| 1. |
- Ali, Alexandre Charifo, et al.
(författare)
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Comparative natural durability of five wood species from Mozambique
- 2011
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Ingår i: International Biodeterioration and Biodegradation. - : Elsevier BV. - 0964-8305. ; 65, s. 768-776
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate the natural durability of five lesser-utilized wood species from Mozambique. Both laboratory methods and field tests were applied for assessing wood decay of muanga (Pericopsis angolensis), metil (Sterculia appendiculata), namuno (Acacia nigrescens), ncurri (lcuria dunensis), and ntholo (Pseudolachnostylis maprounaefolia). Laboratory tests involved soft-, brown-, and white-rot fungi and termites. Heart- and sapwood of ncurri and ntholo were exposed in above-ground field tests; additionally, all species were exposed to in-ground contact tests. The results indicated that namuno, muanga, ncurri, and ntholo are resistant to soft-, brown- and white-rot fungi and the termite species Reticulitermes grassea and Mastotermes darwiniensis. Comparatively, soft-rot caused more severe decay on the studied wood species than did basidiomycete fungi. The brown-rot fungi Coniophora puteana, Gloeophiyllum trabeum, and Postia placenta caused less decay on the tested species than did the white-rot Trametes versicolor. Metil was not resistant to any of the mentioned hazards. Therefore, this species is not recommendable for exterior use if untreated. (C) 2011 Elsevier Ltd. All rights reserved.
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| 2. |
- Råberg, Ulrika, et al.
(författare)
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Brown rot decay of copper-chromated-phosphorus impregnated fence poles: Characterization by molecular analyses and microscopy
- 2009
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Ingår i: International Biodeterioration and Biodegradation. - : Elsevier BV. - 0964-8305. ; 63, s. 906-912
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Tidskriftsartikel (refereegranskat)abstract
- At one location in central Sweden, agricultural pine (Pinus sylvestris L.) fence poles treated with a commercial copper-chromium-phosphorus preservative (CCP) formulation according to use class 4 at retention of 30 kg m(-3) were prematurely degraded by fungi after only two years in-service. Light- and electron microscopy analyses showed decay to result from primarily brown rot attack. Culture studies produced on different agar and copper-containing media using small wood slivers removed from infected poles allowed establishment of a number of pure cultures of Phycomycetes, Ascomycetes, Fungi Imperfecti and Basidiomycete fungi. Using morphological characters, PCR and sequencing of isolated Antrodia vaillantii was determined as the most abundant basidiomycete present and as the major causal agent of decay. Compatibility tests and comparison of the ITS nrDNA sequences of our putative A. vaillantii isolate with other A. vaillantii strains and with Antrodia radiculosa showed differences suggesting a hybrid strain. A combination of site characteristics (e.g. hot spots of A. vaillantii), the use of juvenile poles, copper tolerance and overall ineffectivity of CCP against A. vaillantii is suggested as reasons for premature decay. (C) 2009 Elsevier Ltd. All rights reserved.
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| 3. |
- Råberg, Ulrika, et al.
(författare)
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Characterization of test fields
- 2013
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Ingår i: Proceedings IRG Annual Meeting. - 2000-8953.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Test field characteristics and impact of test fields on wood degradation is important when testing wood protection. The current EN 252 standard has no requirement for knowledge of decay hazards, but most commonly a test field is known as a “brown”,- “white”,- or “soft rot” field. To understand which decay hazard wood preservatives are tested against, each test field should be characterized. Our purpose here is to outline a number of different approaches that we have been using to characterize four test fields belonging to the Department of Forest Products, SLU, Sweden. For characterization we isolated fungi from EN 252 Scots pine stakes by using different media and identified the isolated fungi by DNA sequencing. DNA profiles were established for Scots pine mini- stakes as well as microscopy characterization of stake cross sections for decay type and degree of attack. MOE and mass loss was measured for the mini-stakes at one test field. For all fields, the pick test of EN 252 stakes were performed according to the European Standard EN 252. A summary of problems and possibilities of the techniques are presented. Our results show that by combining different approaches like molecular techniques with microscopy and/or strength tests, it is possible to obtain good characterization of test fields, the inherent fungi, and their decay capacity cannot be described by using only one approach. Keywords: DNA sequencing, fungal isolation, microscopy, MOE, pick test, test field
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| 4. |
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| 5. |
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| 6. |
- Råberg, Ulrika, et al.
(författare)
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Early soft rot colonization of Scots sapwood pine in above-ground exposure
- 2009
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Ingår i: International Biodeterioration & Biodegradation. - : Elsevier BV. - 0964-8305 .- 1879-0208. ; 63:2, s. 236-240
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Tidskriftsartikel (refereegranskat)abstract
- The early colonization of Scots pine (Pinus sylvestris L) sapwood exposed above ground (staple bed) was studied. Two different types of exposures were used, one in an open field and the other in a shaded field. Decay type and degree of degradation due to soft rot and mass and strength loss of wood were correlated. Fungal species in Scots pine sapwood were identified by sequencing, using the fungal nuclear ribosomal DNA (nrDNA) after 24 months. The most abundant decay type found was soft rot, which also agreed with the mass loss (7-8%). Pine sapwood did not differ significantly between the two sites regarding the average mass loss during the time of exposure. The early colonization of wood by soft rot fungi together with mass loss indicates that this fungal type might be more common in above-ground conditions than recognized earlier.
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| 7. |
- Råberg, Ulrika, et al.
(författare)
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Fluorescerande blånad
- 2009
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Ingår i: Research results (Swedish University of Agricultural Sciences, Department of Forest Products). - 1654-9759.
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Annan publikation (populärvet., debatt m.m.)
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| 8. |
- Råberg, Ulrika, et al.
(författare)
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Gravimetric screening method for fungal decay of paper: inoculation with Trametes versicolor
- 2009
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Ingår i: Biotechnology Letters. - : Springer Science and Business Media LLC. - 0141-5492 .- 1573-6776. ; 31, s. 1519-1524
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Tidskriftsartikel (refereegranskat)abstract
- The European standard test EN 113 for fungal degradation of solid wood has been adapted for degradation of paper by white rot fungus (Trametes versicolor). Fungal degradation of paper sheets may potentially be used for screening different wood preservatives on paper instead of solid wood. The paper samples showed higher relative mass losses compared to wood, and samples pretreated with boric acid, copper sulfate and polymerized linseed oil were successfully tested for biodegradation using the paper sheet method. The results on paper degradation were compared with wood, both as wood blocks (according to standard test) and wood cut in sections forming layered structures mimicking paper layers.
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| 9. |
- Råberg, Ulrika, et al.
(författare)
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Impact of soil transfer between test fields on fungal diversity and wood durability
- 2014
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Ingår i: International Wood Products Journal. - 2042-6445 .- 2042-6453. ; 5, s. 83-91
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Tidskriftsartikel (refereegranskat)abstract
- The impact of soil transfer on fungal degradation of Scots pine was investigated using visual inspection, microscopy and DNA profiling. Two test fields in Simlångsdalen with similar soil characteristics were used. Soil has previous been used with the purpose to retain the beneficial original micro-organisms present to imitate field-trials during laboratory condition. We found that fungal degradation in mini-stakes exposed in transferred soil did not correspond to mini-stakes exposed in original soil. Moreover, the type of degradation in the mini-stakes exposed in transferred soil did not match mini-stakes exposed in the original soil. However, established degradation in areas neighbouring the transferred soil was comparable. The fungal community in mini-stakes also varied more between different years than within the field. This suggests that relocation of soil disrupts the original fungal community due to unavoidable mixing of the soil. Therefore, the beneficial micro-organism characteristics of soils is very difficult to transfer elsewhere.
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| 10. |
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