Surface Soil Properties of Black Walnut Sites in Relationship to Wood Color

Abstract

Various soils that supported black walnut (Juglans nigra L.) growth in Indiana and Missouri were analyzed for surface pH, organic matter, available P, exchangeable K, Ca, Mg, total N, silt plus clay content, cation‐exchange capacity (CEC), and depth to mottling or to impervious layer. Quantitative color values (luminance, dominant wavelength, purity) of heartwood of walnut trees grown on these soils were determined by reflectance spectroscopy. The soil properties analyzed were moderate to high for most soils studied. A few soils were found low in available P, silt plus clay content, and organic matter. Regression analyses indicated that variations in soil fertility were correlated with difference in wood color between individual sample trees. The range of observed site quality was rather limited, however, poorer sites showed a tendency toward darker, redder heartwood (lower luminance, higher dominant wavelength). Available P, exchangeable K, Ca, Mg, total N, and pH were found to be most important in relation to color variation.

Genetic and environmental variation in heartwood colour of Australian blackwood (Acacia melanoxylon R.Br.)

“…Clearly, further research is needed to better understand the relationships between blackwood and potential nurse crop species. Rink (1987) found that black walnut heartwood colour was more influenced by environment than genetics, with soil properties being implicated (Nelson et al 1969;Maeglin and Nelson 1970), and Phelps and McGinnes (1983) suggested that increasing competitive or environmental stress resulted in increased production of polyphenols and hence darker coloured black walnut. This result is opposite to that found at the Virginstow trials.…”

La Mesure de Couleur: Une Méthode d’Etude et d’Optimisation des Transformations Chimiques du Bois Thermolysé

“…Par ailleurs, le Sechage du bois ä haute temp6rature est une technique qui se developpe pour les nombreux avantages qu'elle presente par rapport aux methodes plus traditionnelles (Basilico 1985;Martin 1986 (Janin 1986(Janin ,1987a(Janin , 1987bMazet 1988). De nombreux auteurs ont recherche ä correler la variabilite de la couleur du bois avec un certain nombres de parametres naturels: anisotropie du materiau, Physiologie de l'arbre, nature des substances d'impregnation (Maeglin 1970;Nelson 1976;Phelps 1983;Rink 1987;Hoffmann 1987). La mesure de la couleur du bois peut egalement servir d'indicateur dans des etudes de suivi de cinetique de sechage (Brauner 1968), de deterioration sous Irradiation ultra-violette (Kondo 1986;Umehara 1986), ou enfin pour appecier l'efficacite de produits protecteurs anti UV (Minemura 1978;Kai 1985;Dirckx 1988).…”