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  • 1.
    Nilsson, Christer
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lepori, Fabio
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Malmqvist, Björn
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Törnlund, Erik
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hjerdt, Niklas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hjerdt, James M.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Palm, Daniel
    Department of Aquaculture, SLU.
    Östergren, Johan
    Department of Aquaculture, SLU.
    Jansson, Roland
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Brännäs, Eva
    Department of Aquaculture, SLU.
    Lundqvist, Hans
    Department of Aquaculture, SLU.
    Forecasting environmental responses to restoration of rivers used as log floatways: an interdisciplinary challenge2005In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 8, no 7, p. 779-800Article in journal (Refereed)
    Abstract [en]

    Log floating in the 19th to mid 20th centuries has profoundly changed the environmental conditions in many northern river systems of the world. Regulation of flow by dams, straightening and narrowing of channels by various piers and wing dams, and homogenization of bed structure are some of the major impacts. As a result, the conditions for many riverine organisms have been altered. Removing physical constructions and returning boulders to the channels can potentially restore conditions for these organisms. Here we describe the history of log driving, review its impact on physical and biological conditions and processes, and predict the responses to restoration. Reviewing the literature on comparable restoration efforts and building upon this knowledge, using boreal Swedish rivers as an example, we address the last point. We hypothesize that restoration measures will make rivers wider and more sinuous, and provide rougher bottoms, thus improving land-water interactions and increasing the retention capacity of water, sediment, organic matter and nutrients. The geomorphic and hydraulic/hydrologic alterations are supposed to favor production, diversity, migration and reproduction of riparian and aquatic organisms. The response rates are likely to vary according to the types of processes and organisms. Some habitat components, such as beds of very large boulders and bedrock outcrops, and availability of sediment and large woody debris are believed to be extremely difficult to restore. Monitoring and evaluation at several scales are needed to test our predictions.

  • 2.
    Törnlund, Erik
    Umeå University, Faculty of Social Sciences, Department of Economic History.
    "Flottningen dör aldrig": bäckflottningens avveckling efter Ume- och Vindelälven 1945-702002Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The aim of this thesis has been to study and analyse in detail the process by which timber floating in tributaries was phased out. The region covered is that of the Ume and Vindel rivers and the period studied is 1945-70. The years I945-60 have been the most central to the analysis. The approach taken was to study timber floating itself rather than the new transport alternative (lorries) which developed during the post-war period. This brought the increasing costs of timber floating in tributaries into the forefront of the investigation, along with the efforts made to restrain these by means of investment in and partial closure of the floatway network. The consequences in terms of changed labour demand are also discussed.

    An important part of the analysis has been to examine the inherent weaknesses of timber floating in tributaries and the internal driving forces underlying its phasing-out. The term "internal driving forces" connotes those forces which affected timber floating as a means of transport by causing its costs to rise. In other words it has not been a matter of looking at the direct competition from lorry transport and the advantages of the new transport technique but rather of identifying the drawbacks of floating, when, where and how they arose, and how they helped to make it relatively dearer, thus motivating the changeover to lorry transport.

    The internal driving forces were forest structure and labour costs. When labour costs incurred in timber floating in tributaries were rising rapidly and the dimensions of the logs became smaller in size, floating became a dearer transport solution than before. As regards changes in forest structure, the dimensions of logs were diminishing throughout the floating epoch. This meant that the risk of sinking during floating increased. The effect of this was that the need to bark the timber was increasing all the time, which in turn entailed an indirect transport cost for floating. In addition to this, smaller log dimensions affected the labour time and cost of floating.

    The changed labour conditions along with the changed forest structure showed the importance of studying structural change in the Norrland forest region. For during the later 1940s and early 1950s a shortage of labour presented itself, and the cause was to be found in the new job opportunities which were emerging, some in the rural areas, for example in the construction of hydro-electric powerplants, and some in the larger populated localities, and these factors taken together made recruitment for jobs in forestry and timber floating more difficult. One of the chief characteristics of the way events were moving was that recruitment shifted away from having mainly targeted the agrarian lower class of smallholders, crofters and leaseholders so that it now focused increasingly on freehold farmers while at the same time the recruitment base, having previously consisted of younger workers, was now composed mainly of older people.

    Also in this study, various factors have been examined which could conceivably explain the changes in productivity of timber floating in tributaries. The results show, for example, that during the 1950s a partial phasing-out had very small direct effects on productivity in the area studied. Thus the combination of investment and changes in the quantity of timber is the factor which best explains the differences between different tributaries in the trend of productivity. A tributary´s greater capacity to float timber did not necessarily signify a bigger labour requirement since to a certain extent the watercourse itself “did the job”. As regards investment, clearance operations using caterpillar tractors were probably very important. It is true that the genuine dependence of log driving in tributaries on nature influenced conditions varied strongly from year to year, but since the link between investment costs and the trend of productivity is significant, it still seems reasonable to draw the conclusion that investment lent impetus to the rise in productivity during the 1950s.

  • 3.
    Törnlund, Erik
    Umeå University, Faculty of Social Sciences, Demographic Data Base.
    From Natural to Modified Rivers and Back?: Timber Floating in Northern Sweden in 1850-1980 and the Use of Historical Knowledge in Today's Ecological Stream Restoration2011In: Thinking through the environment: Green approaches to global history / [ed] Timo Myllyntaus, Knapwell, Cambridge: White Horse Press, 2011, p. 243-267Chapter in book (Other academic)
  • 4.
    Törnlund, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Östlund, Lars
    Swedish University of Agricultural Sciences.
    Mobility without wheels: The economy and ecology of timber floating in Sweden, 1850-19802006In: Journal of Transport History, ISSN 0022-5266, E-ISSN 1759-3999, Vol. 27, no 1, p. 48-70Article in journal (Refereed)
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