hig.sePublikationer
Ändra sökning
Avgränsa sökresultatet
1 - 6 av 6
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Majdi, Hooshang
    et al.
    Departments of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Nylund, Jan-Erik
    Forest Products and Markets, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Ågren, Göran I.
    Departments of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Root respiration data and minirhizotron observations conflict with root turnover estimates from sequential soil coring2007Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 22, nr 4, s. 299-303Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The turnover of fine roots in northern coniferous forests has conventionally been assumed to be rapid, in line with results from sequential coring in the late 1970s in a Swedish Scots pine stand (SWECON project) where a rate of 7.4 year(-1) was estimated. New quantifications of the root respiration in other stands motivated a recalculation of the SWECON data; an indirect estimation of the turnover rate was much slower, about 2.1 year(-1). As a consequence, fine-root production is considered to be much lower than in previous estimates. Furthermore, direct observations of Norway spruce fine roots (< 1 mm) from minirhizotrons in Sweden, including a site close to the SWECON site, indicated a slower estimate, with fine-root turnover rate of 0.9 year

  • 2.
    Majdi, Hooshang
    et al.
    Departments of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Nylund, JE
    Forest Products and Markets, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Ågren, Göran I.
    Departments of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Response to comments on 'Root respiration data and minirhizotron observations conflict with root turnover estimates from sequential soil coring'2007Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 22, nr 6, s. 473-474Artikel i tidskrift (Refereegranskat)
  • 3.
    Mjöfors, Kristina
    et al.
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Strömgren, Monika
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Nohrstedt, Hans-Örjan
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Johansson, Maj-Britt
    Högskolan i Gävle, Rektors kansli. Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Gärdenäs, Annemieke I.
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Indications that Site Preparation increases Forest Ecosystem Carbon Stocks in the Long-Term2017Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 32, nr 8, s. 717-725Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mechanical site preparation (MSP) causes a mixing disturbance of the soil, which may increase decomposition of soil organic matter and subsequent carbon (C) dioxide emissions to the atmosphere. MSP also promotes the establishment and growth of tree seedlings, and hence ecosystem C fixation. However, there are uncertainties regarding net effects of MSP on C stocks at the ecosystem scale. To assess decennial effects of MSP on ecosystem C stocks, C stocks in soil, ground vegetation and trees at three experimental forest sites with Pinus contorta, Pinus sylvestris and Picea abies in Sweden were sampled and measured ca. 25 years in a control and after three MSP treatments: disc trenching, mounding and ploughing. After 25 years, all of the MSP treatments resulted in larger ecosystem C stocks than the control treatment due to positive effects on the tree biomass C stock. The tree C stock was highest after ploughing, intermediate after mounding or disc trenching, and lowest in untreated control plots at all experimental sites. The MSP treatments did not affect the soil C stocks down to 30 cm. We recommend mounding or disc trenching to promote C sequestration as they disturb sites’ ecological, aesthetic and recreational values less than ploughing.

  • 4.
    Oostra, Swantje
    et al.
    epartment of Landscape Planning, Swedish University of Agricultural Sciences, Alnarp, Sweden.
    Majdi, Hooshang
    Högskolan i Gävle, Institutionen för matematik, natur- och datavetenskap, Ämnesavdelningen för naturvetenskap.
    Olsson, Mats
    Department of Forest Soils, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Impact of tree species on soil carbon stocks and soil acidity in southern Sweden2006Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 21, nr 5, s. 364-371Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The impact of tree species on soil carbon stocks and acidity in southern Sweden was studied in a non-replicated plantation with monocultures of 67-year-old ash (Fraxinus excelsior L.), beech ( Fagus silvatica L.), elm (Ulmus glabra Huds.), hornbeam (Carpinus betulus L.), Norway spruce ( Picea abies L.) and oak ( Quercus robur L.). The site was characterized by a cambisol on glacial till. Volume-determined soil samples were taken from the O-horizon and mineral soil layers to 20 cm. Soil organic carbon (SOC), total nitrogen (TN), pH (H2O), cation-exchange capacity and base saturation at pH 7 and exchangeable calcium, magnesium, potassium and sodium ions were analysed in the soil fraction < 2 mm. Root biomass (< 5 mm in diameter) and its proportion in the forest floor and mineral soil varied between tree species. There was a vertical gradient under all species, with the highest concentrations of SOC, TN and base cations in the O-horizon and the lowest in the 10 - 20 cm layer. The tree species differed with respect to SOC, TN and soil acidity in the O-horizon and mineral soil. For SOC and TN, the range in the O-horizon was spruce > hornbeam > oak > beech > ash > elm. The pH in the O-horizon ranged in the order elm > ash > hornbeam > beech > oak > spruce. In the mineral soil, SOC and TN ranged in the order elm > oak > ash = hornbeam > spruce > beech, i.e. partly reversed, and pH ranged in the same order as for the O-horizon. It is suggested that spruce is the best option for fertile sites in southern Sweden if the aim is a high carbon sequestration rate, whereas elm, ash and hornbeam are the best solutions if the aim is a low soil acidification rate.

  • 5. Tarvainen, O
    et al.
    Markkola, A M
    Ahonen-Jonnarth, Ulla
    Högskolan i Gävle, Institutionen för matematik, natur- och datavetenskap, Ämnesavdelningen för datavetenskap.
    Jumpponen, A
    Strömmer, R
    Changes in Ectomycorrhizal Colonization and Root Peroxidase Activity in Pinus sylvestris Nursery Seedlings Planted in Forest Humus2004Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 19, nr 5, s. 400-408Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plant biomass, root colonization by ectomycorrhizal (ECM) fungi and root peroxidase (POD) activity were monitored in Scots pine (Pinus sylvestris L.) nursery seedlings during the first growing season after planting (after 4, 8 and 16 weeks, in July, August and October, respectively) in forest humus in outdoor open-top chambers with gaseous atmospheric pollutants (combinations of low levels of ozone, sulfur dioxide and nitrogen oxides). The number of ECM morphotypes as well as root biomass increased towards the end of the growing season, while root POD activity decreased. Fungal biomass estimated as ergosterol concentration peaked in August, 8 weeks after planting. The seedling growth, mycorrhizal status and POD activity in the roots were not affected by the gaseous pollutants.

  • 6. Von Arnold, Karin
    et al.
    Ivarsson, Maria
    Öqvist, Mats
    Majdi, Hooshang
    Högskolan i Gävle, Institutionen för matematik, natur- och datavetenskap, Ämnesavdelningen för naturvetenskap.
    Björk, Robert G
    Weslien, Per
    Klemedtsson, Leif
    Can the distribution of trees explain variation in nitrous oxide fluxes?2005Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 20, nr 6, s. 481-489Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The impact of distance to tree stems on nitrous oxide (N2O) fluxes was examined to determine whether it is possible to improve the accuracy of flux estimates from boreal forest soils. Dark static chambers were placed along transects between pairs of trees within a Norway spruce stand and fluxes of N2O and carbon dioxide (CO2) were measured during the period 1999-2003. The groundwater table was measured on every sampling occasion along the transects. In addition, radiation transmission, potential diffusion rate and biomass of forest floor vegetation were measured once at each chamber site along one of the transects and soil samples were collected at three depths, from which pH, denitrification enzyme activity, soil moisture, organic matter, and carbon and nitrogen content were determined. There was a high level of variation in the N2O fluxes, both spatially and temporally. However, the spatial variation in the N2O fluxes within the transect could not be explained by differences in any of the measured variables. Sometimes, mainly when no major peaks occurred, N2O fluxes were significantly correlated with CO2 release. It is concluded that distance to stems cannot be used to improve the design of sampling schemes or for extrapolating flux levels to larger scales.

1 - 6 av 6
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf