Mechanisms Linking Water Stress, Hydraulic Failure, Carbon Starvation And Tree Mortality

Increasing occurrences of drought induced and forest mortality have incited worldwide scientific discussions about how exactly heat kills trees and thcir mechanisms. Drought affects both trcc hydraulics and carbon balance for trees respond to decreasing water stress and declines in leaf turgor with decreasing in stomatal conductance, thereby reduction in C assimilation rates. In the early drought conditions, the hydraulic failure associated with stomatal closure occurs, as such conditions persist. Stored carbon may then be mobilized to meet metabolic needs until reserves are depleted and tree species die from carbon starvation. Therefore, in the absence of catastrophic hydraulic failure, phloem functioning will be negatively affected also and the regulation of water loss from trees during water deficit may lead to an increased likelihood of mortality through the depletion of carbohydrate reserves used in respiration. Here, we summarized recent progresses in our understanding of mechanisms linking water stress, hydraulic failure, carbon starvation and tree mortality, the definitions and functions.