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The ability of bacteria to induce brownstain in western hemlock

https://library.fpinnovations.ca/en/permalink/fpipub5877
Author
Kreber, B.
Hedberg, B.
Date
March 1996
Edition
41145
Material Type
Research report
Field
Sustainable Construction
chemical and physical properties of wood. PhD thesis, University of Wisconsin. Kreber, B. 1995a
Author
Kreber, B.
Hedberg, B.
Contributor
Canada. Canadian Forest Service.
Date
March 1996
Edition
41145
Material Type
Research report
Physical Description
7 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Bacteria
Series Number
Canadian Forest Service No. 32 1/2
Contract no. 1715K024
W-1322
Location
Vancouver, British Columbia
Language
English
Abstract
Three Gram negative bacteria isolated from brownstained western hemlock were investigated for their capacity to produce hemlock brownstain. Brownstain was observed when infecting western hemlock with two bacteria. Oxygen was strongly indicated as being indespensable for the development of brownstain in infected samples. However, pH did not seem to influence the production of this stain.
Tsuga heterophylla - Stains, Chemical
Stains - Chemical
Degradation, Bacterial
Bacteria
Documents
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Causes of hemlock brownstain : final summary report

https://library.fpinnovations.ca/en/permalink/fpipub4377
Author
Byrne, Anthony (Tony)
Kreber, B.
Date
July 1996
Edition
41152
Material Type
Research report
Field
Sustainable Construction
Author
Byrne, Anthony (Tony)
Kreber, B.
Contributor
Canada. Canadian Forest Service.
Date
July 1996
Edition
41152
Material Type
Research report
Physical Description
6 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Wood
Tsuga Heterophylla
Tsuga
Stain fungal
Stain
Growth
Balsam
Fir
Series Number
Canadian Forest Service No. 32
W-1379
Location
Vancouver, British Columbia
Language
English
Abstract
Discolourations of hem-fir, usually called hemlock brownstain, have become an economically important problem with the move towards increased kiln-drying of the wood species mixture and added-value products in which discolourations cannot be tolerated. These discolourations, clearly different from sapstain, can occur in several types and intensities and are a serious problem in high-value markets. Because little is known about their causes means for their control are still unavailable. Therefore fundamental research was initiated to elucidate the biology and chemistry of hemlock brownstain and to suggest control measures. A post graduate student was hired to undertake laboratory and field work as part of a Ph.D. program. The thesis subject was "the role of microorganisms in the phenomenon of hemlock brownstain". The thesis covers: a literature review; laboratory work to locate the stain and define its nature; a storage study of logs and lumber to monitor progress in development of brownstain; fungal isolation work and sap characterization studies; in vitro production of hemlock brownstain in wood and sap; and additional laboratory experiments to determine what factors influence the formation of the brownstain. In addition to the thesis research the role of bacteria in the formation of the stain was investigated in the laboratory and the ability of various chemicals, including fumigants, to prevent the stain was tested in small-scale field test. This report provides an overview of the findings and provides recommendations for future work. The experiments clearly demonstrated that a non-specific microflora can produce brownstain which led to the hypothesis that microorganisms could be involved in hemlock brownstain. Based on our knowledge of the coastal sawmilling industry a strategy of minimizing fungal infection and rapid handling of the tree breakdown into final wood products could probably be the best approach to help reduce the problem. In terms of future work we recommend that work to understand the mechanism of DDAC in mitigation of the browning take precedence in future work on hemlock brownstain.
Abies amabilis - Stains - Fungal
Tsuga heterophylla - Stains - Fungal
Fungi - Growth
Fungi - Wood staining
Stains - Fungal
Hem-Fir - Stains - Fungal
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Causes of hemlock brownstain. Phase 1. Discolourations of hem-fir wood : a status report. (First of six reports)

https://library.fpinnovations.ca/en/permalink/fpipub4312
Author
Kreber, B.
Byrne, Anthony (Tony)
Date
March 1993
Edition
41082
Material Type
Research report
Field
Sustainable Construction
in gelagertem Bergahomholz (Acer pseudoplatanus L ) . Holz als Roh und Werkstoff 33:420-426. Kreber, B. 1992
Author
Kreber, B.
Byrne, Anthony (Tony)
Date
March 1993
Edition
41082
Material Type
Research report
Physical Description
17 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Series Number
Forestry Canada No. 52C
Contract no. 1712K024
W-1033
Location
Vancouver, British Columbia
Language
English
Abstract
The natural wood appearance of many species can be affected by a variety of undesirable "non-microbial" discolourations, which reduce the value of wood products. In contrast to sapstain, caused by fungi, prevention of these discolourations has rarely been demonstrated in practice. Discolourations of hem-fir have become an economically important problem with the move towards increased kiln-drying of the wood species mixture and added-value products in which discolourations are less tolerable. A literature review was done to survey both general information on "non-microbial" discolourations and more specifically information on discolourations of western hemlock and amabilis fir. Although discolouration of hem-fir lumber has been a puzzle for many years, knowledge of its cause(s) is rudimentary. Most research into hem-fir discolourations has been conducted on only a few wood samples. Although polymerization of wood extractives has been proposed as the probable cause, involvement by bacteria and fungi are also suggested in the literature. Other factors involved in discolourations of other wood species, such as factors inherent in the living tree, season of tree felling, post mortem changes and log age and storage, are reviewed. The nature of specific wood extractive chemicals and the significance of other contributory factors need to be understood before preventive treatments can be devised to maintain the natural colour in hem-fir products. Research recommendations include microscopic and histochemical techniques.
Tsuga heterophylla - Stains, Chemical
Stains, Chemical
Documents
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Causes of hemlock brownstain. Phase 2. Microscopic examination of discoloured hem-fir wood. (Second of six reports)

https://library.fpinnovations.ca/en/permalink/fpipub4313
Author
Kreber, B.
Date
March 1993
Edition
41083
Material Type
Research report
Field
Sustainable Construction
Author
Kreber, B.
Date
March 1993
Edition
41083
Material Type
Research report
Physical Description
10 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Series Number
Forestry Canada No. 52C
Contract no. 1712K024
W-1034
Location
Vancouver, British Columbia
Language
English
Abstract
Microscopic examinations were conducted on discoloured hem-fir samples indicating different types of "brownstain" patterns. Distribution of "brownstain" discolouration in hem-fir lumber is variable. Microorganisms were found in all specimens examined. The role of microorganisms in "brownstain" discolourations needs to be elucidated. Research recommendations include monitoring of biological and chemical changes of freshly sawn hem-fir lumber over time.
Tsuga heterophylla - Stains, Chemical
Stains, Chemical
Documents
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Causes of hemlock brownstain. Phase 3. Evaluation of the potential of hem-fir wood extractives as precursors of hemlock brownstain. (Third of six reports)

https://library.fpinnovations.ca/en/permalink/fpipub4314
Author
Kreber, B.
Date
March 1993
Edition
41084
Material Type
Research report
Field
Sustainable Construction
formation in western hemlock. J. of Wood Chem. and Tech. 5(4):451-460. Kreber, B. 1993. Microscopic
Author
Kreber, B.
Date
March 1993
Edition
41084
Material Type
Research report
Physical Description
7 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Series Number
Forestry Canada No. 52C
Contract no. 1712K024
W-1035
Location
Vancouver, British Columbia
Language
English
Abstract
Hemlock brownstain was studied histochemically, in microscopic sections of western hemlock and amabilis fir, and chemically, using wood extractives of western hemlock. For the first time it was histochemically demonstrated that brown pigments, found in amabilis fir and western hemlock, are at least partially composed of catechin and/or epicatechin. Evaluation of nine extractives of western hemlock provided no indication that they play a significant role in hemlock brownstain. However, sap collected from western hemlock showing signs of brownstain produced browning on filter paper. Thus the composition of the sap, yet unidentified, was responsible for discolouration observed in this study.
Tsuga heterophylla - Stains, Chemical
Stains, Chemical
Documents
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Causes of hemlock brownstain. Phase 4. Monitoring of biological and chemical parameters in hem-fir lumber over time. (Fourth of six reports)

https://library.fpinnovations.ca/en/permalink/fpipub4315
Author
Kreber, B.
Daniels, C. Robert
Date
March 1993
Edition
41085
Material Type
Research report
Field
Sustainable Construction
and other related properties of western hemlock sinker heartwood. Wood and Fibre 4(2):99-lll. Kreber, B
Author
Kreber, B.
Daniels, C. Robert
Date
March 1993
Edition
41085
Material Type
Research report
Physical Description
20 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Series Number
Forestry Canada No. 52C
Contract no. 1712K024
W-1036
Location
Vancouver, British Columbia
Language
English
Abstract
Biological and chemical changes were evaluated in freshly sawn amabilis fir and western hemlock lumber (hem-fir) over 10 weeks of outside storage. Both wood species commonly contained brownstain microscopically in heartwood and sapwood. Microorganisms were often found in discoloured samples, but brownstain could not be linked to the presence of microorganisms. Qualitative HPLC analysis was employed on methanol extracted hem-fir segments over time, but this approach provided no indication about potential precursors to hemlock brownstain. However, the HPLC method developed produced a reliable separation and identification of nine wood constituents in hem-fir lumber and can be used for future quantitative analysis. The factors producing macroscopic brownstain were not understood, but a high moisture content appeared to be essential to transport precursors of hemlock brownstain to the wood surface.
Tsuga heterophylla - Stains, Chemical
Stains, Chemical
Documents
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Causes of hemlock brownstain. Phase 5. In vitro production of hemlock brownstain. (Fifth of six reports)

https://library.fpinnovations.ca/en/permalink/fpipub4316
Author
Kreber, B.
Date
March 1993
Edition
41086
Material Type
Research report
Field
Sustainable Construction
hemlock. J. of Wood Chem. and Tech. 5(4):451-460. Kreber, B. 1993. Phase 2: Microscopic examination
Author
Kreber, B.
Date
March 1993
Edition
41086
Material Type
Research report
Physical Description
16 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Series Number
Forestry Canada No. 52C
Contract no. 1712K024
W-1037
Location
Vancouver, British Columbia
Language
English
Abstract
Three strains of Ophiostoma piceae (Münch) H. & P. Syd. and a mixed bacterial culture were studied for their potential to produce in vitro brownstain in sap of amabilis fir, western hemlock and lodgepole pine and in western hemlock wood. Several microorganisms increased the pH of all sap samples evaluated and a distinct brown discolouration developed in sap of western hemlock and amabilis fir over 3 weeks. Although pH shift influenced brown discolourations of sap, nutrient status and the extractive composition of the sap appeared to be critical for promoting browning of sap. O. piceae strains also produced brown discolourations in sapwood of western hemlock but the mixed bacterial culture caused minor brown staining only. While we have demonstrated a link between microorganisms and brownstain in liquid culture more research is needed to understand susceptibility of amabilis fir and western hemlock lumber to brown discolourations.
Tsuga heterophylla - Stains, Chemical
Stain, Chemical
Documents
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Causes of hemlock brownstain. Phase 6. The ability of moulds and sapstaining fungi to discolour sap of western hemlock under laboratory conditions. (Sixth of six reports)

https://library.fpinnovations.ca/en/permalink/fpipub4317
Author
Kreber, B.
Date
March 1993
Edition
41087
Material Type
Research report
Field
Sustainable Construction
formation in western hemlock. J. of Wood Chem. and Tech. 5(4):451-460. Kreber, B. and C.R. Daniels
Author
Kreber, B.
Date
March 1993
Edition
41087
Material Type
Research report
Physical Description
10 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Series Number
Forestry Canada No. 52C
Contract no. 1712K024
W-1038
Location
Vancouver, British Columbia
Language
English
Abstract
A range of moulds and sapstaining fungi produced in vitro brownstain in sap collected from three different western hemlock boards. Colour changes varied among both microorganisms and source of sap used. However, a link has been established between microorganisms and their potential to cause pH changes in sap; the pH seemed to promote discolourations. However, both the susceptibility of sap to discolourations and the mechanism of colour changes have not yet been elucidated.
Tsuga heterophylla - Stains, Chemical
Stains, Chemical
Documents
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Discolorations of hem-fir wood: a status report

https://library.fpinnovations.ca/en/permalink/fpipub41067
Author
Kreber, B.
Byrne, Anthony (Tony)
Date
June 1992
Material Type
Research report
Field
Sustainable Construction
Author
Kreber, B.
Byrne, Anthony (Tony)
Date
June 1992
Material Type
Research report
Physical Description
12 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Tsuga Heterophylla
Tsuga
Stain
Balsam
Fir
Series Number
1743O226
W-927
Location
Vancouver, British Columbia
Language
English
Abstract
The natural wood appearance of many species can be affected by a variety of undesirable "non-microbial" discolorations, which reduce the value of wood products. In contrast to sapstain, caused by fungi, prevention of these discolorations has rarely been demonstrated in practise. Discolorations of hem-fir have become an economically important problem with the move towards increased kiln-drying of the wood species mixture and added-value products in which discolorations are less tolerable. A literature review was done to survey both general information on "non-microbial" discolorations and more specifically information on discolorations of western hemlock and amabilis fir. Although discolorations of hem-fir lumber have been a puzzle for many years, knowledge of their cause(s) is rudimentary. Most research into hem-fir discolorations has been conducted on only a few wood samples. Although polymerization of wood extractives has been proposed as the probable cause, involvement by bacteria and fungi are also suggested in the literature. Other factors involved in discolorations of other wood species, such as factors inherent in the living tree, season of tree felling, post mortem changes and log age and storage are reviewed. The nature of specific wood extractive chemicals and the significance of other contributory factors need to be understood before preventive treatments can be devised to maintain the natural color in hem-fir products. Research recommendations include microscopic and histochemical techniques.
Hem-fir - Stains, Chemical
Tsuga heterophylla - Stains, Chemical
Abies amabilis - Stains, Chemical
Documents
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Mechanical tree harvesters spread fungal inoculum onto freshly-felled Canadian and New Zealand pine logs. Manuscript submitted to Forest Products Journal

https://library.fpinnovations.ca/en/permalink/fpipub5889
Author
Uzunovic, Adnan
O'Callahan, D.
Kreber, B.
Date
March 2003
Edition
41277
Material Type
Research report
Field
Sustainable Construction
. Time limits for holding logs to achieve successful antisapstain treatment. Pp.55-61 in Kreber, B. (Ed
Author
Uzunovic, Adnan
O'Callahan, D.
Kreber, B.
Contributor
Canada. Canadian Forest Service.
Date
March 2003
Edition
41277
Material Type
Research report
Physical Description
21 p.
Sector
Wood Products
Field
Sustainable Construction
Research Area
Advanced Wood Materials
Subject
Trees
Wood decay
Pinus
Logs
Harvesters
Series Number
Canadian Forest Service No. 33;2236
W-1934
Location
Vancouver, British Columbia
Language
English
Abstract
Mechanical tree harvesters damage the exterior of freshly felled logs, loosening and removing bark, and producing punctures and indentations up to several centimeters deep. Damaged logs are susceptible to invasion by a plethora of wood inhabiting fungi. In this study, we investigated the role of tree harvesters in disseminating fungi, particularly wood-discoloring fungi, or inoculating Canadian lodgepole pine and New Zealand radiata pine logs. In the study reported here wood decaying fungi, staining fungi and moulds were isolated from a harvester head and the bark of standing lodgepole pine trees. This microflora may be translocated into the sub-surface regions of a log during the harvesting process. In Canada, Aureobasidium pullulans was the most frequently isolated staining fungus followed by Ophiostoma minus and Leptographium sp. All were isolated from stained areas associated with damage sites. Sphaeropsis sapinea was the most prominent species in New Zealand. Tree harvesters clearly play a role in the dissemination of wood degrading fungi into freshly felled conifer logs.
Pinus radiata D. Don - Diseases - Decay
Logs - Defects
Logs - Handling
Logging - Equipment - Harvesters
Logging - Damage to trees
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12 records – page 1 of 2.