In the 10–20 cm soil layer of the P.koraiensis forest,NO_(3)^(–)-N and slope were the main factors aff ecting the spatial variability of MBC and MBN,respectively,after the burn.The spatial distributions of MBC and MBN in the two forests were largely structured with higher spatial autocorrelation(relative structural variance C/[C 0+C]>0.75).However,the factors infl uencing the spatial variability of MBC and MBN in the two forest types were not consistent between the upper and lower soil layers with prescribed burning.These fi ndings have important implications for developing sustainable management and conservation policies for forest ecosystems.

Usage of Cool Burning as a Contributor to Bushfire Mitigation

This paper considers and describes the cool burning techniques long utilized by Australian Indigenous people as a contributor to bushfire mitigation. Indigenous fire management involves lighting the “cool” fires in selected areas between March and July, in Australia, during the early dry season. The fires burn gradually, reducing fuel loads and creating fire breaks and not all of the area is burnt. Late in the dry season, when the weather is very hot, the method removes fuel for larger fires while maintaining and protecting habitat for mammals, reptiles, insects and birds. The management of Indigenous cultural fire offers an Indigenous viewpoint for wider control of fire and cultural fire management is an opportunity for collaborations to encourage Aboriginal empowerment with public and private sector organisations. Effective cool burning in contemporary prescribed burning activities can be achieved through implementation of good training, strong partnerships, carefully considered on ground practices and appropriate and effective techniques.

Fungal diversity and community composition responses to the reintroduction of fire in a non-managed Mediterranean shrubland ecosystem

Background:More than a decade of fire suppression has changed the structure of fire-adapted shrubland ecosystems in Spain’s National Parks,which are now at extreme risk of uncontrolled wildfires.Prescribed burning can mitigate the risk of wildfires by reducing the fuel load but prescribed burning may also alter the soil properties and reduce microbial and fungal activity,causing changes in the availability of nutrients deep in the soil layer.Although fungal communities are a vital part of post-fire restoration,some fire effects remain unclear.To examine the short-term effects of prescribed burning on soil fungal communities in Doñana Biological Reserve(SW Spain),we collected soil samples pre-burn and 1 day,6 and 12 months post-burn from burned plots to perform physicochemical and metabarcode DNA analyses.Results:Prescribed burning had no significant effect on the total fungal operational taxonomic unit richness and abundance.However,changes in soil pH,nitrogen and potassium content post-burn affected fungal community composition.Small non-significant changes in pH and phosphorous affected the composition of ectomycorrhizal fungi.Conclusions:The ectomycorrhizal fungal community appears to be resilient to the effects of low-to moderate-intensity fires and saprotrophic taxa may benefit from this kind of fire.This finding revealed that prescribed burning is a potentially valuable management tool for reducing fire hazards in shrublands that has little effect on the total richness and abundance of fungal communities.

Health and Environmental Impacts of Smoke from Vegetation Fires: A Review

Smoke exposure is often an inevitable side effect of open vegetation fires (both planned and wild) and is an important public health concern. The objective of this paper is to summarize state-of-the-art knowledge on health and environmental impacts of smoke from vegetation fires, to identify research gaps, and to provide needed information to researchers, land managers, policymakers, health care workers, and the general public. The main components of vegetation fire smoke and their characterizations are identified and evaluated. Concentrations, emission ratios, and emission factors of smoke components and the combined health and environmental effects of all hazardous smoke components from vegetation fire smoke exposure are summarized. Trends in risk assessment of vegetation fire smoke, limitations of current research, and future research needs are discussed.

Structural and chemical changes in pyrogenic organic matter aged in a boreal forest soil

Pyrogenic organic matter(PyOM)is formed during wildfires and prescribed burnings or produced intentionally in the form of biochar for soil amendment purposes.It is attracting a growing scientific and practical interest due to its important role in the global carbon cycle and agronomic applications as a soil enhancer.Most of the studies on the physicochemical properties of PyOM have been conducted using fresh biochars even though the characteristics of PyOM are expected to alter due to aging processes in soil environment.In this paper,we report the results of a study that utilized X-ray microtomography and elemental analysis to investigate the chemical and structural changes in the PyOM formed during prescribed burning events and aged thereafter for 1–71 years in a boreal forest soil.Our results indicate that changes in elemental composition occurred at decadal timescales,and an apparent steady state was reached ca.30 years after PyOM formation and exposure to the environment.At such timescales,PyOM was able to retain its porous structure originating from the cellular structure of the initial wood tissues.However,structural analysis revealed several effects of aging on the pore structure,such as the formation of surface coating layers,pore fillings,and fractures.These changes may alter pore size distribution and accessibility of the pores and further alter the influence of PyOM on soil functions,such as the transfer and retention of water and nutrients in PyOM pores.

Ecological perspectives on variable retention forestry

Forest management globally affects the ecosystem services,especially those related to ecosystem functioning and biodiversity conservation,by altering forest structure and composition.The degree of alteration was related to the intensity and type of harvesting;therefore,the major silvicultural challenge is to develop alternatives to mitigate climate change and maintain forest functions and biodiversity while also providing acceptable levels of timber production.Variable retention forestry(VRF)is a highly flexible concept,with continuity of forest cover,structure,function,and species composition,thereby supporting multiple economic,environmental,and cultural goals.This special issue provides an overview of the concepts and applications related to VRF implementation around the world.It shows that VRF has been applied globally for several decades,with varying levels and retention types,depending on local conditions and the economic importance of forestry.The challenges of VRF seem to differ to some extent on different continents,yet the general aims have been accepted in most of the continents.VRF has been successful in mitigating many effects of intensive harvesting,though in some forests of the world,the retention levels are too low to maintain acceptable levels of biodiversity and ecosystem functions.We conclude that an active collaboration between scientists and forest practitioners is needed to realize all of the opportunities provided by VRF in solving global forestry-related issues.