Oak Group Research Articles

Processing and material properties of Tasmanian yellow gum, Eucalyptus johnstonii

Summary Boards of native forest Tasmanian yellow gum (Eucalyptus johnstonii) were processed using current commercial best practice. Boards were evaluated before and after processing to determine parameters such as board shrinkage, appearance grade and drying degrade. Bending strength and stiffness were determined by standard tests on thirty small clear sections, while Janka hardness was measured at two points on each of ten specimens. Yellow gum boards proved prone to collapse shrinkage and distortion on drying. The results showed that the species produces much denser, stronger and harder timber than the Tasmanian oak group of eucalypts, with seasoned strength rating according to Australian Standards of strength group SD2 (compared with SD4 for the species group) and mean Janka hardness 10.9 kN (compared to 6.1 kN).

Focus on ... Field Foresters: Sudden Oak Death: Where and How to Detect It

Abstract Phytophthora ramorum, the cause of “sudden oak death,” is responsible for widespread tree mortality in central and northern California and appears to be spreading to other areas as well. Although thus far only oaks in the black or red oak group have been found to be susceptible to the disease, at least 11 other unrelated plant species may serve as hosts. Foresters in the field should look for symptoms on these known hosts in proximity to dead and bleeding oakds in order to confirm the presence of the pathogen.

Predicting stump sprouting and competitive success of five oak species in southern Indiana

We measured 2188 oak trees (Quercus spp.) on the Hoosier National Forest in southern Indiana before and 1, 5, and 10 years after clear-cutting to determine the influence of parent tree age, diameter breast height, and site index on the probability that there was one or more living sprouts per stump: (i) 1 year after clear-cutting (sprouting probability) or (ii) that were competitively successful 5 or 10 years after clear-cutting (competitive success probability). We used logistic regression to develop predictive models for five species in each of the three measurement years. Two species were in the white oak group: white oak (Quercus alba L.) and chestnut oak (Qurcus prinus L.). Three species were in the red oak group: black oak (Quercus velutina Lam.), scarlet oak (Quercus coccinea Muenchh.), and northern red oak (Quercus rubra L.). Black oak site index ranged from 15 to 25 m at an index age of 50 years on the study sites. Parent tree age and diameter at breast height were significant predictors in all models. Sprouting and competitive success probabilities decreased with increasing parent tree age and diameter at breast height. Increasing site index was a significant contributor of increasing sprouting probabilities for year 1 and competitive success probabilities for year 5. By year 10, site index was negatively related to competitive success for the white oaks but was not a significant predictor for the red oaks. The models have practical value for predicting the stump sprouting potential of oak stands in southern Indiana and possibly in ecologically similar regions.

Effects of Prescribed Fire on Sand Shinnery Oak Communities

Sand shinnery oak (Quercus havardii Rydb.) communities are shrublands extending from northern Texas and western Oklahoma southward into the Chihuahuan Desert. They are dominated by sand shinnery oak, a member of the white oak group. Structure and composition of sand shinnery oak communities in relation to natural disturbances, such as fire, have not been adequately investigated. The objectives of this study were to determine the influence of fire on shrub composition and vegetation structure of sand shinnery oak communities, and to determine the persistence of structural and compositional changes. Data were collected on Black Kettle National Grassland (BKNG) in western Oklahoma during the growing seasons of 1998 and 1999. Vegetation measurements included line transects, visual obstructions, heights, cone of vulnerabilities, shrub patch sizes, and shrub patch densities were used to estimate functional group canopy cover, shrub composition, and structure of sand shinnery oak communities. One growing season after fire, burned sand shinnery oak communities had significantly less shrub cover (P < 0.01) than unburned communities (38 vs. 51%). Height of vegetation was lower 1 and 2 growing seasons after fire (26 and 35 cm, respectively) (P < 0.05) than unburned communities (44 cm). Visual obstruction was lower the first (30%) and second (40%) year after fire (P < 0.01) compared to unburned communities (59%). Cone of vulnerability indicated significantly more open structure one growing season after fire. After 4 growing seasons, all measures of structure in burned communities were similar to those in unburned communities. We found no differences in composition of shrub species between burned and unburned sites (P = 0.55). Two fire events, 2 growing seasons apart, had less influence on vegetation structure than the initial fire. Sand shinnery oak communities appear to be highly resilient to periodic disturbance by fire. Prescribed fire is an effective tool for short-term alteration (< 3 growing seasons) of sand shinnery oak structure; however, rapid recovery following fire does not indicate any long-term changes in vegetation structure and composition. DOI:10.2458/azu_jrm_v54i6_harrell

Task independence, safety, and adequacy among nondisabled and osteoarthritis-disabled older women.

To examine the constructs of task independence, safety, and adequacy. Fifty-seven nondisabled (ND) and 56 osteoarthritis-disabled (OAK) women were observed performing daily tasks. Intercorrelations among the constructs of independence and adequacy were uniformly high, while the relationship of safety to these constructs was moderate and more variable, although stronger in the OAK group. Task performance of the OAK group was consistently less adequate and independent than that of the ND group; however, the groups were generally equivalent in safety. For individual tasks, adequacy best differentiated between the groups. In both groups, those who performed independently also performed safely, but fewer independent OAK participants also performed totally adequately. The majority of older women who perform tasks independently also perform them safely and adequately; for a clinically significant minority, independence is not always synonymous with safe and adequate performance. Patients may be placed at risk if independence is the only construct used to determine disability.

The Ultimate Basis of the Caching Preferences of Rodents, and the Oak-Dispersal Syndrome: Tannins, Insects, and Seed Germination1

SYNOPSIS. We have shown that eastern gray squirrels and other animals consistently prefer to store intact acorns from the red oak group rather than those from the white oak group. We hypothesized that the ultimate advantage to this behavior comes from the dormancy of red oak acorns. Acorns of the white oak group germinate early in the autumn; thus, we hypothesize that avoiding germination is the primary selective advantage to the preference for caching red oak acorns. Here, we test two alternative hypotheses to explain the benefits of this caching preference: 1) storing red oak acorns allows the high tannin concentrations in red oak acorns to decline (making them more palatable), and 2) storing red oak acorns minimizes losses to insects, presuming they are less infested with insects. We also test the effect of germination schedule on squirrel caching preferences directly, by presenting them with dormant red oak acorns, and red oak acorns about to germinate. We find no evidence that tannin concentrations in red oak acorns decline, although tannin levels did decline in our white oak acorns. We found high losses to insect infestations in one white oak species, but a second white oak species lost very little mass to insects. Finally, we found that germination schedule directly affects squirrel caching preferences: red oak acorns that are near germination are treated like white oak acorns. We conclude that the primary advantage to the preference for caching red oak acorns is that they are less perishable, due to their dormancy. We discuss the effects of this preference on the dispersal of red and white oak acorns, and the subsequent effects of differential dispersal on the ecology and evolution of oaks.

The Proximate Basis of the Oak Dispersal Syndrome: Detection of Seed Dormancy by Rodents1

Abstract Previously we have shown how a range of physical and chemical characteristics of acorns influences the behavioral decisions of food-hoarding rodents which in turn affects the dispersal, establishment and spatial arrangement of oaks. One such behavior involves the selective caching of acorns of red oaks (subgenus: Erythrobalanus) over those of white oaks (Quercus) because of reduced perishability that results from delayed germination of acorns in the red oak group. In this study, we sought to identify the specific proximate cues (visual and olfactory) that eastern gray squirrels (Sciurus carolinensis) use when making these decisions. In two series of field experiments, we presented individual, free-ranging animals with pairs of experimentally altered acorns (that differed with respect to a single chemical or visual characteristic) and recorded their feeding and caching responses. Squirrels cached artificial acorns with pericarps (shells) of red oak acorns and ate those with shells of white oak reg...

Effects of prescribed fire on sand shinnery oak communities

Sand shinnery oak (Quercus havardii Rydb.) communities are shrublands extending from northern Texas and western Oklahoma southward into the Chihuahuan Desert. They are dominated by sand shinnery oak, a member of the white oak group. Structure and composition of sand shinnery oak communities in relation to natural disturbances, such as fire, have not been adequately investigated. The objectives of this study were to determine the influence of fire on shrub composition and vegetation structure of sand shinnery oak communities, and to determine the persistence of structural and compositional changes. Data were collected on Black Kettle National Grassland (BKNG) in western Oklahoma during the growing seasons of 1998 and 1999. Vegetation measurements included line transects, visual obstructions, heights, cone of vulnerabilities, shrub patch sizes, and shrub patch densities were used to estimate functional group canopy cover, shrub composition, and structure of sand shinnery oak communities. One growing season after fire, burned sand shinnery oak communities had significantly less shrub cover (P &lt; 0.01) than unburned communities (38 vs. 51%). Height of vegetation was lower 1 and 2 growing seasons after fire (26 and 35 cm, respectively) (P &lt; 0.05) than unburned communities (44 cm). Visual obstruction was lower the first (30%) and second (40%) year after fire (P &lt; 0.01) compared to unburned communities (59%). Cone of vulnerability indicated significantly more open structure one growing season after fire. After 4 growing seasons, all measures of structure in burned communities were similar to those in unburned communities. We found no differences in composition of shrub species between burned and unburned sites (P = 0.55). Two fire events, 2 growing seasons apart, had less influence on vegetation structure than the initial fire. Sand shinnery oak communities appear to be highly resilient to periodic disturbance by fire. Prescribed fire is an effective tool for short-term alteration (&lt; 3 growing seasons) of sand shinnery oak structure; however, rapid recovery following fire does not indicate any long-term changes in vegetation structure and composition.

Dynamics of twolined chestnut borer Agrilus bilineatus as influenced by defoliation and selection thinning

Abstract1 The twolined chestnut borer, Agrilus bilineatus (Coleoptera: Buprestidae), is a major mortality agent of stressed oak trees. However, patterns of abundance and population change are not well understood.2 We studied the spatial and temporal variation in abundance of twolined chestnut borer adults during a gypsy moth, Lymantria dispar (Lepidoptera: Lymnatriidae), outbreak and examined the influence of both defoliation and thinning on twolined chestnut borer abundance.3 In stands that were defoliated by gypsy moth, extensive defoliation occurred in one year, and major overstory tree mortality followed in the next. Most mortality occurred in the year preceding the peak year of twolined chestnut borer abundance and abundance of twolined chestnut borer was positively associated with defoliation and mortality in the previous year.4 Twolined chestnut borers were more frequently associated with poor or fair crown condition trees than trees with good crown condition and were more abundant on members of the red oak group than the white oak group.

Occurrence of Lepidoptera on Selected Host Trees in Two Central Appalachian National Forests

In 1995 and 1996, Lepidoptera larvae of 13 families were sampled by pruning foliage from canopies of maple, hickory, red oak group, white oak, and chestnut oak. The families were Arctiidae, Geometridae, Hesperiidae, Lasiocampidae, Lycaenidae, Lymantriidae, Noctuidae, Notodontidae, Nymphalidae, Papilionidae, Saturniidae, Sphingidae, and Thyatiridae. Samples were collected from 18 plots (each 200 ha), nine in the George Washington National Forest in Virginia and nine in the Monongahela National Forest in West Virginia. Sampling seasons were from May to mid-August; foliage samples were collected each week. The occurrence of Lepidoptera on host trees within the two forests was compared. A total of 131 species of caterpillars representing 13 families was collected. Most larvae were Noctuidae (47 species) and Geometridae (44 species). Of 6,743 larvae collected over both years, 57% were gypsy moth, Lymantria dispar (L.). The population of this species collapsed during the second year of the study because of the fungus Entomophaga maimaiga. Other particularly abundant species in both forests were Acronicta ovata Grote, Hyphantria cunea (Drury), Polia latex (Guénée), Melanolophia canadaria (Guénée), Alsophila pometaria (Harris), and Nadata gibbosa (J.E. Smith). Some species were found only in one forest. Larval richness and abundance were higher in May and August and the lowest numbers occurred in June and July. Abundance and richness were different for the 2 yr. Population shifts may be directly related to weather conditions or indirectly related through the effects of temperature or rainfall patterns on natural enemies, foliage chemistry, or other factors. The number of species of caterpillars collected from the host tree groups was 62 on maple, 77 on hickory; 76 on the red oak group, 75 on chestnut oak, and 66 on white oak. The abundance of larvae ranged from 14.8% collected on maple to 25.4% collected on the red oak group.

TERPENOID EMISSIONS OF MEDITERRANEAN OAKS AND THEIR RELATION TO TAXONOMY

This paper presents results of a laboratory screening study of biogenic emissions from Mediterranean oak species. The experiment aimed at improving our understanding of oak contributions to overall emissions of volatile organic compounds and to the atmospheric chemistry in the Mediterranean area. We measured type and amount of terpenoid emissions (isoprene, mono- and sesquiterpenes) under standard conditions of light and temperature from 14 different Quercus species of Mediterranean and American origin. Tree saplings were exposed in a controlled environment chamber, and leaf-level trace-gas exchange was analyzed with a minicuvette system and gas chromatography, to study the relation between the emission types and emission spectra found and the taxonomy of Quercus. The holarctic group Lepidobalanus and the North American groups Erythrobalanus and Protobalanus were found to be strong isoprene emitters. The Eurasian oak group Sclerophyllodrys emits monoterpenes; Cerris include mostly non-emitters, but also an isoprene and a monoterpene emitter has been found in this group. Results are discussed with respect to their implications for presently used emission scenarios.

Taxonomy and Distribution of a Natural Group of Black Oaks of Mexico (Quercus, Section Lobatae, Subsection Racemiflorae)

A taxonomy of a small section of Mexican black oaks (Quercus, section Lobatae, subsection Racemiflorae) is presented. Four species are recognized; Q. conzattii, Q. radiata, Q. tarahumara, Q. urbanii.

The influence of drought on red oak group species growth and mortality in the Missouri Ozarks

The effects of drought on growth of red oak group species were studied by examining basal area increment and ring width index patterns of dominant Quercuscoccinea Muenchh. (scarlet oak) and Quercusvelutina Lam. (black oak) trees sampled in 1990–1991 on 62 continuous forest inventory plots located across the southeastern Missouri Ozark Mountains. Trees of both species were older on plots that had suffered high mortality and showed post-1979 reductions in growth rate compared with trees growing on low-mortality plots. Quercuscoccinea trees from high-mortality plots that were dead at the time of sampling exhibited a distinct flattening in growth rate after the mid-1930s, although death did not occur for many years. Severe droughts in 1980 and 1986–1988 were associated with further accentuated reductions in growth rate in dead trees. Dead Q. coccinea that had grown on plots with lower mortality showed comparable reductions in basal area index and similar post-1979 growth patterns, but the departure in basal area index between living and dead trees occurred 2 decades later and was associated with a severe drought during 1953–1956. Additionally, dead trees on lower mortality plots grew faster than living trees for many years before the 1953–1956 drought, suggesting that rapid early growth rates may predispose trees to early death under certain conditions. The ring width index chronologies of both species growing on high- and low-mortality plots were significantly correlated with Palmer drought severity index values, further emphasizing that drought has an important influence on growth of red oak group species in the Missouri Ozarks. Analysis of first differences of ring width index chronologies indicated that severe drought had an additional persistent effect involving long-term reductions in the sensitivity of growth to climate. The results are consistent with previously hypothesized mechanisms of stand dieback and emphasize the role of severe droughts in predisposing trees to eventual death.

The Influence of Evergreen Coniferous Nurse-Crops on the Field Layer in Two Woodland Communities

Evergreen conifers used as nurse-crops to establish Quercus spp. and Fagus sylvatica in old woodland severely reduced the cover of the field-layer and its species content. Deep shade, especially from March to May, and the accumulation of coniferous litter and humus are shown to cause changes in the field-layer. Groups of oaks were important sites for the survival of some species, e.g. Hyacinthoides non-scripta but others, e.g. Anemone nemorosa, were apparently eliminated. There was a convergence in the composition of field-layers derived from originally different woodland communities (...)

Systemic Treatment with Acephate for Gypsy Moth Management: Population Suppression and Wound Response

Oaks were treated with acephate containing ACECAPs or Mauget Inject-A-Cide 0 units 1984 and/or 1 985. In 1985, both twice-treated (treated in 1984 and 1985) and once-treated (treated only in 1985) oaks had significantly fewer gypsy moth egg masses per tree than did control trees, and twice-treated oaks had fewer than those treated only in 1984. Implantation/injection did more damage to white oak than to red oak group trees.

Propagation of Quercus L. Species by Cuttings

Abstract Ten species of oak, Quercus L., were used to determine the feasibility of rooting oak cuttings. Cuttings were taken from the first, second, and third growth flushes from seedling stock plants (2 to 3-year-old) and treated with 1.0% potassium 1H-indole-3-butanoic acid (K-IBA), 5-sec. dip and placed under mist. Rooting ranged from 0% to 80% with Q. phellos L., Q. robur L., and Q. lyrata Walter rooting 80%,69%, and 43%, respectively, on the first date. Generally, rooting decreased with progressive flushes. Quercus alba L. and Q. suber L. rooted 2% or less over all dates. No consistent pattern of rooting was observed for white oak compared to red oak groups. Rooting was strongly species specific.

Tissue proportions and cell dimensions for red and white oak groups

A vast source of oak wood is available for use in the United States for papermaking. Knowledge of the proportions of tissue types and cell dimensions for hardwoods, especially on a weight basis, could help extend their use in the pulp and paper industry. This report provides such information for 11 red and white oak species. A method for calculating tissue proportions by weight from proportions by volume is given. The proportion by weight for fibers varied from 74% for fast-grown trees to 38% for slow-grown trees; for axial and ray parenchyma from 24% for fast grown to 54% for slow grown; and for vessels from 2% for fast grown to 8% for slow grown. Results show the relationship of tissue proportions to both growth rate and site. Information in this report can be used to help decide whether it is economical to separate fines and other components in pulping hardwoods. The amount of axial and ray parenchyma by weight in slow-grown material suggests it may be economically feasible to separate the parenchyma for possible use as fuel, chemical stock, or cattle feed.

Field Recognition of Eastern Poison Oak

Eastern poison oak, Toxicodendron toxicarium, is a nonclimbing shrub whose leaves have three leaflets. The leaflets with their numerous round lobes resemble somewhat the leaves of some oaks in the white oak groups. The plant grows in nutritionally poor, sandy soil, and especially in dry pine-oak woodland. Deposits resembling black enamel paint can often be seen where plants have been injured. During winter, the U- or V-shaped leaf scars, the naked fruit stalks in female plants, and the sparse upright branches all aid in recognition. Other features can be useful in spring and fall. While poison oak and poison ivy are so closely related that the sensitivity of individuals and resulting dermatitis are not markedly different, accurate recognition is important in avoiding contact.

Evaluation of biogeochemical prospecting methods in the search for sulfide deposits in the Appalachian piedmont, Virginia, U.S.A.

Abstract Soil and stream sediment sampling have been the primary geochemical exploration tools in the Appalachian piedmont to date. However, the great thicknesses of soil and saprolite found in the region coupled with the dense vegetation frequently encountered favor biogeochemistry as an alternative or supplemental method since deep-rooted plants sample closer to bedrock. To evaluate this method, an orientation survey was performed in which soils and vegetation at 17 sites north of Mineral, Virginia, were sampled and analyzed for Ag, Cd, Cu, Pb and Zn. The traverse included stations over the host rocks of massive sulfide mineralization, as well as over apparent “barren” country rock. Samples were analyzed by atomic absorption spectrophotometry using standard digestion and analytical techniques. Both A- and B-horizon soil metals generally appear to be reliable indicators of mineralization, with soils developed over sulfides showing up to three-fold enrichment in metal content relative to the average soils developed on the country rock. Correlation of metal concentrations in vegetation to soil metal concentrations reveal plant concentrations expressed on a dry-weight basis correlate stronger and more frequently to soil metals than do ash-weight concentrations. Copper shows some promise in selected organs and species, Ag appears fair but data are limited to one organ of one species, and plant Pb seems totally unresponsive to soil metal concentrations perhaps because foliar absorption is an important plant uptake mechanism here. However, Zn and Cd in organs of the oak group, especially mature leaves and twigs of the current year's growth show the greatest promise as prospecting tools. They correlate well with soil metals and when compared directly to the geology they reliably reflect mineralization. Although results using White oak were slightly less profound than those obtained from the Black-Red oak group, White oak may be preferred as it is a single, more widespread, easily-identifiable species. Copper and especially Zn although essential elements to plants, do not appear to be “difficult” elements for biogeochemical prospecting in the Appalachian piedmont.

Composition and Squirrel Use of Acorns of Black and White Oak Groups

Of 11 species of oak (Quercus sp.) acorns tested, those of the white oak group were higher in nitrogen-free extract, cell wall contents, and hemicellulose than those of the black oak group, which had higher levels of dry matter and crude fat. Acorns of all 11 oak species were low in protein and phospho- rus. In feeding tests with adult fox squirrels (Sciurus niger), negative nitrogen balances were recorded for about two-thirds of the trials. Acorns of the white oak group were consumed at higher rates and thus appeared to be the more palatable of the two groups. Acorns apparently supply squirrels with ade- quate energy but do not satisfy their metabolic requirements for nitrogen or probably phosphorus. J. WILDL. MANAGE. 40(3):479-483 Oak mast is an important source of food for many wildlife species (Martin et al. 1951). Tree squirrels (Sciurus sp.) are es- pecially dependent on the presence of qual- ity acorns in their habitat, and squirrel num- bers have been reported to vary directly with acorn availability (Sharp 1960). Al- though the maintenance of huntable popu- lations of squirrels and the well-being of several other wildlife species necessitate the establishment and management of oaks in forest ecosystems, few studies have deter- mined the metabolic usefulness of acorns to squirrels. Fox squirrels have been reported to use white (Quercus alba) and black (Q. velutina) oak acorns more efficiently than those of red oak (Q. borealis maxima) and to digest lipids and nitrogen free extract more readily than crude protein and crude fiber (Baumgras 1944). Acorns with high lipid contents reportedly serve as high en- ergy rations for squirrels (Smith and Foll- mer 1972). The present paper reports both the composition of acorns of 11 species of oaks and the use of these acorns by fox squirrels. MATERIALS AND METHODS Acorns from the black and white oak groups were collected in autumn 1971 for feeding trials. Black oak group acorns were black and northern red oaks (Q. rubra), both collected in the Sylamore Experi- mental Forest in Arkansas, and water oak (Q. nigra), willow oak (Q. phellos), blue- jack oak (Q. incana), and southern red oak (Q. falcata), all collected in Nacogdoches County, Texas. White oak group acorns in- cluded white oak, swamp chestnut oak (Q. prinus), live oak (Q. virginiana), and post oak (Q. stellata), all collected in Nacogdo- ches County. Acorns from the sawtooth oak (Q. acutissima), also a member of the white oak group, were donated by the Interna- tional Paper Company, Camden, Arkansas. Acorns were selected for soundness and stored at -12 C until fed to squirrels. At the beginning of each feeding trial an ali- quot of whole acorns was dried in a forced- air oven at 40 C to determine the oven-dry weight of consumed acorns. The oven-dried acorns were ground in a Wiley mill and stored in capped glass bottles. The dried material was used for the determination of crude protein, crude fat, crude fiber, ash, Ca, and P, according to standard AOAC procedures (Horwitz 1965); cell wall con- tents (CWC), acid detergent fiber (ADF), acid detergent lignin (ADL), and silica were determined according to the proce-