Wood Removal Research Articles

Downed wood removal effects on survival and site fidelity of woodrats in a California oak woodland

AbstractOwing to the increasing intensity and frequency of wildfires in the western United States, the removal of woody debris (downed dead wood and snags) from fire‐prone landscapes is being evaluated for wildfire mitigation. Consequently, the study of the ecological value of coarse woody debris to sustain dependent species has become of foremost importance. From 2004–2009, we used a before‐after control‐impact (BACI) study design to assess the effects of downed wood removal on a population of big‐eared woodrats (Neotoma macrotis) in an oak woodland (Quercus spp.) in coastal‐central California, USA. Using Pollock's robust design mark‐recapture analyses (with 12 primary capture occasions represented by trapping each spring and fall, and secondary occasions composed of 3 trap nights), we estimated survival and emigration rates. Further, applying mixed‐effects models, we evaluated the effects of 7 habitat attributes on woodrat abundance and reproduction. Following the experimental removal of downed wood from the 11 randomly selected treatment plots, woodrat survival was higher (P = 0.013), and emigration was lower (P = 0.007) among 11 control plots on which downed wood was retained. Woodrat abundance within plots was best predicted by stem density, demonstrating positive demographic associations with habitat complexity. Plot‐level reproductive success (i.e., the presence of juveniles within a plot during spring) was more likely with increasing snag density. These findings indicate that snags and downed dead wood are key components of high‐quality habitat for big‐eared woodrats. Management of woody debris to mitigate wildfire risk should consider the ecological value of this habitat attribute for big‐eared woodrats and other dependent species.

Environmental performance evaluation in the forest sector: An extended stochastic data envelopment analysis approach

This study addresses the global concern about undesirable outputs in the Forest Sector. We propose two innovative models, namely a directional weak disposable DEA model and an extended stochastic DEA model, to measure environmental efficiency. These models make a significant contribution to the field by specifically assessing the uncertain environmental efficiency of the forest sector. We validated our proposed models by conducting an empirical application using the United Nations Economic Commission for Europe (UNECE) forest sector dataset. The study examines important outputs such as above ground biomass stock, export unit prices of industrial roundwood, wood removals (desirable outputs), and CO2 emissions from wildfires (undesirable output). The results demonstrate that our novel stochastic weak disposability DEA model outperforms traditional approaches when the second scenario is applied. Specifically, the average technical efficiency (TE) score decreases to 0.92, and the number of efficient units reduces to 27, representing an approximate improvement of 55 %. Furthermore, the reduction rate of CO2 emissions is 4.09 % lower than the benchmark. Hence, our extended novel stochastic weak disposability DEA approach enhances the assessment of efficiency and inefficiency in decision-making units, contributing to the mitigation of risk and uncertainty. It also improves overall environmental performance in forest management.

A study of resin removal and fixation of radiata pine wood by microwave-superheated steam treatment

A study of resin removal and fixation of radiata pine wood by microwave-superheated steam treatment

Modernization of skidding and primary removal of wood in the Vologda Region through the use of relevant domestic solutions

In the paper on the basis of the analysis of technical indicators and the aggregates used of the applied and introduced forest machinery (multi-operational forest machines) a study was carried out on the efficiency of variants in the sorting of logs during the implementation of technological operations in skidding and primary timber transportation under typical natural and production conditions Totemsky Forestry - a branch of the company SAU Forestry of the Vologda region “Vologda Forestry Association” (Vologda region, Russian Federation). As a result of analyzing the ratio of torque and other given dimensional and qualitative indicators, recommendations are given on the use of wheeled picker “Trom 20” for more efficient work in conditions of insufficient bearing capacity of the forest harvesting area soil.

The Growth Activity and Productivity of Apple Trees Depending on the Form of the Crown and the Time of Pruning

Abstract The apple tree is the most common fruit crop in the temperate climate zone. Modern intensive fruit cultivation involves the use of new, highly productive cultivars and cultivation technologies, thanks to the creation of small crown shapes with an increased number of trees per hectare. Reducing planting patterns and creating more dense plantation systems can significantly improve their yields. However, the limiting factor that can reduce tree productivity and deteriorate fruit quality is the degree of crown illumination. Ensuring even access of sunlight to all parts of the crown is the main task in the formation and pruning trees. The study aimed to determine the effect of crown pruning at BBCH 0 (winter) and BBCH 74 (early summer) and various types of crown formation on the growth activity and productivity of ‘Fuji’ and ‘Honeycrisp’ apple trees. A significant decrease (20%) in the number of newly formed shoots in the form of the French axis crown compared to the ballerina and slender spindle crowns was found. However, their length and total growth were significantly higher. The formation of the ballerina crown (with the removal of overgrown wood in the 25 cm zone on the central conductor above the lower tier of semi-cross-branched branches) contributed to a decrease in shoot length and total growth. The introduction of crown pruning in the summer also improved crown illumination – shoot length decreased by 17% and total growth by 12%. Specific productivity per bole cross-section and total shoot length was the highest in ballerina crown trees, followed by trees with a slender spindle crown, and trees pruned in winter and summer.

Greece’s Forest Sector from the Perspective of Timber Production: Evolution or Decline?

Greece’s trade patterns in wood and wood products align with the broader trade dynamics in the Mediterranean region, where wood and wood products are primarily imported. Using Pettitt’s test, this study revealed a consistent decline in the production of selected wood and wood product categories in Greece, coupled with a noteworthy increase in imports. Following the economic crisis of 2008, a temporary dip in import trends in some categories was observed. Furthermore, Pettitt’s test helped identify the specific years when significant shifts occurred in the time series data. In the latter part of the analysis, the study underscored the significance of various factors within the wood removal production sector, including urbanization, economic growth, personal income, and the labor force. National imports of goods and wood fuel were also identified as playing pivotal roles at the national level. Recognizing the link between economic indicators and wood removals has the potential to inform decisions related to sustainable resource management, conservation initiatives, and strategies for economic development.

Анализ факторов негативного воздействия лесозаготовительного производства на природную среду Северо-Западного региона РФ

Logging operations and timber transportation have a negative impact to natural and natural-anthropogenic
 environmental objects. Accounting, evaluation and forecasting of negative impact types will allow rational planning of
 technological logging operations. The negative impact degree data will allow assessing the total damage to
 environmental objects and, taking into account the loads of a particular work types provide for a set of protective
 measures adequate to the corresponding impact degree. The impact degree of types of logging activities to the
 environment was determined using the method of expert assessments. The variability of the nature and significance of
 the technogenic impact from logging and removal of wood was studied by the method of principal components. The
 generalized list of types of negative impact is ranked in the direction of decreasing degree as follows: pollution of water
 runoff and soils by leaks of fuels and lubricants, changes in biodiversity, damage to forest stands, destruction and
 pollution of soils, air pollution with chemical impurities, wastewater discharges into water bodies, landfill of domestic
 waste and discharge of effluents into the soil. When assessing biodiversity, increased attention should be paid to the
 organization of household and auxiliary technological processes. They are characterized by medium loads, causing
 pollution of water and soil by domestic and industrial effluents, and the formation of landfills for domestic and
 industrial waste. The construction of forest roads and work on refueling, repair and maintenance of logging equipment
 in workshops and fuel filling stations contribute to the manifestation of atypical impacts in the form of water and soil
 pollution with oil products. The obtained theoretical substantiation must be supplemented with relevant data from field
 studies on the identified types of negative impacts. Based on the predicted values of the degree of negative impact on
 the environment, the authors develop a set of scientifically substantiated technical and technological solutions that
 increase environmental safety during logging operations

Identifying bridges prone to instream wood accumulation: insights from bridges across the UK

Accumulation of instream large wood (i.e., fallen trees, trunks, branches, and roots) at bridges during floods may exacerbate flooding, scour and cause structural failure. Yet, explaining and predicting the likelihood of a bridge trapping wood remains challenging. Quantitative data regarding wood accumulation at bridges are scarce, and most equations proposed to estimate the accumulation probability were derived from laboratory experiments, and include variables such as flow velocity, Froude number, and approaching wood volume or size which are difficult to obtain. Other evaluations based on technical reports and information regarding wood removal have been proposed but are mostly qualitative. Until now, a data-driven approach combining multiple quantitative accessible variables at the river reach and catchment scales remains lacking. As a result, the controlling parameters explaining whether a bridge is prone to trap wood are still unclear. This work aims to fill this gap by analysing a database of 49 bridges across the United Kingdom (UK) classified as prone and not prone to wood accumulation. The database contained information regarding the geometry of the bridge (i.e., number of piers and pier shape) and we added parameters describing the upstream river channel morphology, the riparian landcover, and high-flow characteristics. We applied multivariate statistics and a machine learning approach to identify the variables that explained and predicted the predisposition of bridges to wood accumulation. Results showed that the number of bridge piers, the unit stream power, the pier shape, and the riparian forested area explained 87% of the total variability for the training dataset (0.87 training accuracy), and the selected model had a testing accuracy of 0.60 (60%). Although limited by the sample size, this study sheds light on the identification of bridges prone to wood accumulation and can inform bridge design and management to mitigate wood-related hazards.

Detection of decadal time‐series changes in flow hydrology in eastern Australia: Considerations for river recovery and flood management

AbstractSince European colonisation, many coastal rivers of New South Wales (NSW) have been highly modified by channelisation, flow regulation, sediment mining, intensive grazing and agriculture, deforestation, and riparian vegetation and wood removal. Since the late 1980s, nearly 55% of these rivers have undergone a significant ‘re‐greening’ and geomorphic recovery with changes to instream and riparian roughness. However, little research has been undertaken to quantify if there have been any coeval changes in flow hydrology. Approximately 7000 flow hydrographs with one‐hour time‐steps from 117 gauges on 45 study rivers (17 of 20 coastal catchments of NSW) were used to assess changes to in‐channel and overbank hydrology over decadal timeframes. Hydrograph shape and attenuation characteristics for three morphologically defined flow stages were analysed: in‐channel fresh, high flow and overbank flood. Time‐series analysis was used to quantify changes in flow hydrology from the early‐20th century to present and identify trends occurring between known degradation phases (1910s–1940s and 1940s–1980s) and a recovery phase (1990s to present) for these rivers. Our findings indicate that, on average, and for some key examples, changes in flow hydrology are occurring. Flows are slowing and attenuating as indicated by decreases in flood wave celerity and hydrograph kurtosis, skewness and rate of rise and increases in peak‐to‐peak travel time, flood peak attenuation and flood wave attenuation index. The most significant changes have occurred since the 1980s with the most noticeable effects on the behaviour of high flows (around the bankfull stage). However, there is not a consistent direction change in these indicators in all places. We use these findings to categorise the flow mitigation signal of the study regions and catchments and discuss the implication for river and flood management.

Synergies and trade-offs in the management objectives forest health and flood risk reduction

While healthy forest ecosystems deliver various services that can reduce flood risk, they can also contribute to flooding by providing wood that potentially contributes to the clogging of waterways and associated backwater effects. In this regard, deadwood, as a key aspect of healthy forests, is often in focus of post-flood disaster discourses. This research reflects on this ambiguity in the different forest management goals when it comes to managing forests for flood risk reduction versus forest health. A working definition of forest health will be presented and an overview of the different aspects of how a forest potentially can affect the flood hazard will be provided. This will refer to the ways forests influence (1) the discharge of water from the landscape into channels and (2) the characteristics of the channel and its riparian area and their respective influence on the transport of water, sediment, and debris. Often these two determining factors for the development of the flood peak are discussed separately and by different academic fields. This paper aims to connect the existing knowledge spheres and discusses the synergies and trade-offs. The review shows that the two objectives of forest health and flood risk reduction are largely synergetic. However, in direct proximity to watercourses trade-offs might occur. This is especially due to the ambivalent relation of living vegetation and deadwood to flood hazard. In places without susceptible infrastructures to clogging, deadwood and diverse vegetation structures should be supported due to their beneficial effects on water retention and channel characteristics. In places where susceptible infrastructures exist, trade-offs between the two objectives arise. Here the potential of freshly uprooted vegetation to cause damages should be reduced while maintaining the vegetation’s supportive characteristics, for example, concerning bank and slope stability. Where the risk of clogging is assessed as too high, also the selective removal or shortening of dead in-channel Large Wood can be considered. However, based on the literature review the risk deriving from dead Large Wood is evaluated as comparably low. This is related to its generally lower proportions and its smaller and less stable characteristics compared to freshly uprooted vegetation.

Fuelwood Consumption: Its Effects on Carbon Sequestration in the Derived Savannah Region of Cross River North, Nigeria

Fuelwood harvesting accounts for about 40 percent of global removal of wood from forests and half of the World's population depend on it as their main source of energy. This study investigates the fuelwood consumption: Its effects on Carb on sequestration in the derived Savannah region of Cross River North, Nigeria. The study seeks to determine the type of fuelwood consumed and estimate carbon sequester. In order to achieve these objectives, primary data consisted of questionnaire, interviews, and field study while secondary data were obtained from Landsat, Nigeria Meteorological Agency (NIMET) Ogoja and the internet. Three hundred and ninety-one copies of questionnaires were returned out of three hundred and ninety-nine questionnaires administered. Regression, paired sample t test, percentages were used for analysis. Gmelina is the fuelwood tree used in the area with 54.7 percent due to its availability and accessibility. Fuelwood is an energy; income source; and it is affordable. Obanliku Local Government Area has the highest mean fuelwood consumption with 0.621795m3 and the least is 0.476925m3 in Yala Local Government Area. Carbon sequester in the study area is 20,394,418,025 tonnes. The regression model for the relationship between fuelwood consumption and carbon sequestration is expressed as: Fuelwood consumption = - 4855725.118 + 17270584.078carbon sequester. As fuelwood consumption decreases, carbon sequestration increases. Fuelwood consumption needs to be reduced to increase carbon sequestration and alternative energy sources should be made affordable, available and at little or no price by the recommendations.

Parameters of apple tree crowns depending on the crown shape and pruning time

The apple tree is a leading fruit crop in Ukraine in terms of production volumes and planting areas and is a valuable food product with a high content of vitamins. In new modern plantings, fruit producers prefer intensive cultivation technologies that ensure the maximum amount of high-quality fruit yield per unit area. The main criterion for solving this problem is the design of plantings: a narrow-row scheme for planting trees and a low-volume crown shape. The purpose of the study was to establish the influence of the pruning period of different types of crown formations on the growth and productivity of apple trees of two varieties: Fuji and Honey Crisp. The study was conducted in the conditions of the central Forest-Steppe of Ukraine (Uman National University of Horticulture). The scheme of planting was 4x1 m, M.9 rootstock, chernozem sod-podzolic soil, drip irrigation. Field, statistical, and computational-analytical methods were used in the course of the study. It was identified that the growth pattern of the examined varieties differed substantially, and crown volume, projection area, and development of the feeding area prevailed in Honey Crisp trees. However, in terms of productivity, the plantings of the Fuji variety substantially exceeded the values of the Honey Crisp variety. Forming a ballerina crown with the removal of overgrown wood in a 25 cm zone on the central trunk above the lower tier of semi-cellular branches provided an increase in the growth activity of the examined trees by 3-5%. A substantial decrease in the values of crown parameters was provided by the formation of the French axis crown – there was a decrease in the crown diameter by 44%, the crown volume – by 67%, and the crown projection area and the development of the feeding area – by 69%. Performing additional summer pruning of trees also helped to reduce growth activity by 6-11%. However, the specific productivity of plantings doubled in plantings with the formation of the French axis and by 45-50% with the introduction of double pruning of trees. It is recommended that agricultural producers investigate the terms of pruning low-volume crown forms, considering varietal characteristics, to create compacted apple stands and increase the intensification of production

Large Wood in Small Channels: A 20‐Year Study of Budgets and Piece Mobility in Two Redwood Streams

AbstractLarge wood (LW) influences geomorphic and ecological processes. However, most field data sets describing LW dynamics are conducted over the span of only a few years. We present a unique long‐term data set from northern California, USA of LW volumes, inputs, and transport in two small headwater streams, the North Fork (NF) and South Fork (SF) of Caspar Creek. We used data collected approximately every 2 years from 1998 to 2018 to assess how LW budgets change over time between catchments, what factors influence inputs from standing trees to the streams, and controls on LW piece mobility. We find that the SF, which experienced stream‐side logging and instream wood removal in the 1970s, continued to have lower LW volumes (range of 101–153 m3 km−1 over the 20‐year period) compared to the NF (range of 297–313 m3 km−1), which experienced logging in the 1980s but with buffer strips left near the channel. If current trends continue, it will likely take ∼100–200 years from the time of logging for the SF to reach NF instream wood volumes. We show that windstorms combined with precipitation events, very high winds, and hillslope steepness are strongly associated with LW piece inputs from standing trees. LW moves infrequently in the channel, with piece characteristics, the number of wood pieces per meter surrounding an LW piece, and discharge metrics influencing LW entrainment and displacement lengths. Our data set provides strong support to previously identified controls on LW dynamics in streams while also capturing variability over a 20‐year period.

Modeling the relative morphodynamic influence of vegetation and large wood in a dryland ephemeral stream, Arizona, USA

Compared to perennial streams, studies investigating the impact of large wood on sediment transport and river corridor morphology in ephemeral streams are lacking. Due to the flashy nature of ephemeral flow regimes, opportunities to directly investigate the influence of wood in ephemeral channels are limited. Additionally, given prior studies showing a strong association between existing riparian vegetation and large wood deposition in ephemeral streams, the geomorphic impact of wood is entangled with that of vegetation. Here, we develop a hydro-morphodynamic model to investigate changes to channel and floodplain morphology due to wood and vegetation in an ephemeral stream in southeastern Arizona, USA. Three scenarios are modeled: the actual configuration of the river corridor; an experiment in which jams are removed; and an experiment in which vegetation is removed. Both large wood and vegetation effectively confined flow to the main, unvegetated channel, which became wider and deeper over the course of a single moderate flood. When isolating the impact of large wood, model results show that wood enhances channel change created by vegetation, resulting in ±0.1 to 0.3 m of additional scour or aggradation. The simulated removal of vegetation resulted in more channel change than the removal of wood alone, partially because vegetation occupies a much greater area within the stream corridor than large wood. We propose a conceptual framework where large wood could mediate sedimentation as well as the recruitment and growth of vegetation in ephemeral streams, contributing to the evolution of ephemeral stream morphology over time.

Effects of retained dead wood on predation pressure on herbivores in young pine forests.

Retention of logging residue as dead wood could be a method to simultaneously increase biodiversity and predation rates of pest insects, in managed forests. Managed forests are generally low in diversity, and dead wood has been demonstrated to increase species diversity. Moreover, managed forests are predicted to suffer from higher frequency of insect outbreaks in the future, particularly in the northern hemisphere. In this study, we explore the effect of dead wood removal and addition in managed pine forest stands in Sweden on arthropod diversity and abundance and predation rates. We performed a controlled field experiment, focusing on logging residue type of dead wood. We used pitfall traps and sticky traps to measure arthropod diversity and abundance and plasticine larvae to assess predation rates. We specifically targeted generalist arthropods (i.e. non-wood living species), and predation rate on tree-dwelling larvae (corresponding to defoliating outbreak pests). We found no effect of dead wood addition on arthropod abundance or diversity, neither did we find an effect on predation rate. Despite the lack of effects in our study, we argue that dead wood can be an important component for both biodiversity of generalist arthropod and for pest control, but the effect may depend on both the specific arthropod group targeted and the specific life stage of the pest insect as well as on inherent components of the dead wood, such as age.

Impacts of harvesting methods on nutrient removal in Dutch forests exposed to high-nitrogen deposition

ContextForest harvest removal may cause nutrient depletion of soils, when removal of essential nutrients, including nitrogen (N), phosphorus (P), sulphur (S), calcium (Ca), potassium (K) and magnesium (Mg) exceeds their net input by deposition and weImpacts of acid atmospheric deposition on woodland athering minus leaching. Nutrient removal by harvest depends on tree species and the harvesting method, i.e. whole-tree harvesting (removal of stems and branches) versus stem wood removal only.AimThe aim of this study was to assess the impacts of these two harvesting methods on nutrient removal in Dutch forests exposed to high-nitrogen deposition.MethodsTo assess those impacts, we measured nutrient concentrations in stem wood and branch wood of seven major tree species in the Netherlands, i.e. Japanese larch (Larix kaempferi Lamb.), Norway spruce (Picea abies L. Karst.), Douglas fir (Pseudotsuga menziesii Mirb.), Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth), beech (Fagus sylvatica L.) and common oak (Quercus robur L.). Average nutrient concentrations in stems were based on measured concentrations in heartwood, sapwood and bark and estimated volumes and densities of these compartments. Similarly, average nutrient concentrations in branches were based on measured concentrations in coarse branches, fine branches and the bark of coarse branches and estimated volumes and densities of these compartments. Removal was assessed by using the average growth rates of these tree species on nutrient poor sandy soils in the Netherlands.ResultsCompared to other countries, N concentrations in the Netherlands were higher in stems, while phosphorus, Ca, K and Mg concentrations in both stems and branches were nearly always lower. The elevated long-term N deposition levels in the Netherlands most likely contribute to this finding, since N deposition causes soil acidification reducing the availability of Ca, K, Mg and P, that could become limiting to growth. Limits for sustainable harvest, above which outputs exceed inputs of nutrients, depend on nutrient, soil type and tree species and are mostly determined by K and P and sometimes Ca, which may already be depleted at relatively low harvest levels on poor sandy soils, in particular for broadleaved species, while depletion of Mg is not likely. Nevertheless, the average growth of forests in the Netherlands appears to be slightly higher than in most other countries in Europe.ConclusionOverall, we thus conclude that limited P, Ca, Mg and K availability in response to elevated N deposition is reflected in reduced contents of these nutrients in stem wood and branch wood but not in growth.Key messageNutrient concentrations in tree compartments were assessed for seven major tree species in the Netherlands. Concentrations of phosphorus, calcium, potassium and magnesium (base cations) in stems and branches are mostly lower compared to those in other countries, while nitrogen concentrations are higher. A long-term nitrogen deposition has likely contributed to these differences. The average growth has not declined, despite the low availability of phosphorus and base cations. Limiting the harvest of branch wood is suggested on nutrient poor soils to avoid depletion of phosphorus and base cations.

Rediscovering, reevaluating, and restoring Entiatqua: Identifying pre‐Anthropocene valleys in North Cascadia, USA

AbstractA maturing body of evidence suggests that anthropogenic impacts on river‐wetland corridors (RWCs) are greater and more widespread than previously recognized. Partly, this stems from the difficulty of differentiating between legacy anthropogenic impacts and channel evolution resulting from natural disturbances. Here, we apply the geomorphic grade line (GGL) relative elevation model (REM) method to reveal pre‐Anthropocene fluvial features for a 42‐km reach of Entiatqua (English translation—the Entiat River) in the North Cascade Mountains, USA. We began by long profiling the entire length of the river valley and defining distinct valley segments based on breaks in profile. Next, we developed models of the valley profile for each segment, known as GGLs, and used them to develop high‐resolution REMs by detrending LiDAR‐derived digital elevation models. We then used the GGL‐REMs to map relict fluvial features in the valley floor. Validating the GGL‐REMs using surficial geologic maps, 14Cdated soil profiles, and the identifiable remnants of historic dams allows us to differentiate surfaces associated with the pre‐Anthropocene from those resulting from anthropogenic activities, including splash damming, channel straightening, large wood removal, and beaver extirpation. Our findings reveal 1–2.5 m of anthropogenically‐driven channel incision in unconfined and partially‐confined valley segments, wherein fluvial sediment balances transitioned from being net depositional to erosive, and later neutral, with river environments in these segments shifting from being complex, ecologically‐rich, RWCs to simpler, ecologically‐impoverished, single‐thread channels, like those found in confined valley segments. The adverse impacts of post‐Anthropocene fluvial responses on salmon habitats were likely profound and may help explain historical and ongoing declines in populations of listed species, including Chinook Salmon (Oncorhynchus tshawytscha) and Steelhead Trout (Oncorhynchus mykiss). Our study of Entiatqua, together with evidence from other western US rivers, demonstrates that the GGL‐REM approach can be used to re‐envisage pre‐Anthropocene fluvial process‐form domains including identifying valley segments wherein fluvial responses to human development have disconnected RWCs. Once the pre‐Anthropogenic conditions of rivers like Entiatqua have been recognized, the case for restoring lost RWCs to unlock their ecological potential becomes compelling.

Grapevine Wood-Degrading Activity of Fomitiporia mediterranea M. Fisch.: A Focus on the Enzymatic Pathway Regulation.

Fomitiporia mediterranea is a Basidiomycetes fungus associated with some of the Esca complex diseases and responsible for decay in grapevine wood. Its role in the onset of foliar symptoms has recently been reconsidered, mainly after evidence showing a reduction in foliar symptom expression after removal of rotten wood. The study of its degradation pathways has already been approached by other authors, and with this study much information is consolidated. A microscopic observation of degraded wood provides a first approach to the characterization of F. mediterranea modalities of wood cellular structure degradation. The decay of grapevine wood was reproduced in vitro, and the measurement of each wood-forming polymer loss highlighted characteristics of F. mediterranea common to selective white rot and showed how fungal strain and vine variety are factors determining the wood degradation. All these observations were supported by the analysis of the laccase and manganese peroxidase enzyme activity, as well as by the expression of the genes coding 6 putative laccase isoforms and 3 manganese peroxidase isoforms, thereby highlighting substantial intraspecific variability.

Compressive behavior of FRP-tube-confined concrete short columns using recycled FRP materials from wind turbine blades: Experimental investigation and analytical modelling

<abstract> <p>A major challenge in today's concrete construction is to lower its carbon footprint to the least possible level. This study provides insights on a new low-CO<sub>2</sub> alternative concrete whereby glass fiber-reinforced polymer (GFRP) materials from waste wind-turbine blades (WWTB)—termed as WWTB-GFRP—was utilized as: (ⅰ) replacement of Portland cement at 0%, 10%, 20%, and as (ⅱ) lightweight aggregate replacement for natural aggregates at 0%, 50%, and 100%. The resulting WWTB-GFRP concretes were used in concrete-filled fibre-reinforced polymer (FRP) tubes (CFFTs) whereby the latter serves as a stay-in-place formwork and external reinforcement. Pristine WWTB-GFRP materials (containing wood) and processed ones (by wood removal) were investigated. Results indicate that while both WWTB-GFRP powder and aggregates adversely affect the compression resistance (due to, respectively, the retarding effect of the powder and the slippery surface of the aggregates leading to reduced bonding with the bulk cementitious matrix), the confinement of WWTB-GFRP concrete with FRP tubes offers an innovative tool to restore the strength loss. In fact, valorizing WWTB-GFRP concrete in CFFTs allowed to increase the compressive resistance by more than 100%. Interestingly, under axial compression, FRP tube confinement shifted the stress–strain response from the conventional brittle response to a ductile one whereby the confinement affected the elastic and plastic responses differently. While FRP confinement increased in the elastic limit at higher WWTB-GFRP aggregate content, it resulted in lower slope of the plastic response at higher WWTB-GFRP aggregate content. An analytical assessment demonstrated that a WWTB-GFRP aggregate content of 55% will be optimum for enhancing both elastic and plastic responses. Building upon the ACI 440.2R-17 model for predicting the compressive response of confined concrete incorporating conventional aggregates, a modified model more sensitive to GFRP aggregates and with higher predictive ability was proposed. Research outcomes will contribute to recycling waste materials while endowing further sustainability to concrete.</p> </abstract>

Interactive effects of chronic anthropogenic disturbances on Prosopis woodland structure in the Central Monte, Argentina

In drylands all over the world, chronic anthropic disturbances are relevant factors for woodland degradation. Different disturbances can potentially interact to change vegetation structure. Knowing woodland structure is crucial for better predicting forest dynamic because trees of different sizes significantly affect the regeneration processes, number of saplings and young trees, crown traits and competition attributes. Throughout the Monte biogeographic region, grazing and wood extraction are the main anthropogenic disturbances on Prosopis dry woodlands that can generate modifications in key ecosystem processes. First, we aimed to assess woodland structure at sites under chronic anthropic disturbances. Subsequently, we explored how the combination of grazing and wood extraction affected the population structure of P. flexuosa considered by classes: seedlings, saplings and adults. We found that sites under disturbances presented a high density of trees of smaller sizes. Besides, the interaction effect between grazing and wood extraction depended on the intensities of each of the disturbances. The combination of high intensities of both grazing and wood extraction negatively affected the abundance of all classes, but low or moderate grazing intensities combined with high wood extraction had a positive effect on the abundance of saplings and adults. High intensities of co-occurring disturbances decreased seedling abundance affecting forest recruitment which also was negatively reflected in sapling and adult abundance. However, the combination of low or moderate grazing and high wood extraction generated a woodland structure characterized by few seedlings, and many saplings and adult trees of small size. Application of management options (e.g., spatial or temporal separation of human use, programmed management of grazing and wood extraction intensities or planned practices as wood removal for local use) should contribute to enhance the provision of ecosystem services in Prosopis sp. woodlands without risking regeneration persistence and improving the woodland structure.