Linfield University Wine Studies Reports

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This report describes the impacts of climate and phenology on vintage for the Umpqua Valley in Oregon in 2020. A mild and dry winter in 2019-20 was followed by a dry growing season continuing the ongoing drought concerns for Oregon and the majority of the western US. The spring was relatively cool in the Umpqua Valley with mild frosts into mid-April, then followed by wide swings between early season heat then cool, wet conditions leading up to and during flowering. The result was widespread issues with fruit set leading to generally high amounts of shatter, smaller berries and clusters for many in the region. Heat stress during the summer was moderate, leading into what looked like a decent September weatherwise until the Labor Day extreme wind event, which was followed by catastrophic fires and smoke for days. Growing degree-day totals for the Umpqua Valley in 2020 ended up moderately higher than the previous vintage and above the average of the last 15 years. Across sites and varieties in the region the phenological timing averaged April 14th for bud break, June 11th for bloom, August 18th for véraison, and October 2nd for harvest. Growers reported generally low disease pressure, relatively low pest pressure, variable bird pressure with greatest impact at higher elevation and for late picked varieties, and a harvest that presented very good quality fruit at moderate to substantially lower yields due to bloom to fruit set weather conditions.


This research was made possible by funding from the Umpqua Valley Winegrowers Association. In addition, acknowledgement goes to each of the participating vineyards, whose collaborative support provides the framework for the research.



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