Search for dissertations about: "tree line"

Showing result 1 - 5 of 42 swedish dissertations containing the words tree line.

  2. 1. Mosses as mediators of climate change : implications for tree seedling establishment in the tundra

    Author : Signe Lett; Ellen Dorrepaal; David Wardle; Marie-Charlotte Nilsson; Vigdis Vandvik; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; arctic; alpine; B. pubescens; bryophytes; competition; facilitation; mosses; P. sylvestris; precipitation changes; seedlings; traits; tree line; warming;

    Abstract : Alpine and arctic tree line expansion depends on the establishment of tree seedlings above the current tree line, which is expected to occur with climate warming. However, tree lines often fail to respond to higher temperatures. Other environmental factors are therefore likely important for tree seedling establishment. READ MORE

  4. 2. Holocene vegetation dynamics and climate changes in the Torneträsk area, northern Sweden

    Author : Lena Barnekow; Kvartärgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Paleobotanik; palynology; phylogeny; Palaeobotany; northern Sweden; Torneträsk; Abisko; lake-level; radiocarbon dating; forest history; Holocene; tree-line; climate; Vegetation; fylogeni; palynologi; Physical geography; geomorphology; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

    Abstract : The aim of this study was to reconstruct the Holocene vegetation history and the climate changes in a subarctic area. The results are based on pollen and macrofossil records from six lakes in the Torneträsk area. The lakes are situated at altitudes between 370 and 999 m a.s. READ MORE

  5. 3. Reproductive patterns of birches (Betula spp.) in northern Sweden

    Author : Stig-Olov Holm; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Reproduction; Betula; seed-quality; seed-set; pollination; pollen-limitation; pollen-competition; tree-line; environmental gradient; seed weight; seedling survival; Semudobia;

    Abstract : The aim of this thesis was to study patterns of reproduction of Betula pendula and B. pubescens coll. along an altitudinal, coastal-inland, gradient in northern Sweden. The altitudinal variation was related to the distribution of the birch taxa along the gradient. READ MORE

  6. 4. Computational methods for on-line shape inspection

    Author : Per Bergström; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Scientific Computing; Teknisk-vetenskapliga beräkningar;

    Abstract : This licentiate thesis describes computational methods that solve problems occurring in industrial on-line shape quality inspection of produced items. These items are measured and compared with their corresponding CAD object. The meaning of on-line is that the inspection is done on-line in the production line, i.e. READ MORE

  7. 5. Summer Climate Variability during the Past 1200 Years in Central Scandinavia – A Tree-Ring Perspective

    Author : Peng Zhang; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Central Scandinavia; climate variability; dendroclimatology; maximum latewood density; Medieval Climate Anomaly; model-proxy data comparison; Pinus sylvestris L.; temperature; tree-ring width;

    Abstract : To set the current 20th century warming in a long-term context, significant efforts have been made to reconstruct hemispheric-to-global temperatures beyond the instrumental period. Tree-rings, which have annual resolution and can be precisely dated, have been widely used to infer past climate variability. READ MORE