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SYNOPSISRates of litter fall in mature stands of Pinus radiata D. Don have been monitored at the Jonkershoek Forestry Research Station since 1976. Decomposition trials were laid out in June 1977. Litter fall has been collected on six sites in the Bosboukloof experimental catchment, subdivided into its constituent components, and each component examined for production and annual variation. Total annual litter fall for Bosboukloof is estimated at 3 721 kg/ha. Of this, needle fall constitutes 2 645 kg/ha or 71 %. Seasonality of some components is very marked but difficult to express quantitatively. An harmonic analysis on needle fall is included.Rates of litter decomposition have been monitored by means of needle samples in glass-fibre and shade-cloth mesh bags, and branches and cones pegged out in the field. The mass loss for needles after two years was between 40 and 50 %, that for branches 10 %, and that for cones 3,5 %. The mass of accumulated litter on the forest floor has also been sampled to obtain an estimate of turnover.The few chemical analyses which have been done indicate N, Ca, and Mg to be the most abundant elements in needle fall with a return to the forest floor of 17, 12 and 7 kg/ha respectively over one year. No significant seasonal variation in the nutrient content of returning needles was found. A further paper will be required to detail the results of nutrient analyses once these are complete.

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SYNOPSISFast-growing plantations of conifers have replaced areas of mediterranean shrubland in the south-western Cape. This study arises from the need to quantify the impacts of major changes in primary productivity, litterfall, and nutrient cycling in terms of the site utilisation and long-term productivity.Litterfall and decomposition were measured over five years in a catchment under mature Pinus radiata in the Jonkershoek valley near Stellenbosch, with seasonality and nutrient cycling rates assessed for the plantation ecosystem. Data are presented for all components of litterfall including needles, strobili, pollen, seed, bark, branches and cones. Total means annuallitterfall amounted to 3270 kg/ha per annum, of which needles accounted for 76,7 % or 2825 kg/ha, and strobili 8 % (295 kg/ha). Decomposition of needles is at least 50 % after three years and litter accumulation is limited.All components of litterfall have been analysed for nutrient content on at least an annual basis, with detailed seasonal studies of needle litter. Values of N, P, and K at 0,64 %, 0,03 % and 0,29 % of needle mass respectively, are about 50 % of those for fresh needles. The total annual return of nutrients to the forest floor in litter is 26,1 kg of N, 1,5 kg of P, and 10,5 kg of K. Values are also tabulated for Ca, Mg, and the trace elements. The importance of N, P and K in the litter cycle is compared to amounts in standing trees and extracted timber. P. radiata shows an ability to cycle its nutrients very rapidly which may account for its success on nutrient-poor sites.

SYNOPSISForestry is an important user of water. Itis also, in the eyes of some, an efficient user -and it is undoubtedly a nationally important industry.As pressures for the water resources increase, the forest industry finds itselfranged more and more frequently against both accustomed and previously less recognised users. Industrial and agricultural demands are growing, the needs of the environment are no longer ignored, and rural communities dependent on local water sources have at last found a champion. The consequence has been confusion as much as conflict, with understanding perhaps a bigger problem than knowledge. Far reaching modifications in the exercise of control over new afforestation were imposed early in 1995, and these are shaking out as government moves towards a broadly based national forestry policy.It would seem to be policy in practice that research is no longer needed to prove that trees use water (vide the demise of catchment research experiments), and efforts are now being aimed at the search for solutions. A number of approaches present themselves immediately. The country's goal with regard to timber production must be clearly and honestly spelt out, and must be reconciled with its need for water. Strategic planning must be integrated! So too should regions be assessed on a strategic basis, with decisions driven at national, regional and even quaternary catchment level.

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