Live Oak Trees Research Articles

Рост и состояние дуба черешчатого в смешанных древостоях полезащитных лесных полос

An analysis of the creation and operation of protective forest plantations at agricultural enterprises of the Central Chernozem Region allows us to assert that positive ameliorative functions are performed by those forest plantations that have good growth, high stability and longevity. Russian forestry scientists have recognized that the main species in the steppe conditions for all types of protective forest plantations is the English oak. The aim of the research has been to assess the current state of the stands in forest shelterbelts planted via different methods with the English oak as the main species. Taxation works and forest pathology research were carried out in 1997–2021 in the forest shelterbelt no. 9, established in the spring of 1989 by 2-year-old seedlings in the land-use territory of the Federal State Unitary Enterprise Experimental Production Farm “Znamya Oktyabrya” of the Talovskiy District of the Voronezh Region. It has been established that the influence of combinations of tree species in forest belts on the growth of the English oak at the age of 32 years is quite significant. As a result of competitive relations for environmental resources by fast-growing and associate species, the number of live oak trees in a continuous row planting option is 35.6...52.1 % less than in intermittent forest belt options, of their number during planting. The remaining sharply oppressed oak trees in the plantation sown in the continuous row planting way are far behind in height and stem diameter (by 0.8...7.6 m and 4.1...12.7 cm, respectively) compared to the oaks growing in the intermittent forest belts sown in a block planting way. The absence of improvement felling in the experimental plantations during their growth and formation has led to a significant number of dead oak wood and non-viable trees of this species. Moreover, the proportion of dead oak wood and non-viable trees in the forest belt sown via continuous row planting exceeds the indicator in the intermittent forest belts by 36.6...40.6 %. The number of viable oak trees in the intermittent belt options is 17.7...27.3 % higher than in the continuous row planting option, and the number of limitedly viable trees is 11.5...18.9 % higher.

Differential Stomatal Responses to Surface Permeability by Sympatric Urban Tree Species Advance Novel Mitigation Strategy for Urban Heat Islands

As urbanization draws more people to metropolitan areas, a steadfast increase in impervious surfaces ultimately contributes to a pronounced urban heat island effect. While city greening strategies to mitigate urban thermal effects often tout street-tree cover expansion, many plant species are susceptible to heat stress, limiting survivorship, primary productivity, and ecosystem services. Our research objective was to characterize how urban imperviousness impacted the photosynthetic traits of four sympatric tree species in Old Town La Verne, California. We found that while Camphor trees (Camphora officinarum) and Carrotwood trees (Cupaniopsis anacardioides) did not differ significantly in photosynthetic traits at sites with impervious and pervious surfaces, both Coast Live Oak trees (Quercus agrifolia) and Olive trees (Olea europaea) showed significant differences in leaf stomatal length and density. Our findings suggest that the photosynthetic traits of some exotic tree species may be less susceptible to surface permeability than either native or floristically indigenous tree species. We propose that urban greening initiatives adopt a temporal strategy for mitigating urban heat island effects, starting with an urban canopy composed of exotic trees more resilient to impervious surfaces and later transitioning to a recombinant canopy ecology of floristically relevant tree species suited for the soil permeability native to southern California.

Evening Bats Captured in a Managed Wildlife Refuge Used Trees in a Human-Dominated Landscape as Maternity Roosts

Abstract Similar to many chiropteran species, pregnant and lactating evening bats Nycticeius humeralis form maternity colonies to bear and raise their pups. Although evening bat maternity roosts have been studied in other locations, knowledge gaps exist regarding maternity roost site selection on the Gulf Coast of Texas, United States; thus, our objective was to quantify maternity roost characteristics of evening bats in this region. We radiotracked 11 female and subadult evening bats to 9 roosts during June and July 2018 and 2019 captured in San Bernard National Wildlife Refuge (SBNWR). No transmittered bats roosted in SBNWR and instead all roosts were located 3.6–4.5 km from the same capture site, within an 81-ha residential area of a 5,496-ha city. Five of the nine roosts were located in tall, live, live oak trees Quercus virginiana and one roost was in a residential home. Colony size of bats occupying the roosts ranged from 16 to 500+ bats. All evening bats, including those on properties to which we were denied access, stayed in roosts for the full life of the transmitter (5–21 d) and no roost switching occurred. Although evening bats used SBNWR, potentially for foraging, results suggest trees in the residential area provided suitable maternity roost characteristics. A lack of roost switching may suggest a lack of available roost trees in SBNWR and residential areas or the selected roost trees were high quality. We recommend future studies increase sample sizes of evening bat roosts on the Gulf Coast of Texas, as well as assessing roost site selection of evening bats and monitoring bachelor colony and evening bat winter roost ecology.

Implications of Planting Southern Live Oak Trees in the Wrong Urban Space in East Baton Rouge, Louisiana United States

Implications of Planting Southern Live Oak Trees in the Wrong Urban Space in East Baton Rouge, Louisiana United States

Morphological and molecular characterization of Xiphinemella esseri Chitwood, 1957 (Dorylaimida: Leptonchidae) from Florida, with the first molecular study of the genus.

A population of Xiphinemella esseri, recently collected under the canopy of associated live oak trees in north Florida, was studied and described with an integrative approach, including the first molecular study of the genus. This Florida population is characterized by its 2.30 to 3.32 mm long body, labial disc well developed, lip region offset by constriction, and 16.5 to 17.5 μm broad, odontostyle 46 to 49 μm long with minute aperture, neck 288 to 296 μm long, pharyngeal expansion occupying 28 to 30% of total neck length, uterus a tripartite tube-like structure, pars refringens vaginae absent, vulva transverse (V = 45.4-49.7%), tail short and rounded (18-28 μm, c = 94-158, c′ = 0.6-0.9), spicules 41 to 45 μm long, and 8 to 10 irregularly spaced ventromedian supplements bearing hiatus. The phylogenetic analysis inferred from the D2-D3 expansion segments of 28S rRNA gene and 18S rRNA gene sequences showed that X. esseri clustered with other dorylaims from the family Leptonchidae. A brief discussion about the distribution and biological considerations of X. esseri is also provided.

Consequences of drought severity for tropical live oak (Quercus oleoides) in Mesoamerica.

In two Costa Rican and three Honduran sites that vary in rainfall and soil properties, we used natural isotopes, a soil water balance model, and broad-scale climate-based drought indices to study shifts in water use with ontogeny from seedlings to mature tropical live oak (Quercus oleoides) trees. Water use patterns help to explain persistence of this broadly distributed species in Mesoamerica and to evaluate likely threats of ongoing climate changes. At the end of the dry season, soil δ18 O profiles can be described by one-phase exponential decay curves. Minimum values reflect geographic origins of the last significant rain event, and curvature is inversely related to canopy closure, demonstrating its role in controlling topsoil evaporation. Partitioning of soil water sources for transpiration was analyzed with a mixing model. In the Costa Rican sites, in a relatively dry year, saplings and mature trees took up water from the upper soil. In a relatively wet year in the Honduran sites, we observed deeper water extraction. In all sites, soil storage dampens extreme variation in water availability. The size dependence of water uptake with larger stems exploiting deeper layers is translated into variation in bulk leaf δ13 C-based water use efficiency (WUE) with the exception of mature trees. From 1932 to 2015, drought severity was evaluated with the Standardized Precipitation Evapotranspiration Index (SPEI) concurrently with simulations of the soil water balance model. Drought occurrence increased, regardless of the time period, averaged across 6, 12, or 24months. All ontogenetic stages in all populations experienced frequent water limitation. We found evidence for linear trends toward aridification with increases of return periods of drought for October SPEI-24 declining from 42 to 6yr in Costa Rica and from 21 to 7yr in Honduras and recent occurrence of multiyear droughts from 2013 to 2016. October SPEI-12 and SPEI-24 were significantly related to the Oceanic Niño Indices demonstrating that local inter-annual variations in drought severity in Mesoamerica are modulated by large-scale climate forces. Drought severity in the near-term future depends on the extent to which the Pacific will adopt a more La Niña-like vs. a more El Niño-like state under ongoing climatic changes.

Intensive Cultural Resources Survey of the Proposed Dripping Springs Wastewater System Improvements Project (EID 1), Dripping Springs, Hays County, Texas

Intensive Cultural Resources Survey of the Proposed Dripping Springs Wastewater System Improvements Project (EID 1), Dripping Springs, Hays County, Texas

Human-mediated disturbance in multitrophic interactions results in outbreak levels of North America's most venomous caterpillar.

Anthropogenic environmental change is predicted to disrupt multitrophic interactions, which may have drastic consequences for population-level processes. Here, we investigate how a large-scale human-mediated disturbance affects the abundance of North America's most venomous caterpillar species, Megalopyge opercularis. Specifically, we used a natural experiment where netting was deployed to cover the entire canopies of a subset of mature southern live oak trees (Quercus virginiana) to exclude urban pest birds (grackles and pigeons), throughout an 8.1 km2 area encompassing a medical centre in Houston, Texas. We used this experimental exclusion to test the following hypothesis: release from avian predators increases caterpillar abundance to outbreak levels, which increases the risk to human health. Results from a multi-year survey show that caterpillar abundance increased, on average, more than 7300% on netted versus non-netted trees. Thus, increases in caterpillar abundance due to anthropogenic enemy release increase human exposure to this venomous pest, and should be considered a health threat in the area. This study emphasizes the unforeseen consequences of ecological disturbance for species interactions and highlights the importance of considering ecology in urban planning.

Urban Trees Are Sinks for Soot: Elemental Carbon Accumulation by Two Widespread Oak Species.

Urban trees could represent important short- and long-term landscape sinks for elemental carbon (EC). Therefore, we quantified foliar EC accumulation by two widespread oak tree species-Quercus stellata (post oak) and Quercus virginiana (live oak)-as well as leaf litterfall EC flux to soil from April 2017 to March 2018 in the City of Denton, Texas, within the Dallas-Fort Worth metropolitan area. Post oak trees accumulated 1.9-fold more EC (299 ± 45 mg EC m-2 canopy yr-1) compared to live oak trees (160 ± 31 mg EC m-2 canopy yr-1). However, in the fall, these oak species converged in their EC accumulation rates, with ∼70% of annual accumulation occurring during fall and on leaf surfaces. The flux of EC to the ground via leaf litterfall mirrored leaf-fall patterns, with post oaks and live oaks delivering ∼60% of annual leaf litterfall EC in fall and early spring, respectively. We estimate that post oak and live oak trees in this urban ecosystem potentially accumulate 3.5 t EC yr-1, equivalent to ∼32% of annual vehicular EC emissions from the city. Thus, city trees are significant sinks for EC and represent potential avenues for climate and air quality mitigation in urban areas.

Water Use of Juvenile Live Oak (<i>Quercus virginiana</i>) Trees over Five Years in a Humid Climate

To meet minimum spring flows, water management districts in Florida sought to make both agriculture and urban landscapes water efficient, which includes tree farms. Quercus virginiana, commonly known as live oak trees, is endemic to Central Florida and among the most popular landscape trees for their gracefulness and spreading shade. To provide a basis for irrigation allocations both during production and in landscapes, daily actual evapotranspiration (ETA) in liters for three live oak trees was measured with weighing lysimeters over five years, beginning with seedlings and continuing until trees averaged 7.2 meters in height. Empirical models were derived to calculate ETA based on crown horizontal projected area (PCA) or trunk caliper (TCSA), adjusted daily by changes in evapotranspiration (ETO). Average ETA to produce these live oaks was 62,218 L cumulative over 5.5 years. Effectively transpiring leaf, tree water use volume divided by ETO, was closely related to PCA over five years with the slope of this relationship being equivalent to a Plant Factor of 0.93. The product of ETO and this Plant Factor can be used to estimate depth of live oak water demand in urban landscapes. Also, this Plant Factor can estimate water demand volume in nurseries and landscapes when combined with PCA, and similarly the slopes for TCSA can be used to estimate ETA water volume from measured trunk diameter.

Public Swim

Public Swim Elizabeth Lindsey Rogers (bio) In the Bywater In New Orleans, the air smells like standing water, fried food, rotting garbage, and gasoline. Traffic rumbles across the beat-up asphalt. Air conditioners rattle out of house windows, dripping yellow slime onto concrete below. Despite the live oak trees lining St. Charles or Esplanade Avenue, shade is rare in most of the city. Dogs wander down the hot sidewalk and turn around after a block or so, ready to go home. A flat, bleached-out sky hangs low over everything: the crisscrossed metal of the Industrial Canal’s drawbridge; the long blocks of shotgun houses and the stretches of boarded-up shops; the bends of the Mississippi River, where cargo boats stacked with boxcars seem like the only swift-moving things in the world. When a storm is finally conjured up—usually around three o’clock in the afternoon—you can see the entire cloud formation as it moves in over the river, purple and gray in three dimensions. The rain is brief and hard, cooling the air for half an hour or so. And then the city, bathtub-shaped and full of steam, feels twice as hot as before. Sarah and I moved to New Orleans in August, a few months after we got married, both of us in the final year of our twenties. I had two teaching positions in the city. One was in Uptown, instructing the partygoing undergraduates at Tulane, most of whom were wealthy and not from Louisiana at all. Downriver, closer to where I lived, my other job was teaching creative writing to high school juniors and seniors from the New Orleans school system (or what was left of it), kids mostly from poor neighborhoods. On some days they liked me and were eager to read me their poems. On other days they regarded me with deep suspicion. Sometimes they fell asleep during class. The air conditioner roared in the window of our classroom, competing with the sound of my voice. All week I crisscrossed these invisible borders of the city, from downtown [End Page 104] to Uptown and back again, for work. At the end of each teaching day, I was exhausted. I would drive home and shut the door behind me, peeling off my work dress and my sweat-soaked underwear and putting on the most lightweight clothes I could find. I did not want to turn on the stove or the oven to make dinner. I lay on the cool, beat-up floorboards of our rented shotgun on Desire Street and dreamed about going swimming somewhere. Wherever I am living, so long as there is water, I find a way to swim. And in a city like New Orleans—warm and party-happy, and surrounded by water—this seems as if it should be easy. But the river itself, of course, is dangerous and illegal for swimmers, not to mention full of industrial traffic. Lake Pontchartrain, the large estuary north of the city, is also considered risky: a higher salt content (read: global warming) has lead to reports of shark attacks, especially in the summer. And the main public beach closed a few years ago after a number of people drowned. A terrific beach just over the Louisiana border—in Bay St. Louis, Mississippi—can be reached in a few hours. But in New Orleans itself, there isn’t anywhere that’s naturally safe to swim. And before I figured out the locations of the city’s public pools, there was only The Country Club on Louisa Street: an ironically named, no-longer-secret swimming spot close to where we lived, fronted by a respectable-looking café. Housed in a nineteenth-century raised hall cottage with six white columns framing the front entrance, it looked like the quintessential small Southern restaurant as you entered the double parlor. But most people tended to go straight to the bar at the back of the house and then out the rear door, where a sign proclaimed that no one under the age of twenty-one was allowed. Buying one drink got you a towel and access to the pool deck, an area completely secluded...

Ecología y fitosanidad de los encinos (Quercus spp.) en la Sierra Fría, Aguascalientes, México

Durante los años 2007, 2008 y 2009 se condujo un estudio para evaluar la distribución y abundancia de las especies de encinos (Quercus spp), los factores ambientales que afectan su distribución y la identificación de los patógenos e insectos asociados a la declinación y muerte de estos árboles en la Sierra Fría, Aguascalientes. Para evaluar la distribución y abundancia se realizaron 60 inventarios de la vegetación en 60 sitios de muestreo distribuidos al azar utilizando parcelas de 600 m2. Para la identificación de los fitopatógenos se hicieron 28 transectos, revisando 100 árboles en cada uno. Para la identificación de los insectos asociados con la declinación de los encinares se instalaron trampas de emergencia sobre el fuste de árboles con síntomas de ataque de insectos barrenadores y se tomaron muestras de fuste, las cuales se observaron en laboratorio. Se identificaron 10 especies de encinos, siendo la altitud, el relieve, la exposición del sitio y la fisiografía las variables que influyeron sobre su distribución y abundancia. Se identificaron los fitopatógenos Phellinus robustus, P. gilvus, P. everhartii, Ganoderma lucidum e Hypoxylon thouarsianum, siendo el último el más ampliamente distribuido. Se identificó al barrenador Crioprosopus magnificus infestando encinos vivos. La información obtenida contribuye al manejo de la Sierra Fría y se sugiere profundizar en estos estudios.

The Efficacy of Paclobutrazol Soil Application as it Relates to the Timing of Utility Right-of-Way Pruning

The plant growth regulator paclobutrazol’s effect on live oak trees (Quercus virginiana) was evaluated to determine optimum timing of application and pruning time in Louisiana. Variables considered included length of branch regrowth, branch distance to conductor, pruning time and biomass chipping time. Data were evaluated to determine the ideal application timing of paclobutrazol relative to time of pruning. Live oak trees treated with paclobutrazol had significantly reduced branch regrowth, pruning time and chipping time, as compared to control trees regardless of application timing. Paclobutrazol application on live oak trees was idealized within 90 days pre- to 90 days post-prune. Economically, significant gains were found by utilizing this tool ranging from 180 days pre- to 180 days post-prune, allowing for application timing flexibility to reduce the growth of trees near power lines. Paclobutrazol treated live oak trees demonstrated significantly less re-growth response.

Effects of individual, community, and landscape drivers on the dynamics of a wildland forest epidemic

The challenges posed by observing host-pathogen-environment interactions across large geographic extents and over meaningful time scales limit our ability to understand and manage wildland epidemics. We conducted a landscape-scale, longitudinal study designed to analyze the dynamics of sudden oak death (an emerging forest disease caused by Phytophthora ramorum) across hierarchical levels of ecological interactions, from individual hosts up to the community and across the broader landscape. From 2004 to 2011, we annually assessed disease status of 732 coast live oak, 271 black oak, and 122 canyon live oak trees in 202 plots across a 275-km2 landscape in central California. The number of infected oak stems steadily increased during the eight-year study period. A survival analysis modeling framework was used to examine which level of ecological heterogeneity best predicted infection risk of susceptible oak species, considering variability at the level of individuals (species identity, stem size), the community (host density, inoculum load, and species richness), and the landscape (seasonal climate variability, habitat connectivity, and topographic gradients). After accounting for unobserved risk shared among oaks in the same plot, survival models incorporating heterogeneity across all three levels better predicted oak infection than did models focusing on only one level. We show that larger oak trees (especially coast live oak) were more susceptible, and that interannual variability in inoculum production by the highly infectious reservoir host, California bay laurel, more strongly influenced disease risk than simply the density of this important host. Concurrently, warmer and wetter rainy-season conditions in consecutive years intensified infection risk, presumably by creating a longer period of inoculum build-up and increased probability of pathogen spillover from bay laurel to oaks. Despite the presence of many alternate host species, we found evidence of pathogen dilution, where less competent hosts in species-rich communities reduce pathogen transmission and overall risk of oak infection. These results identify key parameters driving the dynamics of emerging infectious disease in California woodlands, while demonstrating how multiple levels of ecological heterogeneity jointly determine epidemic trajectories in wildland settings.

In the Land Where We Were Dreaming

In the Land Where We Were Dreaming Coleman Hutchison (bio) Summer 2015 was a heady time to be in Columbia, South Carolina, researching proslavery southern literature. As per usual, I arrived a day late—just twenty-four hours after Republican governor Nikki Haley oversaw the removal of the Confederate battle flag from the South Carolina State House grounds on July 10, 2015. Responding with remarkable speed to the horrific shootings at Charleston’s Emanuel African Methodist Episcopal Church on June 17, the State Senate voted thirty-seven to three to remove the flag, which had flown over or near the Capitol for more than fifty-four years, since the early days of the Civil War Centennial and Civil Rights Era. By the time I arrived at the South Caroliniana Library, all that remained of decades of fierce debate over this symbol of “hatred” or “heritage” was the concrete base that once held the flagpole. And by Monday July 13, contractors were hard at work replacing that concrete with sod. As a scholar of the Civil War South, I had to go over at lunch and witness in whatever small and belated way what had happened—and happened so quickly—in the “Cradle of Secession.” Having walked the three blocks from the library to the remains of the flagpole, I found that the contractors were more than a bit leery about my interest in their work. While the previous Friday’s six-minute unfurling had drawn a crowd of nearly ten thousand, I was one of a handful of spectators for this much noisier and less ceremonial duty. When some members of the crew finally broke for [End Page 44] lunch, we all walked in the same direction, toward a justly famous sandwich shop just around the corner. One of the workers and I struck up a conversation, first about what to eat—he recommended the “Hambone” sandwich—and then about our respective work for the day. As always, I stammered a bit as I tried to describe why I would spend the summer researching Confederate and proto-Confederate writers—“the bad guys and the losers,” as I call them—especially to an older, African American man. Our awkward conversation turned quickly to his work. After hearing his account of the previous Friday, I asked about the flagpole and concrete removal: “How deep did that thing go, anyway?” Without missing a beat, my lunch line companion put his hand on my shoulder and replied, “Son, it ran pretty damn deep.” His warm laughter and affectionate thumps on my shoulder did as much as they could to ease my embarrassment. ▪ The Oxford English Dictionary takes pains to separate the literal and figurative senses of the adjective “deep.” In asking about how “deep” the State House flagpole ran, I was looking for a simple, literal measure of its “extension” or “dimension downward.” My lunch-mate offered me a more figurative—and thus much more important—measure: “Deep-rooted in the breast; that comes from or enters into one’s inmost nature or feelings; that affects one profoundly” (“deep, adj.” def. 9). Of course I know that symbols of the Confederacy “run deep” for folks on both sides of the “hate versus heritage” debate. Indeed, I had encountered sympathetic forms of deep feeling earlier in the summer, this time a bit closer to home. My office at the University of Texas at Austin looks out onto the South Mall, which features a lovely lawn framed by six midcentury buildings and several imposing live oak trees. UT’s Main Building and Tower perches at the top of the South Mall while the Littlefield Fountain rests at its bottom. The fountain features a dramatic Pompeo Coppini sculpture of a winged Columbia flanked by two World War I soldiers aboard an allegorical ship of state drawn by nymphs on giant sea horses. (Yes, it’s as weird and wonderful as it sounds.) The view looking up from the fountain toward the tower provides the iconic view of the university. Each year thousands of tourists, visitors, and students pose for pictures in front of this impressive backdrop, but very few notice the fountain’s dedication, which is artfully...

A Promise Song: Ernest J. Gaines's Early Fictions and the Community of Black Women Writing

A Promise Song:Ernest J. Gaines's Early Fictions and the Community of Black Women Writing Lucy Biederman (bio) In January 1971, Alice Walker wrote to a senior editor at Dial Press praising Ernest J. Gaines's soon-to-be-published The Autobiography of Miss Jane Pittman. In her letter, Walker concludes that "no other American writer has made such an effort to comprehend the strength and rugged tenderness of the black woman in all her courage and rare beauty" (Letter to William Decker). Later that year, Walker would review Gaines's most recent novel for the New York Times Book Review, characterizing its author as "much closer to Charles Dickens, W. E. B. Du Bois, Jean Toomer and Langston Hughes than he is to Richard Wright or Ralph Ellison" (116). Locating Gaines in a literary lineage that skews toward Victorian and early modernist writers, Walker follows Gaines's own attempts to distance himself from the contemporary politics of racial strife associated with Wright's and Ellison's work. Walker, meanwhile, places herself in a lineage that includes Gaines. Writing to Gaines in 1969, she confesses, "I don't [envy you], but I don't because it is possible for me to think of you as a great teacher. I'm still young enough for that" (Letter to Gaines). Walker's 1969 letter to Gaines and her 1971 letter about Gaines border 1970, often considered a foundational year in what Hortense Spillers calls "the community of black women writing in the United States" (249). In that year, Walker, Toni Morrison, and Maya Angelou published their first books, and Toni Cade's multi-genre anthology The Black Woman was published. Throughout the ensuing decade, critics including Mary Helen Washington, Barbara Christian, and Barbara Smith established a criticism devoted to recovering black women writers, such as Nella Larsen, Jessie Fauset, and Zora Neale Hurston, and to articulating a distinct tradition of black women's writing. Many of the significant creative works to come out of this community, including early novels by Morrison and Walker, Gayl Jones's 1975 Corregidora, the short stories of Cade (Bambara) in volumes like Gorilla My Love from 1972, and the poetry of Maya Angelou, Audre Lorde, Lucille Clifton, Nikki Giovanni, and others, are lauded for their attention to, as Walker puts it in her letter to Dial Press, "the strength and [End Page 1] rugged tenderness of the black woman in all her courage and rare beauty" (Letter to William Decker). By 1970, meanwhile, Ernest Gaines had already published his first two novels, Catherine Carmier in 1964 and Of Love and Dust three years later; Bloodline, a book of short stories, appeared in 1968. Critics of Gaines have typically focused on Gaines's representations of African-American manhood (see, for example, Suzanna W. Jones and, particularly, the incisive work of Keith Clark), and what attention scholars have paid to Gaines's treatment of women generally has been focused on matriarchal elders (see, for example, Marcia Gaudet and Trudier Harris). However, Gaines, in his first four major publications and throughout his ensuing literary career, considers closely the lives of young black women, as well. And like many texts to emerge from the "community of black women writing" that coalesced in and just after 1970, Gaines's fictions in the 1960s are set in the rural South. Gaines's fictions are set in southwest Louisiana, a landscape replete with "dark, fertile soil, the immense pecan and live-oak trees hung with Spanish moss," and air so thick and hot that it "shapes the moods and even the decisions of many of Gaines's characters" (Doyle 5). In important and enduring ways, Gaines and his work stand apart from the community of women writing; however, Gaines's early works also prefigure some of the methods and themes by which black feminist writers like Morrison, Walker, and Angelou came to be known. In this essay, I argue that a more expansive understanding of the subtle and often contradictorily feminist undertones in Gaines's fictions can be gleaned by drawing lines of influence, contiguity, and correspondence between his early works and the works of explicitly feminist black women writers of the 1970s...

First Report of Geosmithia pallida Causing Foamy Bark Canker, a New Disease on Coast Live Oak (Quercus agrifolia), in Association with Pseudopityophthorus pubipennis in California.

Declining coast live oak (Quercus agrifolia) trees have been observed since 2012 throughout urban landscapes in Los Angeles, Orange, Riverside, Santa Barbara, Ventura, and Monterey counties in California. Symptoms causing branch dieback and tree death included a cinnamon-colored gum seeping through multiple 0.95-mm-diameter entry holes on the bole, followed by a prolific, cream-colored foamy liquid. Beneath the outer bark was phloem and xylem necrosis. Fifty 1- to 2.5-mm adult and larval beetles were collected. Adults fit the morphological description of Pseudopityophthorus pubipennis (western oak bark beetle) (R. Rabaglia, personal communication), and ~800 bp of the mitochondrial COI gene was amplified for three beetles using primer pairs and methods previously described (2,3). All three sequences were identical (GenBank Accession Nos. KJ831289 to 91) and a BLAST search confirmed the closest match (94%) as P. pubipennis. Necrotic wood tissues collected from two trees in each county were cultured on potato dextrose agar amended with 0.01% tetracycline (PDA-tet), and incubated at 25°C for 1 week. Ochre-colored cultures with plane or radially furrowed velutinous mycelium were consistently produced. Fifty conidia each measured from two isolates were 3.66 ± 0.04 μm × 1.77 ± 0.03 μm, and arranged in non-persistent conidial chains, at first roughly parallel, becoming tangled with age. These fungal colonies were observed within gallery walls. The rDNA internal transcribed spacer (ITS) was amplified using primer pairs and methods previously described (5). Three isolates were sequenced and matched 100% to known sequences of Geosmithia pallida in GenBank; sequences of two isolates (UCR2208 and UCR2210) were deposited in GenBank (KJ468687 and KJ468688). Pathogenicity tests were performed by inoculating twelve 27.0-cm detached coast live oak shoots for each isolate with a spore suspension of G. pallida (UCR2208 and UCR2210) and sterile distilled water for controls. A 2-mm-wide, 3-mm-deep hole was drilled into the center of each shoot, 20 μl of a 106 conidia/ml spore suspension was pipetted into the hole, and sealed with Vaseline and Parafilm. The experiment was repeated twice. After 4 weeks in a moist chamber at 25°C, lesions produced by G. pallida averaged 8.3 cm and was significantly longer (ANOVA; P < 0.0001) from the control (average 0.4 cm). G. pallida was re-isolated from all inoculated plants and identified by colony morphology. P. pubipennis is a native beetle, common as a secondary agent, and previously not associated with disease. However, cryptic species may be common among bark and ambrosia beetles (4). A larger sample (i.e., populations and loci) is needed to determine the precise taxonomic status of P. pubipennis. G. pallida was shown to inhibit root growth of Q. petraea by 25% in Europe (1), appears to have affinities with a range of subcorticolous insects, and is widely distributed (5), but there is no published record of the fungus occurring in the United States. This is the first report of G. pallida causing foamy bark canker in association with P. pubipennis on Q. agrifolia in California. Results suggest this new disease complex is causing decline of Q. agrifolia throughout the state.

Identification of New Fungal Pathogens of Coast Live Oak in California.

A decline of coast live oak (Quercus agrifolia) has been observed throughout southern California. In this study, the identity and pathogenicity of non-Botryosphaeriaceae fungal species consistently recovered from necrotic tissues of branch and bleeding trunk canker samples from these locations were assessed. Species were identified morphologically and by comparison of the complete sequence of the internal transcribed spacer (ITS) of the ribosomal DNA to sequences available in GenBank. Phylogenetic analyses were then conducted using ITS and partial sequences of the β-tubulin and mitochondrial small ribosomal subunit genes for unknown species. Fungi recovered and identified included Fusarium solani, Phaeoacremonium mortoniae, Diatrypella verrucaeformis, and a fungus described herein as Cryptosporiopsis querciphila sp. nov. One-year-old coast live oak seedlings were wound inoculated under controlled conditions to test pathogenicity of the fungal species. Each fungal species was successfully reisolated from necrotic tissue at 70 and 100% for P. mortoniae and all other species, and xylem necrosis was significantly different between all treatments and controls (P < 0.0001 at α = 0.05). Isolates of F. solani were the most aggressive tested. These species represent new records of fungal pathogens of coast live oak in California. Results from the pathogenicity test suggest that these fungi play a role in the decline of southern California coast live oak trees.

Ultrastructural and chemical studies on waxy secretions and wax-producing structures on the integument of the woolly oak aphid Stegophylla brevirostris Quednau (Hemiptera: Aphididae)

The woolly oak aphid (WOA), Stegophylla brevirostris Quednau, is a recently described oak pest in Florida, USA. Colonies of WOA on live-oak trees are distinguished by a thick layer of white filamentous waxy material covering most individuals. Nymphs and apterous adults have several long waxy threads/bundles extending from their head, thorax and especially from their abdomen. We used scanning electron microscopy of ‘naturally waxed’ and ‘dewaxed’ aphids to study the ultrastructure and distribution of wax-producing structures on the cuticle. Two types of ‘wax pores’ and smaller wax ‘pits’ were found clustered in wax pore plates around dorsal setae on the head, thorax and abdomen. The larger, type-1, wax pores produce short or long wax columns with honeycomb interior; the smaller, type-2, wax pores produce short or long hollow wax tubes; whereas wax pits produce the shorter and more loosely net tufts of wax filaments covering most of the body dorsally. Wax columns or tubes produced by clusters of types-1 and 2 wax pores aggregate together forming the longer and thicker wax bundles that extend dorsally and laterally from the cuticle, especially near the posterior end of the abdomen. Type-2 wax pores and wax pits were also found on parts of the legs and antennae. Infrared spectroscopy indicated that wax esters, containing saturated fatty acids and fatty alcohols, are the major constituents of WOA waxy secretions. The possible roles of these secretions, especially in avoiding contamination with honeydew and providing some protection against natural enemies and adverse climatic conditions, are discussed.

Identification and pathogenicity of Botryosphaeriaceae species associated with coast live oak (Quercus agrifolia) decline in southern California

Symptoms of decline have been observed on dying coast live oak (Quercus agrifolia) trees in areas throughout southern California that are both infested and uninfested by the gold-spotted oak borer (GSOB). The purpose of this study was to identify and assess the pathogenicity of several anamorph species of the Botryosphaeriaceae, including Diplodia corticola, Dothiorella iberica and Diplodia agrifolia sp. nov., that were recovered consistently from symptomatic tissues. Species were identified morphologically and by phylogenetic analyses of the complete sequence of the internal transcribed spacer (ITS) of the rDNA and partial sequences of β-tubulin and elongation factor (EF1-α) genes. Results from morphological assessments and phylogenetic analyses support the erection of a new species closely related to D. mutila, described herein as Diplodia agrifolia sp. nov. Pathogenicity of all species was verified by wound inoculation of 1 y old coast live oak seedlings under controlled conditions. Isolates of D. corticola were the most aggressive tested, and isolates of D. agrifolia were the second most aggressive. Both species caused bleeding symptoms on inoculated seedlings. Seedlings inoculated with D. corticola died within 4 wk, with the pathogen progressing up and down through the xylem in advance of living phloem and moving throughout the taproot in 70% of inoculated seedlings. Colonization and re-isolation was successful for all species. All three fungal species represent newly recorded fungal pathogens of coast live oak in California. Results from the pathogenicity test suggest that these fungi play a role in the decline of coast live oaks throughout southern California.