Lost in the haze: Persistent mega-fire smoke exposure jeopardizes tree carbohydrate reserves and yield

Abstract The global incidence of megafires is on the rise, leading to extensive areas being shrouded in dense smoke for prolonged periods, spanning days or weeks. By integrating, long-term, regional observations of non-structural carbohydrate content in trees with spatiotemporal satellite data, we present compelling evidence of the pronounced impact of dense smoke plumes on carbohydrate stores in trees. Our findings show that the presence of smoke causes a significant decrease in total non-structural carbohydrates, with decreases in the accumulation of both soluble sugar and starch reserves. This decline in carbohydrate levels persists through the trees’ dormancy period into the next season’s bloom, culminating in a reduced yield. Our results highlight a previously unrecognized wildfire threat that could affect plant health and ecosystem stability in both agricultural and natural environments.