Characteristics of normal and discoloured wood of Ilomba (Pycnanthus angolensis Exell)

Starck, M.; Bauch, J.; Simatupang, M. H.

doi:10.1007/bf00353359

Cited by 9 publications

(7 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For some wood species, discoloration of wood has possibly been influenced by pH value (Sandermann and Rothkamm 1959). This may also be applicable to teak, although this result indicates that the discoloration process does not involve a comparatively large gradient of pH such as observed results in C. japonica (Takahashi 1996) or in Pycnanthus angolensis (Starck et al 1984).…”

Section: Measurement Of Color Ph and Inorganic Elementmentioning

confidence: 57%

“…Shigo (1976) observed that discolorations in the living tree are mainly initiated through wounds, dying branches and roots. The natural blackening in the heartwood part has been studied in some species such as Cryptomeria japonica (Takahashi 1996;Kubo and Ataka 1998), Diospyros celebica (Noda et al 2002;Minato and Morita 2005), and Pycnanthus angolensis (Starck et al 1984). Those studies revealed that blackening is related to the chemical properties in the heartwood.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Color and chemical characterization of partially black-streaked heart-wood in teak (Tectona grandis)

Lukmandaru

Ashitani

Takahashi

2009

Journal of Forestry Research

View full text Add to dashboard Cite

The heartwood of teak in certain areas of Java Island displays irregular black streaks along the annual rings. We investigated the color and chemical characteristics in a radial direction of partially black-streaked heartwood samples. Color properties (pH value, inorganic element, extractive content and extractive characterization) were measured in the color co-ordinates CIELAB system. The resultsshow that the black streak part was 12-15 brightness (L*) value units less than the normal heartwood. Furthermore, the black streak part had more red (a*) but less yellow (b*), hue (h) and chroma (C*) than the normal wood. The pH value, ash content and calcium contents of the black streak part were slightly higher than those obtained for the normal wood. The content of the low-polar extractive (n-hexane and ethyl acetate) of the black streak part was considerably higher than that for the normal wood. The blackening process was speculated to be a kind of defense mechanism indicated by remarkable amount of bioactive compound called tectoquinone.

show abstract

Section: Measurement Of Color Ph and Inorganic Elementmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 98%

Color and chemical characterization of partially black-streaked heart-wood in teak (Tectona grandis)

Lukmandaru

Ashitani

Takahashi

2009

Journal of Forestry Research

View full text Add to dashboard Cite

show abstract

“…Furthermore, the cause of pH change in the discolored part is remained unknown. This trend was also differed in another species related to pH values (Starck et al 1984;Takahashi and Mori 2006). Thus, the question about the reason of color changes of woods upon pH change cannot be answered in a definite way.…”

Section: Alkaline and Acidic Treatment Of Quinonesmentioning

confidence: 91%

Discolored Components from the Black-streaked Heartwood Extracts of Teak

Lukmandaru¹,

Ashitani²,

Takahashi³

2023

Wood Res. J

View full text Add to dashboard Cite

With regard to black-streaked discoloration of teak wood, the ethyl acetate extract from successive extraction was examined. By column chromatography, tectol and and two unknown compounds i.e. C-1 (molecular weight of 240) and C-2 (molecular weight of 210) were isolated. Discoloration tests, i.e. air oxidation, acidic (acetic acid), and alkaline (potassiun hydrogen carbonate) treatments were conducted to the isolated and other standard quinoine compounds (tectoquinone, lapachol, 2-tert-buthyl- anthraqunone, 2-hydroxy-methyl-anthraqunone). The results showed that tectol changes its color by the considerable decreasing in brightness whereas C-1 showed huge decrease in yellowness by air oxydation. Tectol did not change its color in pH value of 2.9 to 8.3 but C-1, C-2, and lapachol did change. Tectoquinone was hardly change color under alkaline or acidic treatment. The difference in quinone coloration might be due the structural features of a hydroxyl group and a double bond conjugated

show abstract

“…phenolic substances, are located mainly in the rays and in the longitudinal parenchyma (Perilä 1954, Perilä and Toivonen 1958, Paasonen 1967. Fungi and bacteria may also be involved, as they have been found in both discoloured and light birch wood (Hallaksela and Niemistö 1998); and in other hardwoods it has been shown that the change in pH caused by bacteria and fungi may change the colour of certain phenols in the wood (Zimmermann 1974, Starck et al 1984.…”

Section: Sawing and Dryingmentioning

confidence: 99%

Birch as sawn timber and in mechanical further processing in Finland. A literature study

Luostarinen¹,

Verkasalo²

2000

Silva Fenn., Monogr.

View full text Add to dashboard Cite

This study based on literature and restricted interviews of forest products companies is a compilation of current knowledge concerning utilisation of the wood of birch species growing in Finland, silver birch (Betula pendula) and pubescent birch (B. pubescens), for saw milling and further related processing. As the basis for this, the properties (morphological, anatomical, physical, mechanical and chemical) of birch wood are presented as well as the effects of cultivation and how growing conditions affect these properties. The issues cover resources and use of large- and small-dimensioned birch, current and potential importance of birch for saw milling as well as for furniture and joinery industries, quality and specifi c properties of birch timber for sawing and processing for special purposes, principles and methods of grading the quality of wood, how to improve and control quality, timber procurement, primary processing, machining and surfacing as well as semi- and end-products. Based on the available data, the principal needs for research and develop.

show abstract

Characteristics of normal and discoloured wood of Ilomba (Pycnanthus angolensis Exell)

Cited by 9 publications

References 15 publications

Color and chemical characterization of partially black-streaked heart-wood in teak (Tectona grandis)

Color and chemical characterization of partially black-streaked heart-wood in teak (Tectona grandis)

Discolored Components from the Black-streaked Heartwood Extracts of Teak

Birch as sawn timber and in mechanical further processing in Finland. A literature study

Contact Info

Product

Resources

About