Hydraulic Embolisms
Air bubbles that form in a tree's water-conducting vessels during drought, blocking water flow and causing the tree to die of thirst.
Air pockets that form inside a plant's xylem (water-conducting tissue) when water stress causes the water column to break. Once formed, these bubbles prevent water from moving upward through the plant, eventually leading to tissue death. Common during severe drought when soil water becomes scarce.
What this means in real life
During a prolonged dry spell, a tree's roots cannot pull enough water from parched soil. The water inside its trunk snaps under tension, creating air bubbles that seal off the remaining water below—like a broken straw that can no longer deliver water to the leaves.
What it isn’t
Not simply a tree running out of water. The tree may have water in its roots, but the air bubbles physically block the pathway, making that water unreachable—a plumbing failure, not a supply shortage.
Commonly misused online
Often conflated with general 'tree death from drought' on social media, when in fact it's a specific hydraulic mechanism. Some posts treat it as synonymous with any tree mortality during dry periods, missing the distinction.