An observational study into the recovery of grapevines (Vitis vinifera L.) following a bushfire

Bushfires occur worldwide, including regions in which winegrapes are grown. Recent research on grape and wine composition has demonstrated that wine made from smoke-affected grapes can be tainted. However, little is known about the impact of fire on grapevines, in particular the growth and recovery of grapevines scorched during a bushfire. In 2008, a vineyard in the southern Adelaide Hills region of South Australia was partially burned by a bushfire. Vegetative and reproductive measurements were taken for two cultivars, Pinot noir and Semillon (Vitis vinifera L.), in the subsequent growing seasons to compare the growth and development of scorched and unscorched vines. Reductions in shoot number, bunch number, bunch weight, pruning weight, and yield were observed for scorched vines compared with unscorched vines, in the season following the fire, but both cultivars showed improved signs of recovery two seasons after fire damage occurred. Fire-damaged vines produced lower crop yields due to decreased fruitfulness and berry numbers, and in the season after the bushfire, shoot development was mostly from buds located on the cordon, rather than buds of specific nodes retained after pruning. Elemental analysis of leaf tissue and juice was performed using inductively coupled plasma–optical emission spectrometry, but few meaningful compositional differences were observed. Smoke-derived volatile phenols and guaiacol glycoconjugates were also quantified by gas chromatography–mass spectrometry and high-performance–tandem mass spectrometry, respectively, to investigate the potential carryover of smoke taint between seasons. However, there was no evidence of sequestration of smoke components. Research findings will enable grapegrowers to facilitate the recovery of fire-damaged vines in subsequent seasons through modification of viticultural management practices, including pruning strategies such as retraining the cordon using cane-pruning techniques or leaving longer, more fruitful bearers to increase node number retained after pruning.

Cassandra Collins, Han Gao, and Kerry L. Wilkinson