Grove management
Most of the fire-damaged trees were pollarded at five foot high to enable management of the shoots from the ground as they regrew.
Bushfire recovery two years on In the March 2020 edition we shared the experiences of two South Australian growers whose groves had been impacted by the devastating 2019-20 Cudlee Creek bushfire. The worst affected was Ron and Ethne Baker’s Woodside Farm, with nearly half of the 6400-tree grove heat-effected and 50km of irrigation destroyed. We followed up in the September 2020 edition, reporting on progress at Woodside Farm nine months after the fire via from observation and discussion during an Olives SA field day. In late November 2021 another field visit was held at the grove, providing an update on progress after another year of growth and grove maintenance.
Grove observations and discussion: November 2021
Overview At the time of the latest field visit almost two years had passed since the bushfire in late December 2019. As it was an extremely hot grass fire, not a crown burn, the trees were heat-affected rather than destroyed: the leaves were brown and dead but the trunk and main branches appeared to be okay. It was hoped the damaged trees could be saved so they prioritised getting water back onto the grove. The massive task was achieved in just two weeks thanks to a working bee by fellow Olives SA volunteers. Knowing the fire would stimulate shooting
all over the trees, the Bakers decided to cut all the badly heat-affected trunks off at 5ft (1.5m) to keep the re-growth manageable. From there the plan was for selective re-shooting over two years and hopefully a crop in the third year. On some of the trees, however, the bark had ‘cooked’ and the intense temperature had damaged the trunk down to ground level. Where no signs of regrowth occurred, these trees were later cut further to a sixinch stump and are being re-established from basal suckers. They weren’t grafted, so there’s no risk that the re-growth is root stock. Around 400 of the most severely burned trees were also removed immediately and have since been replaced. Regrowth Many of the pollarded trees have shot from both the branches and the base, others from the base only, and many of those have also shot from the roots. Of those coppiced at ground level, some have grown their new trunks from the roots. These are stronger, as they’ve grown a full heel, while those grown from the trunk often have weaker joins. It was noted that the trees which have shot
34 • Australian & New Zealand Olivegrower & Processor • March 2022 • Issue 123
from the base will be the best in the long term, in practice creating a new tree on old, established root-stock. Overall, most of the damaged trees are doing well and the two-year-old regrowth on some has already created a new, well foliaged (small) tree. Very few have died, however the regrowth on a small number is very weak, so they will also be pulled and replaced. While it was worth trying to preserve them for a faster new crop, it doesn’t always work, and some trees were obviously more damaged than was outwardly visible. Varietal differences In the recovery phase, it’s been noted that Barnea is softer wood, so rots easily. The Mediterranean varieties are very hard and less susceptible to rot. In the initial stages the Coratina trees survived the fire better, followed by the Frantoio and then the Leccino. The latter weren’t doing particularly well, and it was expected that most of them would eventually die. With more time, however, the Leccino have shown the best response in terms of
