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-8-This summer, many parts of Australia experienced unprecedented forest fires on a massive scale, killing firefighters in New South Wales and causing major evacuations. The fires were triggered by heat waves above 40°C in extremely dry areas that haven’t had any rain for several years.Bush fires are a common occurrence in Australia. The public is educated about fire safety while still at school in outdoor education classes, including responding quickly to lightning strikes, making sure empty bottles aren’t left lying around because sunlight refracted through glass can start a fire, and the banning of outdoor fires. In addition, there are planned burn-offs to prevent large-scale fires, and people are taught how to deal with fires. However, a major fire in Victoria in 2009 was the sign of their growing impact.◆The impact on VineyardsOn 7 January this year, Wine Australia CEO Andreas Clark said vineyards and wineries in South Australia, New South Wales, Victoria and Queensland had suffered considerable damage, but that it would take several weeks to get the full picture, as most of the fires were in heavily forested areas and national parks. The worst-case scenario is that up to 1,500 hectares vineyards may be damaged, which is 1 per cent of all vineyards in Australia. However, even within this 1 per cent, not all vineyards will be damaged and unproductive.The impact of bushfires on vineyards is complex, ranging from burning vines and fire damage to smoke taint. It depends on each vineyard’s circumstances. You can clearly see the damage when leaves are dead or the bark is scorched, but vines can also be seriously damaged by radiant heat without any external evidence showing. If the thin tissue just below the outer bark (the layer that forms the annual rings) is alive, the vine will regenerate, but if it is dry and brown the tissue will die and won’t regenerate. If only one side of the vine is burnt and one side is okay, shoots will grow from the tip, but as the core of the vine is partially dead, that part will rot or termites may set in. If the buds survive in the ground they may regenerate, but they will not recover if they are dead.Wine growers have difficult decisions to make in affected vineyards, when many factors affecting the vines’ vitality are still unknown. They range from pruning as normal for the next growing season, pruning the whole vine and waiting for the shoots to emerge, or even replanting the vineyard.◆ Smoke damage Another major problem is smoke taint from the fire in the grapes. Smoke taint takes the form of burnt, bacon, and creosote-like medicinal odours that aren’t found in normal wines and are generally unpleasant. The main component associated with this odour is volatile phenol, which is synthesized by burning lignin in trees, and is released into the atmosphere in large quantities in large-scale fires. The compound enters the grape berry from the waxy cuticle that lines the pericarp, reacts and binds rapidly with the sugars of the fruit, causing smoke taint.The extent to which vines are exposed to smoke increases the risk of developing smoke taint. It depends on the stage of grape berry development, varietal, smoke intensity, amount of time spent exposed to smoke, as well as the concentration of phenol and compounds in the smoke. The closer the grape is to the harvest season, the higher the risk of smoke taint. There are differences between varietals, influenced by factors such as the thickness of the pericarp. In addition, smoke compounds are diffused into the atmosphere, so the concentration of volatile phenol is higher closer to the actual fire. However, although the concentration of specific substances in smoke can be measured, the measurement values don’t necessary correlate directly to the level of smoke taint, and many unknowns remain to enable accurate analysis.◆ In the wineryAdelaide Hills suffered heavy damage in the latest fires, with one-third of the area affected by fire in December 2019. This area included the vineyards of Mike Press Wines which Village Cellars distributes in Japan. Currently there is no clear assessment of the damage to vineyards in this area. Fortunately, the damage to Mike Press Wines was minimal, only affecting fences and irrigation equipment. They have now resumed operations and report the vineyards are healthy and can be expected to produce in 2020. As of January 2020, the fruit was still immature, the size of a bean grain and firm.“Fires are a common occurrence, but sometimes the negative effects of fires are exaggerated, especially by those without scientific knowledge,” says owner-winemaker Mike Press, who has worked in the wine industry for many years. “Susceptibility to smoke damage is highest when a fire occurs close to harvest time, and the grapes are ripe.” Fortunately for Mike Press, the berries were very immature, so he expects the effects of smoke to be minimal. It is said smoke damage can be clearly identified during the fermentation and winemaking. Applying this, Mike Press will manage the production of possible smoke-affected wines in two steps: (1) At veraison, when grapes begin to ripen and the skin changes colour, a selection of grapes from each block will be harvested early, fermented, and tested for smoke taint. (2) The wine will be sent to AWRI, for chemical analysis to determine if the precursors for smoke taint are present. Even if the aroma and flavour show no taint while young, the presence of chemicals can cause smoke taint to appear as the wine ages.By way of contrast to Mike Press Wines, on 14th January, Tahbilk in Nagambie Lakes, Victoria, was hundreds of kilometers away from the largest wildfire, and the smoke from the fires had already blown over. Veraison had yet to begin, so the grape flavours and quality won’t be impacted. However, with rainfall below average, the focus is on irrigation management. Like other vineyards in Australia, we expect the yield to be below average because of the very hot, dry, windy weather, and few frosts in early spring. Also, many employees are volunteers at local fire brigades, and were helping out in affected winegrowing areas, so there has been a struggle to find enough staff.As well as deaths and injuries to people from the fires, large-scale loss of wildlife including koalas was reported, with surviving wildlife rescued and treated, and vegetables dropped from helicopters to feed them. As smoke from the inland fires blanketed coastal cities such as Sydney, fund-raising campaigns were launched to support the various wildlife rescue activities. With global warming in mind, deep consideration of future conservation measures is also expected.photo: Courtesy Eden Hills Country Fire ServiceSupported by: Australian Red Cross: https://www.redcross.org.au/campaigns/disaster-relief-and-recoveryWWF: https://www.wwf.org.au/get-involved/bushre-emergency#gs.qwpyqjMike Press Wines: MPW Adelaide Hills Fire PR-January 2020 http://www.village-cellars.co.jp/pdf/news/MPW_AdelaideHillsFirePR_Jan2020.pdfReferences:Wine Australia: https://www.wineaustralia.com/news/media-releases/bushres-draw-australian-wine-sector-closerAustralian Wine Research Institute: https://www.awri.com.au/industry_support/winemaking_resources/smoke-taint/https://www.awri.com.au/wp-content/uploads/grapevine_recovery.pdfVictoria State Government Agriculture Victoria: http: //agriculture.vic.gov.au/agriculture/horticulture/wine-and-grapes/options-for-managing-re-damaged-grapevinesBBC NEWS JAPAN: https://www.bbc. com / japanese / video-51115829The Australian bushfires and smoke damage

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