The Production and Some Properties of the Brown Pigment of Aeromonas Liquefaciens

The optimum conditions for pigment production by Ae. liquefaciens was found to be 30 °C and aerobic incubation, and the properties of the pigment are shown to be similar to those of the synthetic dopa-melanin referred to. The enzyme phenol oxidase was demonstrated in the culture filtrates, but not in extracts of disintegrated cells. As precursors for the pigment production, which was shown to be strictly pH dependent, DL-tyrosine, DL-dopa and catechol were used with success, while numerous other amino acids failed. The significance of the pigment as a criterium for the identification of strains which are pathogenic to certain animals or fishes, is not known.     

Winteraktive Spinnen auf einem Acker bei Groβenzersdorf (Niederösterreich)

Ground spiders on a cultivated field near Groβenzersdorf (Lower Austria) in the winter months 322 adult spiders caught with pitfall traps on a field near Groβenzersdorf in the period 3. X 1973–5. III 1974 showed: Erigonidae, Linyphiidae,Pachygnatha (Tetragnathinadae) are dominating. 19 spp. have been recognized, most of them being already known as eurochronous or diplochronous respectively. The whole spider fauna resembles very mmuch the situation found in mid-Germany (Leipzig) byGeiler (1963).     

Spatial structure of wood composites in relation to processing and performance characteristics

Summary A rationale is presented for developing a mathematical model which describes a randomly packed, short-fibre-type wood composite. The model will utilize probability theory to insure random packing both in terms of flake position and orientation. Knowledge about the spatial relationship between wood elements will be used, in future, to predict a number of physical parameters associated with the composite structure. This will be accomplished by first developing a single-layer-flake model and subsequently proceeding to a multi-layer mat structure.Financial support for this work from NSERC/Canada through a strategic research grant is gratefully acknowledged     

Pflanzliche Insektizide IV*. Die insektizide Wirkung des ätherischen Öls aus dem Balsamkraut,Chrysanthemum balsamita L

The essential oil ofChrysanthemum balsamita L. revealed insecticidal properties when tested againstM. dirhodum aphids. The insecticidal activity was attributed to the presence of pyrethrine I in the oil. By an appropriate testing procedure, the dependence of the activity upon the time of harvesting of the plants was determined. Furthermore, the insecticidal effect of the oil was compared with that of a commercially available pyrethrum preparation.     

An immersion technique for studying wood wettability

Summary The wetting properties of wood were studied by a modification of the Wilhelmy technique. This method involved continuously monitoring the force exerted on a wood specimen as it was immersed at a controlled rate into a liquid. Wettability was expressed in terms of the area under the force-immersion curve and was referred to in this study as wettability index. The applicability of the technique was demonstrated for padauk and white spruce wood specimens heated for various time periods. The wettability of these woods in both distilled water and sodium hydroxide solutions decreased with increasing heating time. Sodium hydroxide solution yielded higher wettability index values, indicating that it was a better wetting agent than distilled water. The pH of the sodium hydroxide solution had a strong influence on magnitude of the wettability index. The possibility of using the technique for examining wood surface inactivation in relation to bonding with different adhesives is discussed.The authors gratefully acknowledge the assistance of Dr. W. G. Warren and his staff for the statistical analyses and curve fitting. Dr. Casilla also expresses his gratitude to the National Research Council of Canada and to the Canadian Forestry Service, Department of the Environment, for a postdoctoral fellowship     

The carbon budget of an adult <Emphasis Type="Italic">Pinus cembra</Emphasis> tree at the alpine timberline in the Central Austrian Alps

We investigated carbon (C) uptake and respiratory losses of an adult Pinus cembra tree at the alpine timberline throughout an entire year by means of an automated, multiplexing gas exchange system. These chamber measurements were then combined with biomass data for scaling up the C budget to the tree level. Integrated over an entire year, the cumulative C gain of the tree under study was 23.5 kg of C in 2002. The daily C balance was negative for 5 months and the estimated total wintertime respiratory losses were 9% of the amount of C fixed during the growing season. The total annual C loss of the tree consumed 55% of the annual net C gain and the remaining surplus was stored in new tissues (36%) and used for fine root growth (9%). Thus, the overall C budget of P. cembra at the upper timberline is balanced fairly well, although the C sink strength in fine roots is strongly limited owing to low root zone temperatures when compared to conifers at lower elevation sites.     

Modeling spatial variability in the life-cycle costs of low-volume forest roads

Cost estimation is probably the most decisive factor in the process of computer-aided, preliminary planning for low-volume road networks. However, the cost of construction is normally assumed to be route-independent for a specific project area, resulting in sub-optimal layouts. This is especially true for mountainous terrain and in areas with unstable subsoil. Here, we present a model for more accurately estimating spatial variability in road life-cycle costs, based on terrain surface properties as well as geological properties of the subsoil. This parametric model incorporates four structural components: embankment, retaining structures, pavement, and drainage and stream-crossing structures. It is linked to a geo-database that allows users to derive location-specific parameter values as input. In applying this model, we have demonstrated that variability in costs ranges widely for mountainous areas, with the most expensive construction being approximately five times greater there than on more favorable sites. This variability strongly affects the optimal layout of a road network. First, when location-specific slope gradients are considered, costs are reduced by about 17% from those calculated via currently available engineering practices; when both slope gradient and geotechnical formations are included, those costs are decreased by about 20%. Second, the length of the road network is increased by about 4% and 10% respectively, compared with current practices.     

Das Prinzip des integrierten Pflanzenschutzes

Zusammenfassung Nach einer neueren Definition der integrierten Sch?dlingsbek?mpfung werden die Voraussetzungen genannt, die zur praktischen Anwendung dieses Verfahrens notwendig sind. Die Feststellung und Benützung wirtschaftlicher Schadensschwellen ist dabei besonders wichtig. Ferner wird auf die Bedeutung der richtigen Wahl chemischer Pflanzenschutzmittel hingewiesen, solange selektive Pr?parate noch nicht entwickelt und biologische Bek?mpfungsverfahren noch nicht praxisreif sind. Nicht eine pl?tzliche Umstellung von der konventionellen zur integrierten Sch?dlingsbek?mpfung ist erstrebenswert, sondern ein schrittweises Vorgehen, das den jeweiligen M?glichkeiten angepa?t werden mu?. Damit k?nnen auch jetzt schon beachtliche Erfolge erzielt werden.

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Summary A new definition of the integrated control concept is given and the perequisites for practical application are mentioned. Knowledge and use of economic injury levels is of vital importance in this respect. Furthermore, the importance of the choice of pesticides to be used is stressed, as selective materials are not available yet, and purely biological control can not yet be applied in practice. A change from the conventional chemical pest control system into an integrated pest control system has to be realized step by step according to increasing knowledge and experience. With this integrated control system remarkable results have been obtained.

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Résumé Après avoir établi une définition de la lutte integrée, l'auteur indique les conditions à remplir pour l'application pratique de cette méthode. La détermination et l'emploi de seuils de tolérance économiques est particulièrement important. En outre l'importance du choix judicieux des produits antiparasitaires chimiques est soulignée, compte tenu du fait des produits sélectifs ne sont pas encore développés et des procédés de lutte biologique pas encore m?rs pour la pratique. Un changement rapide de la lutte conventionelle à la lutte integrée n'est pas désirable, mais plut?t une évolution progressive qui soit adapté au fur et à mesure aux possibilités du moment. Ainsi, des succés considérables peuvent déjà être obtenus à brève échéance.

     

Strategic Planning of Sustainable Development on the Estate Level – Contributions from Forest Growth and Yield Science

Zusammenfassung:   Die Nachhaltigkeit richtete sich in der Gründerzeit der planmäßigen Forstwirtschaft auf die Holzproduktion (v. Carlowitz 1713, Cotta 1828, Hartig 1804, Hundeshagen 1826). In der Folgezeit wurde ein zunehmend breiteres Spektrum von Leistungen des Waldes in die Planung mit einbezogen (v. Hagen, 1867; Dieterich, 1957). Das heutige Verständnis von multifunktionaler Forstwirtschaft spiegelt sich in den sechs gesamteuropäischen Kriterien und Indikatoren für nachhaltige Forstwirtschaft wider (McPfe, 2000). Vorliegender Aufsatz umreißt, wie diese gesamteuropäischen Kriterien und Indikatoren für den Nachweis und die strategische Planung von Nachhaltigkeit auf Forstbetriebsebene eingesetzt werden können und was die Waldwachstumsforschung dazu beitragen kann. An einer Reihe von Beispielen wird ausgeführt, dass die Forstwirtschaft über eine solide Datenbasis für die Ableitung von Nachhaltigkeitskriterien und Indikatoren verfügt. Diese kann für das Monitoring der Waldentwicklung genutzt werden. Gestalterische Kraft entwickeln die Kriterien und Indikatoren aber erst, wenn sie auch in die strategische Planung einfließen. Für die strategische Planung stehen der Forstwirtschaft Wuchsmodelle, Betriebssimulatoren und Entscheidungsstützungssysteme zur Verfügung. Sofern diese die genannten Kriterien und Indikatoren berücksichtigen, ermöglichen sie Szenariorechungen auf Betriebsebene und eine umfassende Bewertung von Handlungsalternativen. Konzepte und Werkzeuge für den Übergang zu einer multifunktionalen strategischen Nachhaltsplanung sind weit entwickelt (v. Gadow 2003, Hanewinkel 2001, Pretzsch et al. 1998, Spellmann et al. 2001); ihre Einführung in die Forstplanung könnte einen beträchtlichen Innovationsstau beseitigen.