A tool for tracking floodplain age land surface patterns on a large meandering river with applications for ecological planning and restoration design

An alluvial river channel typically meanders by eroding its outer banks and depositing sediments on the inside of bends, producing new land surfaces. Over time the landscape pattern created by these processes is important to the understanding of riparian plant ecology and the spatial structure of riparian forest development for restoration planning and design as well as other purposes. The middle sector of the Sacramento River is an actively meandering channel that deposits sediments in discrete new areas from fluvial geomorphic events creating a land age gradient. Newly formed land undergoes a primary succession by woody species such as willow and cottonwood communities that provide habitat for important conservation target species in California. Conservation and restoration of primary and secondary successional processes is an important management goal on the Sacramento River. The objectives of this paper were: (1) to develop and codify new methods to track the surficial chronological patterns of floodplain land age in a meandering river system, and (2) to analyze land production and the spatial distributions of gravel bars, riparian vegetation communities, and forest structure in relation to the land age gradient. Results from the ecological analysis indicate 71% of extant riparian vegetation was located within the 101-year meander zone; willow (18%) and cottonwood (31–43%) had the highest proportional canopy cover on lands aged 1–9 and 10–44 years, respectively. Potential applications of this approach for conservation and restoration planning and design of alluvial river floodplains are discussed.     

Restoration of a chalk stream using wood: assessment of habitat improvements using the Modular River Survey

The installation of large wood and sediment berms to narrow the overwide channel of the River Bulbourne, Hertfordshire, aimed to restore geomorphological processes, improve channel habitat diversity and increase the amenity value of the park in which the river is located. The Modular River Survey provides a framework and suite of tools for river managers and volunteers to monitor and assess restoration activities. Applying this technique to the River Bulbourne before and after restoration demonstrated that the works increased physical habitat and vegetation complexity. The restored section was narrowed, substrate composition changed and the range of in‐stream vegetation morphotypes increased. The initial slight improvement in riparian habitat complexity immediately following the restoration is expected to increase further over time as the riparian vegetation develops and the restored section of channel matures. A public perception and recreational use survey reviewed how visitor experience and use of the park changed following restoration.     

Trees and wood: working with natural river processes

A history of land clearance and riparian tree and wood management has resulted in limited riparian woodland and wood along British rivers. However, river management approaches are now being promoted that ‘work with natural processes’ to reduce flood risk through measures intended to restore, protect and emulate the natural function of catchments, rivers, estuaries and coasts. Wood has started to be reintroduced into river channels during river restoration and natural flood management activities, but this needs to be undertaken using appropriate quantities, locations and designs that mimic natural tree‐wood features. This paper reviews the knowledge that is needed to support wood reintroduction activities including (i) the characteristics of the riparian tree species and wood that are present; (ii) the importance of river size relative to that of trees and wood pieces; and (iii) the way trees, wood and geomorphic processes interact across rivers and floodplains of different energy and style.     

Restoring Dynamic Fluvial Processes in Urban Rivers: Learning from the Aire and Isar Rivers

In process-based restoration, the objective is not to create a complex river form directly; instead, interventions are intended to “prompt” the natural processes to restore such forms. The improvements in ecological conditions are actually made over time by flowing water during floods (using the stream’s energy), and by the growth of riparian vegetation (using incoming solar energy). On the Aire River in Geneva, ecological function was restored to a formerly canalized river by providing the river with an espace de liberté. A grid of channels cut into the valley bottom allowed the river to freely flood, erode its bed and banks, and deposit bars, creating complex surfaces on which riparian vegetation established to support the food web of the riverine ecosystem. The diamond-shaped bits of land left between these channels (“lozenges”) gradually erode and evolve as the river migrates, creating complex channel forms. The Isar River in Munich restoration involved adding coarse sediment load, creating erodible bed and banks in place of formerly rigid boundaries, expanding process space for river migration, erosion, and deposition, and increased human access to the river over 8 km. Since restoration, natural transport of sediment has resulted in deposition of gravel bars, whose forms evolve during floods, supporting diverse habitats. The Isar and Aire Rivers provide compelling examples of processbased restoration meeting 4 criteria for process-based restoration: space, energy, materials, and time. They demonstrate the possibilities of urban river restoration to achieve both ecological and social goals through restoration of fluvial process.     

Assessing land-use effects on water quality, in-stream habitat, riparian ecosystems and biodiversity in Patagonian northwest streams

Changes in land-use practices have affected the integrity and quality of water resources worldwide. In Patagonia there is a strong concern about the ecological status of surface waters because these changes are rapidly occurring in the region. To test the hypothesis that greater intensity of land-use will have negative effects on water quality, stream habitat and biodiversity we assessed benthic macroinvertebrates, riparian/littoral invertebrates, fish and birds from the riparian corridor and environmental variables of 15 rivers (Patagonia) subjected to a gradient of land-use practices (non-managed native forest, managed native forest, pine plantations, pasture, urbanization). A total of 158 macroinvertebrate taxa, 105 riparian/littoral invertebrate taxa, 5 fish species, 34 bird species, and 15 aquatic plant species, were recorded considering all sites. Urban land-use produced the most significant changes in streams including physical features, conductivity, nutrients, habitat condition, riparian quality and invertebrate metrics. Pasture and managed native forest sites appeared in an intermediate situation. The highest values of fish and bird abundance and diversity were observed at disturbed sites; this might be explained by the opportunistic behavior displayed by these communities which let them take advantage of increased trophic resources in these environments. As expected, non-managed native forest sites showed the highest integrity of ecological conditions and also great biodiversity of benthic communities. Macroinvertebrate metrics that reflected good water quality were positively related to forest land cover and negatively related to urban and pasture land cover. However, by offering stream edge areas, pasture sites still supported rich communities of riparian/littoral invertebrates, increasing overall biodiversity. Macroinvertebrates were good indicators of land-use impact and water quality conditions and resulted useful tools to early alert of disturbances in streams. Fish and birds having a greater ability of dispersion and capacity to move quickly from disturbances would reflect changes at a higher scale.     

Hydromorphological,hydraulic and ecological effects of restored wood: findings and reflections from an academic partnership approach

Large wood (re)introduction can deliver multiple benefits in river restoration, but there is a dearth of the detailed and longer‐term post‐project monitoring and evaluation required for improving best practice. We present findings from an academic partnership approach to post‐project evaluation, based on successive MSc research projects on restored large wood in the Loddon catchment, UK. Field and modelling data reveal: (i) key differences in large wood features between restored and natural reaches; (ii) increased hydraulic retention and changes to mesohabitats associated with large wood; (iii) differences in macroinvertebrate community composition around large wood but a lack of site‐level effects; (iv) interactions between macrophytes and large wood that may be specific to restored reaches; (v) a need for further field and modelling studies to inform the accurate representation of large wood in hydraulic models. Some key challenges in partnership working are identified to aid planning and effectiveness of future collaborations.     

Effects on growth, photosynthesis and pigments of the freshwater moss Fontinalis antipyretica Hedw. after exposure to wood ash solution

The application of wood ash from biofuel sources to the forest has been suggested as a source of nutrients for trees and for restoration of acidified soils and surface waters. Studies on the effects of wood ash on aquatic organisms and ecosystems are, however, few. This study investigated the effects of wood ash (0.1-10 g l(-1)) on the freshwater moss Fontinalis antipyretica Hedw., which has previously been shown to be a sensitive test organism for assessing environmental pollution. After nine weeks of treatment with wood ash, a significant effect of enhanced stem growth was observed at higher concentrations (1-10 g l(-1)). The concentration of wood ash was also correlated with the growth of secondary branches. Photosynthesis (oxygen evolution after 4 h of exposure to wood ash) was significantly lower in the alkaline treatments (no pH adjustment) compared to the treatments with neutral wood ash solutions (pH adjusted to 7.5). Furthermore, photosynthesis in the alkaline wood ash treatments was significantly lower compared to the control. The ratio between the optical density value before and after acidification (OD(665/665a)) was higher for all wood ash concentrations compared to the control. The OD(665/665a) values ranged from 1.52 to 1.61 and there was a difference, however not significant, between the alkaline and the neutral treatment at 10 g l(-1) wood ash. This study clearly demonstrated that wood ash may be beneficial for F. antipyretica at moderate concentrations (0.5-5 g l(-1)), particularly when a sudden increase in pH is avoided.     

Incorporating catchment to reach scale processes into hydromorphological assessment in the UK

Hydromorphological pressures and the measures undertaken to address them are an important element of the delivery of the WFD within the United Kingdom. While assessment procedures currently employed gather useful morphological information for river reaches and their immediate margins and some process information, crucial information on key processes is missing and information gathered on the riparian zone and floodplain is limited. This article presents a newly developed framework that enables existing data to be placed within a multiscale, process‐based context. The framework has great promise for diagnosing hydromorphological pressures, identifying where and how natural recovery is likely to take place, and where more interventionist restoration techniques may be needed. The ability to consider trajectories of river channel adjustments could help us understand how watercourses are still responding to historic changes, improve our confidence in applying restoration measures and the likely hydromorphological consequences of future climate changes.     

Conservation of Riparian Forest Remnants,West Coast,New Zealand

Riparian forest is a priority for protection in New Zealand. Data are provided on the spatial extent and distribution of riparian forest and forest remnants within the West Coast region of New Zealand. Despite the West Coast having the bulk of New Zealand's riparian forest, such forests are under-represented in many of the region's Ecological Districts. Lack of other suitable soils meant that, where possible, floodplains were extensively developed for agriculture. Consequently riparian forest remnants within farmland are small and isolated. The implications of ecological processes and land-management practices for the conservation management of the riparian forest remnants are discussed, and three conservation priorities are identified.     

综合指标法评价城市河流生态系统的健康状况

探讨了河流生态系统健康的概念和评价方法。针对城市河流生态系统，建立了综合指标评价体系，运用层次综合法评价了济南市玉绣河广场东沟和西沟的健康状况。结果表明，东沟整体处于亚健康状态；西沟整体处于健康状态。因此，改善水质、修复水生物栖息环境是玉绣河后期治理的重点，还应加强东沟河滨带的休闲空间和景观生态建设。     

Conservation of Riparian Forest Remnants, West Coast, New Zealand

Riparian forest is a priority for protection in New Zealand. Data are provided on the spatial extent and distribution of riparian forest and forest remnants within the West Coast region of New Zealand. Despite the West Coast having the bulk of New Zealand's riparian forest, such forests are under-represented in many of the region's Ecological Districts. Lack of other suitable soils meant that, where possible, floodplains were extensively developed for agriculture. Consequently riparian forest remnants within farmland are small and isolated. The implications of ecological processes and land-management practices for the conservation management of the riparian forest remnants are discussed, and three conservation priorities are identified.     

The current state of the use of large wood in river restoration and management

Trees fall naturally into rivers generating flow heterogeneity, inducing geomorphological features, and creating habitats for biota. Wood is increasingly used in restoration projects and the potential of wood acting as leaky barriers to deliver natural flood management by ‘slowing the flow’ is recognised. However, wood in rivers can pose a risk to infrastructure and locally increase flood hazards. The aim of this paper is to provide an up‐to‐date summary of the benefits and risks associated with using wood to promote geomorphological processes to restore and manage rivers. This summary was developed through a workshop that brought together academics, river managers, restoration practitioners and consultants in the UK to share science and best practice on wood in rivers. A consensus was developed on four key issues: (i) hydrogeomorphological effects, (ii) current use in restoration and management, (iii) uncertainties and risks and (iv) tools and guidance required to inform process‐based restoration and management.     

Landscape level planning in alluvial riparian floodplain ecosystems: Using geomorphic modeling to avoid conflicts between human infrastructure and habitat conservation

River channel movement processes necessary to maintain the natural heterogeneity in wildlife-dependent riparian ecosystems often conflict with the need to protect adjacent human infrastructure (e.g. towns, bridges, water pumps). This conflict can be avoided through long-term planning efforts which use process-based geomorphic simulation modeling to forecast potential long-term (>50 years) landscape-level effects of water management decisions on river meander migration. We describe two management conflicts from the Sacramento River, California, USA, and analyze alternative management scenarios using results from a meander migration and cutoff simulation model. The first example shows that the existing rock revetment upstream from Woodson Bridge State Recreation Area alters the river meandering and causes erosion problems. Removing the revetment would relocate the channel and create a natural meander-neck chute cutoff, reducing erosion at the park while providing ecosystem benefits. The second example suggests that although a bank revetment is needed to prevent the river from moving away from a major water pump, removing an upstream bank revetment would provide habitat benefits without causing pump facility problems. These examples demonstrate the benefits of taking a long-term, landscape-level view when implementing infrastructure projects in dynamic landscapes.     

中国园林博物馆藏古窗修复简述

在中国园林博物馆开展的第一次文物修复项目中,有 23 套以杉木、樟木为主的明清古窗得以修复。本文简述了其修复过程,并展示了一些修复环节的图片,以期为博物馆的古窗类藏品修复提供一定参考。     

Comparative environmental assessment of wood transport models: A case study of a Swedish pulp mill

Wood transportation from forest landing to forest-based industries uses large amounts of energy. In the case of Sweden, where forest operations are highly and efficiently mechanized, this stage consumes more fossil fuels than other elements of the wood supply chain (such as silviculture and logging operations). This paper intends to compare the environmental burdens associated to different wood transport models considering a Swedish pulp mill as a case study by using Life Cycle Assessment (LCA) as an analytical tool.Five scenarios (the current one and four alternative reliable scenarios) were proposed and analysed taking into account two variables. On the one hand, the influence of imported pulpwood share from Baltic countries and on the other hand, the use of rail transportation for wood transport. In particular, the following impact categories were assessed: Eutrophication, Global Warming, Photochemical Oxidant Formation, Acidification and Fossil fuel extraction. The environmental results indicate that transport alternatives including electric and diesel trains, as well as the reduction in Baltic wood imports should present better environmental performance than the current scenario in terms of all the impact categories under study. Remarkable differences were identified with regard to energy requirements. This divergence is related to different long-distance transport strategies (lorry, boat and/or train) as well as the relative import of wood selected.The combination of lorry and train in wood transportation from Southern Sweden plus the reduction of wood imports from 25% to 15% seems to be more favourable from an environmental perspective. The results obtained allow forecasting the importance of the wood transport strategy in the wood supply chain in LCA of forest products and the influence of energy requirements in the results.     

Variability in energy and carbon dioxide balances of wood and concrete building materials

A variety of factors affect the energy and CO₂ balances of building materials over their lifecycle. Previous studies have shown that the use of wood for construction generally results in lower energy use and CO₂ emission than does the use of concrete. To determine the uncertainties of this generality, we studied the changes in energy and CO₂ balances caused by variation of key parameters in the manufacture and use of the materials comprising a wood- and a concrete-framed building. Parameters considered were clinker production efficiency, blending of cement, crushing of aggregate, recycling of steel, lumber drying efficiency, material transportation distance, carbon intensity of fossil fuel, recovery of logging, sawmill, construction and demolition residues for biofuel, and growth and exploitation of surplus forest not needed for wood material production. We found the materials of the wood-framed building had lower energy and CO₂ balances than those of the concrete-framed building in all cases but one. Recovery of demolition and wood processing residues for use in place of fossil fuels contributed most significantly to the lower energy and CO₂ balances of wood-framed building materials. We conclude that the use of wood building material instead of concrete, coupled with greater integration of wood by-products into energy systems, would be an effective means of reducing fossil fuel use and net CO₂ emission to the atmosphere.     

Fire Resistance of Wood Joist Floor Assemblies

This paper discusses the factors that affect the fire resistance performance of lightweight wood frame unrestrained floor assemblies protected with Type X gypsum board ceiling finishes. Twenty-two fire resistance experiments were conducted on full-scale load-bearing wood joist floor assemblies using the ULC standard fire exposure time–temperature curve that is similar to ASTM E119 standard. Parameters investigated in this study include the effects of gypsum board screws spacing from board edges, insulation installation, insulation type, joist spacing for assemblies with gypsum board attached to resilient channels, joist depth, resilient channel installation, resilient channel spacing, sub-floor topping, number of sub-floor layers, and load magnitude. The impact of these parameters on the fire resistance of wood joist frame floor assemblies is discussed. The fire resistance of wood frame floors appears essentially to be governed by the gypsum board screw spacing from the board edges and the type of insulation in assemblies with one layer of gypsum board and by the resilient channel spacing and the gypsum board screw spacing from the board edges in assemblies with two layers of gypsum board. The effects of other parameters in assemblies with two layers of gypsum board such as the joist spacing where the gypsum boards are attached to resilient channels, installation of resilient channels, insulation installation, insulation type, adding gyp-crete topping above the sub-floor and number of sub-floor layers on fire resistance are relatively insignificant.     

基于景观多样性的北京市域森林质量 综合评价

森林景观多样性是生物多样性的重要组成部分,是综合评价社会经济发展和生态环境损益的前沿和热点,森林景观承载了社会文化、生产、生态等多种生态系统服务功能。采用层次分析法,以北京市森林遥感图像和实地调查数据为基础,选取与景观多样性相关的指标,构建城市森林质量综合评价指标体系,评价森林综合质量,分析北京森林景观现状及问题。结果表明:近年来,森林景观规模增加促进了北京市三生空间的融合,加快了森林生态资产的正向增长。北京市森林景观保护与修复工作已从增加规模阶段转变为提升综合质量阶段,中幼林和成、过熟林是未来改造提升的重点。持续实施碳汇造林、营林工程,提升森林景观多样性,是森林保护、修复与管理工作的重点。     

Limestone and dolomite powder as binders for wood ash agglomeration

Limestone and dolomite powder were tested as binders during wood ash agglomeration on an industrial and a laboratory scale. Two agglomeration methods are compared. Dolomite from Estonia is commonly used as a binder/additive during automatic production of agglomerated wood ash at the central heating plant of Kalmar, Sweden. Swedish limestones from Öland and Ignaberga as well as Swedish dolomite from Glanshammar were used as binders in the production of test agglomerates of wood ash. The chemical and mineralogical composition of the binders as well as of the resulting granules and pellets is presented. The structural, chemical and leaching properties of the hardened ash/binder agglomerates are discussed in relation to their possible environmental impact on forest soil. The environmental acceptance of recycling of agglomerated ashes to forest soils is also discussed in relation to the new recommendations.