Sökning: "cover estimates"

Visar resultat 1 - 5 av 58 avhandlingar innehållade orden cover estimates.

  1. 1. Boreal vegetation responses to forestry as reflected in field trial and survey data and the quality of cover estimates and presence/absence in vegetation inventory

    Detta är en avhandling från Institutionen för fysik, kemi och biologi

    Författare :Johan Bergstedt; Per Milberg; Göran Ståhl; [2008]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Boreal forest; cutting intensity; scarification; cover estimates; presence absence; NATURAL SCIENCES Biology Terrestrial; freshwater and marine ecology Terrestrial ecology; NATURVETENSKAP Biologi Terrestisk; limnisk och marin ekologi Terrestisk ekologi;

    Sammanfattning : Den här avhandlingen belyser hur avverkning och markberedning påverkar markfloran i den svenska barrskogen. Dessutom utvärderas två inventeringsmetoder som används inom växtekologin. LÄS MER

  2. 2. Pollen productivity estimates and pollen-based reconstructions of Holocene vegetation cover in Norhtern adn temperate China for climate modelling

    Detta är en avhandling från Växjö : Linnaeus University Press

    Författare :Furong Li; Linnéuniversitetet.; [2016]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; climate; pollen-vegetation relationships; relative pollen productivity; REVEALS model; anthropogenic land-cover change; Holocene; China; Paleoecology; Paleoekologi;

    Sammanfattning : Model projections of future climate change require that coupled climate-vegetation models are developed and validated, i.e. these models should be able to reproduce past climate and vegetation change. Records of pollen deposited in lake bottoms and peat bogs can provide the information needed to validate these models. LÄS MER

  3. 3. Pollen-based quantitative reconstruction of land-cover change in Europe from 11,500 years ago until present - A dataset suitable for climate modelling

    Detta är en avhandling från Växjö : Linnaeus University Press

    Författare :Anna-Kari Trondman; Linnéuniversitetet.; [2014]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; pollen data; REVEALS model; model testing; land vegetation; land-cover; Holocene; Europe;

    Sammanfattning : The major objective of this thesis was to produce descriptions of the land vegetation-cover in Europe for selected time windows of the Holocene (6000, 3000, 500, 200, and 50 calendar years before present (BP=1950)) that can be used in climate modelling. Land vegetation is part of the climate system; its changes influence climate through biogeophysical and biogeochemical processes. LÄS MER

  4. 4. Estimating source area of pollen and pollen productivity in the cultural landscapes of southern Sweden - developing a palynological tool for quantifying past plant cover

    Detta är en avhandling från Quaternary Sciences, Department of Geology, Lund University

    Författare :Anna Broström; [2002]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; pollen productivity estimates; relevant source area of pollen; southern Sweden; quantitative landscape reconstruction; GIS; pollen dispersal; simulation model; Geology; physical geography; Geologi; fysisk geografi;

    Sammanfattning : Fossil pollen records retrieved from peat and lake sediments have great potential for quantifying past plant cover. This thesis is a contribution to the development of a palynological interpretation tool for reconstructing past cultural landscapes in terms of plant abundance and distribution. LÄS MER

  5. 5. Studies of the Arctic Ocean sea ice cover and hydrothermal heat fluxes

    Detta är en avhandling från Quaternary Sciences, Department of Geology, Lund University

    Författare :Christian Stranne; Göteborgs universitet.; Gothenburg University.; [2012]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Oceanography; Arctic climate sensisitvity;

    Sammanfattning : Since reliable ice extent estimates from satellite data became available in 1979 the Arctic sea ice cover has followed a declining long term trend. Over the last decade the decline has accelerated with record low sea ice extents recorded in 2002, 2005, 2007 and 2012. LÄS MER