| 1. |
- Bergholm, Johan, et al.
(författare)
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Nitrogen fluxes after clear-cutting. Ground vegetation uptake and stump/root immobilisation reduce N leaching after experimental liming, acidification and N fertilisation
- 2015
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 342, s. 64-75
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Tidskriftsartikel (refereegranskat)abstract
- Clear-cutting often results in a dramatic change in the soil nitrogen (N) balance. This study analysed the fate of inorganic soil N over four years (1992-1995) in a new clear-cut containing three replicate blocks. Treatments comprised control (0), 6000 kg CaCO3 ha(-1) (Ca), 600 kg sulphur powder ha(-1) (S) and 600 kg urea-N ha(-1) (U), applied during 1976-1987 to a Norway spruce (Picea abies) forest. Trees were cut in March 1992, after which stems, tops and branches were removed from the 12 experimental plots. Spruce seedlings were planted in May 1992. Clear-cutting resulted in accumulation of approx. 50 kg inorganic N ha(-1) in the 30 cm deep topsoil of the 0, S and U treatments and 25 kg N ha(-1) in the Ca treatment by October of 1992. During the next two years, the inorganic pools increased (S), stabilised (0 and U) or declined (Ca), but from the end of the third year all inorganic pools decreased. Plant cover gradually increased with dominance of Deschampsia flexuosa. Mean plant N uptake in grasses, forbs and spruce seedlings was estimated at 95 (0), 139 (Ca), 52 (S) and 121 (U) kg N ha(-1) for the four-year period. Nitrogen leaching at 50 cm depth was dominated by NO3-N and culminated during the second (Ca and U) and third (0 and S) years. Cumulative N leaching for the four-year period was lower for U and Ca (28 and 31 kg N ha(-1)) than for 0 and S (53 and 81 kg N ha(-1)), and was inversely correlated with plant N uptake. Nitrogen immobilisation in stumps and root necromass (including spruce and grass roots) was calculated to be 35-45 kg N ha(-1) during this period. The four-year N balance showed 5-17% higher inputs (net mineralisation and deposition) than outputs (plant uptake, leaching, immobilisation in dead stumps/roots and accumulation of inorganic N). Gaseous N losses were not studied, but high pH and high NO3--N formation in the organic layers of the Ca treatment in 1992 might have favoured denitrification, which can partly explain the lower amount of inorganic N remaining in this treatment. A novel finding was that stump and dead root immobilisation of N was quantitatively important. A second novel finding was that lime application, although stimulating nitrification, also stimulated plant N uptake so much that nitrate leaching was reduced in comparison with the control and sulphur treatments. (C) 2015 Elsevier B.V. All rights reserved.
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| 2. |
- Hyvönen, Riitta, et al.
(författare)
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Carbon and nitrogen pools and mineralization rates in boreal forest soil after stump harvesting
- 2016
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 377, s. 61-70
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Tidskriftsartikel (refereegranskat)abstract
- The use of forest-derived biomass has steadily increased in Finland and Sweden during the past decades leading to more intensive forest management practices in the region, such as whole-tree harvesting, both above- and belowground. Stump harvesting results in a direct removal of stump and coarse-root carbon (C) from the stand and can cause extensive soil disturbance, which has been suggested to increase C mineralization. In this study, the effects of stump harvesting on soil C and nitrogen (N) mineralization, and soil surface disturbance were studied in two different clear-felled Norway spruce (Picea abies) sites in Central Finland. The treatments were whole-tree harvesting (WTH, removal of stems and logging residues), and WTH and stump harvesting (WTH + S). Both sites, Honkola (2 stands) and Haukilahti (6 stands) were mounded. In both treatments, soil samples were taken from different soil layers down to a total depth of 20 cm in the mineral soil from (i) mounds, (ii) undisturbed soil and (iii) pits. The sampling was performed 11-12 years after treatments. Soil C and N mineralization rates were determined in laboratory incubation experiments. In addition, total C and N pools (g m(2)) were estimated for each disturbance class and soil layer. Soil C and N pools had a tendency to be lower following stump harvesting, but no statistically significant treatment effect was detected. Stump harvesting increased soil mixing as indicated by a significant decrease in C concentration in the mound disturbance class. There was no significant effect of stump harvesting on soil C mineralization rates. A combination of mineralization rates and soil pool data showed that field C mineralization (g CO2-C m(-2) yr(-1)) did not significantly differ between stands where stumps were removed or were retained. Further, stump harvesting did not seem to have any stimulating effect on soil CO2 efflux 11-12 years after treatment. (C) 2016 Elsevier B.V. All rights reserved.
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| 3. |
- Persson, Tryggve, et al.
(författare)
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Long-term effects of stump harvesting and site preparation on pools and fluxes of soil carbon and nitrogen in central Sweden
- 2017
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 32, s. 222-229
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Tidskriftsartikel (refereegranskat)abstract
- Clear-cutting and subsequent site preparation is a common forest management practice in the Nordic countries. Slash and stumps have been suggested to replace fossil fuels in district heating plants. Stump/root removal from clear-cuts will reduce the amount of decomposable substrate in the soil and thus decrease soil CO2 emission, but stump lifting is also supposed to stimulate CO2 efflux and counteract CO2 reduction. To determine the effects of stump/root harvesting in relation to site preparation (stumps retained) on pools and fluxes of carbon (C) and nitrogen (N) after a period of 20-30 years, soil sampling was performed in four pairs of stump/root harvesting (S) and patch scarification (P) stands in central Sweden in 2009. Stump/root harvesting resulted in a significantly lower soil C pool in the humus layer. Annual heterotrophic respiration (R-H) in the whole soil profile was significantly lower after the S than after the P treatment, the mean difference being 38 +/- 23g CO2-Cm(-2)year(-1) (95% CI). This difference was larger than corresponding data from stump/root decomposition models (11-18g CO2-Cm(-2)year(-1)), but both empirical and model data showed that stump/root harvesting will reduce heterotrophic soil CO2 emissions to the atmosphere during the actual period.
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| 4. |
- Persson, Tryggve, et al.
(författare)
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Long-Term Impact of Liming on Soil C and N in a Fertile Spruce Forest Ecosystem
- 2021
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Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 24, s. 968-987
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Tidskriftsartikel (refereegranskat)abstract
- Liming can counteract acidification in forest soils, but the effects on soil C and N pools and fluxes over long periods are less well understood. Replicated plots in an acidic and N-rich 40-year-old Norway spruce (Picea abies) forest in SW Sweden (Hasslov) were treated with 0, 3.45 and 8.75 Mg ha(-1)of dolomitic lime (D0, D2 and D3) in 1984. Between 1984 and 2016, soil organic C to 30 cm depth increased by 28 Mg ha(-1)(30% increase) in D0 and decreased by 9 Mg ha(-1)(9.4% decrease) in D3. The change in D2 was not significant (+ 2 Mg ha(-1)). Soil N pools changed proportionally to those in soil C pools. The C and N changes occurred almost exclusively in the top organic layer. Non-burrowing earthworms responded positively to liming and stimulated heterotrophic respiration in this layer in both D2 and D3. Burrowing earthworms in D3 further accelerated C and N turnover and loss of soil. The high soil C and N loss at our relatively N-rich site differs from studies of N-poor sites showing no C and N loss. Earthworms need both high pH and N-rich food to reach high abundance and biomass. This can explain why liming of N-rich soils often results in decreasing C and N pools, whereas liming of N-poor soils with few earthworms will not show any change in soil C and N. Extractable nitrate N was always higher in D3 than in D2 and D0. After 6 years (1990), potential nitrification was much higher in D3 (197 kg N ha(-1)) than in D0 (36 kg N ha(-1)), but this difference decreased during the following years, when also the unlimed organic layers showed high nitrification potential. Our experiment finds that high-dose liming of acidic N-rich forest soils produces an initial pulse of soil heterotrophic respiration and increases in earthworm biomass, which together cause long-term declines in soil C and N pools.
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| 5. |
- Persson, Tryggve, et al.
(författare)
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Which macroarthropods prefer tree stumps over soil and litter substrates?
- 2013
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 290, s. 30-39
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Tidskriftsartikel (refereegranskat)abstract
- Tree stumps are a potential bioenergy resource to replace fossil fuels and meet the targets for reduced CO2 emissions. However, the effects of stump harvesting on wood-dependent organisms are poorly known. This study assessed the abundances of macroarthropods, especially non-coleopteran groups, in wood, bark and 'periphery' of stumps in comparison with soil to evaluate which species/taxa prefer stumps over soil and would risk a significant population decline following extensive stump harvesting. To assess the effects of stump age on species and individual numbers, 5-, 10- and 20-yr-old stumps were studied at three sites in southern and central Sweden. For each site and age class, stumps of Scots pine (Pious sylvestris) and Norway spruce (Picea abies) were compared. Samples of wood and bark were taken from the full height of the stump and samples of periphery and soil to a depth of 10 cm. The samples were placed in Tullgren funnels for animal extraction during 4 days. A total of 56 species or other taxonomic groups not belonging to Coleoptera were identified. Bark (including the space between bark and wood) had significantly lower species richness of non-coleopteran macroarthropods but higher abundance per m(2) (of cut stump surface) than soil in 10-yr-old stands, which on average contained higher abundances than the other age classes. No significant differences were found between spruce and pine stumps, indicating that one of the tree species can act as a substitute after stump harvesting of the other. Viewed over all substrates, Diplopoda, Coleoptera, Diptera (larvae) and Homoptera contributed most to the total abundance (29, 20, 17 and 15%, respectively). Of these groups, Diplopoda were much more abundant in bark (98%) than in soil (2%). The most common diplopod species was Proteroiulus fuscus, which often demonstrated 100-fold higher abundances (per sample unit) in bark and wood than in soil. Six species/taxa had clearly higher abundances in stumps than in soil. Stump harvesting would thus markedly reduce preferred habitats for these taxa. It is also possible that some species generally considered as soil animals might be occasionally dependent on stumps for, e.g. egg-laying and hatching. For such species, stump harvesting would be more detrimental than indicated by this population survey. (C) 2012 Elsevier B.V. All rights reserved.
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| 6. |
- Taylor, Astrid, et al.
(författare)
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Ant and Earthworm Bioturbation in Cold-Temperate Ecosystems
- 2019
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Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 22, s. 981-994
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Tidskriftsartikel (refereegranskat)abstract
- In temperate ecosystems, earthworms and ants are the most important organisms for bioturbation. Little is known about how these groups contribute to bioturbation in different environments and to what extent overall bioturbation depends on their diversity. We developed a formula that allows quantification of annual earthworm bioturbation, thereby taking differences between earthworm ecotypes into account. With this formula, we calculated earthworm bioturbation at three sites, each with vegetation types typically found in Northern Europe. Earthworm bioturbation was low (1 Mg dry soil ha(-1) y(-1)) in Scots pine and Norway spruce forests with acidic soil (pH 3.9-4.4) and high (between 15 and 34 Mg dry soil ha(-1) y(-1)) in broadleaf forests, grasslands, alder carr and spruce forests on calcareous soil. Burrowing (endogeic and anecic) earthworms accounted for most of the earthworm bioturbation, and these worms had the highest population densities at moderate-to-high soil pH (pH 5-7.2). Estimates of ant bioturbation at the same sites were based on nest abundance, size and residence time. Mean ant bioturbation varied between 0.2 and 1 Mg dry soil ha(-1) y(-1), but individual plots had up to 2.4 Mg dry soil ha(-1) y(-1). In soils with pH higher than 5, the relative contribution of ants to total bioturbation was only 1-5%. Ant bioturbation was higher than earthworm bioturbation only in some forest soils with pH 3.9-4.4. Thus, earthworms appear to be the dominant cause of bioturbation in most types of terrestrial ecosystems in the cold-temperate areas of Europe and when information on local earthworm communities and monthly soil temperatures is available, bioturbation can be quantified using the presented 'earthworm bioturbation formula'.
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| 7. |
- Al-Mashhadi, Ammar, et al.
(författare)
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Changes of arterial pressure following relief of obstruction in adults with hydronephrosis
- 2018
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 123:4, s. 216-224
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Tidskriftsartikel (refereegranskat)abstract
- Background: As much as 20% of all cases of hypertension are associated with kidney malfunctions. We have previously demonstrated in animals and in pediatric patients that hydronephrosis causes hypertension, which was attenuated by surgical relief of the ureteropelvic junction (UPJ) obstruction. This retrospective cohort study aimed to investigate: (1) the proposed link between hydronephrosis, due to UPJ obstruction, and elevated arterial pressure in adults; and (2) if elevated blood pressure in patients with hydronephrosis might be another indication for surgery.Materials and methods: Medical records of 212 patients undergoing surgical management of hydronephrosis, due to UPJ obstruction, between 2000 and 2016 were assessed. After excluding patients with confounding conditions and treatments, paired arterial pressures (i.e. before/after surgery) were compared in 49 patients (35 years old; 95% CI 29–39). Split renal function was evaluated by using mercaptoacetyltriglycine (MAG3) renography before surgical management of the hydronephrotic kidney.Results: Systolic (−11 mmHg; 95% CI 6–15 mmHg), diastolic (−8 mmHg; 95% CI 4–11 mmHg), and mean arterial (-9 mmHg; 95% CI 6–12) pressures were significantly reduced after relief of the obstruction (p < 0.001). Split renal function of the hydronephrotic kidney was 39% (95% CI 37–41). No correlations were found between MAG3 and blood pressure level before surgery or between MAG3 and the reduction of blood pressure after surgical management of the UPJ obstruction.Conclusions: In adults with hydronephrosis, blood pressure was reduced following relief of the obstruction. Our findings suggest that elevated arterial pressure should be taken into account as an indication to surgically correct hydronephrosis.
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| 8. |
- Al-Mashhadi, Ammar Nadhom Farman, et al.
(författare)
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Changes in arterial pressure and markers of nitric oxide homeostasis and oxidative stress following surgical correction of hydronephrosis in children
- 2018
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Ingår i: Pediatric nephrology (Berlin, West). - : Springer. - 0931-041X .- 1432-198X. ; 33:4, s. 639-649
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Tidskriftsartikel (refereegranskat)abstract
- Objective Recent clinical studies have suggested an increased risk of elevated arterial pressure in patients with hydronephrosis. Animals with experimentally induced hydronephrosis develop hypertension, which is correlated to the degree of obstruction and increased oxidative stress. In this prospective study we investigated changes in arterial pressure, oxidative stress, and nitric oxide (NO) homeostasis following correction of hydronephrosis.Methods Ambulatory arterial pressure (24 h) was monitored in pediatric patients with hydronephrosis (n = 15) before and after surgical correction, and the measurements were compared with arterial pressure measurements in two control groups, i.e. healthy controls (n = 8) and operated controls (n = 8). Markers of oxidative stress and NO homeostasis were analyzed in matched urine and plasma samples.Results The preoperative mean arterial pressure was significantly higher in hydronephrotic patients [83 mmHg; 95% confidence interval (CI) 80–88 mmHg] than in healthy controls (74 mmHg; 95% CI 68–80 mmHg; p < 0.05), and surgical correction of ureteral obstruction reduced arterial pressure (76 mmHg; 95% CI 74–79 mmHg; p < 0.05). Markers of oxidative stress (i.e., 11- dehydroTXB2, PGF2α, 8-iso-PGF2α, 8,12-iso-iPF2α-VI) were significantly increased (p < 0.05) in patients with hydronephrosis compared with both control groups, and these were reduced following surgery (p < 0.05). Interestingly, there was a trend for increased NO synthase activity and signaling in hydronephrosis, which may indicate compensatory mechanism(s).Conclusion This study demonstrates increased arterial pressure and oxidative stress in children with hydronephrosis compared with healthy controls, which can be restored to normal levels by surgical correction of the obstruction. Once reference data on ambulatory blood pressure in this young age group become available, we hope cut-off values can be defined for deciding whether or not to correct hydronephrosis surgically.Keywords Blood pressure . Hydronephrosis . Hypertension . Nitric oxide . Oxidative stress . Ureteral obstruction
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| 9. |
- Al-Mashhadi, Ammar Nadhom Farman, et al.
(författare)
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Surgical treatment reduces blood pressure in children with unilateral congenital hydronephrosis
- 2015
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Ingår i: Journal of Pediatric Urology. - : Elsevier BV. - 1477-5131 .- 1873-4898. ; 11:2, s. 91.e1-91.e6
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Tidskriftsartikel (refereegranskat)abstract
- Objective Renal disorders can cause hypertension, but less is known about the influence of hydronephrosis on blood pressure. Hydronephrosis due to pelvo-ureteric junction obstruction (PUJO) is a fairly common condition (incidence in newborns of 0.5-1%). Although hypertensive effects of hydronephrosis have been suggested, this has not been substantiated by prospective studies in humans [1-3]. Experimental studies with PUJO have shown that animals with induced hydronephrosis develop salt-sensitive hypertension, which strongly correlate to the degree of obstruction [4-7]. Moreover, relief of the obstruction normalized blood pressure [8]. In this first prospective study our aim was to study the blood pressure pattern in pediatric patients with hydronephrosis before and after surgical correction of the ureteral obstruction. Specifically, we investigated if preoperative blood pressure is reduced after surgery and if split renal function and renographic excretion curves provide any prognostic information. Patients and methods Twelve patients with unilateral congenital hydronephrosis were included in this prospective study. Ambulatory blood pressure (24 h) was measured preoperatively and six months after surgery. Preoperative evaluations of bilateral renal function by Tc99m-MAG3 scintigraphy, and renography curves, classified according to O'Reilly, were also performed. Results As shown in the summary figure, postoperative systolic (103 +/- 2 mmHg) and diastolic (62 +/- 2 mmHg) blood pressure were significantly lower than those obtained preoperatively (110 +/- 4 and 69 +/- 2 mmHg, respectively), whereas no changes in circadian variation or pulse pressure were observed. Renal functional share of the hydronephrotic kidney ranged from 11 to 55%. There was no correlation between the degree of renal function impairment and the preoperative excretory pattern, or between the preoperative excretory pattern and the blood pressure reduction postoperatively. However, preoperative MAG3 function of the affected kidney correlated with the magnitude of blood pressure change after surgery. Discussion Correction of the obstruction lowered blood pressure, and the reduction in blood pressure appeared to correlate with the degree of renal functional impairment, but not with the excretory pattern. Thus, in the setting of hypertension, it appears that the functional share of the hydronephrotic kidney should be considered an indicator of the need for surgery, whereas the renography curve is less reliable. The strength of the present study is the prospective nature and that ambulatory blood pressure monitoring was used. Future longitudinal prolonged follow-up studies are warranted to confirm the present findings, and to understand if a real nephrogenic hypertension with potential necessity of treatment will develop. Conclusion This novel prospective study in patients with congenital hydronephrosis demonstrates a reduction in blood pressure following relief of the obstruction. Based on the present results, we propose that the blood pressure level should also be taken into account when deciding whether to correct hydronephrosis surgically or not.
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| 10. |
- Appelstrand, Marie, et al.
(författare)
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Kan ett ökat biobränsleuttag kombineras med god miljöhänsyn? : Resultat av en intervjustudie med skogsbrukets aktörer
- 2017
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Ingår i: Stubbskörd - hur påverkas klimat och miljö? - hur påverkas klimat och miljö?. - 9789157694546 - 9789157694553 ; , s. 76-79
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Det är många maskiner och människor engagerade i en avverkning där man tar ut virke, grot och stubbar. En serie djupintervjuer med olika intressenter och aktörer visar att det finns stora brister i planering, logistik och kommunikation mellan de olika leden i kedjan, speciellt då flera olika entreprenörer är inblandade. Svaren visar också att det finns ett behov av bättre utbildning – och att man måste bli bättre på att ta tillvara den kunskap som finns, framförallt hos maskinförare och entreprenörer.
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| 11. |
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| 21. |
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| 23. |
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| 24. |
- Borg, Sixten, et al.
(författare)
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A maximum likelihood estimator of a Markov model for disease activity in Crohn's disease and ulcerative colitis for annually aggregated partial observations.
- 2010
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Ingår i: Medical Decision Making. - 1552-681X. ; 30:1, s. 42-132
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Tidskriftsartikel (refereegranskat)abstract
- Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory bowel diseases that have a remitting, relapsing nature. During relapse, they are treated with drugs and surgery. The present study was based on individual data from patients diagnosed with CD or UC at Herlev University Hospital, Copenhagen, Denmark, during 1991 to 1993. The data were aggregated over calendar years; for each year, the number of relapses and the number of surgical operations were recorded. Our aim was to estimate Markov models for disease activity in CD and UC, in terms of relapse and remission, with a cycle length of 1 month. The purpose of these models was to enable evaluation of interventions that would shorten relapses or postpone future relapses. An exact maximum likelihood estimator was developed that disaggregates the yearly observations into monthly transition probabilities between remission and relapse. These probabilities were allowed to be dependent on the time since start of relapse and on the time since start of remission, respectively. The estimator, initially slow, was successfully optimized to shorten the execution time. The estimated disease activity model for CD fits well to observed data and has good face validity. The disease activity model is less suitable for UC due to its transient nature through the presence of curative surgery.
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| 25. |
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| 26. |
- Gärdenäs, Annemieke, et al.
(författare)
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Knowledge gaps in soil carbon and nitrogen interactions - From molecular to global scale
- 2011
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 43, s. 702-717
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this review was to identify, address and rank knowledge gaps in our understanding of five major soil C and N interactions across a range of scales – from molecular to global. The studied five soil C and N interactions are: i) N controls on the soil emissions of greenhouse gases, ii) plant utilisation of organic N, iii) impact of rhizosphere priming on C and N cycling, iv) impact of black N on the stabilisation of soil organic matter (SOM) and v) representation of fractions of SOM in simulation models. We ranked the identified knowledge gaps according to the importance we attached to them for functional descriptions of soil–climate interactions at the global scale, for instance in general circulation models (GCMs). Both the direct and indirect influences on soil–climate interactions were included. We found that the level of understanding declined as the scale increased from molecular to global for four of the five topics. By contrast, the knowledge level for SOM simulation models appeared to be highest when considered at the ecosystem scale. The largest discrepancy between knowledge level and importance was found at the global modelling scale. We concluded that a reliable quantification of greenhouse gas emissions at the ecosystem scale is of utmost importance for improving soil–climate representation in GCMs. We see as key questions the identification of the role of different N species for the temperature sensitivity of SOM decomposition rates and its consequences for plant available N
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| 27. |
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| 28. |
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| 29. |
- Hansson, Karna, et al.
(författare)
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Carbon and nitrogen pools and fluxes above and below ground in spruce, pine and birch stands in southern Sweden
- 2013
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 309, s. 28-35
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Tidskriftsartikel (refereegranskat)abstract
- We synthesised results on soil carbon (C) and nitrogen (N) fluxes and the accumulation of soil organic C and N under adjacent 50-year-old Norway spruce, Scots pine and silver birch stands growing on similar soils and evaluated the different processes involved. C and N budgets were calculated. Spruce stands had larger stocks of C and N in biomass and soil than birch stands, with pine intermediate. The differences in soil stocks were mainly found in the organic layer, whereas differences in the mineral soil were small. The study showed that there is no simple answer to what is causing the differences in soil C and N stocks, because several processes are interacting. Spruce and pine trees had higher biomass and litter production than birch trees, but total litter inputs showed no significant difference between stands, because the rich ground vegetation under pine and birch contributed with substantial litter inputs, in contrast to the poor ground vegetation under spruce. Decomposition rate (per g of C) was markedly higher under birch than under spruce and pine resulting in lower C and N stocks in the organic layer. This effect was amplified by higher abundance and biomass of earthworms, favoured by higher pH and palatable litter under birch. Earthworm bioturbation probably both increased decomposition rate and damaged the ectomycorrhizal network with negative consequences for the formation of mycorrhizal litter and C storage. In conclusion, the direct effects of spruce, pine and birch litter on C and N pools and fluxes were modified by indirect effects of understorey structure, pH and earthworm responses. (C) 2013 Elsevier B.V. All rights reserved.
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| 30. |
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| 31. |
- Lindroth, Anders, et al.
(författare)
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Hur påverkas lustgas- och metanavgivning av stubbskörd?
- 2017
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Ingår i: Stubbskörd - hur påverkas klimat och miljö?. - 9789157694546 - 9789157694553 ; , s. 39-41
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- I fyra försök var utsläppen av de kraftfulla växthusgaserna lustgas och metan ungefär på samma nivå från stubbskördade ytor som från ytor där stubbarna var kvar. Inte heller markberedning gav några signifikanta effekter. De här studierna är de första i världen på det här området, och resultaten måste därför tolkas med viss försiktighet.
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| 32. |
- Lindroth, Anders, et al.
(författare)
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Stump harvesting can affect the emissions of methane and nitrous oxide
- 2017
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Ingår i: Stump Harvesting : Impact on Climate and Environment - Impact on Climate and Environment. ; , s. 38-42
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The emissions of the greenhouse gases methane and nitrous oxide wereconsistently low in relation to carbon dioxide emissions at four experimental sites.Stump harvesting did not seem to affect the emissions of methane and nitrousoxide. Soil moisture was a major factor for methane emissions – independent ofsoil treatments. These studies are the first ones in the world and should beinterpreted with care until further data have been obtained.
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| 33. |
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| 35. |
- Lohm, Ulrik, 1943-, et al.
(författare)
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Levande jord
- 1978
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Rapport (populärvet., debatt m.m.)
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| 36. |
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| 37. |
- Malmström, Anna, et al.
(författare)
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Do burned areas recover from inside? An experiment with soil fauna in a heterogeneous landscape
- 2012
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 59, s. 73-86
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Tidskriftsartikel (refereegranskat)abstract
- The post-fire soil faunal communities are formed both by animals having survived the fire and by colonizers from the surrounding landscape. The relative impact of these processes is largely affected by fire intensity. However, with the same fire intensity, the severity of the fire and, thus, the survival of soil animals could vary depending on environmental heterogeneity. We hypothesized that much fewer soil animals would survive the same fire intensity on shallow, dry soils than on deep, moist soils. To clarify the impact of soil depth and moisture on animal survival after fire, we conducted a burning experiment in the laboratory. Soil samples containing indigenous populations of soil fauna were taken along two transects from the top, slope and foot of two respective rocky outcrops within a mixed coniferous forest in Central Sweden. Half of the samples were burnt and half were left unburnt. Burning depth varied between 24 mm (soils from the top of the gradient) to 12 mm (slope and foot soils) indicating a difference in flammability. The proportion of animals surviving fire seemed to be fairly independent of burning depth (42 to 62% survival rate). Contribution of eggs which survived fire in the soil to the overall animal abundance restoration was negligible (1–3%). A multi-trophic approach resulted in different sensitivity estimates to artificial burning of various parameters. Abundance and biomass of all fauna groups studied was more sensitive to fire than species richness. Collembolans and macrofauna predators were the groups most tolerant to fire, while oribatid mites and macrofaunal detritivores showed higher mortality after the fire treatment. Despite a more pronounced alteration of the components of soil food-web by burning in the lowland Sphagnum plots, they may be important as refugia, especially for more slowly moving soil-dwelling macro- and microarthropods
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| 38. |
- Malmström, Anna, et al.
(författare)
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Dynamics of soil meso- and macrofauna during a 5-year period after clear-cut burning in a boreal forest
- 2009
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 43, s. 61-74
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine effects of clear-cutting and prescribed clear-cut burning on the abundance and diversity of soil meso- and macrofauna during the early (0-5 years) recovery/recolonisation phase. A 115-year-old stand of mixed Pinus sylvestris and Picea abies in central Sweden was clear-cut in March 1999. Injune 1999, two plots on the clear-cut were burnt and two plots were left unburnt according to an experimental design with two blocks. Two plots of adjacent uncut forest were used as controls. The burning combusted the ground vegetation and the upper half of the 6-cm thick organic layer. In comparison with the unburnt clear-cut, burning decreased the abundances of Collembola, Protura, Mesostigmata, Araneae and Diptera larvae throughout the 5-year period, whereas Enchytraeidae, Lumbricidae, Oribatida, Prostigmata, Astigmata and Tardigrada decreased immediately after the fire but showed tendencies of recovery. Burning also decreased species richness. The majority of the species still absent after 5 years was surface-living species. Even animals with good ability to disperse (Diptera, Coleoptera and Araneae) had not recovered, which indicates a change of habitat or lack of food. Clear-cut burning was particularly detrimental to fungivores and predators, whereas microbidetritivores and herbivores were less affected. Prescribed burning, which is considered to increase aboveground biodiversity, dramatically reduced the soil fauna species richness for at least 5 years and did not add any species to those already present in the forest or clear-cut. (C) 2009 Elsevier B.V. All rights reserved.
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| 39. |
- Malmström, Anna, et al.
(författare)
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Responses of Collembola and Protura to tree girdling – some support for ectomycorrhizal feeding
- 2011
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Ingår i: Soil Organisms. - 1864-6417. ; 83, s. 279-285
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Tidskriftsartikel (refereegranskat)abstract
- Ectomycorrhizal (EM) fungi are very common in forest soils, but their role as a food resource for fungivorous soil animals is poorly known. We used two tree-girdling experiments in Picea abies forests and one experiment in a Pinus sylvestris forest, all in northern Sweden, to indirectly test if Collembola and Protura in boreal forest soils prefer EM fungi over other fungi. We assumed that tree girdling will stop e flux of carbohydrates to roots and associated fungi, and thereby inhibit growth and long-term survival EM fungi. After about one year, proturans decreased in abundance after girdling, indicating that they efer feeding on EM fungi, while most collembolan species seemed to be unaffected by girdling and e presumed reduction in EM fungi. However, the collembolans Mesaphorura macrochaeta, Anurida anaria and Parisotoma notabilis increased in abundance after girdling in one of the three experiments, and Micranurida pygmaea decreased. With the exception of the latter species, this is in accordance with the common opinion that most Collembola prefer saprotrophic fungi over EM fungi, while Protura are at least partly dependent on EM fungi
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| 40. |
- Malmström, Anna, et al.
(författare)
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Why are forest fires generally neglected in soil fauna research? A mini-review
- 2016
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 98, s. 261-271
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Forskningsöversikt (refereegranskat)abstract
- Climate change, unpredictable dry spells and human population growth are expected to increase the frequency of forest fires. Forest fires induce damage on soil ecosystems and seriously compromise their functionality and provision of ecosystem services. They reduce diversity in many soil organism groups, although they also support flora and fauna dependent on fires. Fires disrupt in the cycling of nutrients, and have been argued to threaten the sustainability of forest biomes. However, despite these potentially large effects on soil ecosystems, a literature survey on the forest fire effects on soil fauna demonstrated that the number of publications on this topic between 1979 and 2013 has been surprisingly low compared with studies of other kinds of disturbances. A poll conducted among soil ecologists who actually studied forest fires revealed that more than 50% of the findings about fire effects on soil ecosystems are unlikely to ever be published.The aim of this review was to discover and structure the reasons why forest fires are often neglected by soil zoologists and ecologists and to identify the major problems which deter soil zoologists from this area of research and from publishing obtained results. We show that forest fires are harder to study than many other types of disturbances. Fires are largely unpredictable and are often unique, which makes it difficult to apply statistically robust sampling plans and select proper controls. Spatial heterogeneity of fire intensity and soil fauna distribution complicate the resulting picture. Moreover, high variability of soil biota in time and space, and complicating effects of multiple fires make the results of such studies hard to interpret. We propose several approaches, which may help to document biodiversity and functional changes in soil communities affected by fire more effectively. These include prescribed burnings, indoor and outdoor experiments and meta-analyses of large datasets, including unpublished ones. We further justify the need for closer coordination of researchers to solve the "file drawer problem" for the unpublished data on soil biota shifts in response to forest fires. (C) 2015 Elsevier B.V. All rights reserved.
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| 41. |
- Mikusinska, Anna, et al.
(författare)
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Response of ectomycorrhizal extramatrical mycelium production and isotopic composition to in-growth bag size and soil fauna
- 2013
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 66, s. 154-162
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Tidskriftsartikel (refereegranskat)abstract
- In-growth bags are increasingly used to study extramatrical mycelium (EMM) of ectomycorrhizal fungi in forest soils. In this paper we tested whether bag size and presence of soil fauna in bags influence the production, isotopic composition, carbon (C) and nitrogen (N) content of the EMM. Cylindrical in-growth mesh bags (2- or 5-cm-diameter; with or without openings - (1 or 2 mm), allowing faunal colonization or not) were harvested 37, 48, 81 and 283 days after installation in July and the EMM biomass was determined from elemental analyses of the extractable amount of mycelia. The occurrence of openings allowed animals to invade the bags but this did not affect the amount of EMM. We suggest further studies in this matter since the number of animals was low and variable. In the first harvest, mycelial biomass C was three times greater in 2-cm than in 5-cm-bags. After 81 days, mycelial biomass C was 54% greater in the 2-cm (54 kg ha(-1)) than in the 5-cm bags (35 kg ha(-1)). While total mycelial C did not change over winter, N content increased suggesting a role for the EMM in the storage of N from autumn to spring. The delta C-13 and delta N-15 of the EMM changed between the first three harvests. We hypothesize these changes to be mainly driven by changes in plant C and N sinks. The relation between the isotopic composition of sporocarp exploration type, plant roots and EMM is discussed. (C) 2013 Elsevier Ltd. All rights reserved.
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| 42. |
- Mjöfors, Kristina, et al.
(författare)
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Stubbskörd och markens koldioxidbalans
- 2017
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Ingår i: Stubbskörd - hur påverkas klimat och miljö?. - 9789157694546 - 9789157694553 ; , s. 35-37
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Markstörningar, som stubbskörd och markberedning, leder initialt till minskad koldioxidavgång från marken, visar en serie nya försök. Det är tvärtemot vad man tidigare har antagit. Efter det första året ligger avgången på ungefär samma nivå för störd mark som för ostörd.
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| 43. |
- Mjöfors, Kristina, et al.
(författare)
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Stump harvesting and the soil/atmosphere exchange of CO2
- 2017
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Ingår i: Stump Harvesting : Impacts on Climate and Environment - Impacts on Climate and Environment. ; , s. 33-37
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Soil disturbance from stump extraction and site preparation will initially lead to a reduction in carbon dioxide emissions from the soil. This is one result achieved from a series of new experiments established throughout Sweden and is contrasting to what was previously assumed. After one year however, this initial reduction had disappeared and emissions were around the same level for bothdisturbed and undisturbed soil.
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| 44. |
- Nevéus, Tryggve, et al.
(författare)
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Diuretic treatment of nocturnal enuresis
- 2005
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Ingår i: Scand J Urol Nephrol. - 0036-5599. ; 39:6, s. 474-8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Nocturnal polyuria is considered a major pathogenetic factor in nocturnal enuresis, and the antidiuretic drug desmopressin, given at bed-time, is consequently recognized as a first-line treatment alternative. The aim of this open, non-randomized study was to see whether diuretic medication, given in the afternoon, could give similar therapeutic benefit. MATERIAL AND METHODS: Sixty-three children suffering from primary, monosymptomatic, nocturnal enuresis were included in the study by their primary care paediatrician. After 14 days without any treatment and 14 days for which 0.4 mg of desmopressin was given orally at bed-time, the children were given furosemide 1 mg/kg in the afternoon for 14 consecutive days. The numbers of wet and dry nights were recorded. RESULTS: The numbers of wet nights at baseline, during desmopressin treatment and during furosemide treatment were 10.2+/-3.5, 6.4+/-4.6 and 8.2+/-4.5, respectively. Both drugs were significantly better than no treatment, but only a small proportion of patients became completely dry: 24% on desmopressin and 12% on furosemide. Desmopressin was significantly better than furosemide. Three children who showed no therapeutic effect on desmopressin treatment had a favourable response to furosemide. CONCLUSION: Furosemide, given in the afternoon, has minor therapeutic potential in nocturnal enuresis.
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| 45. |
- Olsson, Bengt, et al.
(författare)
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Effects of long-term N fertilization on nitrate leaching and vegetation responses in a spruce stand after severe wind damage
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 520
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Tidskriftsartikel (refereegranskat)abstract
- Wind damage in a forest stand can result in varying soil effects depending on the pre-history of the site, but areas with storm-felled trees can generally be expected to show more nitrate leaching than undamaged stands. Previous fertilization in such areas, especially with nitrogen (N) fertilizer, may further increase nitrate leaching. This study examined the effect of partial felling of a 42-year-old Norway spruce stand in the Skogaby experimental forest in Sweden during Storm Gudrun in 2005. Nitrate leaching was measured one year before and six years after the storm, in three experimental treatments: fertilization-irrigation with complete nutrient admixture (IF), fertilization with N-free nutrient admixture (V), and an untreated control (0). The 0 and IF treatments had some undamaged replicate plots, but V plots had no trees left after the storm. Compared with undamaged plots and the pre-disturbance level, nitrate leaching was significantly higher in all storm-felled plots, and in the soil solution nitrate dominated strongly over ammonium. Leaching peaked during the second and third post-storm years (2006-2007) and decreased to near pre-storm levels during the fifth and sixth years (2009-2010). Total nitrate leaching 2005-2010 was estimated to be 414, 233, and 218 kg N ha(-1) in the damaged IF, 0, and V plots, respectively. Total nitrate leaching in undisturbed plots in the IF and 0 treatments was 37 and 0.3 kg N ha(-1), respectively. Ground vegetation coverage, biomass, and biomass N increased with time and were negatively correlated with nitrate discharge. However, plant uptake of N only partly explained the significant decline in nitrate leaching between 2006 and 2010. This decrease could also be explained by N immobilization in fungi decomposing woody roots with low N concentrations.
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| 46. |
- Olsson, Bengt, et al.
(författare)
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Heterotrophic respiration and nitrogen mineralisation in soils of Norway spruce, Scots pine and silver birch stands in contrasting climates
- 2012
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 269, s. 197-205
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Tidskriftsartikel (refereegranskat)abstract
- Different tree species are often associated with different soil properties. Earlier studies have shown that Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.), the two dominant tree species in Fennoscandia, often generate soils with larger carbon (C) and nitrogen (N) pools than silver birch (Betula pendula Roth.). Consequently, we hypothesised that spruce and pine would create soils with slower turnover rates than birch. To test this, C and N pools and C and N mineralisation rates were determined in different soil layers (humus, 0-10 cm, 10-20 cm mineral soil) at two sites with contrasting climatic conditions. One site (Tonnersjoheden) was located in the temperate zone in SW Sweden and one (Kivalo) in the north boreal zone in N Finland. At both sites, experimental plots with the three tree species had been established more than 50 years before the study. Samples from the different soil layers were incubated at 15 C in the laboratory for 30 days, and C and N mineralisation rates were determined. In addition, earthworm abundance was estimated at Tonnersjoheden but not at Kivalo (no sign of bioturbation). At Tonnersjoheden, soil C and N pools (g C or N m(-2)) were ranked spruce > pine > birch. C mineralisation rate (mg CO2-C g(-1) C d(-1)) was higher in the birch plots than in the other plots, but because of larger C pools in the spruce plots, field C mineralisation (g CO2-C m(-2) year(-1)) was higher for spruce than for pine and birch. Field net N mineralisation (80-90 kg N ha(-1) year(-1)) did not differ significantly between tree species, but nitrification rates (mu g NO3-N g-1 C d-1) in the topsoil were higher in the birch plots than in the other plots. The birch plots had larger populations of earthworms and a higher degree of bioturbation than any of the coniferous plots, which probably explains the higher turnover rate of birch soil organic matter (SOM). At Kivalo, C and N soil pools were significantly larger in spruce than in birch plots, and C mineralisation rate was higher in birch and spruce humus than in pine humus. Net N mineralisation rate and annual field net N mineralisation (<4 kg N ha-1 year-1) were estimated to be very low, with no effect of tree species. Thus, the hypothesis of a 'birch effect' was supported at Tonnersjoheden, but only partly at Kivalo. The main difference seemed to be that the earthworms at Tonnersjoheden accelerated SOM decomposition under birch, whereas earthworm stimulation was negligible at Kivalo, probably because of climate-related limitations. (C) 2012 Elsevier B.V. All rights reserved.
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| 47. |
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| 48. |
- Olsthoorn, Bart, et al.
(författare)
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Indoor radon exposure and its correlation with the radiometric map of uranium in Sweden
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 811
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Tidskriftsartikel (refereegranskat)abstract
- Indoor radon concentrations are controlled by both human factors and geological factors. It is important to separate the anthropogenic and geogenic contributions. We show that there is a positive correlation between the radiometric map of uranium in the ground and the measured radon in the household in Sweden. A map of gamma radiation is used to obtain an equivalent uranium concentration (ppm eU) for each postcode area. The aggregated uranium content is compared to the yearly average indoor radon concentration for different types of houses. Interestingly, modern households show reduced radon concentrations even in postcode areas with high average uranium concentrations. This shows that modern construction is effective at reducing the correlation with background uranium concentrations and minimizing the health risk associated with radon exposure. These correlations and predictive housing parameters could assist in monitoring higher risk areas.
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| 49. |
- Oulehle, Filip, et al.
(författare)
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Major changes in forest carbon and nitrogen cycling caused by declining sulphur deposition
- 2011
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 17:10, s. 3115-3129
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Tidskriftsartikel (refereegranskat)abstract
- Sulphur (S) and nitrogen (N) deposition are important drivers of the terrestrial carbon (C) and N cycling. We analyzed changes in C and N pools in soil and tree biomass at a highly acidified spruce site in the Czech Republic during a 15 year period. Total S deposition decreased from 5 to 1.1 g m(-2) yr(-1) between 1995 and 2009, whereas bulk N deposition did not change. Over the same period, C and N pools in the Oa horizon declined by 116 g C and 4.2 g N m(-2) yr(-1), a total decrease of 47% and 42%, respectively. This loss of C and N probably originated from organic matter (OM) that had accumulated during the period of high acid deposition when litter decomposition was suppressed. The loss of OM from the Oa horizon coincided with a substantial leaching (1.3 g N m(-2) yr(-1) at 90 cm) in the 1990s to almost no leaching (<0.02 g N m(-2) yr(-1)) since 2006. Forest floor net N mineralization also decreased. This had consequences for spruce needle N concentration (from 17.1 to 11.4 mg kg(-1) in current needles), an increase in litterfall C/N ratio (from 51 to 63), and a significant increase in the Oi + Oe horizon C/N ratio (from 23.4 to 27.3) between 1994 and 2009/2010. Higher forest growth and lower canopy defoliation was observed in the 2000s compared to the 1990s. Our results demonstrate that reducing S deposition has had a profound impact on forest organic matter cycling, leading to a reversal of historic ecosystem N enrichment, cessation of nitrate leaching, and a major loss of accumulated organic soil C and N stocks. These results have major implications for our understanding of the controls on both N saturation and C sequestration in forests, and other ecosystems, subjected to current or historic S deposition.
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| 50. |
- Persson, Tryggve, et al.
(författare)
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Connectivity of litter islands remaining after a fire and unburnt forest determines the recovery of soil fauna
- 2014
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 83, s. 101-108
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Tidskriftsartikel (refereegranskat)abstract
- Forest wildfires can dramatically affect soil communities and reduce abundance and diversity of soil fauna. The recovery of soil animals after a fire depends both on immigration from the unburnt forest and on local survival in less-burnt spots, but the relative importance of these mechanisms is poorly known. Therefore, these factors were studied with regard to soil macrofauna and soil mites seven years after a wildfire occurring in a pine forest area with shallow soil in 2001 in central Sweden. Three replicate transects, each consisting of four plots were studied. The plots were located in (i) the unburnt forest close to the fire edge; (ii) slightly burnt patches directly attached to the unburnt forest; (iii) slightly burnt patches surrounded by bare rock but connected to the unburnt forest edge by a corridor with mostly unburnt litter and vegetation; and (iv) island patches not connected with a corridor to the unburnt forest edge. The hypothesis was that that soil animals would particularly disperse from the unburnt forest to moderately burnt plots inside a burnt area via the network of less-burnt corridors. Poor dispersers would be especially few in the island patches lacking connection to the "mainland", whereas good dispersers would be independent of gaps in connectivity. As expected, the highest abundance of both macrofauna and oribatid mites was found in the unburnt forest. Resident soil macro- and mesofauna representatives had half the abundance in the edge and corridor plots as compared to the control, but their abundance was not lower in the island plots than in the corridor plots indicating on-site survival and recovery. Mobile mesostigmatid mites did not show any significant reduction of abundance in any of the plots. The abundance of soil-dwelling oribatid mites did not differ between islands and unburnt forest, but mobile aboveground oribatids had significantly lower abundance on the islands than in the unburnt forest. The opposite was observed for aboveground and belowground oribatid mite species richness. In conclusion, belowground animals showed mainly local survival and seemed to be independent of corridors presence, whereas most aboveground and mobile macro- and mesofauna seemed to be more responsive to isolation induced by forest fires. Soil and litter corridors connecting unburnt patches inside the burnt forests with the unburnt edges were important mainly for less mobile groups of soil macrofauna. This supports the idea that there is a relatively slow process of soil ecosystem recovery and that external colonization of the burnt areas dominates over the local survival and recovery from refuges. (C) 2014 Elsevier B.V. All rights reserved.
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