One Side of the Tree Has No Leaves

Leaf loss on one side of a tree indicates a health problem.

Premature defoliation of trees indicates a serious health problem. Leaf loss confined to one side of a tree may make it seem like half the tree is dead, but this is not necessarily the case. Some diseases exhibit symptoms in various parts of the tree before spreading to the whole. Identify the cause of the problem to treat the tree.

Anthracnose

Anthracnose is a soil-borne fungal disease that has a deleterious effect on the growth of many tree species, including oaks, fruit trees, ash, birch, maple and others, according to the Oklahoma Cooperative Extension Service. As anthracnose progresses through the wood of the tree, it causes leaf loss, which can occur on one side of the tree or begin at the lower branches and move to the top of the tree. Prune branches that show signs of dieback, and treat the tree with a fungicide.

Verticillium Wilt

Verticillium wilt is another fungal disease that affects deciduous trees. Verticillium alboatrum, or verticillium wilt, causes leaves to become discolored in early summer, lightening the pigmentation of the leaves and leading to eventual premature leaf drop. Verticillium wilt can cause leaf loss on only one side of the tree. Pruning affected branches helps slow the spread of the disease, but there is no effective control for verticillium wilt, according to the North Dakota State University website.

Girdling

Twig-girdling insects and cankers, which are caused by a variety of fungi, have the ability to girdle smaller branches. As girdling insects feed, they cut branches off from nutrients delivered by the root system of the tree, which leads to the death of the branch. Infestations on the tree can occur heavily on one side, leading to leaf loss. Cankers perform a similar function, often sinking into the branch and killing it, leading to leaf loss. Large numbers of cankers lead to leaf loss.

Root Crowding

Crowding of the roots of a tree, as from the close proximity of another tree, construction work that limits the growing space of a tree or a tree that is planted too close to a building, leads to the production of weak, stunted leaves and can contribute to leaf loss on one side of the tree, because the roots are less able to support the growth of the tree. Stunted leaves across the whole crown are a sign of root crowding.

References

• North Dakota State University: Deciduous Tree Diseases; R. W. Stack and H. A. Lamey; Nov. 1995
• Ohio State University Extension Factsheet: Anthracnose; Stephen Nameth and Jim Chatfield
• Oklahoma Cooperative Extension Service: Anthracnose and Other Common Leaf Diseases of Deciduous Shade Trees; Sharon von Broembsen

Resources

• Colorado State University: Aspen and Poplar Leaf Spots; W.R. Jacobi; Mar. 2009
• Clemson Cooperative Extension: Leaf and Needle Drop; Nancy Doubrava and Bob Polomski; May 1999