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Birch dieback is a condition in which the branches die. In some cases, one side of a tree will be dead or one or more stems of a cluster of a birch will die. In individual cases, the specific causes of dieback are often difficult to determine. When birch trees are growing under natural conditions in a forest, the ground is shaded by other trees and is kept fairly cool. Falling leaves form a natural mulch under the trees. Many times birch are planted on a lawn, in the open, and the leaves are raked up each fall. The birch is a shallow-rooted tree where the roots may be damaged or killed by high soil temperatures. The soil temperatures are likely to be higher on the open south or west slopes.

An early freeze in the fall may kill some branches of ornamental birches, especially if the trees are not native to our area. Warm days in late winter and early spring can cause excessive loss of moisture from buds and branches, which can't be replaced because the roots are in frozen ground. Soil moisture can become critical during extended periods of drought during the growing season. Light rains or ordinary watering for the grass will not soak down to the level of the tree roots. Poor soil drainage and heavy rainfall can cause poor soil aeration. This can result in damage to the roots due to lack of oxygen necessary for root growth. Trees that are weakened by one or more of the above conditions are often attacked by secondary invaders. An example is the bronze birch borer whose larvae tunnel into the inner bark. The tunnels often girdle the branches and cut off the flow of sap, causing the branch tips to die back to the point of the girdling.

Birch trees are generally short-lived, living to about fifty years under good growing conditions. Exotic species or non-native birch trees die before that. The cut leaf European weeping birch dies at an early age in Minnesota.

The best safeguard against birch dieback is good growing conditions. Plant trees in locations with at least partial shade for the root area. Organic mulch such as wood chips will help keep the soil moist and cool, along with keeping the weeds down. The mulch should be four to six inches deep and extend from the trunk out under the canopy of the tree as far as is practical. Fertilize every year or two in the spring unless the tree is in rich soil. Apply the fertilizer in a grid of holes beginning three feet out from the trunk and extending beyond the drip line. The best way to keep a birch healthy is to continue to treat it as a young and newly transplanted tree.

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