Wood Loads Research Articles

Effects of Riparian Timber Harvest on Southeast Alaska Stream Habitat after 30–40 Years: Insights for Management

AbstractLogging regulations in the Pacific Northwest and Alaska have evolved over time to alleviate the negative effects that historic harvest practices have had on stream habitat. While natural landscape factors largely control stream habitat, timber harvest can alter these influences, underscoring the importance of clarifying the effects of both for understanding and managing habitat in streams. We sampled areas in Southeast Alaska that had riparian zones harvested between 1980 and 1990, a period of less‐restrictive timber harvest regulations. Relationships between geomorphic and riparian factors with stream habitat informed a comparison of habitat under differing timber management strategies 30–40 years after harvest. Pool, substrate, and large wood characteristics were related to stream size, channel gradient, and channel confinement, whereas wood‐formed pools and large wood density were related to riparian factors. Pool characteristics in streams with harvested riparian zones were similar to those in streams with unharvested riparian zones. Large wood size distributions in streams with harvested riparian zones were also similar to those in streams with unharvested riparian zones and streams within forests managed for timber under contemporary regulations. These findings are likely due to legacy wood loads remaining and functioning to create habitat 30–40 years after harvest. Substrate size was related to timber management practices; streams with harvested riparian zones had smaller median particle sizes than unharvested streams. Wood loads remain and function instream decades after harvest, but the reduced supply of large‐sized wood from young‐growth riparian stands can result in declining habitat quality, especially in unconfined channels. Management strategies to enhance recovery of riparian stands with trees large enough to supply large‐sized wood are recommended. Our approach proved useful in teasing out legacy effects of past timber harvest from the effects of natural drivers on stream habitat, and the results can be used to help prioritize efforts aimed at conserving or restoring stream and riparian habitats in the region.

Spatial and temporal patterns of sediment storage over 45 years in Carnation Creek, BC, a previously glaciated mountain catchment

AbstractThe movement of sediment through mountain river networks remains difficult to predict, as processes beyond streamflow and particle size are responsible for the entrainment and transport of bedload sediment. In deglaciated catchments, additional complexity arises from glacial impacts on landscape organization. Research to date indicates that the quantity of sediment stored in the channel is an important component of sediment transport in systems which alternate between supply and transport limited states, but limited long‐term field data exist which can capture storage‐transfer dynamics over a timescale encompassing episodic supply typical of mountain streams. We use a 45‐year dataset with annual and decadal‐scale data on sediment storage, channel morphology, and wood loading to investigate the spatial and temporal organization of storage in Carnation Creek, a previously glaciated 11 km2 catchment on Vancouver Island, British Columbia.Sediment is supplied episodically to the channel, including additions from debris flows in the early 1980s just upstream of the studied channel region. Analyzing the spatial and temporal organization of sediment storage along 3.0 km of channel mainstem reveals a characteristic storage wavelength similar to the annual bedload particle travel distance. Over time, two scales of variation in storage are observed: small‐scale fluctuation of 3–10 years corresponding to local erosional and depositional processes, and larger scale response over 25–35 years related to supply of sediment from hillslopes. Complex relationships between storage and sediment transfer (i.e., annual change in storage) are identified, with decadal‐scale hysteresis present in storage‐transfer relations in sites influenced by hillslope sediment and logjams. We propose a conceptual model linking landscape organization to temporal variability in storage and to storage–export cycles. Collectively, our results reaffirm the importance of storage to sediment transport and channel morphology, and highlight the complexity of storage–transport interactions. © 2019 John Wiley & Sons, Ltd.

Valoración económica de servicios ecosistémicos de provisión y paisaje del Santuario Histórico Bosque de Pómac

espanolEl objetivo de la investigacion fue determinar la valoracion economica de servicios ecosistemicos de provision y paisaje del Santuario Historico Bosque de Pomac y formular mecanismos de retribucion, se utilizo la metodologia de valoracion contingente expresada en la disponibilidad a pagar; se aplicaron encuestas con 8 items a 374 pobladores de 14 caserios de la zona de amortiguamiento y encuestas con 1 item a 659 visitantes regionales, nacionales y extranjeros del SHBP, ambas validadas con Alfa de Cronbach, el trabajo de campo fue realizado desde el 3 de Junio hasta el 30 de Noviembre de 2017, posteriormente se utilizaron medidas de tendencia central y se determino la disposicion a pagar. Se concluyo que: 1. Los pobladores de la zona de amortiguamiento del SHBP manifestaron su disposicion a pagar en promedio S/.20,98 por el quintal de fruto seco de algarrobo; S/.7,45 por el quintal de fruto seco de sapote, S/.22.37 por la carga de lena charra y S/.10,79 por kilogramo de miel de abeja; 2. Los pobladores encuestados, manifestaron que estan dispuestos a pagar en promedio S/.3,94, los visitantes nacionales S/.10,96 y los extranjeros S/.24,48; 3. La disposicion a pagar promedio por los visitantes nacionales fue de S/. 7,95 por visitar el SHBP y los extranjeros de S/.30, 86, 4. Los mecanismos de retribucion que proponen los encuestados fueron el pago directo del valor del servicio y acciones como parte del programa de guardaparques voluntarios. EnglishThe objective of the research was to determine the economic valuation of the ecosystem services of provision and landscape from the Historical Sanctuary “Bosque de Pomac” and to formulate retribution mechanisms, the methodology of the contingent valuation expressed in the availability to pay was used. 8-item surveys were applied to 374 inhabitants from 14 villages in the buffer zone and 1-item surveys were used to 659 regional, national and foreign visitors of the SHBP, both validated with the Cronbach’s Alfa. Filed work was carried out from June 3rd to November 30th, 2017, central tendency measures were later used and the availability to pay. It was concluded that: 1. The inhabitants from the buffer zone of SHBP expressed their willingness to pay on average S /. 20.98 for a quintal of carob dried fruit; S /.7.45 for a quintal of sapote dried fruit, S /. 22.37 for the fallen branches, better known as the “load of wood” and S /. 10.79 for the kilogram of honey. 2. The inhabitants surveyed showed that they are willing to pay on average S /. 3.94, national visitors S/. 10, 96 and foreigners S /. 24, 48; 3. The average willingness to pay for national visitors was S/. 7.95 for visiting the Historical Sanctuary “Bosque de Pomac” and foreigners agreed to pay S/. 30, 86. 4. The retribution mechanisms proposed by the respondents were the direct payment of the value of the service and actions as part of the voluntary park rangers program.

Response of Brook Trout Biomass to Strategic Wood Additions in the East Branch Nulhegan River Watershed, Vermont

AbstractHistoric logging and log driving have severely degraded fish habitat in many northeastern United States rivers, including the East Branch Nulhegan River, Vermont. To improve the habitat of Brook Trout Salvelinus fontinalis, 43 large woody material structures were constructed using chain saws and grip hoists in the East Branch Nulhegan River and two of its tributaries. The purpose of this study was to assess the effects of these “strategic wood additions” on Brook Trout biomass. Nine pairs of control and treatment sites were electrofished annually for 2 years prior to wood additions and for 4 years afterward. Wood loading increased at treatment sites by 183 to 1,557 pieces/ha, resulting in total wood loadings at these sites ranging from 251 to 1,557 pieces/ha (18 to 66 pieces per 100 m). By the second year of posttreatment sampling, average Brook Trout biomass at treatment sites had approximately tripled. Mean Brook Trout biomass decreased at control sites the first year after wood was added but then rebounded to pretreatment levels, suggesting that added wood contributed to a net increase in Brook Trout abundance in the system and did not simply concentrate fish in favorable habitats. Fisheries managers can consider strategic wood additions as a potential tool for improving Brook Trout habitat and bolstering their populations in streams where the lack of large wood is the most important limiting factor.

Variable hillslope‐channel coupling and channel characteristics of forested mountain streams in glaciated landscapes

AbstractChannel morphology of forested, mountain streams in glaciated landscapes is regulated by a complex suite of processes, and remains difficult to predict. Here, we analyze models of channel geometry against a comprehensive field dataset collected in two previously glaciated basins in Haida Gwaii, B.C., to explore the influence of variable hillslope–channel coupling imposed by the glacial legacy on channel form. Our objective is to better understand the relation between hillslope–channel coupling and stream character within glaciated basins. We find that the glacial legacy on landscape structure is characterized by relatively large spatial variation in hillslope–channel coupling. Spatial differences in coupling influence the frequency and magnitude of coarse sediment and woody material delivery to the channel network. Analyses using a model for channel gradient and multiple models for width and depth show that hillslope–channel coupling and high wood loading induce deviations from standard downstream predictions for all three variables in the study basins. Examination of model residuals using Boosted Regression Trees and nine additional channel variables indicates that ~10 to ~40% of residual variance can be explained by logjam variables, ~15–40% by the degree of hillslope–channel coupling, and 10–20% by proximity to slope failures. These results indicate that channel classification systems incorporating hillslope–channel coupling, and, indirectly, the catchment glacial legacy, may present a more complete understanding of mountain channels. From these results, we propose a conceptual framework which describes the linkages between landscape history, hillslope–channel coupling, and channel form. © 2018 John Wiley & Sons, Ltd.

Passive Recovery of Wood Loads in Rivers

AbstractA growing worldwide body of literature is demonstrating the geomorphic and ecological roles played by wood in rivers. After more than a century of removing wood from rivers in many parts of the world, researchers and managers are now interested in returning the load of wood back to a more natural condition. The mechanical placement of wood in rivers is expensive, and so it is useful to know how long it will take for in‐stream wood loads to passively recover a target load by recruitment from riparian forests. Of fundamental interest to managers and researchers alike are the questions: (1) can a river passively recover to a preremoval load of wood, and (2) if so, how long will recovery take? We address these questions using the example of the anabranching King River, Northeast Victoria, Australia, which was desnagged twice: once in 1957 and again in 1980. We predict a recovery time of 255 ± 23 years using a complete census of recovering wood loads to develop and parameterize a mass balance delivery model run in a Monte Carlo simulation. Our results indicate that with a healthy supply of riparian vegetation and minimal interference from managers, rivers are likely to passively recover natural wood loads at least two and a half centuries after desnagging. Using the data and methods described in this paper, we develop a theory of recovery, conceptually describing the recovery process as a sequence of five stages that can be used to monitor and track wood loads through time.

Natural and Anthropogenic Controls on Wood Loads in River Corridors of the Rocky, Cascade, and Olympic Mountains, USA

AbstractWood in rivers creates habitat, shapes the morphology of valley bottoms, and acts as a pool of organic carbon (OC). Effective riverine wood management depends on a robust understanding of the spatial distribution of wood throughout river networks. This motivates the analysis of wood load in relation to both reach‐ and basin‐scale processes. We present wood load data coupled with precipitation, forest stand characteristic, land use, and geomorphic data across four basins in the Rocky, Cascade, and Olympic Mountains of the western U.S. We compare basins with differing land use within the same climatic region and basins in differing climates and statistically model intrabasin wood load variability. Wood load is a function of metrics that generally describe river corridor spatial heterogeneity, metrics that describe wood storage patterns, and, at a broader scale, metrics that relate to wood supply. From this, we generate a conceptual model to describe controls on wood load across spatial scales. We use this model to propose that spatial heterogeneity and wood storage pattern together determine reach‐scale wood trapping efficiency. Trapping efficiency in turn regulates how wood supply to valley bottoms determines wood load. We also find that wood in an undisturbed basin stores significant amounts of OC and that wood load restoration has the potential to restore significant amounts of OC to valley bottoms. This conceptual model of wood load controls may serve as a framework to guide wood load modeling and restoration at multiple scales.

Optimization of the route of a truck with a hydraulic crane during loading of wood

The article presents a plan to improve the course of routes of a truck with hydraulic crane. The process of loading and transporting wood is covered. The routes of truck with a hydraulic crane that perform loading in various areas of the company are presented.

Feasibility of Chemically Modified Cellulose Nanofiber Based Membrane as a Lithium Ion Battery Separator

One key concern in the lithium based energy storage device industry is its large environmental impacts, especially in terms of high energy input and components materials resulting in environmental pollutions during manufacturing and waste treatment. To overcome that of the conventional compartments of lithium ion batteries, there have been numerous attempts to replace their materials to such with lower environmental impact. Cellulose has been highlighted as a candidate because of its naturally abundance, low cost, bio-degradability. Besides, its thermal and chemical stability make it even more attractive as lithium ion battery materials. Cellulose fibrillated to individual nano-sized fibrils has been suggested as a useful material, which can also form nano-structures with high mechanical strength. Particularly, chemically modified cellulose has functionalized groups which can contribute to its excellent dispersibility in aqueous solutions and solvents. Therefore, chemically modified cellulose materials have advantages to be easily fabricated to light weight porous structures favorable for energy storage applications. TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) mediated oxidized cellulose (TOC) has sodium carboxylated groups converted from the primary hydroxyls at the C6 position. The functional groups give repulsion between fibrils, and facilitate dispersion of fibers. By consecutive mechanical disintegration, the pulp can be fabricated to nano-structured materials with a relatively low amount of mechanical energy input. Furthermore, negatively charged surface groups of the separators contribute to the transport of lithium ions, since a polyanionic surface can improve the transport rate of lithium cations. Furthermore, it is produced in large quantities in Nippon Paper Industries, Japan. Despite of its promising properties, its application for lithium ion batteries has been limited to a small quantity, such as the binders, coating materials, and the mechanical supports of gel-polymer electrolyte. We have found that TEMPO-oxidized cellulose based separator can be used for Li-ion batteries. From a water-based paper making process, fibrous cellulose treated by low mechanical/chemical energy input was fabricated to meso-porous structured membranes by simple filtration. The manufacturing process includes filtration and sequential solvent exchange with organic solvents to obtain desired structures of separators in terms of thickness, porosity, wettability of electrolyte and ionic conductivity. A battery cell composed of lithium Ni1/3Mn1/3CO1/3O2 (NMC) /Graphite electrodes and such separators showed excellent electrochemical performance. TEMPO-oxidized celluloses with different amounts of surface charge densities are produced and fabricated to be heat-resistant lithium ion battery separators. TEMPO-oxidized nanofibers with higher charge densities can facilitate the dispersion of cellulose and it contributes to an increase of mechanical strength. However, when fabricated to be a separator and applied for a battery cell, it showed unexpectedly poor electrochemical performance. We could assume that water remained in the cellulose structure limits the feasibility of high loading of wood based nanocellulose in the lithium ion batteries. Two types of water in TOC of concern are bound water adsorbed to the counter ions, and water in the cellulose amorphous structure which is difficult to remove via normal drying processes. Negatively charged cellulose can interact with higher amounts of water molecules on the cellulose structure while it goes through the water-based manufacturing process. Strong hydrogen bonds between water and cellulose stabilize the cellulose structures. Meanwhile, water can penetrate into amorphous regions of cellulose, whereas it cannot attack the crystalline regions. Therefore, it is inevitable to completely get rid of water from the wood based nanocellulose with low crystallinity and high surface area, prepared by aqueous based process, via normal drying process. Furthermore, since water remained can accelerate unwanted detrimental side reactions, resulting in the degradation of electrolytes and electrodes, it requires a delicate drying process. NMP (N-Methyl-2-pyrrolidone) was employed as the drying solvent for TOC nanofibers. The membrane immersed in NMP solvent and dried at 110 °C under vacuum showed enhanced electrochemical performance. NMP is an organic solvent widely used in industry because of its dispersibility. It is known as one of the cellulose-dissolving solvents, which can penetrate the cellulose structure, and interrupt the hydrogen bonding. We investigate the relationship between the electrochemical stability and the characteristics of separator materials. The results will give an overview for our future studies of the applications of cellulose materials produced by different chemical modification processes. Figure 1

The loss of large wood affects rocky mountain trout populations

AbstractWestern U.S. rivers are currently influenced by legacy effects of reduced large wood (LW) loading and retention that has substantially reduced in‐stream habitat complexity. Large wood is typically associated with streams in undisturbed old‐growth forest and in the correct geomorphic context can drastically alter stream and valley habitat complexity. Streams withLWare typically multichannel and depositional, while streams lackingLW, due to relatively recent wildfire or logging (<200 years ago), are usually single channelled and erosional. We compared population biomass and individual growth rates of Brook TroutSalvelinus fontinalisin streams across a gradient of wood volumes. At both the square metre and valley length scales, standing stock biomass of aquatic invertebrates was the best predictor of trout biomass. However, at the valley scale, the number of pools was important in predicting trout biomass in combination with standing stock biomass of aquatic invertebrates. Individual growth rates of age‐1 Brook Trout were negatively affected by increasing density; however, growth rates for the largest and smallest individuals at each site were unaffected by density. Our results suggest the pool habitat created byLWacts synergistically with prey availability to dramatically increase trout populations. However, in streams lacking LW, negative effects of detrimental land use practices have persisted >100 years, suggesting that recovering lost animal production in mountain stream networks will only occur at decadal to century time scales.

The enhanced abrasion resistance of an anti-fingerprint coating on chrome-plated brass substrate by integrating sputtering and atmospheric pressure plasma jet technologies

We demonstrate the procedure of fabricating an anti-fingerprint coating on plated-Cr/brass substrates by the combination of two processes: (1) Sputtering and (2) Atmospheric pressure plasma jet (APPJ). APPJ surface treatment on sputtered-SiOx glue layer on plated-Cr/brass substrate is conducted to improve its surface property to be hydrophilic for chemical bonding with an anti-fingerprint agent (AF-C01). The results show that the surface energy of original substrate are evolving from 44.2 mN/m to 60.8 mN/m and 76.9 mN/m for the sputtered-SiOx film and APPJ-treated SiOx film, respectively. Subsequently, the spin-coating process using a commercialnt (AF-C01 agent for the prepared sample is implemented. The hydrophobicity of anti-fingerprint characteristics for all of the samples with a quite low surface energy around 10.5 mN/m are obtained. For practical evaluation of abrasion behavior, a good abrasion resistance of AF/APPJ-treated SiOx/plated-Cr/brass sample under 1000 g-steel wood loading is evidently obtained from the slow variation of water contact angle value. The results demonstrate that the feasibility of integrating APPJ process on the sputtered-SiOx film for improving the surface properties of chrome-plated brass substrate is practically achieved.

Large wood potential, piece characteristics, and flood effects in Swiss mountain streams

We present results of two studies on the (1) potential wood load in steep headwater streams and (2) properties of large wood (LW) transported in mountain rivers during the large August 2005 flood event in Switzerland. Ten headwater reaches of 1000 m length were surveyed in different regions of Switzerland. The potential wood load was estimated for in-channel deadwood, and possible driving factors were explored. Correlations were found with dead wood volume on hillslopes and mean channel width. We established size distributions of LW pieces and identified probable recruitment processes. Four reaches were resurveyed after an exceptionally severe flood in August 2005, showing limited LW transport in channels but considerable wood input by mass wasting processes. In addition, characteristics of deposits of LW along mountain rivers affected by the 2005 flood were investigated. Diameter and length distribution of transported and deposited pieces were comparable to those of LW from steep headwater streams, yet with considerably fewer long pieces in the deposits of mountain rivers. Most LW pieces were fresh wood, indicating that the portion of in-channel deadwood transported during the 2005 flood was limited. Findings of the study contribute to a better understanding of LW dynamics in Alpine mountain streams.

Distribution of Large Wood Within River Corridors in Relation to Flow Regime in the Semiarid Western US

AbstractThe cumulative volume and spatial distribution of large wood (LW) along river corridors (channels and floodplains) reflect interactions between rates and volumes of LW recruitment and channel transport capacity through time. Rivers of the semiarid interior western US can have relatively low‐magnitude disturbances associated with annual snowmelt or relatively high‐magnitude disturbances associated with episodic rainfall runoff, especially following wildfires. We use characteristics of LW from 25 river segments in four regions of New Mexico and Colorado to analyze wood loads and spatial patterns of wood distribution in relation to disturbance regime. High‐magnitude disturbances move LW onto floodplains and create longitudinally nonuniform LW distributions with aggregated (closer together than random) LW pieces and abundant LW jams in the floodplain. Sites with low‐magnitude disturbances have a greater proportion of LW in the channel and much of this wood is within segregated (farther apart than random) jams. These results imply that river management, which typically focuses on LW within channels, should focus on floodplain as well as in‐channel LW in rivers with high‐magnitude disturbances. The results also indicate that the proportions of LW loads in channels versus floodplains can differ significantly among rivers with different disturbance regimes that are otherwise similar in terms of forest type or drainage area. This is particularly relevant to mountainous regions with elevation‐related changes in flow and disturbance regime. River management that reintroduces LW to river corridors will be most effective if it incorporates the mobility and spatial distribution of LW.

Calentamiento por radiofrecuencia para esterilizar Pinus radiata como material para embalajes. Parte 1: Tiempo total de tratamiento

In this work the total heating time was studied using radio frequency to sterilize wood packaging material of Pinus radiata, through the conditions 56 ° C and 60 ° C for 30 and 1 minutes respectively, according to international phytosanitary norms. The experimental tests were carried out in a laboratory radiofrequency equipment of 3 m3 capacity. The heating time was determined and prediction models were developed, depending on the thickness, plaque separation and wood loading volume, with confidence levels above 90%. The results showed that the total time of radiofrequency sterilization was greater in the surface of the pile and were statistically similar under both treatment conditions.

Historical land use as a driver of alternative states for stream form and function in forested mountain watersheds of the Southern Rocky Mountains

AbstractWe demonstrate how land use can drive mountain streams in the Southern Rockies across a threshold to induce an alternative state of significantly reduced physical complexity of form and reduced ecological function. We evaluate field data from 28 stream reaches in relatively laterally unconfined valleys and unmanaged forest that is either old‐growth forest or naturally disturbed younger forest, and 19 stream reaches in managed forest with past land use. We evaluate potential differences in stream form, as reflected in channel planform, cross‐sectional geometry, and in‐stream wood loads, and stream function, as reflected in pool volume and storage of organic carbon. Field data indicate a threshold of differences in stream form and function between unmanaged and managed stream reaches, regardless of forest stand age, supporting our hypothesis that the legacy effects of past land use result in an alternative state of streams. Because physical complexity that increases stream retentiveness and habitat can maintain aquatic‐riparian ecosystem functions, the alternative physical state of streams in managed watersheds creates a physical template for an alternative ecological state with reduced pool volume, organic carbon storage, and ecosystem productivity. We recommend maintaining riparian forests that can supply large wood to streams as a stream restoration technique in historically forested stream segments. Copyright © 2017 John Wiley & Sons, Ltd.

GLOBALLY-APPLICABLE PREDICTIVE WILDFIRE MODEL A TEMPORAL–SPATIAL GIS BASED RISK ANALYSIS USING DATA DRIVEN FUZZY LOGIC FUNCTIONS

Abstract. This study (van den Dool, 2017) is a proof of concept for a global predictive wildfire model, in which the temporal–spatial characteristics of wildfires are placed in a Geographical Information System (GIS), and the risk analysis is based on data-driven fuzzy logic functions. The data sources used in this model are available as global datasets, but subdivided into three pilot areas: North America (California/Nevada), Europe (Spain), and Asia (Mongolia), and are downscaled to the highest resolution (3-arc second). The GIS is constructed around three themes: topography, fuel availability and climate. From the topographical data, six derived sub-themes are created and converted to a fuzzy membership based on the catchment area statistics. The fuel availability score is a composite of four data layers: land cover, wood loads, biomass, biovolumes. As input for the climatological sub-model reanalysed daily averaged, weather-related data is used, which is accumulated to a global weekly time-window (to account for the uncertainty within the climatological model) and forms the temporal component of the model. The final product is a wildfire risk score (from 0 to 1) by week, representing the average wildfire risk in an area. To compute the potential wildfire risk the sub-models are combined usinga Multi-Criteria Approach, and the model results are validated against the area under the Receiver Operating Characteristic curve.

Instream large wood loads across bioclimatic regions

Instream large wood in forested rivers creates diverse physical and ecological effects and is a vital component of river process and form. The majority of research on wood in rivers has been conducted within a limited geographic range, raising questions about the applicability of resulting insights. We analyze data from 438 river segments in old-growth or unmanaged forests and 250 river segments in lightly managed forests representing diverse environments. We evaluate whether drainage area, channel width, and channel slope influence instream wood load in unmanaged forests across bioclimatic regions. Here we show that, without accounting for variations across regions, these numeric variables do not correlate significantly with wood loads. When accounting for the influence of all available potential influences on wood load in unmanaged forest rivers, bioclimatic region, drainage area, and channel width are the dominant predictors of wood load, and the relationship between wood load and channel width differs between regions. Combining data across bioclimatic regions, unmanaged rivers have significantly greater wood loads than lightly managed forests. Splitting data by bioclimatic region, unmanaged rivers in the northern dry conifer and northern wet conifer regions have significantly greater wood loads than lightly managed forests, but wood loads in the northern wet deciduous region do not differ between unmanaged and lightly managed forests. Our findings suggest that (i) bioclimatic region is a critical factor in predicting and understanding wood dynamics in rivers, (ii) even historic or relatively light levels of timber harvest and wood removal can create persistent differences in wood loads, and (iii) substantial variation in wood load among river segments within a bioclimatic region suggests that riparian forest and river management should focus on processes that maintain wood loads capable of creating desired physical and ecological effects rather than specified volumes of wood.

Lack of maintenance is a major challenge for stream restoration projects

AbstractEnvironmental infrastructure and practices designed to restore and protect aquatic systems are now mainstream. Yet many of these projects are failing to produce the biophysical outcomes that they are designed for because of poor maintenance. The success of restoration projects is just as much a consequence of how they are maintained, as it is how the project was initially designed and implemented. Successful maintenance relies on understanding the ecological and biological recovery trajectories of aquatic systems. Some interventions will require ongoing maintenance indefinitely, whereas others will reach a self‐sustaining point where maintenance is no longer required. Different management arrangements are required to ensure the maintenance of different types of project. Those projects that involve high costs should be managed using more robust arrangements, such as legal regulation, compared to those projects that involve lower costs. This paper describes the maintenance required for common river restoration projects and outlines a classification of projects based on maintenance and recovery trajectories. It then considers the types of management arrangements required to ensure maintenance. Finally, these points are illustrated with 3 case studies of typical restoration actions (riparian stock exclusion, fish passage, and restoring large wood loads). Projects that require ongoing maintenance, particularly those that involve high costs, such as environmental flows, require strong management arrangements to ensure successful outcomes. Voluntary instruments are more appropriate for self‐sustaining interventions. Regardless of the chosen management arrangements, monitoring and independent assessment are essential for successful maintenance.

Effect of wood drying and heat modification on some physical and mechanical properties of radiata pine

ABSTRACTTo evaluate evolution of physical and mechanical properties due to drying and heat modification, a load of radiata pine wood was selected and properties were measured after each drying process. The results revealed interesting correlations between intrinsic factors and properties; the values of density were highly dispersed after drying or thermal treatment and uncorrelated with other parameters, but the minimum density values were kept constant after heat treatment. Moreover, weight loss (WL) and moisture content (MC) were decreasing proportionally to the treatment intensity, due to wood–water interactions, cell wall changes, and thermal degradation of wood fractions. WL and MC were reasonably correlated with the dimensional stability, improving the dimensional stability after drying treatments, but keeping the same order of anisotropy. Regarding the wood stiffness (modulus of elasticity, MOE), it was unaffected by the drying temperature, and the correlations between MOE and MC or WL appear to be acceptable, and the values of MC or WL did not adversely affect the MOE. However, the modulus of rupture was dropped during the drying process, obtaining three differentiated groups with a decrease in around 59% after thermal modification.

Formation and maintenance of a forced pool-riffle couplet following loading of large wood

Pool-riffle maintenance has been documented in numerous studies, but it has been almost impossible to characterize detailed natural pool-riffle formation mechanisms because of the lack of baseline data prior to pool establishment. In 2013, a study was conducted on the Blackledge River in Connecticut to document the formation of a new pool-riffle couplet on a section of river that had previously been studied from 1999 to 2001. In 2001, the study reach contained a scour hole with a residual depth of 0.08±0.09m downstream of a 1930s paired deflector with no identifiable riffle immediately downstream. At this time, a large, severely undercut, hemlock tree was noted along the left bank. Sometime between fall 2001 and 2004, the tree fell perpendicular to flow across the channel and formed a large wood (LW) jam and new pool-riffle couplet several meters downstream of the old scour hole. Pool spacing along the reach decreased from 4.47 bankfull widths (BFW) in 1999 to 3.83 BFW after the new pool-riffle couplet formed. The new pool has a residual depth, the water depth of the streambed depression below the elevation of the immediate downstream hydraulic control, of 1.36±0.075 to 1.59±0.075m, which resulted from a combination of 1.32±0.09m or less of incision below the old scour hole (95.6% or less of the depth increase) and up to 0.18±0.09m of downstream deposition and associated backwater formation (13.2% or less of the depth increase). To assess dynamic stability of the pool-riffle couplet over several flood cycles, surficial fine-sediment and organic material along the reach were quantified. The 23-m-long pool stores 25.7% of the surficial fine grained sediments and 15.4% of organic material along a 214-m-long reach that includes one additional artificially created pool. An adjacent 50-m-long secondary channel impacted by the LW jam stores 65.3% of the surficial fine-grained sediments and 54.8% of organic material along the full reach.