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- Berg, Björn, et al.
(author)
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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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In: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 522
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Journal article (peer-reviewed)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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| 2. |
- Menkis, Audrius, et al.
(author)
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Occurrence and impact of the root-rot biocontrol agent Phlebiopsis gigantea on soil fungal communities in Picea abies forests of northern Europe
- 2012
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In: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 81:2, s. 438-445
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Journal article (peer-reviewed)abstract
- The aim of this study was to assess belowground occurrence, persistence and possible impact of the biocontrol agent Phlebiopsis gigantea (Fr.) Julich on soil fungi. Sampling of soil and roots of Picea abies (L.) H. Karst. was carried out at 12 P.similar to gigantea-treated and five nontreated control sites representing 1- to 60-month-old clear-cuts and thinned forest sites in Finland and Latvia. The 454-sequencing of ITS rRNA from fine roots, humus and mineral soil resulted in 8626 high-quality fungal sequences. Phlebiopsis gigantea represented 1.3% of all fungal sequences and was found in 14 treated and nontreated sites and in all three substrates. In different substrates, the relative abundance of P.similar to gigantea at stump treatment sites either did not differ significantly or was significantly lower than in nontreated controls. No significant correlation was found between the time elapsed since the tree harvesting and/or application of the biocontrol and abundance of P.similar to gigantea in different substrates. In conclusion, the results demonstrate that P.similar to gigantea occasionally occurs belowground in forest ecosystems but that stump treatment with the biocontrol agent has little or no impact on occurrence and persistence of P.similar to gigantea belowground, and consequently no significant impact on soil fungi.
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