Dielectric properties of hardwood species at microwave frequencies

Dielectric measurements at 9.8GHz and 2.45GHz were made for the three hardwoods Euramerican hybrid poplar, alder, and oriental beech. The method used was based on Von Hippels transmission line method. The measurements were carried out at room temperature of 20°–24°C. The dielectric properties of the wood species were determined for the three principal structural directions at six different moisture conditions, covering the range of 0% to 28% moisture content. Results indicated that the behavior of all wood species studied is quantitatively similar. In general, the dielectric properties increase within the range studied with rising moisture content. The grain direction of the wood also plays a significant role.     

Die Massenvermehrung des Hagebuchenspanners,Himera pennaria L., 1962 in Niederösterreich und im Burgenland und die Ursachen des Zusammenbruches der Kalamität

Summary The Outbreak of Himera pennaria L. in 1962, in Lower Austria and Burgenland, and Causes of its break-down.The Hornbeam Measuring Worm,Himera pennaria L., hitherto described but once in forest-entomological literature as a bigscale forest pest, performed mass-attacks in 1962 in the Leitha hills (1500 acres) and Maria-Ellend wood, even clean-eating several hardwood species, especially hornbeam and also oak. The outbreak which occurred about mid-May broke perfectly down as soon as early June. The paper characterizes several bionomical and morphological data obtained during the course of the outbreak from individual development stages, also discussing the possible causes of the outbreak illustrated by climatograms. In conclusion, the biotical factors of the breakdown are treated, pointing out a virus disease (cytoplasmic polyhedrosis of mesenteron) as playing the greatest part. Along withH. pennaria L., alsoHibernia defoliaria L.,Hibernia aurantiaria Esp., andCheimatobia brumata L., as well as 4 species ofNoctuidae and 1 species ofArctiidae occurred rather frequently in the above-mentioned area, especially in the marginal zones of the Hornbeam Measuring Worm's mass-attack.

---

Résumé La gradation de l'Arpenteuse du Charme —Himera pennaria L. — en 1962, en Basse-Autriche et au Burgenland, et les causes de la débâcle de la calamité.L'Arpenteuse du Charme,Himera pennaria L., signalée une seule fois dans la litérature entomologique forestière comme ravageur en masse, s'est manifestée en dimensions calamiteuses en 1962, dans les montagnes du Leitha (600 ha) et au bois de Maria- Ellend, dépouillant — par endroits même de leur feullage eiitier — différentes espèces de bois feuillus, surtout des charmes mais aussi des chênes. La gradation qui s'était manifestée vers la mi-mai, subit une débacle complète dès le début de juin. Le mémoire présente quelques données bionomiques et morphologigues, obtenues au cours de la gradation, sur les différentes phases du développement, tout en discutant à l'aide de climatogrammes quelles pourraient être les causes de la gradation. En conclusion, on traite spécialement les facteurs biotiques de la débâcle, parmi lesquels une maladie à virus (polyédrose cytoplasmique du mésentère) a joué le premier rôle. Em même temps que l'Himera pennaria L., les insectes suivants ont été trouvés dans le territoire en question, le plus fréquemment dans les zones marginales de l'aire de grádation de l'Arpenteuse du Charme:Hibernia defoliaria L.,Hibernia aurantiaria Esp.,Cheimatobia brumata. L., 4 espèces de Noctuides et l espéce d'Arcttides.

---

Himera pennaria L. 1962 . . . . ,Himera pennaria L., -- , 1962 . (600 .) , , . , , . , , , . , ( ). H. Pennaria L. Hiberia defoliaria L., Hibernia aurantiaria Esp., Cheimatobia brumata L., 4 Noctuidade 1 Arctiidae, .

---

---

Herrn Prof. Dr. A. Acatay zum 60. Geburtstag gewidmet.

---

Die Untersuchungen erfolgten in Zusammenarbeit mit der Landesforstinspektion für Niederösterreich, speziell mit der Bezirksforstinspektion Wien-Umgebung und der Landesforstinspektion für das Burgenland, wofür an dieser Stelle herzlichst gedankt sei.

---

Für Herstellung der mikroskopischen Präparate sei Frl. H. Meldt, für die Freilandaufnahmen und mikroskopischen Aufnahmen Herrn N. Maisner bzw. Herrn O. Baschny der Forstlichen Bundesversuchsanstalt Mariabrunn, für die Aufnahmen der elektronen-mikroskopischen Präparate Herrn Hayek vom Physikalisch-chemischen Institut der Universität Innsbruck gedankt.     

Die Übertragung des Enationenvirus der Erbse durch verschiedene Morphen der BlattlausartenMacrosiphum euphorbiae (Thomas) undAcyrthosiphon pisum (Harris)

Zusammenfassung Unterschiedliche Vektoreignungen können zwischen Rassen, Morphen und Altersstadien einer Blattlausart auftreten. Es wurden verschiedene Morphen vonMacrosiphum euphorbiae (Thomas) undAcyrthosiphon pisum (Harris) hinsichtlich ihrer Übertragungsfähigkeit für das persistente Enationenvirus der Erbse geprüft. Dabei erwiesen sich ovipare Weibchen und adulte Männchen vonM. euphorbiae als ungeeignete Überträger, während die gleichen Morphen von zweiA. pisum-Populationen die Virose übertrugen. Auch die Fundatrix desA. pisum-BastardsTrifolium pratense rot XSarothamnus scoparius grün übertrug zu einem relativ hohen Prozentsatz. Ovipare Weibchen und Männchen der inaktiven RasseLotus uliginosus gelb konnten keine Infektion bewirken; die persistente Virusübertragungsfähigkeit ist im Falle vonAcyrthosiphon pisum (Harris) offenbar ein genetisch fixiertes Merkmal.

---

Summary Different vector abilities may exist between races, morphs and development instars of a given aphid species. Several morphs ofMacrosiphum euphorbiae (Thomas) and ofAcyrthosiphon pisum (Harris) were tested in their transmission ability for the persistent pea enation mosaic virus. Oviparous females and adult males ofM. euphorbiae proved insuitable for transmission, the corresponding morphs of twoA. pisum-populations, however, were successful in transmitting. The fundatrix of theA. pisum hybridTrifolium pratense red xSarothamnus scoparius green transmitted to a relatively high percentage. Oviparous females and males of the inactiv raceLotus uliginosus yellow failed completely in transmitting; in the present case ofA. pisum the transmission character of the persistent virus evidently is genetically fixed.

---

Résumé Différentes aptitudes de vecteur peuvent se trouver entre les races, les morphes et les périodes d'âge d'une espèce de pucerons. Différentes morphes deMacrosiphum euphorbiae (Thomas) et deAcyrthosiphon pisum (Harris) ont été examinées en ce qui concerne leurs aptitudes de transmettre le virus persistant du pois(pea enation mosaic). En ce cas les femelles ovipares et les mâles adultes deM. euphorbiae se montraient impropres à la transmission, pendant que les mêmes morphes de deux populations deA. pisum transmettaient la virose. C'était la fondatrice du bâtard deA. pisum Trifolium pratense rouge avecSarothamnus scoparius vert qui transmettait à une pourcentage relativement haute. Les femelles ovipares et les mâles de la race «inactive» deLotus uliginosus jaune ne pouvaient pas effectuer d'infection; en cas deAcyrthosiphon pisum (Harris), l'aptitude persistante à transmettre le virus évidemment est un caractère fixé d'une façon génétique.

---

, . Macrosiphum euphorbiae (Thomas) Acyrthosiphon pisum (Harris) peaenation mosaic virus). M. euphorbiae , {A. pisum} . A. pisum-Trifolium pratense Sarothamnus scoparius . «» Lotus uliginosus ; Acrythosiphon pisum (Harris) .

     

The reaction of guaiacol with iron III and chromium VI compounds as a model for wood surface modification

Summary The reaction of ferric chloride with the lignin model guaiacol affords primarily a complex mixture of coupled guaiacol oligomers. Major components were the symmetrical carbon-carbon coupled dimer 3,3-dimethoxy-[1,1-biphenyl]-4,4diol and the trimer 3,3,5-trimethoxy-[1,1:3,1-terphenyl]-4,4,4-triol which were isolated by preparative HPLC and characterized by ¹HNMR spectroscopy and mass spectrometry. An unstable component believed to be a 4,4-diphenoquinone derived from the trimer was also prominent. The reaction of chromium trioxide with guaiacol yields the same dimer, trimer and diphenoquinone as well as 2-methoxy-p-benzoquinone. The major product with chromium trioxide, however, is an inert, highly insoluble polymer which was shown by degradation to contain guaiacol oligomers bound or crosslinked by hydroxylated chromium species. Magnetic susceptibility measurements clearly indicated that the valency of chromium in the polymer was + 3. It is postulated that similar complexes formed from phenolic lignin units are responsible for the weather resistance of chromium trioxide treated wood surfaces. In a broader context this study is relevant to the fixation of hexavalent chromium from a range of widely used wood preservative formulations.The authors wish to thank the following: Tom Syers (CSIRO Division of Forest Products) for technical assistance, Mary Reilly (CSIRO Division of Forest Products) for NMR spectral determinations and Ivan Vit (CSIRO Division of Chemicals and Polymers) for mass spectral determinations     

Wood drying and Fick's second law

Summary The diffusion equation (sometimes referred to as Fick's second law) is derived in terms of water movement under the action of capillary forces. The mass diffusivity is thereby expressed in terms of the capillary diffusion coefficient. A numerical calculation is given for yellow poplar.Notations C diffusion coefficient for water in wood with capillary pressure as the driving force, kg/msPa - D diffusion coefficient for water in wood with moisture content as the driving force, kg/ms - F mass flux, kg/m²s - p_c capillary pressure, Pa - p_cf capillary pressure extrapolated linearly to fibre saturation, Pa - T absolute temperature, K - t time, s - x distance ordinale in the direction of flow, m - mass diffusivity, m²/s - density of liquid water, kg/m³ - _g basic density (dry mass/green volume), kg/m³ - _w density of wood substance, kg/m³ - moisture content of wood - _cls moisture content at continuous liquid saturation - _cs moisture content at complete saturation - _f moisture content at fibre saturation     

Non-steady state water adsorption of wood

Summary The validity of the following equation of water adsorption into wood substance which was derived in the previous report, is examined: d(W)/dt = k₀(1 – exp(-k₁/t))W(l – W), which can approximately be written as: d(W)/d(logt) = rW(l – W), where W is moisture content; t is time (t > 0); k₀, k₁ and r are constants. After measuring dimensional change with change in time under various relative humidities, the change of moisture content was indirectly calculated from the proportional relationship between dimensional change and moisture content. It was found that the theoretical equation satisfactorily agreed with the experimental results. These results lead to the conclusion that the equation was valid. Furthermore, the properties of the equation, whose constants are determined from experimental results, is discussed. The rate of water adsorption of wood shows interesting and systematical properties, especially near relative humidities corresponding to the fiber-saturation point.     

Neuere Beobachtungen und Untersuchungen zur Kartierung von Pflanzenschädlingen

Summary In the introduction a historical survey is given about the development of the registration service of pests. It can be seen that originally informations of the appearance of pests was mostly given by agricultural and horticultural experts in special journals of agriculture and horticulture.It is well known that a registration service was set up when a Plant Protection Organisation was foundet. Its efficiency has never ceased since its beginnings. These efforts are foundet intensionally to register the existence of pests as completely as possible.The registration service starting first of all from the damage caused by the pests maybe well understood.Our research work being a continuous contribution to the systematic registration of pests generally shows in a number of examples the heterogeneous character of the problem which must be studied concerning the individual pests and difficulties which arise. This is shown with regard to someElaterides and also because of experiments withLaspeyresia funebrana Tr. during several years.In accordance withKirchner and F. P.Müller, Rostock, we propose to register systematically a number of pests on index cards according to uniform principles in the whole of Europe, to register the vertical and horizontal appearance of pests with the same measure, in the same periods of classification and in the same way (seeAuersch 1 to 3).We are encouraged to do so by a number of appreciated views of specialists from Germany and foreign countries however it is, not enaugh to see the great importance of the card index (card-register) and to acknowledge its practicability, but it can only prove its efficiency if it is generally introduced.The systematic registration of pests will enable us to gather in the course of time empirical data, the reliability and evidence of which will steadily increase.

---

Résumé On commence par livrer un aperçu historique sur le développement du système de rendre compte relativement aux plantes nuisibles. En lisant ces comptes rendus on peut reconnaître que les rapports donnés au début sur l'apparition des plantes nuisibles furent livrés en substance par la pratique agricole et jardinière par des revues spéciales de l' agriculture et de l'horticulture.Il est connu qu'avec l'établissement du service pour la protection des plantes on a établi un service de comptes rendus, au perfectionnement duquel on a travaillé dès son existance.Ces efforts furent influencés et activés par l'idée de saisir l'apparition des plantes nuisibles aussi complétement que possible. Le service des comptes rendus s'est orienté d'abord en première ligne aux dommages produits, ce qui est aisé à comprendre.Puisque notre traité doit être en général une contribution ultérieure à la connaissance systématique de l' apparition des plantes nuisibles, on explique au moyen de plusieurs exemples, comment sont différentes les questions se rapportant aux plantes nuisibles individuelles, questions qu'il faut ainsi prendre en considération et quelles difficultés en résultent. Cela est démontré pour quelques élatérides de même que sur la base d'examinations exécutées pendant plusieurs années avecLaspeyresia funebrana Tr.En concordance avecKirchner et F. P.Müller, Rostock, nous proposons de saisir systématiquement en classeurs à fiches une série de plantes nuisibles selon des points de vue uniformes, cela veut dire d'enregistrer dans les fiches proposées l'apparition verticale et horizontale des plantes nuisibles avec des mesures égales, dans les mêmes périodes d'examen et appréciation des qualités productives du sol et dans la même manière (voireAuersch 1 à 3).Nous sommes encouragés à faire ces propositions avant tout par des assentiments à notre disposition, qui nous ont été envoyés de la part des cercles compétents de notre pays et de l'é tranger. Il ne suffit pas cependant de reconnaître le fichier dans sa signification variée et d'apprécier son utilisation; le fichier peut faire ses preuves plutôt seulement, s'il est introduit en général. Au cours du temps il sera possible d'obtenir des valeurs expérimentelles par le fichement systématique des plantes nuisibles, dont la sûreté et faculté de déposition augmente constammant avec la durée de leur existence.

---

õ . : . . . . õ . . , . Elateriden uLaspeyresia funebrana Tr. . . . , , , . . ( 1 3.) . . , . . .

     

Structure of xylan from culms of bamboo grass (Sasa senanensis Rehd.)

Xylan prepared from culms of kumaizasa (Sasa senanensis Rehd.), a representative species of bamboo grass, was hydrolyzed with-xylanase ofStreptomyces olivaceoviridis E-86. Four arabinoxylo-oligosaccharides and two glucuronoxylo-oligosaccharides were isolated from the enzymatic hydrolysate of the xylan by chromatography on a charcoal column, a Dowex 1-x8 column, a Toyo-pearl HW-40S column, and a LiChrospher 100 NH₂ column and on preparative paper chromatography. The results of the structural analyses of the saccharides showed that the isolated oligosaccharides had the structures of 3²--l-arabinofuranosyl-xylobiose, 3²--l-arabinofuranosyl-xylotriose, 3²--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylobiose, 3³--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylotriose, 2³--4-O-methyl-d-glucuronosyl-xylotriose, and 2³--d-glucuronosyl-xylotriose. From the structural analysis of the oligosaccharides derived from the xylan, kumaizasa xylan was concluded to be a kind of arabinoglucuronoxylan having not only stubs of singlel-arabinose and singled-glucuronic acid but also stubs of disaccharide units such as-d-xylopyranosyl-(1 2)-l-arabinofuranose.     

Isolation of a β-1,3-glucan (laricinan) from compression wood of Larix laricina

Summary A -d-(13)-linked glucan has been isolated from compression wood of tamarack [Larix laricina (Du Roi) K. Koch]. The polysaccharide, which had []_D + 17.6°, consumed 0.17 mole of periodate per glucose residue and gave a methyl derivative which consisted of 115 2,4,6-tri- and 2,3,4,6-tetra-O-methyl-d-glucose residues in a ratio of 17.8:1. Partial acid hydrolysis yielded a series of -d-(13)-linked oligosaccharides, while enzymic hydrolysis with a -1,3-glucanase afforded glucose, laminaribiose, and laminaritriose. The glucan occurred in amounts varying from 2 to 4% in compression wood of this and other conifer species and was present in the wall of both tracheids and ray cells. It is proposed that this structural polysaccharide be designated as laricinan to distinguish it from callose and the various -1,3-glucans in lower plants.     

On movement of water through wood — The diffusion coefficient

Summary It is demonstrated that there can be only one driving potential for the movement of water through wood and this will be a function of wood state. On the assumption that the driving potential is the partial pressure of water vapour, a theoretical expression is derived for the diffusion coefficient. Such expression is fitted to diffusion coefficients for Scots pine and a remarkably good fit is obtained.Symbols a reciprocal mean radius of curvature of a capillary meniscus; also taken to be the radius of the corresponding exposed liquid surface, m - b spacing between flow paths in the cell wall, m - D diffusion coefficient for water in wood with vapour pressure as the driving potential, kg/ms Pa - D_a diffusion coefficient for water vapour through air, kg/ms Pa - D diffusion coefficient for water in wood with the driving potential - D diffusion coefficient for water in wood with the driving potential - D₀ diffusion coefficient for water in wood with vapour pressure as the driving potential, which is associated with leakage paths through the wood, kg/ms Pa - D_f diffusion coefficient for water in wood with vapour pressure as the driving potential, corresponding to fibre saturation and with no leakage paths, kg/ms Pa - D_c diffusion coefficient for water in wood with vapour pressure as the driving potential, which is associated with the constriction of the vapour flow as it approaches the cell wall, kg/ms Pa - D diffusion coefficient for water in wood with moisture content as the driving potential, kg/ms - diffusivity for water vapour in air, m²/s - F flux of water, kg/m² s - p partial pressure of water vapour, Pa - R specific gas constant for water, J/kg K - r fractional relative humidity - T temperature, K - x length coordinate in direction of flow, m - the dimensionless ratio D_f/D_c evaluated at r=1/e - arbitrary driving potential for movement of water in wood - cell spacing in the direction of water flux, m - density of liquid water, kg/m³ - coefficient of surface tension, N/m - arbitrary driving potential for movement of water in wood - fractional moisture content     

Beitrag zur Epidemiologie und Biologie des BuchenspringrüblersRhynchaenus (Orchestes) fagi L. an Obstgewächsen

Zusammenfassung Im Jahre 1963 wurde in verschiedenen Gebieten Deutschlands ein Massenauftreten des BuchenspringgrüßlersRhynchaenus (Orchestes) fagi L. beobachtet. Die Jungkäfer gingen ab Mitte Juni an Obst über und verursachten dort große Schäden. Bevorzugt wurden Aprikosen, Süßkirschen und Äpfel der Sorten Cox Orange, Golden Delicious und Goldparmäne, wä hrend Ontario nicht befallen war.In Rheinland-Pfalz wurden noch Ende Oktober agile und lebhaft fressende Käfer in großen Massen selbst an lagerndem Obst beobachtet.Im Frühjahr 1964 wurden in Rheinland-Pfalz erneut Massen von Altkäfern in Buchenbeständen beobachtet. Die Jungkäfer schädigten außer Obst auch Beta-Rüben.In künstlichen Zuchten konnten lediglich 8 von Hundert der Versuchstiere überwintert werden.Zur Bekämpfung erwiesen sich Kontaktinsektizide auf Lindan-DDT-Basis den Phosphor-Estern überlegen.

---

Summary In 1963 an enormous appearance ofRhynchaenus (Orchestes) fagi L. was observed in many parts of Germany.The young beetles attacked fruits in the second part of June. Apricots, cherries and especially the apple varieties Cox Orange, Golden Delicious and Goldparmaine were most severe damaged. Only the variety Ontario remained unattacked.Observations in Rhineland-Palatinate proved thatRh. fagi attacked apples still in October even at store houses.During the spring 1964Rh. fagi attacked beech-trees and fruits once more and even beets.Kept in special assays only 8 percent of the caged beetles survived the winter.In experiments for controllingRh. fagi proved more susceptible to Lindane-DDT and less susceptible to parathion and diazinon.

---

---

Meinem verehrten Lehrer, Herrn Professor Dr. Hans von Lengerken zum 75. Geburtstag gewidmet.     

The role of extension in agroforestry development: evidence from western Kenya

The extension strategy used by the CARE International in Kenya Agroforestry Extension Project (AEP) is described. This strategy is evaluated in terms of documented changes in farmer's agroforestry practices and the importance of AEP relative to other changes in economic incentives, institutional support, and land use and tenure rules for agroforestry. The project served mainly to increase awareness of the multipurpose potential of agroforestry, expand available technical options, and strengthen local institutions. Its community-based extension approach was more suitable for local conditions than commodity-based, training-and-visit, farming systems, or media-based extension. Projects are encouraged to tailor extension design to local circumstances, use community participation to guide extension priorities, and use extensionists as catalysts and information brokers.Research undertaken while the author was a Principal Scientist at the International Council for Research in Agroforestry, Nairobi, Kenya.     

Multiple purpose forests and the national forest system

The history of the legislative basis for managing National Forests in the USA has led to forests managed for multiple uses for a wide diversity of users and interests. Evolution of emphasis on National Forests from mandates to preserve and protect and provide a continuous supply of timber to concerns about owls, ecosystem management and contemporary rural development have included changes in on-the-ground forest management. All of these phases include needs for planted forests established and maintained for multiple purposes and benefits.     

Modelling the long-term strength of timber columns

Summary This paper studies the influence of the used creep function, and the duration of the experimental sustained loading from which the creep function was derived, in modelling the long-term buckling strength of timber columns. The sensitivity of this buckling strength to creep and initial deflection is numerically studied using an energy approach that takes into account the initial deflection. Various creep functions — power laws as well as exponential laws — derived from bending experiments of different durations are used for the numerical simulation. The crucial need for experimental results issued from very long load period experiments is identified. Such experiments may lead to a more credible creep analysis of timber structures.Symbols i radius of giration - s stress level - E_L effective MOE - E₀ instantaneous MOE - I inertia moment - K,K geometrical matrices - L length of beam or column - L_f effective length - N_cr axial force, buckling load - U elastic strain energy - W external forces work - t time variable - u moisture content (m.c.) - v total deflection - v_c, v_e, v₀ creep, instantaneous elastic and initial deflections respectively Greek Letters (t) time function - , _e, ₀ total, instantaneous and initial strains respectively - twist rotation - (t) creep coefficient or fractional creep or relative creep - (x) shape function - load factor - longitudinal shortening - total potential energy - creep factor - relaxation time     

Stress-strain state of wood at kiln drying

Summary A model has been suggested which allows the calculation of stresses arising in kiln drying and humidification of wood, as well as the total residual strain, i.e. set strain _s, consisting of purely residual strain _r and the so-called frozen strain _f. Frozen strains arise under the operating influence of loading when the stiffness is increased because of a decrease in moisture content (or temperature) of the wood. The process of formation of set strains _s has been shown to depend on the history of loading, variations of the moisture content of the wood, as well as cooling of the section before the measurement of _s. The possibility of using set strain as a parameter of the state of stress of wood in kiln drying has been noted.Presented at the VIII. International Symposium on Fundamental Research of Wood. Warsaw, Poland, October 1990     

Estimated stocks of organic carbon in mangrove roots and sediments in Hinchinbrook Channel,Australia

Aboveground and belowground root biomasses (Babove and Broot) were measured for young, isolated Rhizophorastylosa on Iriomote Island, Japan. The relationship between these two parameters was significant and given as the equation, Broot(g dry weight) = 0.394 × Babove(g dry weight) – 485 (r = 0.986). Multiple regression analyses also revealed good correlation between diameter and biomass of prop roots (Dprop and Bprop) and between prop root and root biomasses. Consequently, root biomass could be estimated from the measurements of diameter and biomass of prop roots using the multiple regression equation, Broot(g dry weight) = 80.0 ×Dprop(cm) + 0.86 ×Bprop (g dry weight) – 251. The relationship between DBH (diameter at breast height) and prop root biomass was also adequately described using an allometric equation.In Hinchinbrook Channel, Australia, redox potential (measured as Eh) and organic carbon stocks in the top 5cm of mangrove sediments were measured along a 600m transect from the frequently inundated, Rhizophora dominated zone on the creek edge, towards higher grounds, where Ceriops spp. became increasingly dominant. Eh values were about –60mV near the creek edge and increased to 260mV on higher grounds. Organic carbon stocks showed an opposite trend to Eh, with the values decreasing from about 360tCha–1 to 160tCha–1. At 18 sites, representing six different habitats, organic carbon stocks were also measured along with the DBH of mangrove trees. DBH was converted into aboveground biomass and then into root biomass using the equations obtained in the study on Iriomote Island. The average organic carbon stocks in the top 50 cm of sediments, aboveground biomass and root biomass were 296tCha–1, 123 tCha–1 and 52 tCha–1, respectively, and accounted for 64%, 25% and 11% of the total organic carbon stock.     

Moisture content-water potential relationship of red pine sapwood above the fiber saturation point and determination of the effective pore size distribution

Summary The pressure membrane and pressure plate techniques were used to establish the moisture content-water potential (M-) relationship of red pine (Pinus resinosa Ait.) sapwood in desorption above the fiber saturation point. The moisture content-water potential relationship is required for the development of a model of drying considering the gradient of water potential as the driving force of moisture in wood. This relationship was established at 18, 56 and 85 °C for radial desorption. The results obtained demonstrate that water potential increases with temperature T at a given moisture content M. There is no significant variation of /T with temperature. Also, there is no plateau at intermediate moisture contents as was the case for the M- relationship of aspen sapwood established in a previous work. The effective integral and differential pore size distributions inferred from the M- relationship are also presented. The largest proportion of effective pore openings was found for a radius of 0.2 m. This value can be related to the pit membrane openings of red pine.This research project is currently supported by the Natural Sciences and Engineering Research Council of Canada under grant no. OGP0121954     

Unsteady-State gas permeability of wood

Steady-state permeability experiments yield a single value for permeability in each of the three structural directions of wood. A high value indicates that passage through the wood is easy, but it does not necessarily mean that all voids are filled readily with a fluid.This research aimed at developing an experimental method that would give a better insight in this dual nature of wood permeability.Cylindrical wood specimens, 50 cm x 7.5 cm diameter were evacuated and a known quantity of gas was admitted to the system. A comparison of the pressure/time curve with theoretically derived results gave values for the transverse or longitudinal gas permeability.The most important results are: 1. Several species show a definitely dual permeability in the transverse direction; 2. the longitudinal/transverse permeability ratio for large specimens is considerably lower than steady-state results on small specimens indicate.Paper No. 2793 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, N.C.; a condensation of part of Ph. D. thesis from the Department of Wood and Paper Science of North Carolina State University 1967 under the direction of Alfred J. Stamm, Robertson, Professor of Wood and Paper Science.     

Stock quality and field performance of Pinus patula seedlings produced under two nursery growing regimes during seven different nursery production periods

Two types of containerized P. patula seedlings, referred to as hard and soft seedlings, were raised by droughting and different fertilizer applications. Hard seedlings were raised by applying half the water and a quarter of the fertilizer (0.01 g per seedling 21%N:7.1%P:14.2%K) applied to the soft seedlings. At the end of the nursery cultural treatments the two types of seedlings were morphologically distinct. Hard seedlings had lower heights, height to root collar diameter ratios and seedling dry masses than soft seedlings, but mortality was similar for both seedling types when planted during seven different production periods within the planting season on three sites which differed climatically and geologically. Correlations between mortality and height to root collar diameter ratio (r = 0.76), root to shoot ratio (r = 0.83) and root growth potential (r = --0.69) were obtained indicating that grading of seedlings on these parameters may improve survival. However, it was evident that survival could be significantly improved by identifying the best time of year and conditions for planting, as well as improving stock quality.     

Die Stubenfliege lä043-01043-01043-01t sich ausrotten

Ohne ZusammenfassungDer Originalaufsaß erschien unter dem Titel The house Fly can be eradicated in The Southern Planter im Mai 1948 in Richmond (Virginia, USA.).