Quantifying the effects of forestry practices on the recovery of upland streams and lochs from acidification

Trends in long-term chemistry data are presented for 37 acidified upland streams and lochs, located in four areas (A, B, C and D) across Scotland, to provide a comparison between recovery rates of moorland catchments and forest catchments at different stages of the management cycle. For all sites, non-marine sulfate (nm-SO(4)) showed a significant decline in annual median concentrations, the greatest decline being in streams draining felled catchments, which showed a 50% greater decline than catchments with moorland or young, aggrading forests. A similar pattern was found for chloride (Cl) concentrations in Area C, which reflected the reduced interception of sea-salt aerosols following clearfelling. However, high elevation moorland sites in Area D also revealed significant declines in Cl while trends in aggrading forest sites in this area were insignificant. Alkalinity (ALK) and pH increased more at sites where felling had taken place than at moorland or young forest sites while aggrading forest catchments appeared to be most resistant to changes in pH and ALK. Associated with these acid-base changes was a corresponding decline in labile aluminium (Al-L) concentrations. The pattern of nitrate (NO(3)) change was especially affected by the timing of felling in forested catchments. Large negative trends in NO(3) at stream sites were associated with felling during the early part of the study period. This downward trend was further enhanced as NO(3) concentrations fell below pre-felling levels as the second rotation crop became established. Few forest sites showed significant increases in NO(3) due to felling in the latter part of the study period. Most moorland loch sites showed a small but significant increase in NO(3,) probably in response to similar increases in N deposition and/or climatic impacts. Dissolved organic carbon (DOC) increased significantly at both forest and moorland sites, however, the extent of these increasing trends appeared to be positively correlated with absolute DOC concentrations. Despite the complex response of streams and lochs during the various stages of the forest cycle, especially for NO(3), both forest and moorland catchments showed generally similar and rapid responses to reductions in S deposition. Nevertheless, forested sites are still more acid and have higher concentrations of toxic forms of Al than moorland sites. Although the proposed emission reductions in Europe are likely to result in a continuing decline in S and N loadings to catchments, the continuing policy of planting second rotation forests in these acidified catchments may, in the long-term, delay or halt chemical and biological recovery. However, in the short-term, any increase in the uptake of N deposition by aggrading forests should help to counteract the acidifying effects of a small increase in the interception of S and N compounds.     

Database for a debate: a review of upland research

ENVIRONMENTAL GROUPS IN POLITICS by Philip Lowe and Jane Goyder, George Allen and Unwin, London, 1983. £15 (hardback); £6.95 (paperback).

LANDSCAPE, LAND USE AND THE LAW: AN INTRODUCTION TO THE LAW RELATING TO THE LANDSCAPE AND ITS USE by J. D. C. Harte, 450 pages, E. &; F. N. Spon Ltd., London, 1985. £25 (hardback); £14.95 (paperback).

ARCADIA FOR ALL: THE LEGACY OF A MAKESHIFT LANDSCAPE by Dennis Hardy and Colin Ward, Mansell, London, 1984. £9.95.     

The nitrogen composition of streams in upland Scotland: some regional and seasonal differences

The nitrogen (N) composition of streams draining four upland regions of Scotland was compared in samples collected monthly between April 1997 and April 1998. Stream samples were analysed for total N (TN), particulate N (PN), nitrate (NO3), ammonium (NH4), dissolved organic N (DON) and dissolved organic carbon (DOC). Concentrations of TN were small, generally less than 1 mg l(-1) , dominated by dissolved forms of N, and varied significantly between upland regions. Nitrate accounted for most of the variability in TN; largest concentrations were observed in the Southern Uplands and smallest concentrations were observed in the Highlands. Nitrate concentrations were positively correlated with the percentage cover of improved grasslands and brown forest soils and negatively correlated with the percentage cover of peat. Concentrations of DON also varied between regions, but to a lesser extent than those of NO3. Largest concentrations occurred in SW Scotland and smallest concentrations in the Cairngorms. Although a significant positive correlation between DON and DOC was observed, stream water DON content was not related to the percentage cover of peat in the catchment, as was the case for DOC. The average DOC:DON ratio was narrower for streams in the Southern Uplands than for those in the Cairngorms and Highlands. Nitrate and DON displayed contrasting seasonal trends; NO3 concentrations were larger in the winter while DON concentrations were larger in the summer. Only a small proportion, < 8% and < 7%, of TN was PN and NH4, respectively, the majority of N was present as either NO3 or DON. Nitrate was the dominant fraction (58-65%) in all regions except the Highlands where DON accounted for 57% of TN. However, the relative importance of the DON component increased in the summer in all regions. This study has demonstrated that the DON fraction is an important component of the total N transported by streams from upland catchments in Scotland. Thus, assessments of anthropogenic impacts on N losses from upland ecosystems need to consider not only the dissolved inorganic species but also DON.     

An investigation into the effects of forestry plantations on the water quality of upland reservoirs in northern ireland

A study was made of a wide range of Northern Ireland lakes to determine the effect of the fertilisation of forestry plantations. Lakes with fertilised forest catchments contained very high phosphorus levels. Bioassay with Selenastrum suggested that nitrogen and phosphorus were the only elements limiting growth and the supply of iron and trace metals was sufficient for large crops in nearly all cases.     

经济棘皮动物种质资源保护与利用研究进展

水产种质资源是渔业发展的重要物质基础。中国现有棘皮动物500余种,其中海参、海胆是中国水产重要养殖种类。自20世纪90年代,水产原良种建设工程启动以来,中国经济棘皮动物种质资源保护取得了长足进步,初步建立起具有中国特色的经济棘皮动物种业体系,但仍存在不同层面的诸多问题和挑战。本文综述了经济棘皮动物(海参、海胆)的种质资源分布、鉴定、评价、保护及种质资源创新,并就建设经济棘皮动物国家水产原良种场、种质资源测试评估体系、种质资源库和信息共享平台,以及海参、海胆"育繁推一体化"提出建议,以期推动中国棘皮动物种质资源保护,种业、养殖业体质增效、绿色发展。     

Importance of interactions between the water column and the sediment for microbial concentrations in streams

The effect of interactions between the sediment and water column on concentrations of microbes in streams is quantified with a one-dimensional, steady state model. The effects of nine main parameters describing the flow, sediment transport, and microbial growth and decay are encapsulated in two dimensionless parameters: the Damköhler number Da, or the ratio of the time scales of advection and net growth, and the sediment interaction parameter S, or the ratio of the amount of microbes lost or gained in the sediment and the amount of microbes lost or gained in the water column. Applications of the model illustrate the importance of the sediment and identify parameters that require further study. The model predicts the field measurements of Jamieson et al. (2005b) within a factor of 2 in two of three cases, while concentrations predicted by ignoring the sediment exceed the measured values. In general, the effects of ignoring interactions with the sediment depend on Da and S. The loading predicted to meet water quality standards when the sediment is considered can be either greater than or less than the loading predicted when it is not considered. The applications of the model and an analysis of uncertainty suggest that further work on the settling velocity, attached fraction, resuspension rate, and net growth rate in the sediment would help to improve predictions of the fate and transport of microbes.     

From crisis to conservation: a critical review of the intertwined economic and political factors driving built heritage conservation policy in Hong Kong and a possible way forward

This paper provides a deeper understanding of Hong Kong’s built heritage conservation policies as they have been developed during the city’s colonial and post-colonial periods, especially the political and social factors that have prompted and influenced their development and evolution. Initial observations and thoughts are derived from the authors’ extensive conservation involvement with UNESCO and local and overseas governments as well as their experience with some of Hong Kong’s key statutory boards and government committees that deal with built heritage conservation. Through their first-hand experience, coupled with extensive research, the authors argue that conservation policies in Hong Kong have not been created with a local vision, but instead have been catalysed by external factors, in particular, those relating to economics and politics. The paper concludes with a recommendation that Hong Kong should focus on social considerations in reshaping future conservation policy, as articulated in UNESCO’s Historic Urban Landscape approach.     

Performance characteristics of enhanced soil blocks: a quantitative review

Several studies have focused on improving the properties of soil blocks/bricks due to perceived and real strength and durability limitations. A review of 56 published studies is presented on the effect of stabilization on the performance characteristics of soil blocks. The review found that few studies have been conducted on durability properties of enhanced soil blocks as compared with physico-mechanical properties. Fibre-enhanced soil blocks tended to have peak performance with an optimal content that achieved maximum performance. The maximum performance improvement was generally less than a doubling of the strength of the soil without the fibres. Binders showed a continual improvement with greater concentrations, so much greater improvements can be obtained if the economic and social costs can be justified. Both fibres and binders have variable performance on water absorption with both reductions and increases possible. Generally, both fibre and binder inclusion in soil blocks enhance the performance characteristics of the blocks. Binders are typically more effective on a mass-fraction basis. However the supply of fibres is usually at a lower cost and a reduced environmental impact, and therefore may have a better performance on a per-cost or per-impact basis.     

Climate change: the views of forestry students in a Greek university

The trend to global warming is one of the most important problems of our time. This paper reports the findings of self‐management questionnaires, in regard to views held on the issue of climate change by the students of the Department of Forestry and Management of the Environment and Natural Resources of the Democritus University of Thrace.     

Effects of soil conservation measures in a partially vegetated area after forest fires

After forest fires on the east coast of Korea in 2000, some burnt areas were left untreated. Although 80% of the area was reasonably revegetated within 3 months, about 20% of the area was partially vegetated, mainly due to a low density of sprouters and poor growing conditions (eroded soil and steep slopes). Three years after the fires, the effect of soil conservation measures, such as mulching with wood chips, seeding with native plant species and log erosion barriers (LEBs), on runoff and soil erosion were examined using runoff plots. Wood chip mulching greatly reduced runoff and sediment yields and these effects were consistent regardless of the volume of rainfall. Neither seeding nor LEBs reduced runoff and sediment yields. No positive or negative effects of mulching, seeding or LEBs on ground vegetation cover were observed. The ineffectiveness of seeding and LEBs may have been due to the steep slope, the failure of germination and establishment of seeded plants, and the small diameter of logs. Treating hill slopes with mulch should be considered where post-fire regeneration is slow and there is an absence of organic material such as litter.     

A pilot study of the efficacy of residuum lodges for managing sediment delivery to impoundment reservoirs

Residuum lodges comprise small dams constructed on feeder streams immediately before they enter a reservoir, behind which ponds form, where sediment is deposited. Despite their construction on many impoundment reservoirs (IRE) and catchwaters, little research has previously investigated their efficacy at removing sediments from feeder streams. The current pilot study has, therefore, been carried out at an IRE supplying Halifax, West Yorkshire, UK, where a residuum lodge was recently cleaned out. Sediment concentrations reaching the reservoir were reduced by up to 42% although no certain impacts were noted on the other water quality variables that were measured. Moreover, it was found that the clearance operation did not result in the release of excessive quantities of sediment into the reservoir. It was estimated that the cleared residuum lodge would take 12 years to refill. A survey of other residuum lodges in the Yorkshire region showed there to be considerable differences in their remaining capacities.     

Captured streams and springs in combined sewers: A review of the evidence,consequences and opportunities

Captured streams and springs may be flowing in combined sewers, increasing clean baseflow in pipes and wastewater treatment works (WwTWs), reducing pipe capacity and increasing treatment costs. The UK water industry is aware of this in principle, but there has been no explicit discussion of this in the published literature, nor have there been any known attempts to manage it. Instead, the current focus is on the similar intrusion of groundwater infiltration through pipe cracks and joints. We have conducted a thorough review of literature and international case studies to investigate stream and spring capture, finding several examples with convincing evidence that this occurs. We identify three modes of entry: capture by conversion, capture by interception, and direct spring capture. Methods to identify and quantify capture are limited, but the experience in Zurich suggests that it contributed 7–16% of the baseflow reaching WwTWs. There are negative impacts for the water industry in capital and operational expenditure, as well as environmental and social impacts of loss of urban streams. For a typical WwTW (Esholt, Bradford) with 16% of baseflow from captured streams and springs, we conservatively estimate annual costs of £2 million to £7 million. A detailed case study from Zurich is considered that has successfully separated captured baseflow into daylighted streams through the urban area, with multiple economic, environmental and social benefits. We conclude that there is a strong case for the UK water industry to consider captured streams and springs, quantify them, and assess the merits of managing them.     

Synthesis of dawsonite: a method to treat the etching waste streams of the aluminium anodising industry

Synthesis of dawsonite was studied as a way to deal with the etching waste streams of the aluminium anodising industry in order to reduce the emissions to the environment and also to recover useful and marketable mineral resource materials. The process of synthesis was carried out using two different waste streams arising from the etching section of an anodising process when a cascade rinsing system is employed, the spent etching bath solution (132 g/l of Al and 151 g/l of Na), and the first stage effluent from the cascade rinsing system (67 g/l of Al and 71 g/l of Na). The synthesis of dawsonite was studied as a function of NaHCO3/Al molar ratio (1-10), crystallization temperature (30-150 degrees C), and reaction time (2-48 h) using supersaturated NaHCO3 solutions. A NaHCO3/Al molar ratio of 3 was optimal to obtain dawsonite as a single phase, and a reaction time of 24 h and high crystallization temperature (150 degrees C) to improve its crystallinity. The mineral characterisation was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential thermal analysis (DTA), all of which indicated characteristics typical of the desired compound. Almost 100% of the aluminium initially present in the etching waste streams was recovered in the form of dawsonite when the appropriate conditions for its synthesis were used.     

The physical factors affecting heavy metals accumulated in the sediment deposited on road surfaces in dry weather: a review

The main objective of this review is to identify and analyse physical factors (PF) involved in the heavy metal accumulation phenomenon in the road-deposited sediment (RDS) in dry weather. Electronic databases were used to establish an order of prevalence by establishing quartiles (Q-citation frequency) for the PF identified. The results show that the eleven PF can most likely be classified into three categories: climatic-anthropogenic-morphometric. The studies most frequently referenced land use (Q1), rainfall (Q2), particle size (Q2) and vehicles (Q3) as key PF. There is a similar behaviour between the concentrations of Zn-Pb-Cu associated with the RDS in dry weather and the dissolved fraction washed from the surface in road runoff. The size fraction <250 μm is representative of RDS to characterize the metals. The review expands knowledge about the influences of the PF in the processes of deposition-suspension-interception-removal of the metals load in road environments.     

Water quality in the Scottish uplands: a hydrological perspective on catchment hydrochemistry

Land above 300 m covers approximately 75% of the surface of Scotland and most of the nation's major river systems have their headwaters in this upland environment. The hydrological characteristics of the uplands exert an important influence on the hydrochemistry of both headwater streams and downstream river systems. Thus, many of the spatial and temporal patterns in the chemical quality of surface waters are mediated by hydrological processes that route precipitation through upland catchments. These hydrological pathways also have an important influence on how the hydrochemistry of upland streams is responding to increasing pressures from environmental changes at the global and regional scales. At the present time, atmospheric deposition remains an issue in many parts of the Scottish uplands, where critical loads of acidity are exceeded, particularly in areas affected by increasing N deposition. Moreover, climatic change forecasts predict increasingly wetter, warmer and more seasonal conditions, which may modify the hydrochemical regimes of many river systems, particularly those with a strong snowmelt component. On a more localised scale, land management practices, including felling of commercial forests, expansion of native woodlands, agricultural decline and moorland management all have implications for the freshwater environment. Moreover, increasing public access to upland areas for a range of recreational activities have implications for water quality. Understanding the hydrology of the uplands, through integrated field and modelling studies, particularly of the hydrological pathways that regulate chemical transfers to streamwaters, will remain an important research frontier for the foreseeable future.     

Reproducibility of the BCR sequential extraction procedure in a long-term study of the association of heavy metals with soil components in an upland catchment in Scotland

Humic iron podzol soils from three different plots at the Glensaugh Research Station, Aberdeenshire have been sampled on an annual basis since 1990 and analysed using both total digestion and the original BCR sequential extraction procedure. Particular care was required during the oxidation of these organic soils to prevent loss of material. The residue from the sequential extraction was analysed so that the values for total concentration derived from the total digestion and from the sum of the concentrations in the fractions of the extraction procedure could be compared. The comparison was good for all three soils indicating that not only did the sequential extraction give good recovery but that this was reproducible over a period of several years. The proportion of metals extractable at each step remained relatively constant thereby demonstrating the reproducibility of the procedure and the stability of the metals in the soils over the time scale of the sampling used. Whereas the total concentrations of Cr, Cu and Ni were highest in the soil from a roadside plot, this was not the case for Cd, Pb and Zn. In the case of Pb, concentrations in soils (0-25-cm depth) well away from the road were over 100 mg/kg and well above the expected background level. The distribution of metals between each of the extracted fractions varied not only between each metal but also between each of the three soils indicating that both metal and soil influenced the measured distribution. The distribution of Pb in the roadside soil was different from those in the other two soils and over 10% was extracted in the first, acetic acid soluble, fraction.     

Ethical practices in the landscape profession: a research note

This paper addresses the concept of ethics within the landscape professions. A definition of ethics shows how important the perceived role played by an individual is. Four elements of ethics — professional, personal, business and environmental — are identified along with their associated responsibilities, relationships and conflicts. The role of professionals in society is discussed with special reference to the environmental role of landscape professionals. The paper refers to interviews, which took place in the summer of 1994, with the Registrar and President of the Landscape Institute and relates those discussions to the ethical elements defined earlier. The paper concludes that the environmental ethic is presently left up to the individual professional and is not taken up by the professional body. Concern for the environmental ethic in the twenty first century is raised as an issue for both individuals and the Landscape Institute.