hig.sePublications
Change search
Refine search result
1 - 16 of 16
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Berggren Kleja, Dan
    et al.
    Svensson, M
    Majdi, Hooshang
    Langvall, O
    Jansson, P-E
    Lindroth, A
    Weslien, P
    Bergkvist, B
    Johansson, Maj-Britt
    Swedish University of Agricultural Sciences.
    Pools and fluxes of carbon in three Norway spruce ecosystems along a climatic gradient in Sweden2008In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 89, no 1, p. 7-25Article in journal (Refereed)
  • 2.
    Björk, Robert G.
    et al.
    Department of Plant and Environmental Sciences, Göteborg University, Gothenburg, Sweden.
    Majdi, Hooshang
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Klemedtsson, Leif
    Department of Plant and Environmental Sciences, Göteborg University, Gothenburg, Sweden.
    Lewis-Johnsson, Lotta
    Department of Plant and Environmental Sciences, Göteborg University, Gothenburg, Sweden.
    Molau, Ulf
    Department of Plant and Environmental Sciences, Göteborg University, Gothenburg, Sweden.
    Long-term warming effects on root morphology, root mass distribution, and microbial activity in two dry tundra plant communities in northern Sweden2007In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 176, no 4, p. 862-873Article in journal (Refereed)
    Abstract [en]

    • Effects of warming on root morphology, root mass distribution and microbialactivity were studied in organic and mineral soil layers in two alpine ecosystems over > 10 yr, using open-top chambers, in Swedish Lapland.

    • Root mass was estimated using soil cores. Washed roots were scanned and sortedinto four diameter classes, for which variables including root mass (g dry matter(g DM) m –2 ), root length density (RLD; cm cm –3 soil), specific root length (SRL; m gDM –1 ), specific root area (SRA; m 2 kg DM –1 ), and number of root tips m –2 weredetermined. Nitrification (NEA) and denitrification enzyme activity (DEA) in the top10 cm of soil were measured.

    • Soil warming shifted the rooting zone towards the upper soil organic layer in bothplant communities. In the dry heath, warming increased SRL and SRA of the finestroots in both soil layers, whereas the dry meadow was unaffected. Neither NEA norDEA exhibited differences attributable to warming.

    • Tundra plants may respond to climate change by altering their root morphologyand mass while microbial activity may be unaffected. This suggests that carbon maybe incorporated in tundra soils partly as a result of increases in the mass of the finerroots if temperatures rise.

  • 3.
    Børja, Isabella
    et al.
    orwegian Forest and Landscape Institute, Ås, Norway.
    de Wit, Helene A.
    Norwegian Institute for Water Research ( NIVA), Oslo, Norway.
    Steffenrem, Arne
    orwegian Forest and Landscape Institute, Ås, Norway.
    Majdi, Hooshang
    Department of Ecology and Environmental Research, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Stand age and fine root biomass, distribution and morphology in a Norway spruce chronosequence in southeast Norway2008In: Tree Physiology, ISSN 0829-318X, E-ISSN 1758-4469, Vol. 28, no 5, p. 773-784Article in journal (Refereed)
    Abstract [en]

    We assessed the influence of stand age on fine root biomass and morphology of trees and understory vegetation in 10-, 30-, 60- and 120-year-old Norway spruce stands growing in sandy soil in southeast Norway. Fine root (< 1, 1–2 and 2–5 mm in diameter) biomass of trees and understory vegetation (< 2 mm in diameter) was sampled by soil coring to a depth of 60 cm. Fine root morphological characteristics, such as specific root length (SRL), root length density (RLD), root surface area (RSA), root tip number and branching frequency (per unit root length or mass), were determined based on digitized root data. Fine root biomass and morphological characteristics related to biomass (RLD and RSA) followed the same tendency with chronosequence and were significantly higher in the 30-year-old stand and lower in the 10-year-old stand than in the other stands. Among stands, mean fine root (< 2 mm) biomass ranged from 49 to 398 g m–2, SLR from 13.4 to 19.8 m g–1, RLD from 980 to 11,650 m m–3 and RSA from 2.4 to 35.4 m2 m–3. Most fine root biomass of trees was concentrated in the upper 20 cm of the mineral soil and in the humus layer (0–5 cm) in all stands. Understory fine roots accounted for 67 and 25% of total fine root biomass in the 10- and 120-year-old stands, respectively. Stand age had no affect on root tip number or branching frequency, but both parameters changed with soil depth, with increasing number of root tips and decreasing branching frequency with increasing soil depth for root fractions < 2 mm in diameter. Specific (mass based) root tip number and branching density were highest for the finest roots (< 1 mm) in the humus layer. Season (spring or fall) had no effect on tree fine root biomass, but there was a small and significant increase in understory fine root biomass in fall relative to spring. All morphological characteristics showed strong seasonal variation, especially the finest root fraction, with consistently and significantly higher values in spring than in fall. We conclude that fine root biomass, especially in the finest fraction (< 1 mm in diameter), is strongly dependent on stand age. Among stands, carbon concentration in fine root biomass was highest in the 30-year-old stand, and appeared to be associated with the high tree and canopy density during the early stage of stand development. Values of RLD and RSA, morphological features indicative of stand nutrient-uptake efficiency, were higher in the 30-year-old stand than in the other stands.

  • 4.
    Finér, L.
    et al.
    Joensuu Research Unit, Finnish Forest Research Institute, Finland.
    Helmisaari, H.-S.
    Vantaa Research Unit, Finnish Forest Research Institute, Finland.
    Lohmus, K.
    Institute of Geography, Tartu University, Estonia.
    Majdi, Hooshang
    Department of Ecology, Swedish University of Agricultural Sciences, Sweden.
    Brunner, I.
    Swiss Federal Institute for Forest, Snow and Landscape Research, Switzerland.
    Borja, I.
    Norwegian Forest and Landscape Institute, Norway.
    Eldhuset, T.
    Norwegian Forest and Landscape Institute, Norway.
    Godbold, D.
    School of Environment and Natural Resources, University of Wales, UK.
    Grebenc, T.
    Slovenian Forestry Institute, Slovenia.
    Konopka, B.
    National Forest Centre, Forest Research Institute Zvolen T. G. Masaryka 22, Slovak Republic.
    Kraigher, H.
    Slovenian Forestry Institute, Slovenia.
    Möttönen, M.-R.
    Faculty of Forestry, University of Joensuu, Finland.
    Ohashi, M.
    School of Human Science and Environment, University of Hyogo, Japan.
    Oleksyn, J.
    Institute of Dendrology, Polish Academy of Sciences, Poland.
    Ostonen, I.
    Institute of Geography, Tartu University, Estonia.
    Uri, V.
    Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Estonia.
    Vanguelova, E.
    Environmental and Human Science Division, Forest Research, UK.
    Variation in fine root biomass of three European tree species: Beech (Fagus sylvatica L.), Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.)2007In: Plant Biosystems, ISSN 1126-3504, E-ISSN 1724-5575, Vol. 141, no 3, p. 394-405Article in journal (Refereed)
    Abstract [en]

    Fine roots (< 2 mm) are very dynamic and play a key role in forest ecosystem carbon and nutrient cycling and accumulation. We reviewed root biomass data of three main European tree species European beech, (Fagus sylvatica L.), Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.), in order to identify the differences between species, and within and between vegetation zones, and to show the relationships between root biomass and the climatic, site and stand factors. The collected literature consisted of data from 36 beech, 71 spruce and 43 pine stands. The mean fine root biomass of beech was 389 g m(-2), and that of spruce and pine 297 g m(-2) and 277 g m(-2), respectively. Data from pine stands supported the hypothesis that: root biomass is higher in the temperate than in the boreal zone. The results indicated that the root biomass of deciduous trees is higher than that of conifers. The correlations between root biomass and site fertility characteristics seemed to be species specific. There was no correlation between soil acidity and root biomass. Beech fine root. biomass decreased with stand age whereas pine root biomass increased with stand age. Fine root biomass at tree level. correlated better than stand level root biomass with stand characteristics. The results showed that there exists a strong relationship between the fine root biomass and the above-ground biomass.

  • 5.
    Gaudinski, JB
    et al.
    University of California, Santa Cruz, CA, USA, and Lawrence Berkeley National Laboratory, Berkeley, CA, USA, and University of California, Berkeley, CA, USA.
    Torn, MS
    Lawrence Berkeley National Laboratory, Berkeley, CA, USA, and University of California, Berkeley, CA, USA.
    Riley, WJ
    Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
    Swanston, C
    Lawrence Livermore National Laboratory, Livermore, CA, USA.
    Trumbore, SE
    University of California Irvine, Irvine, CA, USA.
    Joslin, JD
    Belowground Forest Research, Apartado, Santa Elena de Monteverde, Puntarenas, Costa Rica.
    Majdi, Hooshang
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Dawson, TE
    University of California, Berkeley, CA, USA.
    Hanson, J
    Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
    Use of stored carbon reserves in growth of temperate tree roots and leaf buds: analyses using radiocarbon measurements and modeling2009In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 15, no 4, p. 992-1014Article in journal (Refereed)
    Abstract [en]

    Characterizing the use of carbon (C) reserves in trees is important for understanding regional and global C cycles, stress responses, asynchrony between photosynthetic activity and growth demand, and isotopic exchanges in studies of tree physiology and ecosystem C cycling. Using an inadvertent, whole-ecosystem radiocarbon ((14)C) release in a temperate deciduous oak forest and numerical modeling, we estimated that the mean age of stored C used to grow both leaf buds and new roots is 0.7 years and about 55% of new-root growth annually comes from stored C. Therefore, the calculated mean age of C used to grow new-root tissue is similar to 0.4 years. In short, new roots contain a lot of stored C but it is young in age. Additionally, the type of structure used to model stored C input is important. Model structures that did not include storage, or that assumed stored and new C mixed well (within root or shoot tissues) before being used for root growth, did not fit the data nearly as well as when a distinct storage pool was used. Consistent with these whole-ecosystem labeling results, the mean age of C in new-root tissues determined using 'bomb-(14)C' in three additional forest sites in North America and Europe (one deciduous, two coniferous) was less than 1-2 years. The effect of stored reserves on estimated ages of fine roots is unlikely to be large in most natural abundance isotope studies. However, models of root C dynamics should take stored reserves into account, particularly for pulse-labeling studies and fast-cycling roots (< 1 years).

  • 6.
    Majdi, Hooshang
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Fine root turnover in forest ecosystems: Preface2005In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 276, no 1-2, p. VII-VIIIArticle in journal (Refereed)
  • 7.
    Majdi, Hooshang
    Swedish University of Agricultural Sciences, Department of Ecology, Uppsala, Sweden.
    Root and root-lignin degradation in a Norway spruce stand: effects of long-term nitrogen addition2007In: Plant Biosystems, ISSN 1126-3504, E-ISSN 1724-5575, Vol. 141, no 2, p. 214-221Article in journal (Refereed)
    Abstract [en]

    Mass loss, degradation of lignin and the qualitative change of the organic C structures of spruce root litter (2-5 mm in diameter) in O-horizon were studied for a period of 6 years (1995-2001) in a Norway spruce stand with a current deposition of 13 kg N and 12 kg S ha(-1) yr(-1). The stand was fertilized annually by addition of 100 kg N and 114 kg S ha(-1) (NS). Litterbags, acid detergent lignin (ADL), CuO-oxidation as well as C-13-NMR were used for measurements of mass loss, lignin concentration, degradation of lignin and changes of the organic C structures, respectively. The roots originating from the NS-treated plots lost 20% of their mass in the first year while in control (CON) plots the corresponding value was 10%. After 1879 days of decomposition the fertilized roots had a cumulative mass loss of 54% compared with the CON roots of 44%. The C/N ratios were significantly lower in the NS roots (35) than in the CON roots (59) after 1879 days of decomposition. The initial concentrations of ADL were 34.7 and 36.6 in CON and NS roots and increased to 50 and 56%, respectively, after 1879 days. Using CuO-oxidation method the degree of lignin degradation was significantly higher in the NS than CON roots after 853 days while C-13 NMR method showed no change. Our results indicate that CuO-oxidation and solid-state C-13 NMR methods give a qualitative measure of lignin decomposition, while the litterbag and ADL methods allow us to quantify mass loss and lignin concentration, respectively. It is concluded that the mass loss of root litter in fertilized plots is higher than needle litter decomposition in the same stand and the higher nitrogen concentration increases the lignin degradation.

  • 8.
    Majdi, Hooshang
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Andersson, P
    Fine Root Production and Turnover in a Norway Spruce Stand in Northern Sweden: Effects of Nitrogen and Water Manipulation2005In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 8, no 2, p. 191-199Article in journal (Refereed)
    Abstract [en]

    Abstract: Fine root length production, biomass production, and turnover in forest floor and mineral soil (0-30 cm) layers were studied in relation to irrigated (1) and irrigated-fertilized (IL) treatments in a Norway spruce stand in northern Sweden over a 2-year period. Fine roots (<1 mm) of both spruce and understory vegetation were studied. Mini-rhizotrons were used to estimate fine root length production and turnover, and soil cores were used to estimate standing biomass. Turnover was estimated as both the inverse of root longevity (RTL) and the ratio of annual root length production to observed root length (RTR). RTR values of spruce roots in the forest floor in I and IL plots were 0.6 and 0.5 y(-1), respectively, whereas the corresponding values for RTL were 0.8 and 0.9 y(-1). In mineral soil, corresponding values for I, IL, and control (C) plots were 1.2, 1.2, and 0.9 y(-1) (RTR) and 0.9, 1.1, and 1 y(-1) (RTL). RTR and RTL values of understory vegetation roots were 1 and 1.1 y(-1), respectively. Spruce root length production in both the forest floor and the mineral soil in I plots was higher than in IL plots. The IL-treated plots gave the highest estimates of spruce fine root biomass production in the forest floor, but, for the mineral soil, the estimates obtained for the I plots were the highest. The understory vegetation fine root production in the I and IL plots was similar for both the forest floor and the mineral soil and higher (for both layers) than in C plots. Nitrogen (N) turnover in the forest floor and mineral soil layers (summed) via spruce roots in IL, I, and C plots amounted to 2.4, 2.1, and 1.3 g N m(-2) y(-1), and the corresponding values for field vegetation roots were 0.6, 0.5, and 0.3 g N m(-2) y(-1). It was concluded that fertilization increases standing root biomass, root production, and N turnover of spruce roots in both the forest floor and mineral soil. Data on understory vegetation roots are required for estimating carbon budgets in model studies.

  • 9.
    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 coring2007In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 22, no 4, p. 299-303Article in journal (Refereed)
    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

  • 10.
    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'2007In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 22, no 6, p. 473-474Article in journal (Refereed)
  • 11.
    Majdi, Hooshang
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Pregitzer, Kurt
    Nylund, Jan-Erik
    Morén, Ann-Sofie
    Ågren, Göran I
    Measuring Fine Root Turnover in Forest Ecosystems2005In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 276, no 1-2, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Development of direct and indirect methods for measuring root turnover and the status of knowledge on fine root turnover in forest ecosystems are discussed. While soil and ingrowth cores give estimates of standing root biomass and relative growth, respectively, minirhizotrons provide estimates of median root longevity (turnover time) i.e., the time by which 50% of the roots are dead. Advanced minirhizotron and carbon tracer studies combined with demographic statistical methods and new models hold the promise of improving our fundamental understanding of the factors controlling root turnover. Using minirhizotron data, fine root turnover (y−1) can be estimated in two ways: as the ratio of annual root length production to average live root length observed and as the inverse of median root longevity. Fine root production and mortality can be estimated by combining data from minirhizotrons and soil cores, provided that these data are based on roots of the same diameter class (e.g., < 1 mm in diameter) and changes in the same time steps. Fluxes of carbon and nutrients via fine root mortality can then be estimated by multiplying the amount of carbon and nutrients in fine root biomass by fine root turnover. It is suggested that the minirhizotron method is suitable for estimating median fine root longevity. In comparison to the minirhizotron method, the radio carbon technique favor larger fine roots that are less dynamics. We need to reconcile and improve both methods to develop a more complete understanding of root turnover.

  • 12.
    Majdi, Hooshang
    et al.
    Swedish University of Agricultural Sciences, Department of Ecology, Uppsala, Sweden.
    Truus, Laimi
    nstitute of Ecology, Tallinn University, Tallinn, Estonia.
    Johansson, Ulf
    Swedish University of Agricultural Sciences, To ̈ nnersjo ̈ heden and Skarhult Experimental Forests, Simlångsdalen, Sweden.
    Nylund, Jan-Erik
    Swedish University of Agricultural Sciences, Department of Forest Products, Uppsala, Sweden.
    Wallander, Håkan
    Lund University, Department of Microbial Ecology, Ecology Building, Lund, Sweden.
    Effects of slash retention and wood ash addition on fine root biomass and production and fungal mycelium in a Norway spruce stand in SW Sweden2008In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 255, no 7, p. 2109-2117Article in journal (Refereed)
    Abstract [en]

    In the study reported here we examined the short-term effects (1-3 years) of slash retention (SR) and the long-term effects (13-15 years) of wood-ash application (A) on fine roots and mycorrhizae in a 40-year-old Norway spruce forest in southwest Sweden. Soil cores were used to obtain estimates of the biomass (g m(-2)) of roots in three diameter classes (< 0.5, 0.5-1 and 1-2 mm), root length density (RLD), specific root length (SRL) and mycorrhizal root tip density (RTD). Fine root (< 1 mm) length production and mortality, and mycelium production, were estimated using minirhizotron and mesh bag techniques, respectively. Compared with the control plots (C), the biomass of fine roots in diameter classes < 0.5 mm and 0.5-1 mm was significantly higher in A plots, but lower in SR plots. In addition, RLD was significantly lower in the humus layer of SR plots than in the humus layers of C and A plots, but not in the other layers. None of the treatments affected the SRL. In all soil layers, the SR treatment resulted in significant reductions in the number of ectomycorrhizal root tips, and the mycelia production of fungi in mesh bags, relative to the C treatment, but the C and A treatments induced no significant changes in these variables. Fine root length production in the C, A and SR plots amounted to 94, 87 and 70 turn tube(-1) during the 2003 growing season, respectively. Fine root mortality in treated plots did not change over the course of the study. We suggest that leaving logging residues on fertile sites may result in nitrogen mineralisation, which may in turn induce reductions in root biomass, and both root and mycelium production, and consequently affect nutrient uptake and the accumulation of organic carbon in soil derived from roots and mycorrhizae. (C) 2008 Elsevier B.V. All rights reserved.

  • 13.
    Majdi, Hooshang
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Viebcke, CG
    Effects of fertilization with dolomite Lime plus PK or wood ash on root distribution and morphology in a Norway spruce stand in Southwest Sweden2005In: Forest Science, ISSN 0015-749X, E-ISSN 1938-3738, Vol. 50, no 6, p. 802-809Article in journal (Refereed)
    Abstract [en]

    Pelleted wood ash (A) or crushed dolomite lime with added potassium and phosphorous (CaMgPK) was applied to plots in a 60-yr-old Norway spruce stand in Southwest Sweden. Eight years later, we measured the effect of these treatments on a number of root parameters, including root biomass and distribution (in different diameter classes), root length density (cm cm(-3) Soil), specific root length (SRL, mg(-1) DM), and number of mycorrhizal root tips. Layers sampled included the humus layer and the upper 30 cm of the mineral soil. The total fine root (0-1 mm) biomass in the mineral soil layer was lower in the A plots than the control plots, and the fine root (1-2 mm) systems were shallower in the A plots compared to both the control and CaMgPK plots. SRL was higher in the humus layer in both the CaMgPK and A plots than in the controls, and higher in the CaMgPK than in the A plots. The number of mycorrhizal root tips was also higher in the treated plots than in the controls, with the highest numbers being found in CaMgPK plots. Based on our results, we conclude that both the CaMgPK and ash treatments resulted in changes in root morphology and, therefore, presumably increased the capacity for nutrient uptake.

  • 14.
    Oostra, Swantje
    et al.
    epartment of Landscape Planning, Swedish University of Agricultural Sciences, Alnarp, Sweden.
    Majdi, Hooshang
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, 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 Sweden2006In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 21, no 5, p. 364-371Article in journal (Refereed)
    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.

  • 15.
    Ostonen, I.
    et al.
    Institute of Geography, University of Tartu, Estonia.
    Püttsepp, Ü.
    Department of Ecology, Swedish University of Agricultural Sciences, Sweden; Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Estonia.
    Biel, C.
    RTA, Departament d’Horticultura Ambiental, Carretera de Cabrils, Spain.
    Alberton, O.
    Department of Soil Quality, Wageningen University, The Netherlands.
    Bakker, M.R.
    ENITA de Bordeaux, UMR 1220 TCEM (INRA-ENITAB), France.
    Lohmus, K.
    Institute of Geography, University of Tartu, Estonia.
    Majdi, Hooshang
    Department of Ecology, Swedish University of Agricultural Sciences, Sweden.
    Metcalfe, D.
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Sweden.
    Olsthoorn, A.F.M.
    Van Hall Larenstein University of Professional Education, The Netherlands.
    Pronk, A.
    Plant Research International, Wageningen University and Research Centre, The Netherlands.
    Vanguelova, A.
    Environmental & Human Sciences Division, Forest Research, UK.
    Weih, M.
    Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Sweden.
    Brunner, I.
    Swiss Federal Institute for Forest, Snow and Landscape Research, Switzerland.
    Specific root length as an indicator of environmental change2007In: Plant Biosystems, ISSN 1126-3504, E-ISSN 1724-5575, Vol. 141, no 3, p. 426-442Article in journal (Refereed)
    Abstract [en]

    Specific root length (SRL, m g(-1)) is probably the most frequently measured morphological parameter of fine roots. It is believed to characterize economic aspects of the root system and to be indicative of environmental changes. The main objectives of this paper were to review and summarize the published SRL data for different tree species throughout Europe and to assess SRL under varying environmental conditions. Meta-analysis was used to summarize the response of SRL to the following manipulated environmental conditions: fertilization, irrigation, elevated temperature, elevated CO(2), Al-stress, reduced light, heavy metal stress and physical disturbance of soil. SRL was found to be strongly dependent on the fine root classes, i.e. on the ectomycorrhizal short roots (ECM), and on the roots < 0.5 mm, < 1 mm, < 2 mm and 1-2 mm in diameter SRL was largest for ECM and decreased with increasing diameter. Changes in soil factors influenced most strongly the SRL of ECM and roots < 0.5 mm. The variation in the SRL components, root diameter and root tissue density, and their impact on the SRL value were computed. Meta-analyses showed that SRL decreased significantly under fertilization and Al-stress; it responded negatively to reduced light, elevated temperature and CO(2). We suggest that SRL can be used successfully as an indicator of nutrient availability to trees in experimental conditions.

  • 16. Von Arnold, Karin
    et al.
    Ivarsson, Maria
    Öqvist, Mats
    Majdi, Hooshang
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för naturvetenskap.
    Björk, Robert G
    Weslien, Per
    Klemedtsson, Leif
    Can the distribution of trees explain variation in nitrous oxide fluxes?2005In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 20, no 6, p. 481-489Article in journal (Refereed)
    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 - 16 of 16
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf