The damage usually shows up as browned needles and leaves, dead branch tips, delayed leaf-out, or even dieback.
Anatomy of a tree during too-dry Winters
During dry spells, a tree’s anatomy works overtime to conserve water and survive stress. The roots are the first line of defense, stretching outward and downward in search of moisture; fine feeder roots absorb water, but they can die back quickly if soil stays dry, reducing the tree’s ability to hydrate itself.
Inside the trunk and branches, xylem vessels act like tiny pipelines, moving water from roots to leaves, but prolonged dryness can introduce air bubbles that interrupt this flow, a process known as cavitation.
Above ground, the leaves or needles respond by closing microscopic pores called stomata to reduce water loss, which also slows photosynthesis and growth. The bark helps limit moisture loss and protect internal tissues, but during extreme drought even this barrier can’t prevent dehydration.
Together, these systems shift the tree into survival mode, prioritizing water conservation over growth until moisture returns and normal function can resume.
When winter is too dry, a tree can suffer from desiccation, which means it loses more moisture than it can replace. Even while dormant, trees continue to lose water through their bark and, in the case of evergreens, through their needles.
In dry winter conditions — especially with wind and sun — the soil lacks moisture, leaving roots unable to take up enough water. This imbalance causes tissues to dry out, leading to stress that often isn’t visible until spring.
Evergreens are especially vulnerable, but deciduous trees can also be affected, showing weak growth, shedding or scorching of needles, or increased susceptibility to pests and disease.
Prolonged winter drought also reduces a tree’s overall vigor, making it harder to recover when the growing season begins.
Regular winter watering, mulching, and protection from wind can help prevent this type of stress.
During dry spells, a tree’s anatomy works overtime to conserve water and survive stress. The roots are the first line of defense, stretching outward and downward in search of moisture; fine feeder roots absorb water, but they can die back quickly if soil stays dry, reducing the tree’s ability to hydrate itself.
Inside the trunk and branches, xylem vessels act like tiny pipelines, moving water from roots to leaves, but prolonged dryness can introduce air bubbles that interrupt this flow, a process known as cavitation.
Above ground, the leaves or needles respond by closing microscopic pores called stomata to reduce water loss, which also slows photosynthesis and growth. The bark helps limit moisture loss and protect internal tissues, but during extreme drought even this barrier can’t prevent dehydration.
Together, these systems shift the tree into survival mode, prioritizing water conservation over growth until moisture returns and normal function can resume.
When winter is too dry, a tree can suffer from desiccation, which means it loses more moisture than it can replace. Even while dormant, trees continue to lose water through their bark and, in the case of evergreens, through their needles.
In dry winter conditions — especially with wind and sun — the soil lacks moisture, leaving roots unable to take up enough water. This imbalance causes tissues to dry out, leading to stress that often isn’t visible until spring.
Evergreens are especially vulnerable, but deciduous trees can also be affected, showing weak growth, shedding or scorching of needles, or increased susceptibility to pests and disease.
Prolonged winter drought also reduces a tree’s overall vigor, making it harder to recover when the growing season begins.
Regular winter watering, mulching, and protection from wind can help prevent this type of stress.
Pro Tip: Use an anti-desiccation spray to protect plant foliage (especially evergreens) from 'winter burn' (desiccation). This spray seals water in leaves and needles when roots can't absorb moisture from the ground. Apply immediately!