A Note on Density Change Patterns in Charred Wood

Apparent and real densities of seven species of wood and chars were measured. The chars had been prepared by heating in flowing nitrogen at rates of 1, 10 and 50 C/min. Generally, maximum rate of change was between 300 and 350 C. The decrease continued up to 600 C, the maximum charring temperature

Macroscopic and Microscopic Analyses of Color Changes of Wood Pressure Steam-Dried Above Atmospheric Pressure

Yellow poplar, silver maple, red oak, and southern pine heartwood samples were evaluated for color changes occurring as a result of pressure steam-drying above atmospheric pressure. Luminance significantly decreased, purity increased, and dominant wavelength shifted toward the red zone of the spectrum for yellow poplar and silver maple. Luminance significantly decreased, while other color parameters did not significantly change, for red oak wood. Southern pine wood decreased in luminance and increased in purity. Extractives of all woods appeared to have "softened" upon pressure steam-drying and became migratory, moving from the ray tissue system to the surface through the vessel system for the hardwood species. Pressure steam-dried white oak exhibited a drastically modified tyloses system; tyloses were missing from numerous heartwood vessels and those remaining appeared torn or ruptured

A Note On Effects of Wounds On Heartwood Formation in White Oak (Quercus ALBA L.)

Heartwood formation was retarded by wounds on white oaks in Maine and Missouri. Maine samples with fire wounds had 22-23 rings of sapwood near the wound whereas control trees had 9. Missouri samples subjected to frill and herbicide treatments averaged 16-17 rings of sapwood near the wound, whereas control trees averaged 12. The effects of wounding on Missouri trees were pronounced at heights of 1, 2.5, and 6 m

Inorganic Concentrations in Selected Woods and Charcoals Measured Using NAA

Neutron activation analysis was used to determine the levels of several inorganic elements in seven species of wood- and laboratory-prepared charcoals. The samples were exposed for 1 min to a thermal neutron flux of 1 x 1014 n/cm2-sec. Following a 10-min decay period, sample activity was measured for 500 sec. Concentrations of Al, Ca, Cl, K, Mg, Mn, and Na were measured. Ba, Cu, Sr, and V were also identified in several samples. Matched samples of southern pine earlywood and latewood contained similar amounts of inorganics

Wood Quality in Hildegardia Barteri (MAST.) Kossern—An African Tropical Pioneer Species

Hildegardia barteri (Mast.) Kossern is a fast-growing African tropical pioneer species that often colonizes open spaces and disturbed vegetation, forming almost pure stands extending over several hectares. The results of anatomical and specific gravity studies of Hildegardia grown on four different sites in southern Nigeria are presented. Fiber length and fiber and vessel element tangential diameters varied significantly among the four sites. Most anatomical features varied with distance from the pith. Height above ground was not a significant factor. Specific gravity varied with site, distance from the pith, and height above ground

Small Angle X-ray Scattering Study of Oak Charcoals

Small angle X-ray scattering data have been used to characterize the microscopic and submicroscopic structure of oak charcoals produced at different temperatures. The specific surface has been calculated for each sample. The observed scattering is ascribed to voids in a carbon matrix. The scattering data suggest that these voids have average dimensions that fall into two groups: (1) a relatively large-scale structure that is similar to the structure of the original wood and that has dimensions of the order of microns, and (2) a much finer structure, with dimensions about 15Å. In samples prepared at low temperature, only the large-scale structure is detectable. When charcoals are prepared at temperatures above approximately 1000 F, additional voids are generated. As a result, the average dimensions of the large-scale voids are apparently reduced and a small-scale structure develops

Small Angle X-Ray Scattering Study of The Porosity in Charcoals

Small angle X-ray scattering data have been obtained for a series of charcoal samples produced by heating in a laboratory furnace under conditions chosen to simulate those encountered in commercial kilns. The scattering curves suggest that the samples contain three types of pores: (1) relatively large pores, with dimensions of the order of a few microns, which are similar to the pores in the lignincellulosic skeleton of the wood from which the charcoal was made; (2) platelet-like pores, with one dimension that does not exceed 2 or 3 nm and with the other two average dimensions being considerably larger; and (3) small pores, which have no dimensions greater than about 1 or 2 nm. For charcoals heated to 400 C, only the large pores are present in appreciable numbers. As the maximum heating temperature is increased, the platelet and small pores make an increasing contribution to the scattering. Estimates have been made of the fraction of the volume of the porous charcoal occupied by each of the three types of pores

Fusain in Carboniferous shallow marine sediments, Donegal, Ireland: the sedimentological effects of wildfire

Evidence from fusain deposits in Lower Carboniferous rocks of western Ireland indicates that a catastrophic wildfire destroyed thousands of square kilometres of Carboniferous ‘forest’. In addition to yielding large quantities of charcoal, this wildfire event resulted in increased surface water runoff which affected sedimentation in an adjacent estuarine environment where the fusain is now preserved. This is the oldest documented evidence for a catastrophic palaeowildfire and a clear example of the sedimentological effects of large-scale fires. The Lower Carboniferous (Visean) rocks in the Largymore Syncline of western Donegal, Ireland, are shallow marine sandstones, mudstones and limestones. The Upper Shalwy Beds are mudstones and cross-bedded sandstones which show bi-polar cross-stratification and mud drapes on cross-bed foresets indicating deposition in a tidal environment, probably a large estuary. In three coastal exposures a bed containing up to 20% fusain is found at the same stratigraphic horizon. The fusain is interpreted as fossil charcoal produced by palaeowildfire in a land area to the north-west. The volume of fusain present in the unit can be estimated and by comparison with charcoal production in modern wildfires it has been calculated that around 95 000 km2 (more than the present land area of Ireland) was burnt. Along with the fusain, other effects of the wildfire can be seen in the deposits, which are poorly sorted compared to the rest of the Upper Shalwy Beds and are characterized by inclined heterolithic stratification produced by the draping of underlying bedforms. These features are considered to be due to a considerably increased sediment load in the estuary, resulting from enhanced surface runoff and soil erosion due to the wildfire