C. de Ronde

The Resistance of Pinus Species to Fire Damage

SYNOPSIS Differences have been observed in the resistance to fire of Pinus species in the Cape Province. This information was used to draw up a species-specific fire damage classification. The classification can be used to advantage after controlled burning exercises in pine stands and after the occurrence of wild-fires.

Controlled Burning in Pine Stands in the Cape: The Influence of Crown Scorch on Tree Growth and Litterfall

SYNOPSIS Results from controlled burning trials in Pinus elliottii and P. pinaster stands of the Cape indicate that burning has no significant effect on tree growth two years after burning, provided crown scorch is avoided or at least limited to the lowest living branches. Where serious crown scorch occurred in these trials, it had a detrimental effect on tree growth and caused excessive needle fall as a result of which some of the benefit of litter reduction by fire was lost.

Phosphate Fertilisation of Mature Pinus radiata Stands

SYNOPSIS The response of mature Pinus radiata (16–20 years old) to phosphate fertilisation was highly significant, resulting in a potential increase in volume at 35 years of age of between 44 and 130 m3 per hectare, depending on site Conditions. These responses have been recorded on different soil forms and types. Gains from phosphorus application were economically viable and it appears that between 35–60 kg per hectare P applied to P-deficient mature P. radiata is the optimum economic application rate. Further growth responses are expected on the better Sites With a subsequent nitrogen top dressing.

Litter Accumulation Problems Identified in P. Pinaster Stands of the Cape Province

SYNOPSIS Litter loading in first rotation P. pinaster stands on high quality sites can increase by more than 4 t/ha a year and early results indicate that this accumulation continues in second rotation stands. The accumulation of litter aggravates the fire hazards and increased problems with accessibility will make silvicultural treatments more expensive. Nutritional problems may also develop on marginal sites. Where these problems have been identified, serious consideration should be given to litter reduction by the use of controlled burning.

Observations of Damage of a Secondary Nature Following a Wild Fire at the Otterford State Forest

SYNOPSIS An inspection of stands damaged in the wild fire that occurred during October 1984 revealed that trees seriously damaged and still growing under severe stress are exposed to attack of a secondary nature in the form of the fungus Rhizina undulata, the bark beetle Ips erosus and Cerambycid beetles.

The Effects of Different Intensities of Pruning on the Growth of Pinus radiata in South Africa

SYNOPSIS Five pruning schedules were tested using a Latin Square design at the Stormsriver State Forest, Tsitsikamma Forest Region. Treatments included those standard at the time and combinations of prunings at earlier ages or to greater heights. The severity of each pruning regime was expressed with a severity index factor which incorporates the percentage live crown removed, age and mean tree height. Volume increment loss (as much as 16,7%) and the extent of epicormic shoot development were significantly correlated with the index factor. It is concluded that severe pruning of Pinus radiata leads to loss of growth and stimulation of epicormic shoot development. Recommendations are made for an improved pruning regime.

History, Distribution and Treatment of Manganese Deficient Pinus radiata

SYNOPSIS Manganese deficiency has been reported from 24 isolated sites in the southern and western Cape. The history, distribution and treatment of deficient areas is discussed. A decision table to facilitate judgement on fertiliser application shows foliar analysis and soil morphology can provide an adequate diagnosis of responsive sites.

Evaluation of Wildfire Damage in Pine Stands

During 1984 two wildfires burned through 2 585 ha of pine stands in the Cape Province. Fire damage evaluation methods, based on experience gained in controlled burning research, were tested. The re...

Spatial Variation of Forest Floor Loading in Pine Stands of the Tsitsikamma

SYNOPSIS A lack of litter breakdown was recorded in Pinus taeda stands on the Tsitsikamma plateau, particularly in humus layers. A total litter mass of 195 t/ha was recorded in these stands. Litter was also significantly more compacted in these stands, and a lack of fungal occurrence was recorded. Accumulation of humus was also observed in Pinus elliottii and Pinus pinaster stands, but total litter loading there did not exceed 82 t/ha, In contrast, decomposition of Pinus radiata litter was adequate. Slash burning after clearfelling is recommended in these pine stands, except for P. radiata.

The Response of Pinus radiata to Manganese Applications at the Ruitersbos State Forest

SYNOPSIS Although ranked as a minor nutritional problem when compared to the serious phosphate shortages in the Cape forest regions, manganese deficiencies are recorded from time to time, and growth losses have been recorded in P. radiata. Species such as P. pinaster and P. elliottii only show yellowing of needles where extreme deficiencies occur. P. radiata recovers where marginal manganese deficiencies are present, but completely stagnates and eventually dies where deficiencies are more serious. Treament of P. radiata in the nursery before field planting and after establishment is discussed and recommendations are made to prevent or cure disorders.