Removal Of Forest Residues Research Articles

An integrated PROMETHEE II-Roadmap model: Application to the recovery of residual agroforestry biomass in Portugal

Rural fires are currently one of the main global disasters, and Portugal is among the countries that have suffered from them for decades. These fires pose economic, environmental, and social threats to the country. A primary cause of rural fires is the burning of biomass to clear agroforestry residues. Thus, combating rural fires requires more effective forest management, particularly the removal of forest residues that serve as fuel. These residues, also known as biomass, have significant potential for energy production and biofuel use. This paper proposes a model that integrates the PROMETHEE decision-making method with the roadmapping. This proposed model includes 7 steps, including the planning of the roadmap, the definition of the decision problem, gathering information and building the roadmap. The proposed model was applied to develop a roadmap proposal for the recovery of surplus agroforestry biomass in Portugal, identifying the most emerging conversion technologies in the national context. With the roadmap developed, it was possible to understand that the recovery of surplus agroforestry biomass in Portugal involves several sectors. The energy sector is one of those that can benefit from the recovery of leftover agroforestry biomass, both from the point of view of carbon neutrality and energy independence. Forestry management is another of the great advantages of recovering leftover forestry biomass and, consequently, reducing the number of fires. In the context of recovery, combustion is the most widely used technology for producing energy or heat. The technology identified as most emerging in the upcoming years is gasification. Investment in scientific research is essential for the success of this sector, as is the development of public incentive policies and more engagement from all stakeholders. This paper conclude that valorizing agroforestry residues can reduce rural fire risks while promoting energy independence, sustainable regional development, and innovation in Portugal.

Soil Cu and Zn pools and their availability in response to forest residue management and micronutrient fertilization in a Eucalyptus grandis plantation

Eucalyptus is one of the most commonly planted genera worldwide for commercial timber purposes. Brazil has approximately 25% of the total Eucalyptus spp. planted worldwide. However, nutritional disorders caused by copper (Cu) and zinc (Zn) deficiencies have been more frequent in Eucalyptus plantations. Furthermore, the scientific knowledge regarding micronutrient fertilization is scarce. Sequential extraction can determine the distribution of metals in the soil, giving an order of magnitude to its bioavailability. The present study aimed to assess the soil Cu and Zn pools and evaluate the effects of mineral Cu and Zn fertilization on the nutritional status and nutrient fractionation in a Ferralsol in a cultivated Eucalyptus grandis plantation. The study considered two conditions—namely, forest residue management or removal of forest residues. The treatments included complete fertilization, no application of Cu, no application of Zn, maintenance of forest residues, and total removal of forest residues. High quantities of Cu and Zn were found in the soil, mainly in the low plant-available forms (>60%). There were no differences in the nutritional status of the trees, despite the absence of Cu and Zn via fertilizers and the removal of harvest residues. Foliar Cu concentration was positively correlated with soil exchangeable and oxide-bound Cu content, whereas foliar Zn concentration was positively correlated with soil exchangeable and organic matter-bound Zn content. The access to moderately labile forms of Cu and Zn by eucalypts may justify the absence of response to mineral fertilization, especially in areas where forest residues remain on the soil, and consequently, work as a source of Cu and Zn.

The effects of forest clearance for peatland restoration on water quality

Recognition of the importance of peatlands has led to increased efforts to protect and restore these environments but there are concerns about the impact of restoration on water quality, particularly in terms of sediment delivery, nutrient transport and carbon losses. In this study we present the results of almost 10 years of water quality monitoring in 3 catchments at a lowland raised bog that was afforested with conifers in the 1960s and 1970s and cleared over the 2010s.Phosphate concentrations increased after clearfelling with the main peaks seen in the summer after forest clearance; the use of low ground impact harvesting methods, removal of forest residues and especially phased felling tempered phosphate losses. Annual mean phosphate concentrations returned to pre-felling levels 3–5 years after felling finished. Nitrate concentrations increased slightly from baseline levels during and after felling. DOC concentrations increased at two sites with mean annual concentrations still elevated at one site after 4 years; little increase in DOC was recorded with phased felling. Colour levels increased and remain elevated at all sites relative to pre-felling. In only one stream, pH increased improving the WFD water body status from ‘poor’ to ‘high’ in the space of 3 years.Our results show that forest clearance for peatland restoration can impact negatively upon water quality due to phosphate, DOC, colour and suspended sediment releases. The mechanisms by which the releases occur require further investigation but are thought to be driven by nutrient leaching from forest residues, soil disturbance by machine trafficking and indirect effects of forest clearance, such as water table rise following cessation of forest water use. Climatic effects also play a significant role, particularly drying-rewetting cycles and periods of extended drought. To prevent negative impacts, phased felling and less intensive forest harvesting techniques should be employed.

Soil microbial functions are affected by organic matter removal in temperate deciduous forest

A growing demand for renewable carbon (C) has led to intensified forest management resulting in the use of forest residues (e.g. canopy, bark or litter layer) as energy sources with potential modifications of soil properties and tree productivity. Because microbes mediate the recycling of C and nutrients sequestered in organic matter, we investigated the effects of organic matter (OM) removal on soil properties, root surfaces, microbial functions and abundance using a new observational forest network. We compared leaf litter and logging residue removal plots to reference plots in six beech forests located in the northern half of France. After three consecutive years of OM removal, C and nitrogen (N) pools were not affected, but OM exportation decreased the cation exchange capacity and available phosphorus (P) pool by respectively 12% and 30% in the topsoil (0–5 cm depth). Fine root surface area significantly increased by 21% in the subsoil (5–10 cm depth) in response to OM removal. Enzymatic activities involved in N and P mobilisation decreased from 12 to 38% with the manipulation of OM. Community-level profiling (CLPP) based on BIOLOG approach revealed that the metabolic potential of the microbial community strongly decreased in response to OM removal. Our results indicated that intensive forestry could affect microbial functions implicated in nutrients mobilisation. We demonstrated that soil organic matter (SOM) content is a predictor of microbial functions resistance to forest residue removal. We recommend that intensive forestry should be reduced or limited in beech forests characterised by low soil OM contents.

Forest residue removal decreases soil quality and affects wood productivity even with high rates of fertilizer application

Forest residues are frequently used as energy sources by Brazilian forest companies. The removal of such residues is known to reduce wood productivity, especially when fertilizer application rate is low. This study aimed to evaluate after two forest rotations the effects of forest residue management on wood productivity when fertilizer is applied at a high rate; and the effect of timber harvest intensity on soil organic matter and microbial activity. We assessed tree growth, soil microbial biomass and activity, and we fractionated soil organic matter (SOM) via its oxidation resistance. These assessments were performed after conducting a field trial comparing harvest residue management over two successive rotations in the same plots. We found no significant effect of treatments on wood productivity when the residues were removed for the first time; however, wood productivity reduced by 15% during the second rotation with residue removal even with high rates of fertilizer application. Further, 40% reduction in microbial biomass and soil respiration was noted with forest residue removal. At the reestablishment time, the SOM in the top soil (0–0.05 m layer) was 25% lower at the site where the forest residues were removed, and this difference increased to 50% at 300 days after the reestablishment. This reduction was found mainly in the SOM labile fraction.

Forest residue maintenance increased the wood productivity of a Eucalyptus plantation over two short rotations

Forest residue (i.e., litter layer, slash and bark), when used as biomass for energy production, represents an important strategy for use as a renewable energy source in many countries. However, these residues can also have importance as sources of nutrients for trees and soil conservation. The objectives of the present study were to assess the effects of forest residue management on soil, wood production and nutrient accumulation dynamics during two crop rotations in a Eucalyptus grandis plantation. Thus, we set up an experimental site with different intensities of removal, burning and incorporation of forest residues (first crop rotation of study – R1). The stands of all treatments were harvested after eight years, and the trial was re-established with all forest residues maintained on the soil across all treatments (second crop rotation of study – R2). R2 was conducted for eight more years. The growth and nutritional status, biomass and nutrient accumulation of the trees were assessed. The forest residue burn increased the initial nutrient availability in the soil; however, this availability returned to initial levels in a short period of time. Wood productivity decreased by approximately 40% with the removal of all forest residues in R1. In R2, wood productivity after the removal or burning of forest residues was 6% lower than when all forest residues were maintained on the soil.

Механизация удаления порубочных остатков и отдельных деревьев из защитных лесных насаждений

Механизация удаления порубочных остатков и отдельных деревьев из защитных лесных насаждений

Harvesting Carbon from Eastern US Forests: Opportunities and Impacts of an Expanding Bioenergy Industry

Eastern forests of the US are valued both as a carbon sink and a wood resource. The amount of biomass that can be harvested sustainably from this biome for bioenergy without compromising the carbon sink is uncertain. Using past literature and previously validated models, we assessed four scenarios of biomass harvest in the eastern US: partial harvests of mixed hardwood forests, pine plantation management, short-rotation woody cropping systems, and forest residue removal. We also estimated the amount and location of abandoned agricultural lands in the eastern US that could be used for biomass production. Greater carbon storage was estimated to result from partial harvests and residue removals than from plantation management and short-rotation cropping. If woody feedstocks were cultivated with a combination of intensive management on abandoned lands and partial harvests of standing forest, we estimate that roughly 176 Tg biomass y−1 (~330,000 GWh or ~16 billion gallons of ethanol) could be produced sustainably from the temperate forest biome of the eastern US. This biomass could offset up to ~63 Tg C y−1 that are emitted from fossil fuels used for heat and power generation while maintaining a terrestrial C sink of ~8 Tg C y−1.

Forest bioenergy climate impact can be improved by allocating forest residue removal

AbstractBioenergy from forest residues can be used to avoid fossil carbon emissions, but removing biomass from forests reduces carbon stock sizes and carbon input to litter and soil. The magnitude and longevity of these carbon stock changes determine how effective measures to utilize bioenergy from forest residues are to reduce greenhouse gas (GHG) emissions from the energy sector and to mitigate climate change. In this study, we estimate the variability of GHG emissions and consequent climate impacts resulting from producing bioenergy from stumps, branches and residual biomass of forest thinning operations in Finland, and the contribution of the variability in key factors, i.e. forest residue diameter, tree species, geographical location of the forest biomass removal site and harvesting method, to the emissions and their climate impact. The GHG emissions and the consequent climate impacts estimated as changes in radiative forcing were comparable to fossil fuels when bioenergy production from forest residues was initiated. The emissions and climate impacts decreased over time because forest residues were predicted to decompose releasing CO2 even if left in the forest. Both were mainly affected by forest residue diameter and climatic conditions of the forest residue collection site. Tree species and the harvest method of thinning wood (whole tree or stem‐only) had a smaller effect on the magnitude of emissions. The largest reduction in the energy production climate impacts after 20 years, up to 62%, was achieved when coal was replaced by the branches collected from Southern Finland, whereas the smallest reduction 7% was gained by using stumps from Northern Finland instead of natural gas. After 100 years the corresponding values were 77% and 21%. The choice of forest residue biomass collected affects significantly the emissions and climate impacts of forest bioenergy.

The impact of forest residue removal and wood ash amendment on the growth of the ectomycorrhizal external mycelium

Intensive harvesting of forest residues for energy production may lead to the depletion of organic matter and mineral nutrients in the forest floor. In order to restore nutrient content wood ash has been suggested as a fertiliser. Ectomycorrhizal (EM) fungi are involved in the nutrient uptake of forest trees and this study investigates the influence of intensive harvesting and wood ash fertilisation on the external EM mycelium in forest soil. Nylon mesh bags filled with sand were buried in September 1997 in field plots which had or had not been intensively harvested. The effect of wood ash on the production of external EM mycelium was studied in mesh bags amended with wood ash. Mesh bags were retrieved in May and October 1998. The relative amount of fungal mycelia in the mesh bags was estimated with phospholipid fatty acid analysis. The fungi colonising the mesh bags were mainly (>90%) ectomycorrhizal. Fungal biomass in the mesh bags was low in the spring but high in the autumn. No significant effect on EM fungal biomass was observed in the mesh bags collected from intensively harvested plots compared with those from control plots, but wood ash amendment resulted in 2.4 times more EM fungal biomass (P<0.05). The effect of external EM mycelium on the dissolution of wood ash was studied in mesh bags filled with wood ash, using mesh bags buried in soil isolated from roots as EM-free controls. The external EM mycelium had no effect on the dissolution rate of the wood ash. 80% of the potassium was lost from the wood ash within a month, whereas no phosphorus was lost during the experimental period (up to 13 months).

The impact of forest residue removal and wood ash amendment on the growth of the ectomycorrhizal external mycelium

Intensive harvesting of forest residues for energy production may lead to the depletion of organic matter and mineral nutrients in the forest floor. In order to restore nutrient content wood ash has been suggested as a fertiliser. Ectomycorrhizal (EM) fungi are involved in the nutrient uptake of forest trees and this study investigates the influence of intensive harvesting and wood ash fertilisation on the external EM mycelium in forest soil. Nylon mesh bags filled with sand were buried in September 1997 in field plots which had or had not been intensively harvested. The effect of wood ash on the production of external EM mycelium was studied in mesh bags amended with wood ash. Mesh bags were retrieved in May and October 1998. The relative amount of fungal mycelia in the mesh bags was estimated with phospholipid fatty acid analysis. The fungi colonising the mesh bags were mainly (>90%) ectomycorrhizal. Fungal biomass in the mesh bags was low in the spring but high in the autumn. No significant effect on EM fungal biomass was observed in the mesh bags collected from intensively harvested plots compared with those from control plots, but wood ash amendment resulted in 2.4 times more EM fungal biomass ( P<0.05). The effect of external EM mycelium on the dissolution of wood ash was studied in mesh bags filled with wood ash, using mesh bags buried in soil isolated from roots as EM-free controls. The external EM mycelium had no effect on the dissolution rate of the wood ash. 80% of the potassium was lost from the wood ash within a month, whereas no phosphorus was lost during the experimental period (up to 13 months).

Effects of repeated harvesting of forest residues on the ectomycorrhizal community in a Swedish spruce forest

The use of biofuels has been proposed as one possible substitute for fossil fuels, which contribute substantially to the increase in [CO2] in the atmosphere. However, increased harvesting of forest residues for biofuel might affect the availability of base cations, P and N, as well as the development, community dynamics and function of ectomycorrhizas. This in turn might influence nutrient uptake and tree growth. In this study we investigated the effects of repeated forest residue harvesting on ectomycorrhizal species colonizing spruce roots in the humus layer of a 35‐yr‐old forest. Harvesting significantly decreased the thickness of the humus layer as well as decreasing the numbers of ectomycorrhizal root tips both per metre root length and per unit humus volume. Changes in mycorrhizal community structure were studied by ITS typing with the use of PCR–RFLP analysis. In total, 19 different ITS types were found on two different sampling occasions (autumn and spring); 11 of these were common to both samplings. Nine of the ITS types were identified to at least the genus level by comparison with RFLP patterns of identified fruiting bodies or axenic cultures. Five species, Cortinarius sp. 2, Thelephora terrestris (Ehrenb.) Fr., Lactarius theiogalus (Bull.∶Fr.) S. F. Gray s.st. Neuhoff, Tylospora fibrillosa Donk and Tö‐96‐12, occurred on over 5% of the total sampled root tips. Together these five types colonized 63% of the mycorrhizas screened. A similarity index assessment showed no shift in mycorrhizal community structure as a result of harvesting. Our findings suggest that the repeated removal of forest residues might have a strong effect on the quantity and development of ectomycorrhizal roots in the organic horizon, but little effect on the species composition of the community.