Suraj Kar, Ricky W. Clark, Joseph B. DeShields, Ian Ivey, Cole Cerrato, Elizabeth Tomasino, and Alexander D. Levin*
*Oregon State University, Southern Oregon Research & Extension Center, 569 Hanley Road, Central Point, OR, 97502 (alexander.levin@oregonstate.edu)

Changing climate is increasing wildfire events across the United States, exposing some of the most productive vineyard regions of the world to wildfire smoke. Wildfire smoke contains thousands of chemical compounds that can diminish growth and productivity of grapevines, delay ripening, and impart an offensive flavor in wine referred to as “smoke taint.” However, these effects are contingent upon numerous factors, including time and distance of the smoke event, smoke concentration, fuel type, and growth stage of the vine. Field experiments involving custom-built smoking chambers, described in previous research, have provided inadequate information on how to simulate a natural wildfire event and achieve a predetermined smoke concentration within these chambers. Therefore, a field trial was conducted at the Southern Oregon Research and Extension Center in the Rogue Valley AVA, where chambers constructed from PVC frames and covered with transparent plastic sheets were used to cage six vines within a vineyard row. Smoke was generated by burning Douglas fir pellets in a battery-operated grill and channeled into the chambers, with smoke treatments including an open-air control, a chamber control, and two levels of smoke treatments (low and high PM 2.5 at 1200 and 4000 µg/m3, respectively), to mimic typical concentrations recorded during low and moderate smoke years, converted over a two-hour period. A battery-operated mixing fan was installed inside each smoking chamber to distribute smoke evenly and regulate vine stomatal action. Smoke levels inside the chambers were monitored in real time using an air quality monitor and were regulated using valves attached to inlet tubes. Stable predetermined smoke concentrations were achieved inside chambers within 20 min of experiment initiation. Temperature and relative humidity inside the chambers were monitored in real time with sensors. This research highlights key technical challenges for simulating wildfire smoke events at a vineyard scale and demonstrates methods to achieve this goal.

Funding Support: USDA-NIFA-SCRI