pgbison2
Case study

Disaster recovery action reduces risk of loss

High barriers
to entry
Scarce raw
materials
A total plantation area of 4 456 hectares was damaged, amounting to 403 777 m³ of timber that potentially needed to be harvested.
A full assessment of damage was done within 24 hours from the fire being contained.

Located in the Knysna district, PG Bison’s southern Cape commercial plantation (SCF) spans a total area of 19 936 hectares, of which 10 508 hectares is planted with pine trees. The objective of the plantation is to optimise the production of pine saw timber for logs supplied to the group’s Thesen sawmill, situated in the southern Cape province of South Africa, and also to maximise the production of building and fencing poles for delivery to Woodline, PG Bison’s nearby pole treating plant.

Although SCF is situated in a coastal area with a lower risk exposure to fires and subsequent damages, fire risk – especially during unfavourable weather conditions – remains a threat.

In the early morning of 7 June 2017, several fires entered the company’s plantations from neighbouring properties.

Due to very strong winds, high temperatures and severe drought conditions, the fires could not be contained and they spread through SCF landholding. Two days after they started, a 100 km/h wind shifted the fires’ direction. Two fires raged simultaneously across an extended area, causing damage to numerous properties over a span of 80 km before being contained after four days.

Impact
Determining the impact of the fire and deciding when to harvest the trees is of great financial and economic importance. The objective is to salvage all pine timber that can still be used in the shortest possible time, before it deteriorates and becomes unusable because of damage by fungi and insect borers.

The fire damage was assessed and certified based on the severity of the damage to cambium (tissue layer beneath the bark); needle scorch; live crown; and root damage due to ground fire intensity. A harvesting priority rating was put in place to determine the sequence in which to harvest the different compartments of damaged trees. A continued monitoring programme was also put in place to check and adjust the harvesting priority, should anything change.

Salvage
A plan is in place to salvage 70% to 80% of all trees older than 10 years. To ensure that the harvesting process is completed in the shortest possible time, assistant teams have been deployed from operations in KwaZulu-Natal, Mpumalanga and Ugie. A total volume of 130 000 m3 will be harvested within 14 months after the fire and the timber will be used by the Thesens sawmill, Woodline and other customers.

The rest of the timber that cannot be used immediately by the processing plants (estimated at about 250 000 m³), will be stored in a wet deck preservation system positioned close to the harvested areas. Logs from the preservation deck will supply the operations with their raw material requirements for the next two years.

The estimated damage of R200 million was reduced by R160 million as a result of the salvage procedures described above, with the balance being covered by insurance.

Preservation
Logs are stacked in a continuous pile of 5 m high, 28 m wide and 3 km long. This deck of logs will be under irrigation to preserve the timber for use. The continuous wetting of the logs will create a shortage of oxygen in the wood to prevent fungi from entering and damaging the timber.

Groundwater has been identified as a viable option to keep the wet deck irrigated and will be supplied from an unpotable borehole field, to be developed for this purpose. A geophysical survey of the proposed area was done to select the most productive ground formations for borehole development and drilling. Borehole positions were identified, drilled and yield-tested to determine their consistency in discharge and recovery rate, to manage the well-field and pumping regime from the boreholes. Ongoing groundwater monitoring will be done to ensure sustainable use of the resource through optimal abstraction.

Replanting
It is estimated that the damaged area will be replanted over a three-year period, and a Pinus radiata seed source has been identified to supply the seedling quota required for this process. SCF’s own nursery capacity will be supplemented by nurseries from North East Cape Forest (NECF) in Ugie and two other nurseries in the immediate vicinity.

The future
The effects of the fires will be felt for several years and will change the face of the forestry and sawmilling industry in the southern Cape.

Our management teams are formulating plans to further optimise resources and to mitigate against the longer term impact of the fires.

Start typing and press Enter to search