Long-term exposure to wildfire smoke may deplete the energy reserves of California’s orchard trees and reduce nut production by up to 50%, according to a study published in Nature Plants. Smoke affects trees for months after mega-fires. It impacts seasonal blooms and harvests.

University of California, Davis researcher Jessica Orozco led research that concluded trees are like humans. They are vulnerable to smoke.

The study focused on almond, pistachio and walnut trees in California’s Central Valley from 2018 to 2022. Smoke particles interfere with photosynthesis by blocking sunlight and reflecting light. This limits carbohydrate storage, which is essential for tree survival. Wildfires that are active when trees store energy for winter further exacerbate the issue.

Nut yields declined by 15 to 50% in affected orchards. Researchers observed persistent exposure to smoke caused a significant drop in energy reserves and tree productivity, though they remain unsure of the exact smoke components responsible.

Read more about the impact of wildfires on tree nut yields here.