| 1. |
- Berg, Björn, et al.
(författare)
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Calcium in decomposing foliar litter – A synthesis for boreal and temperate coniferous forests
- 2017
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Ingår i: Forest Ecology and Management. - : Elsevier B.V.. - 0378-1127 .- 1872-7042. ; 403, s. 137-144
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Tidskriftsartikel (refereegranskat)abstract
- We have synthesized available data for calcium (Ca) dynamics in decomposing foliar litter of mainly pine (Pinus), spruce (Picea), and birch (Betula) species to determine patterns of Ca concentration with climate in newly shed litter and its dynamics in decomposing litter as well as a possible role for Ca as regards limit values. Initial Ca concentration was negatively related to mean annual precipitation (MAP) with different relationships among genera. A limited data set showed a positive relationship across species (p < 0.05) to extractable Ca in soil. In paired stands, litter of both Norway spruce (Picea abies) and lodgepole pine (Pinus contorta) had higher Ca concentrations than Scots pine (Pinus silvestris), Norway spruce litter even twice as high. Relationships between initial concentrations of Ca and those of other nutrients appeared to be dominated by the positive ones to potassium (K) and magnesium (Mg) and specifically for deciduous litter there was a negative relationship to nitrogen (N). In decomposing litter, Ca concentration followed a negative quadratic (Ca = a + t − t2) function and had a maximum, which was variable. The Ca maximum concentration during decomposition was positively related to initial Ca concentration both within and among species. Separate linear relationships based on species were combined into one, in common for all investigated species and genera (R2 = 0.914, n = 63, p < 0.001). Limit values for decomposition were positively related to maximum Ca concentration at p < 0.05 with separate functions for pine and spruce litter. Calcium net release started directly after the incubation and was linear to accumulated mass loss of litter, giving a slope coefficient for each study. The net release rates were linear to initial Ca concentration both within and across species/genera. All studies combined gave a negative linear relationship (R2 = 0.894, n = 67, p < 0.001).
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| 2. |
- Berg, Björn, et al.
(författare)
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Decomposition rates in late stages of Scots pine and Norway spruce needle litter: Influence of nutrients and substrate properties over a climate gradient
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 522
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to show different patterns for decomposition of the main mass of needle litter from two boreal and temperate coniferous tree species, both leading to a stabilized fraction of litter. To this purpose we have reviewed information on decomposition patterns in the lignin-dominated (late) stages of two local foliar litter types, namely those of Scots pine (Pinus silvestris) and Norway spruce (Picea abies) from two climatic gradients of equal extension. We have also reviewed factors determining the limit values for both species.Long-term decomposition studies were used to calculate annual mass loss in the lignin-dominated decomposition stage and relate these to mean annual temperature (MAT), mean annual precipitation (MAP) and concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn) and acid unhydrolyzable residue (gravimetric lignin, AUR).There was no effect of MAT on decomposition of either needle litter type. MAP had a rate-dampening effect on decomposition of Norway spruce litter. There was a rate-stimulating effect of Mn for Norway spruce litter but not for that of Scots pine. In spite of the strong negative effect of AUR and N on decomposition of Scots pine litter there was none at all for that of Norway spruce.Limit values for decomposition were related to the litters’ initial concentrations of N, Mn and AUR and differed between litter types for locally collected, natural litter and for that from experimental litter, the latter having higher N and lower Mn concentrations than the natural litter.We conclude that the two litter types have clear differences as regards rate- regulating factors for decomposition in the late lignin-dominated stage as well as for the stable fraction and suggest two different pathways for their decomposition. This is the first time that different pathways have been suggested for decomposing litter.
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| 3. |
- Ni, Xiangyin, et al.
(författare)
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Formation of forest gaps accelerates C, N and P release from foliar litter during 4 years of decomposition in an alpine forest
- 2018
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Ingår i: Biogeochemistry. - : Springer Science and Business Media LLC. - 0168-2563 .- 1573-515X. ; 139:3, s. 321-335
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Tidskriftsartikel (refereegranskat)abstract
- Relative to areas under canopy, the soils in forest gaps receive more irradiance and rainfall (snowfall); this change in microclimate induced by forest gaps may influence the release of carbon (C) and nutrients during litter decomposition. However, great uncertainty remains about the effects of forest gaps on litter decomposition. In this study, we incubated foliar litters from six tree and shrub species in forest gaps and canopy plots and measured the release of C, nitrogen (N) and phosphorus (P) in different snow cover periods in an alpine forest from 2012 to 2016. We found that N was retained by 24–46% but that P was immediately released during an early stage of decomposition. However, forest gaps decreased litter N retention, resulting in more N and P being released from decomposing litters for certain species (i.e., larch, birch and willow litters). Moreover, the release of C and nutrients during litter decomposition stimulated by forest gaps was primarily driven by warmer soil temperature in this high-altitude forest. We conclude that gap formation during forest regeneration may accelerate C turnover and nutrient cycling and that this stimulation might be regulated by the litter species in this seasonally snow-covered forest. © 2018, Springer Nature Switzerland AG.
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