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Field observations made during a reconnaissance soil survey of the Central Orange River Basin for the Orange River Development Project, showed significant relationships between soil landscapes and associated vegetation. Although no intentional ecological studies were made it was clear that certain soil types (soil forms and/or series) are always associated with particular plant communities. In view of this general consistent soil-plant relationship observed in the survey area, it is reasoned that apart from climatic and topographic factors, the soil should in future be taken into consideration in defining and mapping of veld types.

A multichannel analysis of the resonantF-wave 1/2+ baryon octet-0− meson oetet scattering on the basis of the dynamical mechanisms of Agarwal and Cook-Lee is presented. The analysis provides an understanding of the 5/2+ alpha-baryon octet and suggests the existence of a new 5/2+ baryon singlet for a reasonable choice of theF/D ratios. The implications of these results regarding the higher-symmetry schemeW 3 are briefly discussed. A further result of the analysis is the prediction of the $$\left( {\bar B_{\frac{5}{2}} B_{\frac{1}{2}} P} \right)$$ mixing parameter as 0.43. This result is compared to the experimental value calculated from branching ratios.

SUMMARY In South Africa there are approximately 2,700 plantations with an area of less than 500 acres each. The small plantation owner cannot adopt the profitable, big scale approach to forestry and timber utilization. He suffers disadvantages because he cannot afford to engage technical staff; he cannot manage his small plantation on a sustained yield basis; he cannot mechanize his heavy operations; he cannot establish industries based on the yield of his plantations alone; he does not have the bargaining power to negotiate favourable terms with industry for the disposal of his product. Small forest owners in Europe have organized themselves into co-operative forestry associations. The more progressive associations engage professional staff, train forest workers, assist in standardizing products, promote forest research and establish forest industries on behalf of their members. A case in point is the Woodland Owners' Association in the south of Sweden. A large cellulose company was financed with money d...

Summary Results of an investigation into the relationships between tree size, relative bark thickness and bark yield of black wattle trees (Acacia mollissima Willd) are presented. The method of least squares was employed. Relative bark thickness has probably been introduced for the first time in South Africa as a controlled variable in an investigation of this nature. Significant differences in the ratio of bark thickness to diameter at breast height were established for different localities from which trees were selected for stripping. The bark weight equations permit the accurate determination of bark yields for research and management purposes. It is proved that indiscriminate application of bark weight tables to territories for which they were not prepared originally may lead to serious errors.

Summary Regression equations are derived in which relationships are established between stand density, crown size and basal area growth in pure, even-aged stands of P. taeda L. in the Piedmont of North Carolina, U.S.A. The findings are based on observations on 129 tenth-acre sample plots of variable stocking, age and site index. It is shown that: Single trees of given d. b.h. make more than twice as much basal area growth when basal area per acre is 60 square feet as when basal area is 140 square feet. Single trees of large diameters may make more than twice as much basal area growth as trees of relatively small diameters when basal area per acre is fixed. Basal area growth per acre generally increases as stocking in basal area declines from 140 to 60 square feet per acre. However, basal area growth per acre at relatively high stockings may be greater than basal area increment at lower stockings when the average d.b.h. of the trees at the high basal area is comparatively small. Basal area growth per acre ...

Studies were undertaken to obtain preliminary information on the availability of Zn sorbed by hydrated Fe oxides as a source of Zn for plants. The results presented suggest that Zn bound to hydrated Fe oxides in soils, through the medium of polyvalent phosphate ions, is unavailable to plants. In the absence of phosphate ions, only the more strongly-crystalline hydrated Fe oxides, such as goethite, fix Zn against plant uptake.

Summary The demand for wattle timber is increasing and reliable volume tables are needed. A timber volume table and alinement chart for Acacia mollissima Willd. in the Eastern Districts of Southern Rhodesia are presented in this paper. The mathematical relationship between timber volume and bark weight per tree was established. Regressions were fitted by the method of least squares.

Summary A brief review is first given of a few practical ways of regulating and expressing stand density. An illustration is then given of the application in even-aged stands of Pinus taeda in the native habitat of this species of a regression equation in which stocking is expressed in terms of number of trees per unit of area and total basal area. Not only does the equation permit the expression of the density of anyone plot as a percentage of the average stocking of a number of sample areas, but it enables the research worker to determine the ground area occupied by a tree of given size in the overstory or in the understory. Graphs are presented which illustrate the application of the tree-area equation, as this “stocking norm” is called.

A simplified model of the radiative decays of pseudoscalar and vector-mesons is investigated in the framework of a three-particle formalism for unstable composite particles in order to illustrate the role that unstable particles may play in providing information on the question of constituents of bosons.

A rapid procedure developed for the preliminary purification of soil extracts and plant digests preceding the polarographic determination of zinc is described. The procedure meets the necessary requirements of precision and when used in conjunction with the polarographic procedure described by Barrows and Drossdoff (1960), proved desirable for routine analysis involving large numbers of soil or plant samples.

Summary Research and development of adhesives and timber connectors have made it possible to extend the use of wood as an engineering material. The utilization of wood as a structural material is no longer confined to sizes and lengths of existing supplies. The Department of Forestry has applied some of the latest timber engineering techniques in the design and construction of large wood structures—where in the past use had only been made of steel and/or reinforced concrete—such as laminated roof trusses and bridges, examples of which are to be seen at the Weza and Blyde State Sawmills.

Most preparations of infectious virus nucleic acids retain only about 0.1% or less of the infectivity of the original virus material. This is not necessarily the result of destruction of much of the intact nucleic acid during chemical procedures, but may be due to the insensitivity of the assay methods employed (Holland et al. 1961; Tovell & Colter, 1967). For the titration of infectious DNA obtained from polyoma virus, one of the methods in current use requires the direct plating of DNA in 0.55 m-NaCl on the monolayers of mouse embryo cells (Weil, 1961). This procedure has the disadvantage that the cell damage caused by the hypertonic NaCl renders accurate plaque counts difficult. A more recently described method (Warren & Thorne, 1968) avoids this complication by infecting monolayers in the presence of diethylaminoethyldextran (DEAE-dextran) in an isotonic medium.

The possible effect of a cosmological background (such as proton-neutron preponderance) on the meaning of time"reversal violation is discussed in the context of the Dürr-Heisenberg degenerate vacuum theory of strangeness.

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