Development of an assay to determine the bioavailability of potassium in feedstuffs for the young pig

A series of four trials was conducted to verify the published requirement of .26% total K in the diet and to identify response variables useful in an assay of the bioavailability of K in feedstuffs for the young pig. Purified diets were supplemented with K at four levels as KC2H3O2 in three trials and as KHCO3 in the fourth trial. In the first three trials, the requirement was estimated by least-squares analysis of a linear-plateau response of average daily gain. Additional measures in each trial were taken for linear response to dietary K levels. The three estimates of K requirement obtained were .30, .33 and .26% total K in the diet. These three estimates were not found to be inconsistent with the published value of .26% total K in the diet. Various urinary and hematological measures also were examined during the four trials for linear response to dietary K levels. Plasma K was the only hematological response to show a significant linear relationship to dietary K levels. Urinary K concentrations and daily excretion showed a highly significant linear response to dietary K levels. Based on these results, a K bioavailability assay using urinary K measures as the primary response variable and plasma K as the secondary response variable seems the most promising.     

A sequential broncho-alveolar washing in non-anaesthetized normal bovines: Method and preliminary results

The method of lung lavage under fiberoptic control allowed collection of alveolar cells in non-anaesthetized adult cows.The median section of the diaphragmatic lobe was lavaged with five consecutive aliquots of 30 ml each. Every one was analysed separately. A mean of 25.6% of instilled fluid was recovered and this is lower than amounts obtained on isolated lungs or in anaesthetized calves (about 50%).The cellular formula of 30 samples showed 83.5% of macrophages, 6.0% of lymphocytes, 9.4% of polymorphonuclear cells, 0.5% of monocytes. Cellular viability and total cell count were similar to previously published data. All results were found to be independent of the washing sequence. This simple and well tolerated technique appeared to be a useful tool for the study of defence mechanisms of deep lung.     

Biochemical and molecular effects of a commercial diuretic with herbal extract on experimentally induced urolithiasis in chickens

Veterinary Research Communications - This study evaluated the diuretic, antioxidant, anti-inflammatory, and immunological effects of a commercial diuretic (CD) (composed of ammonium chloride,...     

The reflectance method for testing the effectiveness of fungicides against surface mould growth on materials: I. Wood

Summary An instrumental method for the measurement of the toxic value of preservatives against mould fungi on wood and wood products was tested as an alternative to the widely used visual method with its inherent disadvantage of subjectivity. The new criterion of effectiveness to be used was light reflectance as measured by either the Zeiss photometer (Leukometer) or the Zeiss spectrophotometer (Spekol 10) fitted with the Rd/0 reflectance adapter. Sodium pentachlorophenate and the WR-3 (quaternary ammonium compound), applied to pine and birch wood samples were tested for effectiveness against five species of fungi capable of causing surface moulding. Although the reflectance method was more laborious, the results obtained seem to be better than those obtained by the visual method. The proposed method appears to be of practical value in eliminating difficulties involved in the subjective assessment of both the intensity of surface growth and the effectiveness of the wood preservatives themselves.Paper sponsored by the State Enterprise of Conservation of Fine Arts Objects, Warszawa ul. Zielna 3The authors thank Dr. J. D. Thornton, CSIRO Division of Forestry and Forest Products, Highett, Australia, for kindly correcting the English text of this paper     

On the fracture morphology in wood

Summary Structural changes in spruce and aspen wood samples subjected to axial compression were examined by means of the scanning electron microscope. For comparison, macroscopic model experiments were carried out on tube-shaped samples made of paper so as to represent segments of fibriform xylem cells. The results show that there are fracture patterns characteristic of wood in general and others characteristic of the species of wood. The phenomena characteristic of wood in general are prevalent at the cellular level and in the fracture behaviour of the cell wall layers and perforations. The characteristics of the various species of wood dominate at the level of the growth rings and are decisively influenced by the composition and arrangement of the tissues. The model experiments show that the failure morphology of the individual cells of the xylem may be explained to some extent by their geometry.     

Modeling the process of absorption and desorption of water above and below the fiber saturation point

Summary The process of absorption of water along the tangential direction of the wood is studied by immersing the sample in water. The transport of water is then obtained below the fiber saturation point at the beginning of the absorption and above this fiber saturation point during the process. The potential which drives the transport of the bound-water and free-water through the wood has been considered by testing a diffusional transport model. The transient diffusion with a constant diffusivity has been found to describe not only the process of absorption but also the process of desorption with diffusion of water through the solid and evaporation from the surface. Analytical solutions have been successfully used to describe the stage of absorption during a time of four hours at the end of which an equilibrium of absorption is attained, as well as the following stage of desorption. A model based on a numerical method with finite differences has been found to describe the process of absorption and desorption in various cases, and especially when the equilibrium of absorption has not been attained.This work was carried out with the help and support of the M. R. T. and the French CTB (Wood Technical Center)     

High-speed steel tool wear during wood cutting in the presence of high-temperature corrosion and mineral contamination

Dulling of high-speed steel (HSS) cutting tools after milling five wood species has been analyzed. The wood investigated varied in mineral contamination, high-temperature corrosivity (HTC) and density (D). Experiments performed proved that up to date methods for evaluation of mineral contamination in wood should be improved. A new pipe-like form of mineral contamination particles was evidenced. The correlation between the presence of 3D aggregates of silica in wood and high content of K and Ca in the ash was established. Employing multivariable theoretical simulation method, the combined effect of mineral contamination, HTC and wood density on the tool dullness appeared to be a reasonable explanation of the results obtained.     

Die Verjüngung gemischter Bergwälder—Praktische Konsequenzen aus 10jähriger Untersuchungsarbeit

Zusammenfassung Seit zehn Jahren betreibt der Lel-irstuhl für Waldbau and Forsternrichtung der Universit?t M?nchen intensive Verjüngungsstudien auf 25 Dauerversuchsfl?chen im Bergmischwald der ostbayerischen Kalkalpen. Am Bei-spiel der Aufnahmedaten yon fünf ausgew?hlten Versuchsfl?chen werden grundlegende Prinzipien des Ver-jüngungsprozesses im Bergmischwald aufgezeigt and daraus praktische Konsequznzen abgeleitet. Alle am Autbau der Altbest?nde des Bergmischwaldes beteiligten Baumarten bilden bislang trotz d utli-cher Waldschadenssvmptome reichlich Samen von hochwertiger Qualit?t aus. Damit aus diesem Verjüngungspotential Naturverjüngung entstchen kann, müssen die en tsprechenden überschirmungsverh?ltnisse lurch den Altbestand gegeben sein. Für die Dichte, Baumartenztusammenset zung and H?henentwicklung der Naturverjüngungspflanzen ist n?mlich die Uberschirrnung von ganz ent-scheidender Bedeutung. In einem sehr dichten Altbestand, in derv der überschirmungsgrad fiber 75% liegt , haben Verjüngungspflanzen Schwierigkeiten, sick zu etablieren. Eine Ieichte Auflichtung auf einen über-schirmungsgrad von 60 (der dann gegeben ist, wenn die rich unter dem Schirm entwickelnde Bodenvege cation Bedeckungsgrade zwischen 20 and 3C einstellt) erm?glicht den Naturverjüngungsflanzen ein überleben. Diese Uberschirmung kann durch einen schwachen Schirmhieb (Entnahme von etwa einem Vier-tel der Grundtl?che eines geschlossenen Bestandes) erreicht werden. Diese Eingriffsst?rke dürfte auch unter den Gesichtspunkten der Stabilit?it and des Zuwachsverlustes dill Altbestand zu vertreten sein. Vor einer st?rkeren Auflichtung des Altbestandes müsses genügend Naturverjüingungspflanztn ant Bo den vorhanden sein. Nur so is[ gew?hrleistet, daβ these einen Vorsprung vor der Bodenvegatation bekom Men. Die Pflanzung ist immer dann, wenn sich Schwierrigkeiten mit der Naturverjüngung ergeben, ein geeigne-tes Mittel, um einen neuen Bergmischwald zu begründen. Derzeit ist für das Entstehen tines neuen Bergmischwaldes - sei es durch Naturverjüngung odor lurch Pflanzung - Zaunschutz erforderlich. Summary In 1976, a research project entitled ’Natural Regeneration of Mixed Mountain Forests ’ was etablished in the Calcareous Alps of eastern Bavaria, by the Chair of Silviculture and Forest Management of the University Of Munich. Over the past ten years, the multi-variate aspects of regenaration have bean intensively investigated on 25 permanent research plots. The data from 5 selected plats were extracted and processed. from these data, it will be possible to present some fundamental principles of natural regenaration processes. From these prin-ciples, it is hoped that some practical applications can be derived. The mature stands of mixed mountain forests are still able to produce high quantities and good quality of seed, although distinct symptoms of forest decline are present. In order to utilize this potential for natural regeneration, an adequate canopy density is necessary. Canopy density is the crucial factor which regulates the density, species composition and height development of regeneration. In a very heavily, stocked mature stand with a canopy density of over 75 establishment of regenerations is difficult. When canopy density is reduced to, for example, 60% (this percentage can be estimated from a ground vegetation covering approximately 20–30 of the soil), the naturally regenerated, plants have a better opportunity to survive. A 60% canopy density can be achieved by light shelterwood cutting (removal of approximately 25% of basal area of a closed stand). This type of cutting can maintain the stability and prevent increment loss of forest stands. It is important that regeneration is established before opening up the stand, only, then these plants are capable to compete with the other ground vegetation. Planting is always appropriate when natural regeneration fails. Fencing is necessary for undisturbed development of natural and artificial regeneration.

---

---

Dieses Heft enth?lt waldbauliche Beitr?g zu den Forschungsschwerpunkten Bergwald, Waldschaden und Kiefer. Sie sind überwiegen als Vortr?ge auf der Hochschulwoche der Forstwissenschaftlichen Fakult?t München im Oktober 1987 gehalten worden. Ihre Autoren widmen sie Herrn Professor Dr. Peter Burschel zum 60. Geburtstag.

---

Auf der Forstlichen Hochschulwoche 1987 in München gehaltener Vortrag.     

Ecophysiological and genetic variation in seedling traits and in first-year field performance of eight <Emphasis Type="Italic">Acacia senegal</Emphasis> provenances in the Blue Nile,Sudan

The genetic variation in seed weight, seed number per kg and seedling traits was compared among eight Acacia senegal provenances originating from the clay plain (east) and sand plains (west) of the gum belt in Sudan. The main objective of this study was to identify germplasm sources of A. senegal that have a good seed germination capacity and seedling traits suitable for reforestation in the clay-soil part of the dryland gum belt in the Blue Nile region in Sudan. A specific objective was to tentatively explore the adaptive strategy of A. senegal populations. Seventeen-week-old seedlings were planted in the field at spacing of 3 m × 3 m, giving 100 trees per plot and replication; within a randomized complete block design with four replications. The experimental site was in the clay plain region. Seed variables showed significant differences. Clay plain provenances showed considerable variation in seed weight and seed number. They had the smallest seed weight but the highest seed number, while the sand (western) provenances had the largest seed weight but lowest seed number. Seedling branch number, root length, root to shoot ratio and shoot dry weight differed significantly among the provenances 12 weeks after germination. Clay provenances had the highest branch number and shoot dry weight but the shortest roots and lowest root to shoot ratio. This was interpreted as showing better adaptation to the site in these local provenances in comparison to those originating from the western sandy soil regions. High positive correlations were observed between seedling variables, such as root nodule and branch numbers; this could be used for early selection. The variation was greater between provenance groups than within them, suggesting that especially selection among groups would yield genetic gain.