Using UAV-based remote sensing to assess grapevine canopy damage due to fire smoke

Area of Science:

• Viticulture
• Plant Physiology
• Remote Sensing

Background:

• Bushfires increasingly threaten the wine sector, causing grape and vine losses and smoke taint.
• Volatile phenols from smoke contaminate wine by absorption into plants and berries, impacting vine physiology.
• Assessing smoke-induced vine damage is crucial for mitigating economic impacts on viticulture.

Purpose of the Study:

• To investigate the use of unmanned aerial vehicle (UAV)-based visible images for studying smoke-affected vine physiology.
• To assess the efficacy of UAV-based imagery in quantifying vineyard damage and vine compromise due to smoke exposure.
• To establish a novel method for evaluating physiological responses and damage in grapevines exposed to wildfire smoke.

Main Methods:

• Procanico grapevines were subjected to two smoke treatments administered one week apart.
• Physiological parameters including gas exchange and leaf biochemical traits were measured at short-term (30 min) and long-term (24 h) intervals post-exposure.
• Canopy damage was evaluated using conventional vegetation indices (VIs) and a new index, the Canopy Area Health Index (CAHI), derived from UAV-based visible images.

Main Results:

• Initial smoke exposure caused a temporary reduction in gas exchange, with vines recovering within 24 hours.
• A second smoke exposure resulted in an irreversible decline in functional vine parameters.
• Vegetation indices showed significant differences, while the CAHI effectively mapped a damage gradient correlated with bushfire proximity.

Conclusions:

• UAV-based visible imaging provides a valuable tool for assessing physiological activity in smoke-affected vines.
• This technology enables quantification of vine losses, distinguishing between destroyed and damaged grapevines.
• The Canopy Area Health Index (CAHI) demonstrates potential for detailed vineyard damage assessment following smoke events.