Followmg a hail storm in the southern Cape Province of South Africa, about 2000 ha of pine plantations were infected by Sphaeropsis sapinea. The timber loss due to S. sapinea infection in compartments prematurely clearfelled was about 28 % of volume and 55 % of value of potential production. Total predicted volume of timber lost in compartments not felled prematurely was an average of 11.4%. Percentage volume lost increased with age, with the greatest losses being recorded on good quality sites.

SYNOPSISThe maturation and ageing effects of parent or donor plants have been reported to have both positive and negative influences on the performance of rooted cuttings. A general decline in rooting ability, root quality and speed of rooting in the nursery, and a reduction in tree survival, growth and form in the field, have been associated with donor plants that have reached a state of reproductive or ontogenetic maturity. Increased maturation has also been shown to affect wood quality negatively. Provided that donor plants are still relatively young, positive effects from increased donor age have been observed through an improvement in tree form and branching habit, as well as a reduction in bark thickness and stem taper. These improvements have resulted in increased timber yields over seedlings of the same genetic origin. This report summarises current understanding of the effects of donor maturation.

Following a hail storm in the southern Cape Province of South Africa, Sphaeropsis sapinea infected about 2000 ha of pme plantations. A series of sample plots yielded information on symptom development in relation to site factors and stand characteristics. Aerial photography and ground inspection of the area showed that, although the intensity of disease was not affected by site quality or age, it was inversely proportional to altitude.

A study was established in the southern Cape Province, South Africa, to examine survival and growth in response to seedling grade and various methods of site preparation. Second-year performance was examined in relation to (i) initial groundline diameter, (ii) intensity of weed control, and (iii) method of soil cultivation. Weeds were controlled with (i) manual release 1 year after planting (the standard method used by the Department of Water Affairs and Forestry) or (ii) total weed control for 1 year involving the use of herbicides and additional hoeing. Soil cultivation treatments included (i) pitting by hand, (ii) pitting with a mechanical auger, (iii) ripping, and (iv) ripping plus disking. The influence of initial seedling diameter on survival was significant. Seedlings with a 2-mm groundline diameter averaged 62% survival, whereas 5-mm seedlings averaged 85% survival. Use of large-diameter stock improved survival regardless of soil cultivation or weed control treatments. For survival, there was an interaction between soil cultivation treatments and the use of herbicides. Total weed control with herbicides and hoeing improved survival for plots that received ripping or disking treatments. However, seedling survival was decreased where herbicides were used on plots where pits were used. On average, seedlings with larger diameters grew better than those with smaller diameters. However, small-diameter seedlings with total weed control grew better than large-diameter seedlings with standard weed control. Average seedling volume after 2 years was 33% greater for high-grade seedlings (2.4 dm3) than for low-grade seedlings (1.8 dm3). However, there were interactions between soil cultivation and weed control treatments for height and diameter growth. With the standard method of weed control, ripping improved height and diameter growth. Total weed control with herbicides and hoeing greatly improved growth for all treatments, and as a result, little or no differences in average seedling volume were observed between pitting and ripping treatments.

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