The effects of forest management on water quality

Water quality is generally high in watercourses draining forested areas. However, forest management can lead to detrimental effects on water quality and the aquatic environment. Key concerns include diffuse pollution, carbon transport and harmful effects on freshwater ecology.Here, we undertake a review of the effects of a range of forestry activities including cultivation and site preparation, fertilisation and harvesting on water quality.We attempt to summarise the literature across a wide geographical area focusing on empirical studies. Studies report a wide range of water quality impacts after forest operations including sediment delivery, nutrient losses, carbon transport, metal and base cation releases, and changes to acidity and temperature. Spatial and temporal resolution is an important consideration. Changes in water quality at the local scale are often not seen at the catchment level and the effects of operations may be manifest many years after the work was carried out, highlighting the importance of monitoring at an appropriate spatial and temporal scale. The development of best management practices (BMPs) such as the use of buffers, low impact techniques and phased felling have led to significant changes in operational activity, reducing and, in some cases, preventing impacts on water quality. We highlight some of the most effective techniques that can protect water quality from cultivation, drainage, fertiliser and harvesting operations.We also take a forward look to technological, methodological and climatic developments that may alter forest management effects on water quality

Riparian vegetation patterns and links with surface waters in the boreal forest

Riparian areas in the Canadian boreal forest represent the transition zone between terrestrial and aquatic ecosystems. Factors that influence riparian vegetation communities and the associated interactions with boreal streams were reviewed. Regional and local drivers (e.g., climate and site hydrology) that affect upland boreal vegetation also operate in riparian areas. However, the proximity of riparian areas to the stream channel not only modifies some of these drivers, but it means that the stream itself becomes a driver of riparian vegetation dynamics. For example, hydrological disturbances like flooding and ice scour affect soil texture and alter successional pathways, sometimes completely denuding streambanks of vegetation. Even in riparian areas unaffected by such catastrophic disturbances, saturated soil conditions can influence riparian forest composition and nutrient cycling

The effects of legacy sulphur deposition on methylmercury production in northern peatlands; geochemical and biological considerations

Mercury is a ubiquitous element with a complex geochemical cycle. Aquatic ecosystems such as wetland soils convert inorganic mercury to organic, neurotoxic methylmercury though the activity of sulphate-reducing bacteria (SRB). Sulphate stimulates the activity of SRB, and the production of methylmercury in these environments. My aim was to investigate the effect that legacy sulphate has on Hg methylation in northern peatlands through a laboratory sulphate addition experiment with differentially sulphate-exposed peats and a field study of peatlands subjected to different levels of sulphate. Results from the laboratory study indicate that peatlands in regions of higher atmospheric sulphate deposition show enhanced Hg methylation responses compared to pristine peatlands, while field results indicate that sulphate deposition increases Hg methylation dependence on other nutrients as opposed to sulphate supply. Management for peatlands impacted by industrial sulphate sources will have to consider legacy sulphate deposition within peatland geochemical context to mitigate potential Hg methylation

Nutrient and Hydrologic Conditions Post-Fire: Influences on Western Boreal Plain Aspen (Populus tremuloides Michx.) Re-establishment and Succession

The Western Boreal Plains of Alberta (WBP) contains a mixture of peatlands and forests, with the latter dominated by trembling aspen (Populus tremuloides Michx.). Given the sub-humid climate of the WBP, where evapotranspiration (ET) often exceeds precipitation (P), uplands are usually dependent on peatlands for water supply. The process of hydraulic redistribution (HR), the transfer of water from one area to another through roots, is a mechanism by which aspen obtain moisture from peatlands. However, the effects of disturbances such as fire on this process remain unknown, and it is uncertain if connectivity between land units through HR continues post-fire. During May 2011, a wildfire affected 90 000 ha of north central Alberta including the Utikuma Region Study Area (URSA). Portions of a glacio-fluval outwash lake catchment was burned which included forests and a ~0.5 ha peatland. Within one year after the fire, aspen were detected in peatlands and at peatland margins. The purpose of this study was to monitor aspen recovery across a burned hillslope, and determine if nutrients, soil moisture conditions, or both were sufficient to permit regeneration in peatlands. The role of aspen in peatlands in forest recovery was also investigated. Across recovering land units in 2013 and 2014, plot transpiration (Eplot) measurements were taken to evaluate stress levels where on average midslope (0.42 mm hr-1) > hilltops (0.29 mm hr-1) > riparian (0.23 mm hr-1) > peatlands (0.095 mm hr-1); similar trends were observed with leaf area and stem heights. To determine if aspen required excess nutrients for regeneration, plant available nitrate (NO3-), ammonium (NH4+), and water extractable phosphorus (Ext-P) were measured in both growing seasons. While Ext-P remained elevated with the highest levels in burned peatlands, aspen stem height and leaf area were not greatly dependent on P. Similarly, negative relationships with growth were observed with increasing soil moisture content (VWC). Although VWC was below field capacity (<25%) in forests, P. tremuloides were sustained through roots present, likely before fire, in peatland margins through hydraulic redistribution. Evidence for this was observed in oxygen (δ18O) and hydrogen (δ2H) isotopes (‰) where upland xylem and peat core signatures were -10.0 ‰, -117.8 ‰ and -9.2 ‰, -114.0 ‰, respectively, highlighting their importance in hydrologically connecting forests to water sources. This study showed that while peatlands were resource rich post-fire, aspen was able to regenerate in nutrient and moisture-poor forests and that peatlands are unsuitable areas for further re-establishment. This research also highlighted the significance of hydraulic redistribution to forest recovery. The continuation of HR and water table fluctuations however, may result in soil moisture changes and the encroachment of aspen. Therefore, peat margins post-disturbance may be at risk during succession resulting in margin loss

Puuston hakkuiden tai palamisen aiheuttamat typen ja fosforin ravinnehuuhtoumat

Tiivistelmä. Tässä työssä tarkasteltiin avohakkuiden vaikutuksia typen ja fosforin huuhtoumiin. Työssä pyrittiin selvittämään huuhtoumia aiheuttavia mekanismeja ja niitä lieventäviä metsänhoidon käytäntöjä. Lisäksi verrattiin avohakkuiden aiheuttamia huuhtoumia maastopalojen aiheuttamiin huuhtoumiin. Tutkimusmenetelmänä käytettiin kirjallisuuskatsausta boreaalisella alueella toteutetuista alan tutkimuksista sekä viranomaisten tuottamista tutkimusraporteista. Ennen tutkimuskysymyksen vastausta työssä käytiin läpi typen ja fosforin kiertokulkua metsäekosysteemissä sekä metsien hydrologiaa. Sen jälkeen kerrottiin avohakkuiden vaikutuksista metsän hydrologiaan ja tarkasteltavien ravinteiden kulkuun. Yleisesti ravinnehuuhtoumien kasvua selittävä tekijä oli ravinteita sitovan ja vettä haihduttavan puuston poisto, joka lisäsi paikallista valumaa. Pohjaveden pinnan nousun todettiin mahdollisesti aiheuttavan fosforin lisääntynyttä huuhtoumaa hapettomien olosuhteiden lisätessä redox-herkkien rauta-fosforiyhdisteiden liukoisuutta. Vesiliukoista nitraattia muodostavan nitrifikaation havaittiin kohonneen maaperässä, mikä saattaa lisätä typen huuhtoumaa. Ravinteikkailla turvemailla tehtyjen avohakkuiden arveltiin joissain tutkimuksissa aiheuttavan enemmän typpihuuhtoumaa kuin köyhemmillä turvemailla toteutettujen hakkuiden. Fosforihuuhtoumien taas on tutkimuksissa havaittu olevan mahdollisesti suurempia köyhistä kuin rikkaista turvemaista johtuen köyhien maiden alhaisista fosforia sitovien alkuaineiden pitoisuuksista. Jatkuvapeitteisen metsänkasvatuksen hyödystä fosforihuuhtoumien lieventämisessä on hieman tutkimusnäyttöä. Typen suhteen tutkimusnäyttö ei ole selkeää. Avohakkuissa syntyvien hakkuujätteiden korjaamisen vaikutukset ravinnehuuhtoumiin eivät ole selkeitä tarkastellun kirjallisuuden perusteella. Suojavyöhykkeiden havaittiin joissain tutkimuksissa alentavan hakkuiden jälkeisiä ravinnehuuhtoumia tehokkaasti, pintavalutuskenttien käytön tehosta sen sijaan on ristiriitaisia tuloksia. Maastopalojen vaikutuksien ravinnehuuhtoumaan havaittiin tutkimuksissa olevan tarkasteltujen ravinteiden kohdalla avohakkuihin rinnastettavia.Leaching of nitrogen and phosphorus caused by clear-cutting or wildfires. Abstract. This thesis examined eutrophication causing leaching of nitrogen and phosphorus caused by clear-cutting. The thesis aimed to find mechanisms which cause leaching and forestry practices to alleviate it, and compared leaching caused by clear-cutting to that caused by wildfires. The research method utilized was literature review of research done in the boreal region and research reports produced by governmental agencies. Before answering the research question, topics such as the cycle of nitrogen and phosphorus in forests, the hydrology of forests and the effects of clear-cutting on the cycles and hydrology were examined. Clear-cuts were found in many studies to cause increase in runoff from forested areas in response to the disappearance of processes which cause trees to evaporate water. The nutrient take-up of trees also disappeared, and these two factors explained the cause of universal nutrient leaching. The rise of groundwater table level and subsequent creation of anoxic conditions was discovered to possibly cause increased leaching of phosphorus in studies with anoxic conditions increasing the solubility of redox-sensitive iron-phosphorus compounds. Nitrification, which forms water-soluble nitrate, was found to increase in soil after clear-cutting, possibly increasing the leaching of nitrogen. Clear-cutting on rich peat soils was thought in some studies to cause more nitrogen leaching than similar logging on poorer peat soils. Phosphate leaching, on the other hand, was found to be greater on poorer than richer peat soils, because of the low amount of strongly phosphorus-binding elements in poor peat soils. Based on studies there is some evidence of continuous coverage of forests to slightly alleviate phosphorus leaching. The evidence is not clear on the effects on nitrogen leaching. The collection of logging waste after clear-cutting did not have any clear effects on nutrient leaching based on the research studied. Buffer zones were found in some studies to effectively lower nutrient leaching from areas of clear-cutting, whereas the studies on overland-flow fields discovered mixed results. The leaching of nitrogen and phosphorus caused by wildfires was found to be similar as that of clear-cutting

ECOSSE: Estimating Carbon in Organic Soils - Sequestration and Emissions: Final Report

Background Climate change, caused by greenhouse gas ( GHG) emissions, is one of the most serious threats facing our planet, and is of concern at both UK and devolved administration levels. Accurate predictions for the effects of changes in climate and land use on GHG emissions are vital for informing land use policy. Models which are currently used to predict differences in soil carbon (C) and nitrogen (N) caused by these changes, have been derived from those based on mineral soils or deep peat. None of these models is entirely satisfactory for describing what happens to organic soils following land-use change. Reports of Scottish GHG emissions have revealed that approximately 15% of Scotland's total emissions come from land use changes on Scotland's high carbon soils; the figure is much lower for Wales. It is therefore important to reduce the major uncertainty in assessing the carbon store and flux from land use change on organic soils, especially those which are too shallow to be deep peats but still contain a large reserve of C. In order to predict the response of organic soils to external change we need to develop a model that reflects more accurately the conditions of these soils. The development of a model for organic soils will help to provide more accurate values of net change to soil C and N in response to changes in land use and climate and may be used to inform reporting to UKGHG inventories. Whilst a few models have been developed to describe deep peat formation and turnover, none have so far been developed suitable for examining the impacts of land-use and climate change on the types of organic soils often subject to land-use change in Scotland and Wales. Organic soils subject to land-use change are often (but not exclusively) characterised by a shallower organic horizon than deep peats (e.g. organo-mineral soils such as peaty podzols and peaty gleys). The main aim of the model developed in this project was to simulate the impacts of land-use and climate change in these types of soils. The model is, a) be driven by commonly available meteorological data and soil descriptions, b) able to simulate and predict C and N turnover in organic soils, c) able to predict the impacts of land-use change and climate change on C and N stores in organic soils in Scotland and Wales. In addition to developing the model, we have undertaken a number of other modelling exercises, literature searches, desk studies, data base exercises, and experimentation to answer a range of other questions associated with the responses of organic soils in Scotland and Wales to climate and land-use change. Aims of the ECOSSE project The aims of the study were: To develop a new model of C and N dynamics that reflects conditions in organic soils in Scotland and Wales and predicts their likely responses to external factors To identify the extent of soils that can be considered organic in Scotland and Wales and provide an estimate of the carbon contained within them To predict the contribution of CO 2, nitrous oxide and methane emissions from organic soils in Scotland and Wales, and provide advice on how changes in land use and climate will affect the C and N balance In order to fulfil these aims, the project was broken down into modules based on these objectives and the report uses that structure. The first aim is covered by module 2, the second aim by module 1, and the third aim by modules 3 to 8. Many of the modules are inter-linked. Objectives of the ECOSSE project The main objectives of the project were to: Describe the distribution of organic soils in Scotland and Wales and provide an estimate of the C contained in them Develop a model to simulate C and N cycling in organic soils and provide predictions as to how they will respond to land-use, management and climate change using elements of existing peat, mineral and forest soil models Provide predictive statements on the effects of land-use and climate change on organic soils and the relationships to GHG emissions, including CO 2, nitrous oxide and methane. Provide predictions on the effects of land use change and climate change on the release of Dissolved Organic Matter from organic soils Provide estimates of C loss from scenarios of accelerated erosion of organic soils Suggest best options for mitigating C and N loss from organic soils Provide guidelines on the likely effects of changing land-use from grazing or semi-natural vegetation to forestry on C and N in organic soils Use the land-use change data derived from the Countryside Surveys of Scotland and Wales to provide predictive estimates for changes to C and N balance in organic soils over time

Forest harvest effects on mercury in streams and biota in Norwegian boreal catchments

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The impact of conifer plantation forestry on the ecology of peatland lakes

Blanket bog lakes are a characteristic feature of blanket bog habitats and harbour many rare and threatened invertebrate species. Despite their potential conservation value, however, very little is known about their physico-chemical or biological characteristics in western Europe, and their reference conditions are still unknown in Ireland. Furthermore, they are under considerable threat in Ireland from a number of sources, particularly afforestation of their catchments by exotic conifers. Plantation forestry can potentially lead to the increased input of substances including hydrogen ions (H+), plants nutrients, dissolved organic carbon (DOC), heavy metals and sediment. The aims of this study were to investigate the effect of conifer plantation forestry on the hydrochemistry and ecology of blanket bog lakes in western Ireland. Lake hydrochemistry, littoral Chydoridae (Cladocera) and littoral macroinvertebrate communities were compared among replicate lakes selected from three distinct catchment land use categories: i) unplanted blanket bog only present in the catchment, ii) mature (closed-canopy) conifer plantation forests only present in the catchment and iii) catchments containing mature conifer plantation forests with recently clearfelled areas. All three catchment land uses were replicated across two geologies: sandstone and granite. Lakes with afforested catchments across both geologies had elevated concentrations of phosphorus (P), nitrogen (N), total dissolved organic carbon (TDOC), aluminium (Al) and iron (Fe), with the highest concentrations of each parameter recorded from lakes with catchment clearfelling. Dissolved oxygen concentrations were also significantly reduced in the afforested lakes, particularly the clearfell lakes. This change in lake hydrochemistry was associated with profound changes in lake invertebrate communities. Within the chydorid communities, the dominance of Alonopsis elongata in the unplanted blanket bog lakes shifted to dominance by the smaller bodied Chydorus sphaericus, along with Alonella nana, Alonella excisa and Alonella exigua, in the plantation forestry-affected lakes, consistent with a shift in lake trophy. Similarly, there was marked changes in the macroinvertebrate communities, especially for the Coleoptera and Heteroptera assemblages which revealed increased taxon richness and abundance in the nutrient-enriched lakes. In terms of conservation status, despite having the greatest species-quality scores (SQS) and species richness, three of the four International Union for the Conservation of Nature (IUCN) red-listed species of Coleoptera and Odonata recorded during the study were absent from lakes subject to catchment clearfelling. The relative strengths of bottom-up (forestry-mediated nutrient enrichment) and top-down (fish) forces in structuring littoral macroinvertebrate communities was investigated in a separate study. Nutrient enrichment was shown to be the dominant force acting on communities, with fish having a lesser influence. These results confirmed that plantation forestry poses the single greatest threat to the conservation status of blanket bog lakes in western Ireland. The findings of this study have major implications for the management of afforested peatlands. Further research is required on blanket bog lakes to prevent any further plantation forestry-mediated habitat deterioration of this rare and protected habitat

Effectiveness of Water Diversion Structure to Mitigate Runoff, Sediment Yield, Nitrate and Phosphate Concentrations in Skid Trail of Mountainous Forest Ecosystem

It is well-known that soil and water conservation actions (e.g., installing water diversion structures) are necessary to restore skid trails after logging operations. However, there are some points that have yet to be determined concerning the efficacy of rehabilitation on sediment yield and nutrient export to the aquatic environment. The objectives of this study were to determine the optimal distance among the water diversion structures (WDSs) to suppress runoff, sediment yield, and measure nitrate and phosphate concentrations on the skid trails of a mountainous ecosystem. The study was conducted on a total of 18 bounded runoff plots, each with a width of 4 m and a length of 120 m, divided into six treatment compartments done in triplicate. Beech logs were placed at a distance of 5, 10, 20, 30, and 40 meters. An untreated area (U) was set up during the recording period from 18 September 2015 to 17 September 2016. In all the WDS treatments and untreated trails (U), the observed peaks of runoff, sediment yield, as well as nitrate and phosphate concentrations was found to be significantly correlated with the amount of rainfall events. Results show that there was a decrease in surface runoff and runoff coefficient, sediment yield, and nitrate and phosphate concentrations by installing of WDS at different distances. The runoff and runoff coefficients (2.67 mm and 0.101, respectively) were at the lowest level in the WDS20 (WDS at a distance of 20 m). The sediment yield was significantly higher on the U, 13.52 g m-2 followed by WDS40, whereas the lowest values were detected at the WDS10. Significantly higher values of nitrate were found in the U (3.63 mg l-1), while the lowest amounts of nitrate were determined at WDS5 followed by the WDS20 treatment. The highest values of phosphate were found on the U treatment (0.278 mg l-1) followed by the WDS40 treatment, whereas the lowest phosphate values were measured in the WDS20 treated area. Therefore, it can be deduced that the recommended water diversion structure should be placed at a distance of 20 m to mitigate runoff, sediment yield, nitrate and phosphate exports on the skid trails