Many trees are dying primarily due to prolonged and frequent periods of drought, which leads to a critical condition known as hydraulic failure.
While various factors can impact tree health, one significant cause for the increase in dead trees, as highlighted by research, is the impact of changing climate patterns, specifically drought.
The Impact of Drought on Tree Survival
Trees, like all living organisms, require water to survive. Many tree species possess natural defenses and adaptations to endure typical dry spells. However, the increasing intensity and duration of dry periods overwhelm these natural capabilities.
- Frequent and Lengthy Drought: When periods of drought become more frequent and lengthy, trees face extended periods without adequate water supply. This sustained lack of water stresses the trees beyond their ability to recover naturally.
- Hydraulic Failure: During prolonged or severe drought, the lack of water leads to a phenomenon called hydraulic failure. The water transport system within the tree, responsible for moving water from the roots to the leaves, essentially breaks down. Air bubbles can form, blocking the flow of water, similar to how air gets into a pipe.
This hydraulic failure prevents the tree from getting the water it needs for essential functions, such as photosynthesis and maintaining structural integrity. This lack of water transport hastens their decline and eventual death.
In summary: The increased frequency and length of drought periods are key drivers behind the rise in dead trees because they induce severe water stress and cause the tree's internal water transport system to fail.
