Controls on coarse wood decay in temperate tree species: birth of the LOGLIFE experiment

Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term 'common-garden' experiment to disentangle the effects of species' wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation.     

Measuring carbon in forests: current status and future challenges

To accurately and precisely measure the carbon in forests is gaining global attention as countries seek to comply with agreements under the UN Framework Convention on Climate Change. Established methods for measuring carbon in forests exist, and are best based on permanent sample plots laid out in a statistically sound design. Measurements on trees in these plots can be readily converted to aboveground biomass using either biomass expansion factors or allometric regression equations. A compilation of existing root biomass data for upland forests of the world generated a significant regression equation that can be used to predict root biomass based on aboveground biomass only. Methods for measuring coarse dead wood have been tested in many forest types, but the methods could be improved if a non-destructive tool for measuring the density of dead wood was developed. Future measurements of carbon storage in forests may rely more on remote sensing data, and new remote data collection technologies are in development.     

Carbon accounting model for forests in Australia

CAMFor (Carbon Accounting Model for Forests) is a sophisticated spreadsheet model developed to assist in carbon accounting and projection. This model can integrate information from a range of alternate sources including user input, default parameters and third party model outputs to calculate the carbon flows associated with a stand of trees and the wood products derived from harvests of that stand. Carbon is tracked in the following pools: * Biomass (stemwood, branches, bark, fine and coarse roots, leaves and twigs) * Soil (organic matter and inert charcoal) * Debris (coarse and fine litter, slash, below ground dead material) * Products (waste wood, sawn timber, paper, biofuel, reconstituted wood products). These pools can be tracked following thinning, fires and over multiple rotations. A sensitivity module has been developed to assist examination of the important assumptions and inputs. This paper reviews the functionality of CAMFor and reports on its use in a case study to explore the precision of estimates of carbon sequestration in a eucalypt plantation. Information on variability in unbiased models, measurement accuracy and other sources of error are combined in a sensitivity analysis to estimate the overall precision of sequestration estimates.     

Advanced research tools for fungal diversity and its impact on forest ecosystem

Fungi are dominant ecological participants in the forest ecosystems, which play a major role in recycling organic matter and channeling nutrients across trophic levels. Fungal populations are shaped by plant communities and environmental parameters, and in turn, fungal communities also impact the forest ecosystem through intrinsic participation of different fungal guilds. Mycorrhizal fungi result in conservation and stability of forest ecosystem, while pathogenic fungi can bring change in forest ecosystem, by replacing the dominant plant species with new or exotic plant species. Saprotrophic fungi, being ecological regulators in the forest ecosystem, convert dead tree logs into reusable constituents and complete the ecological cycles of nitrogen and carbon. However, fungal communities have not been studied in-depth with respect to functional, spatiotemporal, or environmental parameters. Previously, fungal diversity and its role in shaping the forest ecosystem were studied by traditional and laborious cultural methods, which were unable to achieve real-time results and draw a conclusive picture of fungal communities. This review highlights the latest advances in biological methods such as next-generation sequencing and meta’omics for observing fungal diversity in the forest ecosystem, the role of different fungal groups in shaping forest ecosystem, forest productivity, and nutrient cycling at global scales.

     

The carbon budget of Canadian forests: a sensitivity analysis of changes in disturbance regimes, growth rates, and decomposition rates

Ecosystem responses to climate changes will affect the exchange of carbon (C) with the atmosphere, thus providing feedback for future climate response. We have developed a C budget model of Canadian forests and forest sector activities and used sensitivity analysis runs with changes in productivity, decomposition, and disturbance regimes to assess the sensitivity of the Canadian forest sector C budget over the next century. The model operates on data derived from Canada's National Forest Biomass Inventory, from the Oak Ridge National Laboratory global soil C data base, and from Canadian data bases that document areas annually disturbed by fire, insects, and harvesting. It simulates the dynamics of biomass and soil C pools (including detritus and coarse woody debris) as they are affected by growth, decomposition, and disturbances. For the reference run of the model, we assumed unchanging climate and disturbance regimes. Under these conditions, total ecosystem C increased by 2 Gt C (2.3%) over the 100-year simulation period. In the sensitivity analysis, we explored the effects of changes in the area annually disturbed by fire and insect-induced stand mortality (-60 to +300%), growth rates (-10 to +20%), decomposition rates (-10 to +25%), and combined changes in growth and decomposition rates. In every model run, the change of total ecosystem C relative to the reference run was less than 10%. Combined changes to growth and decomposition rates yielded very small deviations from the results of the reference run (-0.8 to +1.2%). Because disturbance regime changes affect forest age-class structure as well as forest dynamics, they are expected to affect C budgets strongly. Total ecosystem C, however, is slightly more sensitive to changes in growth and decomposition parameters than to changes in disturbance regimes. Although the sensitivity analysis results suggest that C budgets are little affected by the range of parameter changes implemented here, we must emphasize that our sensitivity analyses do not account for potentially important processes, such as regeneration failure or the shifts in forest distribution.     

Metal/metalloid fixation by litter during decomposition affected by silicon availability during plant growth

Organic matter is known to accumulate high amounts of metals/metalloids, enhanced during the process of decomposition by heterotrophic biofilms (with high fixation capacity for metals/metalloids). The colonization by microbes and the decay rate of the organic matter depends on different litter properties. Main litter properties affecting the decomposition of organic matter such as the nutrient ratios and the content of cellulose, lignin and phenols are currently described to be changed by silicon availability. But less is known about the impact of silicon availability during plant growth on elemental fixation during decay. Hence, this research focuses on the impact of silicon availability during plant growth on fixation of 42 elements during litter decay, by controlling the litter properties. The results of this experiment are a significantly higher metal/metalloid accumulation during decomposition of plant litter grown under low silicon availability. This may be explained by the altered litter properties (mainly nutrient content) affecting the microbial decomposition of the litter, the microbial growth on the litter and possibly by the silicon double layer, which is evident in leaf litter with high silicon content and reduces the binding sites for metals/metalloids. Furthermore, this silicon double layer may also reduce the growing biofilm by reducing the availability of carbon compounds at the litter surface and has to be elucidated in further research. Hence, low silicon availability during plant growth enhances the metal/metalloid accumulation into plant litter during aquatic decomposition.     

A market modeling review study on predicting Malaysian consumer behavior towards widespread adoption of PHEV/EV

With the rising concern about climate change, there has been an increased public awareness that has resulted in new government policies to support scientific research for mitigating these problems. Malaysia is among the major energy-intense countries and is under an excessive burden to advance its energy efficiency and to also work towards the reduction of its carbon emission. Plug-in hybrid electric vehicles (PHEVs) have the potential to lessen the carbon emission and gasoline consumption in order to alleviate environmental problems. Most of the energy problems linked to the increasing transportation pollution are now being reduced with the solution of the adoption of PHEVs. PHEVs are seen as a solution to cut carbon emission, which prevents environmental damages. Furthermore, PHEVs’ driving range and performance can be comparable to the other hybrid vehicles as well as the conventional IC engines that have gasoline and diesel tanks. Thus, many efforts are being initiated to promote the use of PHEVs as an innovative and affordable transportation system. In order to achieve making the consumers aware of the adoption of PHEVs, we used a model which is based on the extended theory of planned behavior (TPB). This review is based on the factors affecting the adoption of PHEVs among Malaysian consumers. The model takes into account the ten key features that influence the adoption of PHEVs, such as environmental concern, personal norm, attitude, vehicle ownership costs, driving range, charging time, intention, subjective norm, perceived behavioral control, and personal norm. All these constructs are drivers towards the adoption of PHEVs. These factors affect the relationship between the adoption of PHEVs and how consumers intend to protect the environment. This review is based on improving how the “attitude-action” gap is understood as it is an important element for further studies on PHEVs. The aim of the research is to come up with a framework that examines how to modify the consumer’s environmental concerns in acquiring PHEVs. This will pave the way for more academic research and future works that can emphasize how to obtain empirical results. The authors’ recommendation is that, before a consumer’s behavior is assessed and considered, an observation of the current technology is needed with methods and knowledge of the existing technology adoption aspect.     

Effects on the function of Arctic ecosystems in the short- and long-term perspectives

Historically, the function of Arctic ecosystems in terms of cycles of nutrients and carbon has led to low levels of primary production and exchanges of energy, water and greenhouse gases have led to low local and regional cooling. Sequestration of carbon from atmospheric CO2, in extensive, cold organic soils and the high albedo from low, snow-covered vegetation have had impacts on regional climate. However, many aspects of the functioning of Arctic ecosystems are sensitive to changes in climate and its impacts on biodiversity. The current Arctic climate results in slow rates of organic matter decomposition. Arctic ecosystems therefore tend to accumulate organic matter and elements despite low inputs. As a result, soil-available elements like nitrogen and phosphorus are key limitations to increases in carbon fixation and further biomass and organic matter accumulation. Climate warming is expected to increase carbon and element turnover, particularly in soils, which may lead to initial losses of elements but eventual, slow recovery. Individual species and species diversity have clear impacts on element inputs and retention in Arctic ecosystems. Effects of increased CO2 and UV-B on whole ecosystems, on the other hand, are likely to be small although effects on plant tissue chemisty, decomposition and nitrogen fixation may become important in the long-term. Cycling of carbon in trace gas form is mainly as CO2 and CH4. Most carbon loss is in the form of CO2, produced by both plants and soil biota. Carbon emissions as methane from wet and moist tundra ecosystems are about 5% of emissions as CO2 and are responsive to warming in the absence of any other changes. Winter processes and vegetation type also affect CH4 emissions as well as exchanges of energy between biosphere and atmosphere. Arctic ecosystems exhibit the largest seasonal changes in energy exchange of any terrestrial ecosystem because of the large changes in albedo from late winter, when snow reflects most incoming radiation, to summer when the ecosystem absorbs most incoming radiation. Vegetation profoundly influences the water and energy exchange of Arctic ecosystems. Albedo during the period of snow cover declines from tundra to forest tundra to deciduous forest to evergreen forest. Shrubs and trees increase snow depth which in turn increases winter soil temperatures. Future changes in vegetation driven by climate change are therefore, very likely to profoundly alter regional climate.     

The likely impact of rising atmospheric CO2 on natural and managed Populus: a literature review.

Because of their prominent role in global biomass productivity, as well as their complex structure and function, forests and tree species deserve particular attention in studies on the likely impact of elevated atmospheric CO2 on terrestrial vegetation. Poplar (Populus) has proven to be an interesting study object due to its fast response to a changing environment, and the growing importance of managed forests in the carbon balance. Results of both chamber and field experiments with different poplar species and hybrids are reviewed in this contribution. Despite the variability between experiments and species, and the remaining uncertainty over the long term, poplar is likely to profit from a rising atmospheric CO2 concentration with a mean biomass stimulation of 33%. Environmental conditions and pollutants (e.g. O3) may counteract this stimulation but with managed plantations, environmental constraints might not occur. The predicted responses of poplar to rising atmospheric CO2 have implications for future forest management and the expected forest carbon sequestration.     

A carbon balance method for paper and wood products

The approach used to track the flow of carbon sequestered in the forest through harvest, processing into products, and final disposition of products is described. The methodology is broadly flexible and applicable to forest-based carbon balance assessments. A carbon balance is computed across all forestland ownerships for the production facility of interest. The balance considers forest uptake, harvest, combustion of fuels, emissions from process steps and losses from product use, disposition and recycling. The method also allows for sensitivity and marginal assessments of a variety of real and hypothetical situations using variable assumptions. Example results for a vertically integrated pulp and paper mill are presented. Results suggest that integrated forest products facilities drawing their raw material from sustainably managed forests can achieve a net positive carbon balance over the product cycle. The amount of net carbon sequestration attributable to such facilities depends upon a number of factors. The most critical of these include net forest growth, the method for allocating the growth in forest carbon among all of those harvesting from the drain area of a given facility, and the use and disposal patterns for the paper or wood products manufactured.     

Comparison of carbon balances between continuous-cover and clear-cut forestry in Sweden

Continuous-cover forestry (CCF) has been recognized for the production of multiple ecosystem services, and is seen as an alternative to clear-cut forestry (CF). Despite the increasing interest, it is still not well described how CCF would affect the carbon balance and the resulting climate benefit from the forest in relation to CF. This study compares carbon balances of CF and CCF, applied as two alternative land-use strategies for a heterogeneous Norway spruce (Picea abies) stand. We use a set of models to analyze the long-term effects of different forest management and wood use strategies in Sweden on carbon dioxide emissions and carbon stock changes. The results show that biomass growth and yield is more important than the choice of silvicultural system per se. When comparing CF and CCF assuming similar growth, extraction and product use, only minor differences in long-term climate benefit were found between the two principally different silvicultural systems.     

Degradation of organic pollutants in Mediterranean forest soils amended with sewage sludge

The degradation of two groups of organic pollutants in three different Mediterranean forest soils amended with sewage sludge was studied for nine months. The sewage sludge produced by a domestic water treatment plant was applied to soils developed from limestone, marl and sandstone, showing contrasting alkalinity and texture. The compounds analysed were: linear alkylbenzene sulphonates (LAS) with a 10–13 carbon alkylic chain, and nonylphenolic compounds, including nonylphenol (NP) and nonylphenol ethoxylates with one and two ethoxy groups (NP1EO + NP2EO). These compounds were studied because they frequently exceed the limits proposed for sludge application to land in Europe. After nine months, LAS decomposition was 86–96%, and NP + NP1EO + NP2EO decomposition was 61–84%, which can be considered high. Temporal trends in LAS and NP + NP1EO + NP2EO decomposition were similar, and the concentrations of both types of compounds were highly correlated. The decomposition rates were higher in the period of 6–9 months (summer period) than in the period 0–6 months (winter + spring period) for total LAS and NP + NP1EO + NP2EO. Differences in decay rates with regard to soil type were not significant. The average values of decay rates found are similar to those observed in agricultural soils.     

As(V) retention on soils and forest by-products and other waste materials

As(V) retention capacity is determined by means of adsorption/desorption trials performed for coarse and fine ground mussel shell, forest and vineyard soils with or without fine shell, pine wood ash, oak wood ash, pine sawdust and slate-processing fines. Pine ash shows the highest arsenic retention potential (with >97 % adsorption and ≤1 % desorption), followed by shell-amended forest soil (adsorption between 96 and 92 %), by un-amended forest soil (adsorption between 98 and 86 %) and by the amended vineyard soil (adsorption between 92 and 75 %). Sawdust is the material with the lowest arsenic retention capacity in most cases, with un-amended vineyard soil also showing poor results. In the case of oak ash, As(V) percentage adsorption becomes higher with increasing added arsenic concentrations, while this increase in added arsenic causes lower percentage adsorption in the case of slate fines. Regarding adsorption ability, As(V) adsorption data were fitted to Freundlich and Langmuir models, showing good fitting, with pine ash and shell-amended forest soil having the highest K _F values. In view of that, mussel shell amendment would be useful to increase arsenic retention on forest and vineyard soils, while pine ash could be used to retain arsenic even from wastewaters.     

Does tradeoff between financial and social indicators matters in environmental consideration: evidence from G7 region

The study tries to discover the impact of financial and social indicators’ growth towards environmental considerations to understand the drivers of economic growth and carbon dioxide emissions change in G7 countries. The DEA-like composite index has been used to examine the tradeoff between financial and social indicator matters in environmental consideration by using a multi-objective goal programming approach. The data from 2008 to 2018 is collected from G-7 countries. The results from the DEA-like composite index reveals that there is a mixed condition of environmental sustainability in G-7 countries where the USA is performing better and Japan is performing worse among the set of other countries. The further result shows that the energy and fiscal indicators help to decrease the dangerous gas emissions. Divergent to that, the human and financial index positively contributes to greenhouse gas emissions. Fostering sustainable development is essential to successfully reduce emissions, meet established objectives, and ensure steady development. The study provides valuable information for policymakers.

     

Characterization and reactivity assessment of organic substrates for sulphate-reducing bacteria in acid mine drainage treatment

Acid mine drainage (AMD), which contains high concentrations of sulphate and dissolved metals, is a serious environmental problem. It can be treated in situ by sulphate reducing bacteria (SRB), but effectiveness of the treatment process depends on the organic substrate chosen to supply the bacteria's carbon source. Six natural organic materials were characterized in order to investigate how well these promote sulphate reduction and metal precipitation by SRB. Maple wood chips, sphagnum peat moss, leaf compost, conifer compost, poultry manure and conifer sawdust were investigated in terms of their carbon (TOC, TIC, DOC) and nitrogen (TKN) content, as well as their easily available substances content (EAS). Single substrates, ethanol, a mixture of leaf compost (30% w/w), poultry manure (18% w/w), and maple wood chips (2% w/w), and the same mixture spiked with formaldehyde were then tested in a 70-day batch experiment to evaluate their performance in sulphate reduction and metal removal from synthetic AMD. Metal removal efficiency in batch reactors was as high as 100% for Fe, 99% for Mn, 99% for Cd, 99% for Ni, and 94% for Zn depending on reactive mixtures. Early metal removal (0-12d) was attributed to the precipitation of (oxy)hydroxides and carbonate minerals. The lowest metal and sulphate removal efficiency was found in the reactor containing poultry manure as the single carbon source despite its high DOC and EAS content. The mixture of organic materials was most effective in promoting sulphate reduction, followed by ethanol and maple wood chips, and single natural organic substrates generally showed low reactivity. Formaldehyde (0.015% (w/v)) provided only temporary bacterial inhibition. Although characterization of substrates on an individual basis provided insight on their chemical make-up, it did not give a clear indication of their ability to promote sulphate reduction and metal removal.     

Arsenic contamination in wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) on abandoned mine sites in southwest Britain

Arsenic can be highly toxic to mammals but there is relatively little information on its transfer to and uptake by free-living small mammals. The aim of this study was to determine whether intake and accumulation of arsenic by wild rodents living in arsenic-contaminated habitats reflected environmental levels of contamination and varied between species, sexes and age classes. Arsenic concentrations were measured in soil, litter, wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) from six sites which varied in the extent to which they were contaminated. Arsenic residues on the most contaminated sites were three and two orders of magnitude above background in soil and litter, respectively. Arsenic concentrations in the stomach contents, liver, kidney and whole body of small mammals reflected inter-site differences in environmental contamination. Wood mice and bank voles on the same sites had similar concentrations of arsenic in their stomach contents and accumulated comparable residues in the liver, kidney and whole body. Female bank voles, but not wood mice, had significantly higher stomach content and liver arsenic concentrations than males. Arsenic concentration in the stomach contents and body tissues did not vary with age class. The bioaccumulation factor (ratio of arsenic concentration in whole body to that in the diet) in wood mice was not significantly different to that in bank voles and was 0.69 for the two species combined, indicating that arsenic was not bioconcentrated in these rodents. Overall, this study has demonstrated that adult and juvenile wood mice and bank voles are exposed to and accumulate similar amounts of arsenic on arsenic-contaminated mine sites and that the extent of accumulation depends upon the level of habitat contamination.     

A classification and regression tree model of controls on dissolved inorganic nitrogen leaching from European forests

Often, there is a non-linear relationship between atmospheric dissolved inorganic nitrogen (DIN) input and DIN leaching that is poorly captured by existing models. We present the first application of the non-parametric classification and regression tree approach to evaluate the key environmental drivers controlling DIN leaching from European forests. DIN leaching was classified as low (<3), medium (3-15) or high (>15 kg N ha⁻¹ year⁻¹) at 215 sites across Europe. The analysis identified throughfall NO₃⁻ deposition, acid deposition, hydrology, soil type, the carbon content of the soil, and the legacy of historic N deposition as the dominant drivers of DIN leaching for these forests. Ninety four percent of sites were successfully classified into the appropriate leaching category. This approach shows promise for understanding complex ecosystem responses to a wide range of anthropogenic stressors as well as an improved method for identifying risk and targeting pollution mitigation strategies in forest ecosystems.     

Heterogeneous and homogeneous catalytic ozonation of benzothiazole promoted by activated carbon: kinetic approach

Ozone oxidation combined with activated carbon adsorption (O(3)/AC) has recently started to be developed as a single process for water and wastewater treatment. While a number of aspects of aqueous ozone decomposition are well understood, the importance and relationship between aqueous ozone decomposition and organic contaminant degradation in the presence of activated carbon is still not clear. This study focuses on determining the contribution of homogeneous and heterogeneous reactions to organic contaminants removal in O(3)/AC system. Benzothiazole (BT) was selected as a target organic pollutant due to its environmental concern. A reactor system based on a differential circular flow reactor composed by a 19 cm(3) activated carbon fixed bed column and 1 dm(3) storage tank was used. Ozone was produced from pure and dry oxygen using an Ozocav ozone generator rated at 5 g O(3)h(-1). Experimental results show that BT removal rate was proportional to activated carbon dosage. Activated carbon surface contribution to BT oxidation reactions with ozone, increased with pH in absence of radical scavengers. The radical reaction contribution within the pH range 2-11 accounted for 67-83% for BT removal in O(3)/AC simultaneous treatment. Results suggest that at pH higher than the pH of the point of zero charge of the activated carbon dissociated acid groups such as carboxylic acid anhydrides and carboxylic acids present on activated carbon surface could be responsible for the observed increase in the ozone decomposition reaction rate. A simplified mechanism and a kinetic scheme representing the contribution of homogeneous and heterogeneous reactions on BT ozonation in the presence of activated carbon is proposed.     

The sustainable management and protection of forests: analysis of the current position globally

The loss of forest area globally due to change of land use, the importance of forests in the conservation of biodiversity and in carbon and other biogeochemical cycles, together with the threat to forests from pollution and from the impacts of climate change, place forestry policy and practice at the center of global environmental and sustainability strategy. Forests provide important economic, environmental, social, and cultural benefits, so that in forestry, as in other areas of environmental policy and management, there are tensions between economic development and environmental protection. In this article we review the current information on global forest cover and condition, examine the international processes that relate to forest protection and to sustainable forest management, and look at the main forest certification schemes. We consider the link between the international processes and certification schemes and also their combined effectiveness. We conclude that in some regions of the world neither mechanism is achieving forest protection, while in others local or regional implementation is occurring and is having a significant impact. Choice of certification scheme and implementation of management standards are often influenced by a consideration of the associated costs, and there are some major issues over the monitoring of agreed actions and of the criteria and indicators of sustainability. There are currently a number of initiatives seeking to improve the operation of the international forestry framework (e.g., The Montreal Process, the Ministerial Convention of the Protection of Forests in Europe and European Union actions in Europe, the African Timber Organisation and International Tropical Timber Organisation initiative for African tropical forest, and the development of a worldwide voluntary agreement on forestry in the United Nations Forum on Forests). We suggest that there is a need to improve the connections between scientific understanding, policy development, and forestry practice, and also the cooperation between the various international initiatives and processes, so that the international framework is more effective and its influence is extended geographically.     

石油类污染物自然衰减能力现场试验验证研究

在北京地区某加油站开展的前期石油类污染物自然衰减现场试验的基础上,进一步开展了验证试验,结果表明本次试验得到的挥发性有机物(VOCs)变化趋势及O2、CO2含量沿土壤深度分布和前期试验结果呈现相同的规律,说明基于自然衰减法设计实施的加油站现场试验检测分析结果可靠,试验方法具有合理性、可操作性及可重复性.进一步的理论分析对前期试验结果进行了验证,得出以下结论:(1)通过氧平衡和碳平衡计算对加油站土壤内的自然衰减方式进行评价,验证了该加油站地下土壤中实际发生的微生物降解既有需氧降解也有厌氧降解；(2)利用有机物的一级衰减模型对该污染现场土壤中石油类污染物的降解速率和半衰期进行计算表明,2次试验计算得到的石油类污染物的半衰期基本一致,该污染现场石油类污染物的半衰期为50 d左右；(3)在此基础上,对该加油站包气带土壤的自然衰减能力和环境质量进行评价,2次试验结果均表明该污染现场在自然衰减的作用下已经不存在环境风险.