Locust Trees Research Articles

Size- and Age-dependent Variation in the Properties of Sap- and Heartwood in Black Locust (Robinia pseudoacaciaL.)

Dissection and mechanical bending experiments showed that the cross-sectional area and elastic moduli of sap- and heartwood varied within the trunk and branches as a function of the distance from the top of a 43-year-old black locust tree (Robinia pseudoacaciaL.). Wood in branches less than 1 m from the top of the tree consisted entirely of sapwood; the majority of the wood from more basipetal (and older) parts of the tree was heartwood. The Young's elastic moduli of sap- and heartwood increased towards the base of the trunk, and, on average, the modulus of the sapwood was 35%less than that of the heartwood. Younger, more distal tree limbs, therefore, were more flexible than older portions of the same tree. Simple bending experiments showed that the flexural rigidity of young limbs was governed by the location, physical properties, and the relative quantities of the two types of wood. The rigidity of limbs increased toward the base of the tree, and was dominated by sapwood in young limbs and by heartwood in the oldest parts of the tree. These trends predict that the younger, distal limbs of this tree can more easily deflect and bend in the wind, thereby reducing drag and the total bending moment on the tree trunk, while older limbs and the trunk are sufficiently rigid to support static self-loadings. Further study, however, is required to determine whether the trends reported here apply to all trees of this species and to trees of different species.

Mechanical Properties of Black Locust (Robinia pseudoacaciaL.) Wood. Size- and Age-dependent Variations in Sap- and Heartwood

Abstract Variations in the density and stiffness (Young's elastic modulus) of fresh wood samples drawn from different parts of the three main trunks of a 32-year-old black locust tree, Robinia pseudoacacia (measuring 19.8 m at its highest point), were studied to determine whether tree ontogeny can achieve a constant safety factor against mechanical failure. Based on the properties of isolated wood samples, the fresh density of sapwood decreased along radial transects from bark to pith, while that of progressively older heartwood samples increased, on average, towards the centre of each of the three trunks. Along the same radial transects, the Young's elastic modulus of sap- and heartwood increased. In terms of longitudinal changes in wood properties, mean wood moduli (averages of sap- and heartwood samples) increased, on average, towards the base of each of the three trunks of the tree. However, the mean fresh densities of wood samples increased towards the top and the bottom of each trunk and were lowest roughly near trunk mid-length. The mean density-specific stiffness (the quotient of Young's modulus and fresh density) of wood was thus lower toward the top and the bottom of the trunks and highest near trunk mid-length. Mean values of fresh wood density-specific stiffness were used to estimate the critical buckling heights for sections of the trunks differing in diameter and age. These estimates indicated that ontogenetic variation in the physical properties and relative amounts of sap- and heartwood in trunks could maintain a constant factor of safety (approximately equal to 2) as a sapling grows in height and girth into a mature tree. This expectation was supported by data from 16 black locust trees differing in height and diameter at breast height (DBH).

Relationship between environmental factors, effects of fungicide applications, and premature defoliation of black locust trees (Robinia pseudoacacia L.)

From 1989 through to and including 1994 extensive premature defoliation of black locust ( Robinia pseudoacacia L.) was observed in a progeny test plantation in Greene County, in the Georgia Piedmont. During July 1991 and 1992, all observed trees suffered greater than 50% defoliation. Leaflets of black locust showing symptoms of leaf spotting began abscising as early as mid-June following wet springs. Onset and progress of defoliation was followed on 50 trees in two plots in 1993 and 1994. In both years, sample trees were cut at the base and allowed to regrow from sprouts. A protectant fungicide, chlorothalonil (Daconil WDG 1.5 g/l water) was applied to run-off weekly to one-half of the growing sprouts beginning 17 April through 22 August 1994 by backpack sprayer. Air temperature, relative humidity, rainfall, and leaf wetness were monitored. Abscission of unprotected leaflets in 1993, a dry, hot year, began in mid-July and averaged 36% by late August; abscission of unprotected leaflets in 1994, a wet, cool year, began in mid-June and averaged 80% by late August; whereas, abscission of protected leaflets in 1994 began in late June and averaged 70% by late August. The Gompertz model described the increase of leaflet abscission with time. The estimated rate of leaflet abscission for unprotected leaflets in 1993 was significantly slower ( k = 0.056/wk) compared to the rate of abscission of unprotected leaflets in 1994 ( k =0.070/wk). Estimated rates of leaflet abscission were not significantly different between protected ( k = 0.063/wk) and unprotected trees ( k =0.070/wk) in 1994. Cumulative hours of leaf wetness of 600 h were associated with initial leaf spotting and defoliation in 1993 and in 1994. Delay in leaflet abscission of protected trees indicates that fungal infection may have contributed to premature defoliation of black locust with onset related to moisture conditions favourable for infection.

Food allergy to honey: Pollen or bee products?: Characterization of allergenic proteins in honey by means of immunoblotting

OBJECTIVE: To characterize the allergenic components of honey, 23 patients allergic to honey were investigated. All displayed allergic symptoms after ingestion of honey or honey-containing products, ranging from itching in the oral mucosa to severe systemic symptoms to anaphylactic shock. METHODS AND RESULTS: Immunoblot analyses of the patients’ sera revealed IgE binding to proteins at a molecular mass of 54 kd, 60 kd, 72 kd, or to a 30 kd/33 kd double band, or to both in sunflower honey extracts. The three bands corresponding to higher molecular mass proteins could also be detected in the three other kinds of honey (locust tree, European chestnut and forest honey) that were tested and represented bee products because IgE binding to these proteins was inhibited by extracts of honeybee heads and extracts of isolated bee venom sacs. The 30 kd/33 kd bands could be identified as sunflower honey–specific. When testing sera from patients allergic to bee venom with honey extracts, in seven of 10 cases IgE binding to bee-specific components could be observed. CONCLUSION: Both proteins derived from secretions of pharyngeal and salivary glands of honeybee heads and pollen proteins contained in the honey cause allergic reactions to honey. (J A LLERGY C LIN I MMUNOL 1996;97:65-73.)

Honeylocust Plant Bug Control, Ft. Collins, Co 1995

Abstract Trials were conducted on a mature thornless honey locust tree on the campus of Colorado State University. Plots consisted of the terminals of individual branches, each averaging over 4 ft in length and plot design was a RCB with 5 replications. Treatments were applied with a hand-operated pump mister on 6 Jun to point of run-off. Evaluations were made 16 Jun by striking the terminals over a tray to dislodge the insects on the terminal 2 ft of the branch.

Locust 1 (Orthoptera: Acrididae) Outbreak in Africa and Asia, 1992–1994: An Overview

Desert locust, Schistocerca gregaria (Forskal), began to exhibit gregarious behavior and amassed into swarms in the fall of 1992 along the Red Sea coast; successive generations of gregarious locusts over the next 18 mo gave rise to localized outbreaks west to Mauritania and east to India. Concurrent African migratory locust, Locusta migratoria migratorioides (Reiche ' Fairmaire), and tree locust, Anacridium melanorhodon (Walker) outbreaks compounded the locust infestations in the Horn of Africa. Evolution of the overall outbreak is described, including ways in which locusts were found and controlled. Preparation and lack of armed conflict in critical locust breeding areas, particularly in Eritrea and the Red Sea coast of Sudan, facilitated early intervention with relatively selective and low residual insecticides. Preventive, proactive, and reactive locust control approaches are described, and future trends for locust management in Africa and Asia are identified. Sustained and successful preventive and proactive approaches, especially against S. gregaria would help to alleviate a serious constraint to agricultural production with the aim of reducing localized famine in regions chronically plagued by drought, poverty, and hunger.

Biomass yield equations for short rotation black locust plantations in the central Great Plains

The objective of this research is to develop equations to predict yields for short rotation black locust ( Robinia pseudoacacia) tree plantations. The data set is from experimental black locust plantation sites located throughout the State of Kansas. Stepwise ordinary least-squares regression techniques are used to derive the equations. The final model selection is based on simplicity of use, statistical accuracy, and consistency with known biological relationships. Two models are selected: both models use precipitation and herbicide treatments as variables, however, one model also includes nitrogen content in the soil. The model predictions are compared to other plantation yield studies in the area and found to give similar yield estimates.

Cambial tissue culture and subsequent shoot regeneration from mature black locust (Robinia pseudoacacia L.)

Callus initiation and subsequent shoot regeneration were obtained from cambial tissue of mature black locust trees. Shoot regeneration was highly tree specific, and was only achieved when calli derived from a particular genotype (tree #1) were transferred to medium containing 6-benzylaminopurine. The studies described here show that the immediate use of a mature genotype as starting material for tissue cultural manipulation is possible by using cambial explants with the proper in vitro conditions. We also found that stems could be stored at 4°C for 8 months prior to culture initiation, with no decline in the viability of the cultures. Tissue sources can thus be continuously available.

Regeneration of a transgenic woody legume ( Robinia pseudoacacia L., black locust) and morphological alterations induced by Agrobacterium rhizogenes-mediated transformation

A repeatable and fast transformation-regeneration system has been developed for a woody legume, black locust ( Robinia pseudoacacia L.). Hairy roots were produced from hypocotyl segments inoculated with Agrobacterium rhizogenes R1601, a super-virulent strain with eukaryotic kanamycin resistance gene, in less than 1 week and resulted in subsequent shoot regeneration within 4 weeks. Transgenic black locust trees were established in soil 12 weeks after inoculation with the A. rhizogenes strain. The hairy root phenotype found in regenerated plants, which has been characterized as having wrinkled leaves and abundant root development, became evident after 3 months of growth. Southern blot analysis clearly showed multiple integration of T-DNA (transferred DNA) and the presence of neomycin phosphotransferase (NPTII) gene sequences in the transformed black locust genome.

A Wound Treatment System to Supress Cankers and Wood Rot in Trees

Liquid and paste formulations of Nectec, an experimental fungicidal tree wound healing product, were evaluated for the prevention or suppression of canker and wood rot in trees. A broad activity spectrum against several wood inhabiting fungi was demonstrated in the laboratory. The Nectec paste, when applied to cut ends of maple branches prior to inoculation with Nectria cinnabarina, significantly reduced fungus penetration. Disease control was not consistent when the cut ends of maple limbs were treated 40 days after the wounds were inoculated with N. cinnabarina. Application of the Nectec liquid and paste combination or the Nectec paste alone to newly wounded trunks of maple, planetree, locust, poplar and dogwood trees did not inhibit, but tended to favor callus formation. When the products were applied to cut ends of large branches of these trees, fungus penetration and staining of wood was significantly reduced after one year when compared to non-treated limbcuts. The products show promise as canker and wood rot preventatives in trees.

Differential responses persist in shoot explants regenerated from callus of two mature black locust trees.

Callus cultures were established from internodal segments of shoot cultures from two mature black locust Robinia pseudoacacia L. trees. Callus of both trees produced shoots on Murashige and Skoog (MS) medium supplemented with 10 microM 6-benzylaminopurine alone or in combination with 1 microM naphthaleneacetic acid. Regenerated shoots were successfully multiplied on MS medium containing 0.32 microM 6-benzylaminopurine, and produced roots on 0.1 strength MS medium containing 1 microM indole-3-butyric acid. One clone consistently outperformed the other with respect to shoot proliferation and proportion of shoots that produced roots. This distinction had previously been observed in shoots produced from bud explants obtained from the mature trees.

Height Distribution of Locust Borer Attacks (Coleoptera: Cerambycidae) in Black Locust

Black locust trees ( Robinia pseudoacacia L.) of variable age and height were studied in relation to vertical distribution of larval tunnels made by the locust borer, Megacyllene robiniae (Forster), in Maryland. Tunnel concentrations were negatively correlated with height above ground level and with bolt diameter. With greater tree size, attacks were concentrated higher on the main trunks. However, upper extremities of trees of all sizes and ages were lightly attacked.

Homecoming

By morning, Shelly wasn't any better. If anything, he was worse, and considering his condition, Hester decided she best not leave him. Long toward late morning he developed a dreadful deep, hacking cough but nothing came up and several times Hester had to thump his back so he could catch his breath. By evening, Hester knew her Shelly was dying. With each long-drawn-out breath, his body shook so violently the cot seemed about to collapse. He hadn't uttered a word since midmorning, and along about midnight, his skin turned the palest gray Hester'd ever seen on a body. Shelly lingered on toward next noon. When she was sure he was gone, Hester pulled the coverlet up around his neck and sobbed bitterly. "Oh, Shell, you was a kind and thoughtful man," she wailed. "You always knowed what to do. You always made plans. What'll I do now? Lord, what'll I do now?" she cried and when she had finished her crying, she put on her coat and wrapped her woolen scarf around her head and set out for the village to get help burying her Shelly. She'd walked almost to the Patterson place when she first saw the wagon approaching. She stopped and waited. When the driver come alongside, he stopped. "I don't s'pose you could tell me how far it be up to the Cochran place?" he inquired . "Well, I reckon I could," Hester said, "Fm Hester Cochran." "I got this here delivery," the man said. He reached back and flung aside the canvas. "I reckon you know your old man ordered this." "Well ... no. No, I can't say as I did, but if'n you don't mind I'll ride on back up to the house with you. Shelly . . . Shelly ... he always knowed what to do." Homecoming The trainless track is overgrown With little locust trees And memories. I pick my way along The tangles of too many years. My mind still hears Bill Jolly's fiddle. The gospel melodies Aunt Vicie sang. I smell crisp October when the school bell rang Week days and for church call on Sunday. Streaming window glass; the haunt of sulphur gas The mine shut down before I went away. My feet feel drawn down by the rails To play in springs I left turned on. To see what washed away In all those years of flowing. And when I make that last sharp turn At Cattail Bend. A mud-wasp's busy whining Mourns my going. -Susan Staff 57 ...

Racial Diversity of Black Locust in Growth Rate and in Susceptibility to the Locust Twig Borer

Abstract Twenty-five different geographic sources of black locust trees from Ohio, Maryland, West Virginia, and Virginia were studied for 3 years in a replicated experiment in Maryland. Significant differences were found in heights, diameters, kiln-dry weights, and susceptibility levels to locust twig borer. None of these variables were related to either longitude or latitiude of the seed source. However, high-elevation sources included more rapidly growing populations than those from low elevations. The third-year sprouts of the most productive source had the kiln-dry weights equivalent to 70,000 kg/ha. This suggests that selected black locust sources may qualify for short-rotation mass yield of energy. The most outstanding in kiln-dry weight per square growth space were some sources from Tucker, Randolph, and Mineral counties of West Virginia. North. J. Appl. For. 7(1):38-43, March 1990.

The relationship between foliar nitrogen content and feeding by Odontota dorsalis Thun. on Robinia pseudoacacia L.

The relationship between total foliar nitrogen content and feeding by Odontota dorsalis Thun. on Black Locust trees (Robinia pseudoacacia L.) was examined via experimental manipulation of foliar nitrogen levels. Trees with high concentrations of foliar nitrogen received more herbivory by adult O. dorsalis, but herbivory by larvae was independent of foliar nitrogen concentration. Late in the growing season, leaf abscission induced by herbivory tends to mask the dependence of herbivory by adults on foliar nitrogen concentration. The percentage of variation in herbivory attributable to foliar nitrogen concentration drops from 20% in June to 2% by August. These observations suggest that variation in the interaction between R. pseudoacacia and O. dorsalis is at least partially conditioned on variation in foliar nitrogen concentration.

Po Chü-i’s “Government Ox”

T'angStudies 7 (1989) Po Chu-i's "Government OX" DENIS TWITCHETI PRINCETON UNIVERSITY The forty-first of Po Chii-i's 8 15~ "New Yiieh-fu" 1fi ~ Jif poems is entitled the Government Ox (Kuan-niu) 13 !F.1 It reads as follows: Government ox, government ox, yoked to a government wagon, Driven to cart sand from the banks of the Ch'an. A bushel of sand, how many pounds does it weigh! Morning to evening he carts the sand: what will it be used for? He is taking it west of the official street at the Five Gates, To be spread on the gravelled path under the shade of the locust trees. Yesterday a new Chancellor of the Righe was appointed, And they fear the mud in the roads will sully his horses' hooves. Oh Chancellor of the Right, Your horses may tread upon sand and remain spotless; But the ox's neck under your yoke will stream with blood. Oh Chancellor of the Right, Are you only able to benefit the people, bring the state to order, and harmonize the yin and yang? Can't you also prevent the galls on the neck of your governmentox ? Po Chii-i's own comment to the title of the poem says that it is a satire against "those directing the government,,,3 that is, on the Chief Ministers. It can, of course, be read at one level simply as an attack in general terms on an oppressive government's placing intolerable burdens upon the population in order to pay for unnecessary expenditures on behalf of the ruling elite. But it 1 See Po Cha-i chi (Peking: Chung-hua, 1984),4.85. 2 Literally the "Assistant Chancellor of the Right" (yu ch 'eng-hsiang:ti iE :m ). 3 See Po Cha-i chi, 3.54. 23 Twitchett: Po Chu-;'s "Government Ox" seems likely, particularly since its target, "the new Assistant Chancellor of the Right," is so clearly and repeatedly pinpointed, that it is also an attack directed against a particular individual. Ch'en Yin-k'o, in his brilliant and wide-ranging comnlentary on these poenls,4 also accepted this, and pointed out that in 809 (to which date he somewhat arbitrarily assigned this poem) there were five persons holding office either as Chief Minister (tsaihsiang ) or as one of the Senior Statesmen (san-kung, san-shih). One of these, Tu Yu tt 1ti, who had been Grand Minister for Education (ssu-t'u) since the fourth month of 806, was semi-retired , and had in any case already been the target of an earlier poem in the series, "The Royal Observatory."s Li Fan ~ flf (754-811t who served as ad hominem Chief Minister from the second month 809 until the second month 811, had replaced Cheng Yin ~tJ!] (752-829)7 who served from the end of 805 until 809. Neither they nor P' ei Chi ~ j:ft (d. 811),8 ad hominem Chief Minister from the ninth month 808 until the eleventh month 810 had, so far as we know, done anything to deserve Po Chii-i's harsh censure. This left only Yii Ti T~ (d. 818).9 Yii Ti, whose career I have dealt with in detail elsewhere,10 certainly filled the role. By the time Po wrote this poem, Yii was 4 See Ch'en Yin-k'o, YUan Po shih chien cheng kao (Peking: Chung-hua, 1955; rpt., 1959) 280-82. 5 Ibis is the eleventh of the New YUeh-fu. See Po Cha-i chi, 3.64. For a discussion and the identification of the poem's subject as Tu Yu, see Ch'en Yin-k'o, YUan-Po shih chien cheng kao, 179-81; also Margaret T. South, "Po ChU·i's 'The Observatory Tower'," Journal of the Oriental Society of Australia 9.12 (1972-73), 3-13. 6 Biographies: CTS, 148.3997-4001; FITS, 169-5150-52. 7 Biographies: CTS, 159.4180-81; FITS, 165.5074-76. 8 Biographies: CTS, 148.3989-92; FITS, 169.5147-50. 9 Biographies: CTS, 156.4129-33; FITS, 172.5199-201. 10 See Denis Twitchett, "The Seamy Side of Late Tang Political...

Economics of sawmill residues in the establishment of black locust biomass plantations on surface mines

ABSTRACT Although the short term benefits of bark mulch to tree survival and growth on surface mines are well documented, its long term effects and economic performance are not as well established. A study to compare the biomass production of black locust trees grown with bark mulch and fertilizer to that of trees grown with fertilizer alone indicated that bark mulch significantly improved biomass production. These results, however, were not apparent until after seven years. Although the use of bark mulch involved higher plantation establishment costs, an economic analysis indicated that these costs were more than offset by the added biomass produced.

LOCUST BORER (COLEOPTERA: CERAMBYCIDAE) ATTACK IN RELATION TO PULSED ELECTRIC CURRENT IN BLACK LOCUST TREES

Resistance to pulsed electric current (ER) applied to the cambium layer was studied in black locust trees, Robinia pseudoacacia L., in relation to tree thrift indices, and particularly to intensity of current-season attacks by the locust borer Megacyllene robinia. A total of 415 borer attacks were sustained by 241 trees, with a maximum of 20 attacks per tree. Although variation in the data was high both within and among study sites, ER was positively correlated with borer mines per tree and with increased degrees of tree suppression, represented by dominance classes. ER ranged from 2 to 32 kohms per tree, with roughly 95% of the trees reading less than 25 kohms. Borer mines per tree were also correlated with tree dominance class, with more attacks incurred by increasingly suppressed trees.

Presentation of the Murphy gavel.

At the end of my term as president of this Association, it was apparent that the gavel from the plates of Her Majesty's Ship Beaver and the locust trees in British Columbia, which had served for so many years as the gavel of the Pacific Coast Surgical Association, had space remaining on it for the names of only a few of the future presidents. While visiting the B. Building owned by the American College of Surgeons in Chicago last year, I saw some beautiful old pieces of wood going into retirement. I persuaded the officers of the College to allow me to have a piece of a birch window sill. It was my pleasure to design a new gavel and to work with two fine craftsmen to be able to present this new John B. Murphy gavel to the Pacific Coast Surgical Association (Figure). B. was

Differential responses to in vitro bud culture in mature Robinia pseudoacacia L. (black locust)

Buds excised from the stems of five dormant, mature (20- to 30-year old) black locust (Robinia pseudoacacia L.) trees were placed on MS basal medium with various levels of 6-benzylaminopurine. In all treatments, bud explants from two of the trees produced shoots which could be subcultured. Whole plants were obtained from cultures of these two trees. Explants from two other trees became vitrified or produced callus, respectively, when cultured on medium containing between 0.032 and 1.0 μM 6-benzylaminopurine; subculturable shoots were only obtained when the buds from these trees were cultured on medium containing 3.2 μM 6-benzylaminopurine. No shoot cultures which could be subcultured were obtained from the fifth tree used in these experiments. The whole plants produced in these experiments were transferred to a greenhouse, and were phenotypically normal five months after culture initiation (three months after transfer to the greenhouse).