Southern Red Oak Research Articles

Wood Colors and their Coloring Matters: A Review

A number of colored specialty woods, such as ebony, rosewood, mahogany and amboyna, and commercially important woods, such as morus, logwood, Brazilwood, Japanese yellowwood, blackwood, kwila, red beech and myrtle beech, exhibit a wide range of colors from black, violet, dark red, reddish brown, to pale yellow. These colors are not only due to colored pigments contained in extractives from those woods but also to insoluble polymers. Wood and bark from many species of both hardwood and softwood trees contain many types of flavonoid compounds. Research on flavonoids has been conducted mainly from two points of view. The first is chemotaxonomy with flavonoid compounds as taxonomic markers, and the second relates to the utilization of woods for pulp and paper and the use of tannins from bark for wood adhesives. Most chemotaxonomic studies have been conducted on flavonoids in the extracts from softwoods such as Podocarpus, Pinus, Pseudotsuga, Larix, Taxus, Libocedrus, Tsuja, Taxodium, Sequoia, Cedrus, Tsuga, Abies and Picea. Hardwood chemotaxonomic studies include those on Prunus and Eucalyptus species. Studies on flavonoids in pulp and paper production were conducted on Eucalyptus woods in Australia and woods from Douglas fir in the USA and larch in Japan. Flavonoids as tannin resources from black wattle tannin and quebracho tannin have been used commercially as wood adhesives. Flavonoids in the bark from radiata pine and southern pine, from western and eastern hemlock, southern red oak and Quercus dentata are also discussed. In addition, the distribution of flavonoids among tree species is described, as is the first isolation of rare procyanidin glycosides in nature.

Season of Fine Woody Debris Death Affects Colonization of Saproxylic Coleoptera

A study was conducted to explore the effect of season on colonization of dead twigs by beetles in a Louisiana secondary forest. Previous research showed that twigs cut during spring yielded many specimens and species. The present companion study utilized twigs averaging 14 mm in diameter cut from one tree of Quercus falcata Michaux (southern red oak) during fall (October) 2008, placed in bundles of 10 each, and left in the forest at three sites. Half the bundles were retrieved during winter (January, four months later) and the other half were retrieved during summer (July, nine months later). Coleoptera were collected from bundles using emergence chambers. Only 39 specimens of adult Coleoptera were collected, representing 12 families, 20 genera, and 21 species. Beetle colonization of oak twigs in Louisiana appears to be affected by the interaction of season and twig “quality” (apparently freshness) with the highest colonization taking place in fresh, dead twigs during spring and an order of magnitude lower colonization in 1) fresh twigs during fall or 2) stale twigs during spring and summer.

Experimental Test of Heat Treatment Effect on Physical Properties of Red Oak (Quercus falcate Michx.) and Southern Pine (Pinus taeda L.).

The objective of this work was to evaluate the effect of heat treatment and compression on the swelling and surface roughness of Southern red oak (Quercus falcate Michx.) and Southern pine (Pinus taeda L.). Specimens were exposed to temperature levels of 110 °C or 200 °C for 8 h before they were compressed using 2.5 MPa pressure for 5 min. Swelling values of the control and heat-treated samples in three grain orientations were evaluated by soaking them in water for 48 h. A stylus method was employed to determine the surface characteristics of the samples. Three main roughness parameters, namely mean arithmetic deviation of profile (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) were used to evaluate the effect of heat treatment on surface characteristics of the samples. Oak and pine specimens had 39.8% and 28.7% lower tangential swelling values, respectively, than those of control samples as a result of exposure to a temperature of 200 °C. Heat treatment did not make any significant difference on surface quality. Micrographs taken from cross sections of the specimens revealed that there was some cell distortion and modification due to heat treatment as well as compression. Combination of heat treatment and compression can be considered an alternative method to improve certain physical properties of these two species.

Evaluation of hardness and surface quality of different wood species as function of heat treatment

The objective of this study was to evaluate the effect of heat treatment on surface roughness and hardness of four wood species, namely black alder (Alnus glutinosa L.), red oak (Quercus falcata Michx.), Southern pine (Pinus taeda L.) and yellow poplar (Liriodendron tulipifera). Samples were exposed to heat treatment schedules having two temperature and exposure levels of 120°C and 190°C for 3 and 6h, respectively. Average hardness value of red oak samples exposed to a temperature of 190°C for 6h was 41.7% lower than that recorded before the heat treatment. Temperature of 190°C produced 7.9% lower hardness values for black alder with the increased exposure time from 3h to 6h. No significant differences were found between same type of Southern pine and yellow poplar specimens before and after the heat treatment in terms of their hardness values. Among the four species considered in this study red oak having the most porous anatomical structure showed the roughest surface. An improvement in surface quality (Ra) with 7.46% with extending exposure time from 3h to 6h at the temperature level of 190°C was noticed. However all four types of wood species kept in the oven at 190° for 6h presented smoother surface quality. It was found that increased temperature from 120°C to 190°C for both exposure times showed significant differences from the surface quality of nontreated samples at 95% confidence level. The anatomical structure of samples was also observed by scanning electron microscope (SEM) and some damage of the cell wall was determined due to heat treatment. The findings of this study demonstrated that heat treatment resulted in adverse effect on hardness characteristics of the samples. It appears that strength losses can be limited through alternative modified heat treatment techniques. On the other hand, surface quality of the samples from all species was enhanced as a result of heat treatment. Therefore such heat treatment would be considered to improve surface quality of the sample for furniture applications where smooth surfaces are ideal adding potential value on wood material to be used more effectively in furniture manufacturing.

Southern Pine Beetle, Dendroctonus frontalis, Antennal and Behavioral Responses to Nonhost Leaf and Bark Volatiles

A growing body of evidence suggests that bark beetles detect and avoid release points of volatile compounds associated with nonhost species, and thus such nonhost volatiles may have potential utility in the management of bark beetles. We used a coupled gas chromatograph-electroantennographic detector (GC-EAD) to assay the olfactory sensitivity of the southern pine beetle, Dendroctonus frontalis Zimmermann, to volatiles from leaves and bark of eight species of nonhost angiosperm trees that are common in the range of D. frontalis. Tree species sampled were red maple (Acer rubrum L.), mockernut hickory [Carya alba (L.) Nutt. ex Ell.], sweetgum (Liquidambar styraciflua L.), black tupelo (Nyssa sylvatica Marsh.), black cherry (Prunus serotina Ehrh.), southern red oak (Quercus falcata Michx.), blackjack oak [Quercus marilandica (L.) Muenchh.], and water oak (Quercus nigra L.). Beetle antennae responded to a total of 28 identifiable compounds in these samples. The relative olfactory responsiveness to 14 of these, as well as to nonanoic acid and four additional volatiles reported to be associated with nonhost angiosperms, was assessed in GC-EAD analyses of synthetic dilutions spanning six orders of magnitude. The largest response voltage amplitudes were obtained with trans-conophthorin, nonanoic acid, terpinen-4-ol, phenylethyl alcohol, and eucalyptol, whereas the lowest response thresholds were to nonanoic acid, nonanal, linalool, (E)-2-hexen-1-ol, and phenylethyl alcohol. Funnel traps baited with various combinations of eleven antennally-active angiosperm volatiles along with a standard attractant captured significantly fewer male and female D. frontalis than traps baited with the standard attractant alone. Our data suggest that a diversity of semiochemicals may be involved in host species discrimination by D. frontalis, and several may have utility in their management.

Effects of the ecological restoration practices of prescribed burning and mechanical thinning on soil microbial enzyme activities and leaf litter decomposition

The effects of ecological restoration on belowground processes such as decomposition are generally unknown. To assess the immediate effects of prescribed fire and mechanical thinning on belowground processes, we measured the activities of five extracellular enzymes (phosphatase, β-glucosidase, β-N-acetylglucosaminidase, phenol oxidase, and lignin-peroxidase) in soils and on decomposing Quercus falcata leaf litter in unburned, burned, and burned and thinned plots in a mesic forest in northern Mississippi. Decomposition rates of Q. falcata leaf litter were also assessed at each plot. Soil phosphatase activity decreased after a prescribed burn and was related to an increase in soil organic matter in plots that had been burned. Soil β-N-acetylglucosaminidase activity increased after a burn, and was related to a decrease in leaf litter. Leaf litter enzyme activity showed no consistent patterns amongst treatments, or between individual enzymes, while decomposition rates of leaf litter were slightly accelerated in the treatment plots, but not significantly so. Decomposition rates were related to cumulative enzyme activity, with phenol oxidase and lignin-peroxidase having the highest apparent efficiencies in degrading the leaf material. Overall, the microbial degradation of Q. falcata leaf litter was more efficient in plots that were burned and thinned than in the other plots. Increases in the efficiency of litter decomposition coupled with reductions in litter inputs due to canopy thinning likely allows for increased solar penetration to the soil, and could promote the restoration of the shade-intolerant species that once dominated the understory. Post-burn increases in β-N-acetylglucosaminidase activity and decreases in phosphatase activity also suggest a potential shift in the soil community from phosphorus limitation to nitrogen limitation following a fire.

Finite element analysis of wooden chair strength in free drop

Wooden furniture is being widely used in all countries due to its convenience and being produced from the natural raw material. In furniture design esthetic, ergonomics and safety are the main criteria. Safety means the strength of furniture. Unfortunately, most of the time the strength of furniture is not taken into account in design as much as esthetic and ergonomics. This leads to the use of excess material meaning high cost or usage of less material causing some dangers in use. In literature, the first study of finite element method (FEM) in furniture design was in 1966. The technological developments in software and hardware promoted those studies. In those researches, the strength analysis had been done for different kinds of wood. In one of the latest studies, irregular types of sitting on the chair had been analyzed by FEM. In our study, the chair produced from southern red oak (Quercus falcata), pine red (Pinus resinosa) and Spruce Engelmann (Picea engelmannii) wood are simulated by free drop from two different heights defined in packaging standards. The strength at different parts and corners of the chair is analyzed as free dropped on its front legs by ANSYSTM. In this study, some suggestions are developed for furniture designers and manufacturers. Key words: Free drop test, strength design of chair, finite element method.

Community Analysis of Green Pitcher Plant (Sarracenia oreophila) Bogs in Alabama

Abstract Multivariate analysis of vegetation and environmental variables from green pitcher plant (Sarracenia oreophila) bogs in northeast Alabama revealed three communities with unique species compositions and soil characteristics. Discriminant analysis of environmental variables revealed that A-horizon percent N, A and B horizon pH, humus layer thickness, and B-horizon K (kg/ha) were significantly related to the communities. A Quercus rubra, Arundinaria appalachiana, Pinus echinata community was found on upland seepage bogs located exclusively on Lookout Mountain close to the rim of the Little River Canyon and scattered along perennial streams. A Quercus falcata, Diospyros virginiana, Rhododendron canescens community was found on both Lookout and Sand Mountain in flat broad swales bisected by ephemeral streams. A Rhexia virginica, Dichanthelium scoparium, Carex glaucescens community was found primarily on Sand Mountain in open flood prone areas.

Supplemental Treatments for Timber Bridge Components

A series of joint treatments on southern pine, red oak, and yellow-poplar were evaluated. These included treatments applied in holes that were subsequently capped, treatments applied to bolt holes and/or bolts, treatments applied to felt pads located between wooden members, and treatments applied directly to the surfaces of the joints. Water-soluble diffusible systems applied in holes adjacent to joints generally performed more poorly than expected because of the lack of rainfall during the exposure period. The notable exception was a copper-borate paste applied directly to the joint area. Application of a solvent-borne copper naphthenate with or without a water repellent to felt pads was also very effective. Water repellent alone and fumigant treatments gave unsatisfactory performance over the long term. To simulate hazards encountered by piling, kiln-dried untreated southern pine pole stubs that received various supplemental treatments were placed in the field for 41 months. Upon groundline evaluation of these test specimens, it was noted that seven preservatives or combinations of preservatives looked very favorable. The following treatments yielded sound stubs with no evidence of decay or insect attack: (1) copper-borate paste applied to the surface at and below groundline; (2) copper-borate paste applied to the surface at and below groundline plus boron rods inserted into holes near groundline; (3) copper-borate paste applied to the surface at and below groundline plus fumigant inserted into holes near groundline; (4) pentachlorophenol grease applied to the surface at and below groundline; (5) fluoride paste applied to the surface at and below groundline; (6) fluoride paste applied to the surface at and below groundline plus boron rods inserted into holes near groundline; and (7) fluoride paste applied to the surface at and below groundline plus fumigant inserted into holes near groundline.

Bulk Density (Scaling Factor) of 14 Hardwood Species in Arkansas

With the monetary exchange for hardwood trees and logs changing from log-scale board feet to tons, it is important that bulk density values (also called scaling factors) be developed to aid in determining the value of standing trees and logs. This study included 14 species of hardwoods and a total of 325 trees. Ten species were oak, which were divided into a red oak group (seven species) and a white oak group (three species). The red oak group had an average bulk density of 80.7 lb/ft3, and the white oak group had an average bulk density of 79.2 lb/ft3. A significant difference was found between the groups, as were significant differences between species within each group. Southern red oak (Quercus falcate) had the highest value (83.0 lb/ft3), and white oak (Quercus alba) had the lowest (77.0 lb/ft3). Three hickory types had an average bulk density of 79.4 lb/ft3. Sweetgum (Liquidambar styraciflua) had a bulk density of 78.3 lb/ft3.

Surface Energy Characterization of Three Partially Hydrolyzed Hardwood Species Determined by Dynamic Contact Angle Analysis

The effects of a partial hydrolysis treatment on the surface energies of three southern hardwood species, red oak, sweetgum, and yellow-poplar were examined. Miniature beams machined to 3 × 15 × 150 mm (t × r × l) were water-saturated and subjected to a partial hydrolysis at 150°C for 30 min in 1% sulfuric acid, water, or 1% sodium hydroxide solutions. Untreated wood beams were used as controls. Dynamic contact angle specimens were planed from the beams to a thickness of 0.25 mm and cut to a length of 15 mm for analysis via the Wilhelmy plate technique. Surface energies for the wood/treatment combinations were calculated using the geometric mean procedure. Results indicated that acid and water treatments improved the wettability for all species. Alkaline treatment effects were species-specific. All treatments improved the surface energy of red oak. The dispersive forces accounted for the majority of the surface energies.

Thermal plasticity of photosynthesis: the role of acclimation in forest responses to a warming climate

AbstractThe increasing air temperatures central to climate change predictions have the potential to alter forest ecosystem function and structure by exceeding temperatures optimal for carbon gain. Such changes are projected to threaten survival of sensitive species, leading to local extinctions, range migrations, and altered forest composition. This study investigated photosynthetic sensitivity to temperature and the potential for acclimation in relation to the climatic provenance of five species of deciduous trees, Liquidambar styraciflua, Quercus rubra, Quercus falcata, Betula alleghaniensis, and Populus grandidentata. Open‐top chambers supplied three levels of warming (+0, +2, and +4 °C above ambient) over 3 years, tracking natural temperature variability. Optimal temperature for CO2 assimilation was strongly correlated with daytime temperature in all treatments, but assimilation rates at those optima were comparable. Adjustment of thermal optima was confirmed in all species, whether temperatures varied with season or treatment, and regardless of climate in the species' range or provenance of the plant material. Temperature optima from 17° to 34° were observed. Across species, acclimation potentials varied from 0.55 °C to 1.07 °C per degree change in daytime temperature. Responses to the temperature manipulation were not different from the seasonal acclimation observed in mature indigenous trees, suggesting that photosynthetic responses should not be modeled using static temperature functions, but should incorporate an adjustment to account for acclimation. The high degree of homeostasis observed indicates that direct impacts of climatic warming on forest productivity, species survival, and range limits may be less than predicted by existing models.

The Beetle Community of Small Oak Twigs in Louisiana, with a Literature Review of Coleoptera from Fine Woody Debris

We conducted a study to explore which beetles utilize dead twigs in a Louisiana secondary forest and the effect of debris position on the beetle community. Twigs averaging 14 mm in diameter from one tree of Quercus falcata Michaux (southern red oak) were placed randomly into bundles of ten. At each of three sites, three bundles were laid on the ground, three were propped at the base of a living tree, and three were tied tightly above the ground against the branch of a living woody plant. The bundles were collected 10 months later and each was placed into an emergence chamber. More than 400 adult Coleoptera specimens were collected, representing 35 species within 16 families. Cerambycidae (longhorn beetles) and Curculionidae (weevils) exhibited the highest species richness, with nine and five species, respectively. Species richness was significantly different among treatments. Bundles placed on the ground had the lowest richness, aboveground bundles had the highest, and propped bundles were intermediate. Twelve species (34%) were represented by singletons.

CREEP BEHAVIOR OF BORATE-TREATED STRANDBOARD: EFFECT OF ZINC BORATE RETENTION, WOOD SPECIES, AND LOAD LEVEL

Creep performance of zinc borate-treated strandboard from southern pine (Pinus taeda L.) and red oak (Quercus falcata) was investigated at 25°C temperature and 65% relative humidity. It was shown that the borate treatment had some signifi cant effect on creep defl ection of the test panels, and the effect varied with wood species. There was no signifi cant effect of creep loading on residual bending properties of treated strandboard under the stress levels used. The four element spring-dashpot creep model fi tted the creep data well. The predicted creep defl ection for a 10-year loading duration under both 15% and 40% stress levels met the National Design Specifi cation for Wood Construction despite of the noticeable borate treatment effect on creep. Future work is needed to study the creep behavior under combined mechanical and moisture loadings for treated structural panels.

Physiological responses of seedlings of two oak species to flooding stress

The physiological responses of 2-year-old seedlings of Nuttall’s oak (Quercus nuttallii) and Southern red oak (Q. falcata) with two treatments i.e., deep-drowning and shallow-drowning, were studied. Taxodium distichum was selected as a control. The survival rates of seedlings were calculated, the photosynthetic indices were detected by Licor-6400 photosynthetic system instrument, and the root activities of seedlings were tested by the method of triphenyltetrazolium chloride (TTC). Results showed that: 1) By experiencing flooding for 76 d and recovering for 60 d after water was drained off, all seedlings survived under the shallow-drowning treatment. None of Q. falcata seedlings died in the deep-drowning treatment until the 49th day. The survival rate of Q. falcata in the deep-drowning treatment was 30%. 2) Within 61 d of waterlogging treatments, the net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) showed a tendency of declining, but intercellular concentration of CO2 (Ci) increased. With the prolongation of flooding stress, the extents of variation for all indices under deep-drowning treatment were larger than those under the shallow-drowning treatment. The variation of Q. falcata in flooding stress was larger than that of Q. nuttallii. 3) The root vigor and alcohol dehydrogenase (ADH) activities were detected at the 61st day in flooding stress. Waterlogging obviously inhibited root activities. Shallow-drowning made root vigor of Q. nuttallii decreased by 11.7%, and for Q. falcata, by 51.88%. Shallow-drowning treatment had no remarkable effects on ADH activities of seedlings, but deep-drowning increased those of Q. nuttallii seedlings by 227.24%, and decreased those of Q. falcata seedlings by 59.22% in the meantime. We conclude that Q. nuttallii had a stronger waterlogging resistance than Q. falcata, but weaker than T. distichum.

Oak decline in the Boston Mountains, Arkansas, USA: Spatial and temporal patterns under two fire regimes

A spatially explicit forest succession and disturbance model is used to delineate the extent and dispersion of oak decline under two fire regimes over a 150-year period. The objectives of this study are to delineate potential current and future oak decline areas using species composition and age structure data in combination with ecological land types, and to investigate how relatively frequent simulated fires and fire suppression affect the dynamics of oak decline. We parameterized LANDIS, a spatially explicit forest succession and disturbance model, for areas in the Boston Mountains of Arkansas, USA. Land type distribution and initial species/age class were parameterized into LANDIS using existing forest data. Tree species were parameterized as five functional groups including white oak ( Quercus alba L., Quercus stellata Wangenh., Quercus muehlenbergii Engelm.), red oak ( Qurecus rubra L., Quercus marilandica Muenchh., Quercus falcata Michx., Quercus coccinea Muenchh.), black oak ( Quercus velutina Lam.), shortleaf pine ( Pinus echinata Mill), and maple ( Acer rubrum L., Acer saccharum Marsh.) groups. Two fire regimes were also parameterized: current fire regime with a fire return interval of 300 years and a historic fire regime with an overall average fire return interval of 50 years. The 150-year simulation suggests that white oak and shortleaf pine abundance would increase under the historic fire regime and that the red oak group abundance increases under the current fire regime. The black oak group also shows a strong increasing trend under the current fire regime, and only the maple group remains relatively unchanged under both scenarios. At present, 45% of the sites in the study area are classified as potential oak decline sites (sites where red and black oak are >70 years old). After 150 simulation years, 30% of the sites are classified as potential oak decline sites under the current fire regime whereas 20% of the sites are potential oak decline sites under the historic fire regime. This analysis delineates potential oak decline sites and establishes risk ratings for these areas. This is a further step toward precision management and planning.

Influences on Oak and Pine Establishment with Time Since Fire in Sandhills Pinus paulustris (Longleaf Pine) Forests

Abstract We investigated biotic and abiotic mechanisms that affect Quercus falcata (southern red oak) establishment from seeds in southeastern Pinus paulustris (longleaf pine) forests along a time-since-fire chronosequence (unburned since 1950, the mid-1990s, or winter 2001) and slope gradient. To determine if seed availability limits southern red oak recruitment, we measured seed production, populations of small mammals, and seed removal across sites. To determine if seedling survival limits establishment, we outplanted greenhouse-raised southern red oak seedlings and followed their survival throughout one growing season. We also measured abiotic conditions such as canopy openness, soil moisture, and soil temperature, and censused longleaf pine recruitment. Contrary to expectations based on species' fire-tolerances, longleaf pine recruitment was consistent over the chronosequence, but there was little oak seedling establishment in the long-unburned sites. Sites last burned in the mid-1990s had the lowest...

Scientific Note: Quercus sinuata Walter—the Hybrid of Q. falcata and Q. phellos—Rediscovered and Neotypified

The name Quercus sinuata, published by Thomas Walter in 1788, has been interpreted to apply to some species of oak native to the southeastern United States, most often the Bluff Oak (Q. austrina Small). Inspection of the vegetation in the immediate vicinity of Walter’s North Carolina homesite disclosed no Bluff Oak, but did reveal several trees that well matched Walter’s description. Specimens from these trees have been identified as the hybrid of the Southern Red Oak (Q. falcata Michx.) and the Willow Oak (Q. phellos L.), both of which were found at the same location. To provide stability to the name Q. sinuata, a neotype has been selected. In the second half of the 18th century Thomas Walter, an English expatriate, maintained a home and plantation on the Santee River, Berkeley County, South Carolina. In 1788 Walter published his Flora Caroliniana, a record of the plants he had encountered, matching many as best he could with those in the books of Carl Linnaeus, and including others that he believed to be new. His modest volume, the first flora published in America to follow the new Linnaean system of binomial nomenclature, contained 436 genera and approximately 1050 species. For each species he gave a brief diagnosis in Latin and a two-part Latin name. Walter described 13 species of Quercus, the oaks. Most are readily recognized: Q. sempervirens Walt. (5Q. virginiana Mill., Live Oak), Q. phellos L. (Willow Oak), Q. humilis Walt. (5Q. incana Bartr., Blue-jack Oak), Q. prinus non L. (5Q. michauxii Nutt., Swamp Chestnut Oak), Q. nigra non L. (Q. marilandica Muench., Blackjack Oak), Q. aquatica Walt. (5Q. nigra L., Water Oak), Q. rubra non L. (5Q. falcata Michx., Southern Red Oak), Q. laevis Walt. (Turkey Oak), Q. alba L. (White Oak), Q. lyrata Walt. (Overcup Oak), Q. villosa Walt. (5Q. stellata Wangenh., Post Oak). These determinations are in agreement with conclusions of a recent careful study of Walter’s oaks (Wilbur 2002). One of Walter’s oaks is less clear. The Running Oak, a shrubby, rhizomatous species, has been known since its publication as Quercus pumila Walt. Recently Wilbur (2002) has argued that Walter’s diagnosis was inadequate and that a new name was required; he supplied the need with Q. elliottii Wilbur. Walter had described the lower leaf surface as glaucis. Wilbur is correct in noting the lower surface is densely gray-puberulent, not glaucous. But Walter, probably lacking adequate magnification, can be forgiven for interpreting the gray lower surface as showing glaucescence. Granting this reasonable latitude, Walter’s description fits the Running Oak quite well. Further, Wilbur’s dismissal of Q. pumila leaves Walter’s work without a name for the Running Oak, a plant he could not help but have known in the dry oak-pine habitat adjacent to his Santee River home. Yet another of Walter’s oaks has continued to puzzle later workers. He named this species Quercus sinuata, with the diagnosis ‘‘foliis sinuatis laevibus obtusis supra pallidis, subtus subglaucis, glandibus mediocribus globosis calyce subplano’’ (i.e., leaves sinuate-margined, obtuse, pale above, subglaucous beneath, the

Product Analysis and Thermodynamic Simulations from the Pyrolysis of Several Biomass Feedstocks

The pyrolysis of southern pine, red oak, and sweet gum sawdust is reported. Pyrolysis experiments were conducted under either a helium or nitrogen atmosphere at ∼371−871 °C, to determine the balance between liquid and gas products. Gas- and liquid-phase pyrolysis products were identified using gas chromatography (GC) and GC/mass spectrometry (MS). A total of 109 liquid and 40 gas compounds were identified. A total of 59 chemical compounds (35 liquids and 24 gaseous products) were quantitatively determined. The influence of the gas-phase residence time and biomass feed particle size were studied. The gas residence time determined the extent of secondary reactions. Very short residence times enhanced liquid production versus gas production. Particle sizes (d < 105 μm, 105 μm < d < 149 μm, 149 μm < d < 297 μm, and d > 297 μm) did not have a pronounced effect on either the yield or product distributions, indicating that heat-transfer limitations within the particles were negligible. The pyrolysis of pine, red oak, and sweet gum sawdust yielded similar product distributions. Simulations were conducted using the ASPEN/SP software package based on Gibbs energy minimization. At high temperatures, dominant species were hydrogen and carbon monoxide, while at lower temperatures, methane, carbon dioxide, and water were the predominant species. Above 871 °C, further increases in the temperature did not affect the product distribution. Lower gasification temperatures and higher steam/carbon ratios resulted in higher hydrogen and carbon monoxide production.

Species-specific effects of a 1994 ice storm on radial tree growth in Delaware1

Ice storms are recurrent disturbances that alter forest succession and forest structure throughout North America. However, long-term effects of ice storms on tree growth are largely unknown. Following a 1994 ice storm in Delaware, the Delaware Forest Service established seventy-five study plots to sample four species of trees (southern red oak [Quercus falcata Michx.], white oak [Quercus alba L.], loblolly pine [Pinus taeda L.], and yellow poplar [Liriodendron tulipifera L.]) affected by the ice storm. The objective of this study is to identify multi-year species-specific responses to the 1994 Delaware ice storm using tree ring data collected statewide four years following the disturbance. A ground survey classified affected trees into damage class categories based on the percentage of crown limbs broken. Dendrochronology was used to identify the radial growth response of the four species studied across four damage classes (control, light damage, moderate damage, and severe damage). Yellow poplar was most susceptible to ice storm damage followed by loblolly pine, red oak, and white oak. In general, severely damaged trees experienced the greatest reduction in annual radial growth. Yellow poplar had the fastest recovery rate following the storm, followed by white oak, red oak, and loblolly pine. The results of this study suggest that species have differential growth responses to ice storms that is in part attributable to the species' ability to produce epicormic branches.