Question
Linden Tree Damage
I have a Linden tree which is about 20' high and has a trunk 5" in diameter. It has something eating the leaves in sections and just the brown framework of the leaf is left. Also I noticed splits in the trunk where it appears some insect may be eating. I don't know if the two problems are related. I have attached a picture
AnswerThe cracks look like frost cracks or sun scald usually on the SE side of the tree.
Frost cracks--Cracks or seams start at wounds or branch stubs. Serious damage can result from seemingly minor wounds. A sudden, sharp drop in winter temperature causes the outer layer of wood to contract more rapidly than the inner layer, which can result in a long vertical crack at weak points in the trunk.
"Frost cracking" can occur repeatedly in the same place, causing a buildup of tissues and the formation of frost ribs or seams. Depending on the tree species, the tissues at the margins of the injury may grow so rapidly that they curl in on themselves, preventing complete closure of a wound.
Sun Scald--This disease occurs during late winter or early spring when the temperature is above freezing during the day and below freezing at night. During the day the tree tissues, warmed by the sun, become active. Freezing at night kills this tissue, resulting in an elongated canker usually on the southwest side of the tree. Thin barked trees such as maples are most susceptible to this type of injury.
In this case I would lean toward frost cracks. This disease occurs during late winter or early spring when the temperature is above freezing during the day and below freezing at night. During the day the tree tissues, warmed by the sun, become active. Freezing at night kills this tissue, resulting in an elongated canker usually on the southwest side of the tree. Thin barked trees such as maples are most susceptible to this type of injury. The wound will heal itself over time. watch for insect activity in the crack--boring dust or oozing of sap. If these are seen spray the area with an insecticide called Merit to control borers that have attacked the wound.
I do not have enough information on the leaf insects to ID them. In any case hardwood can be completely defoliated and not harm since they have the ability to leaf out again. A few leaves eaten will not harm the health or growth of the tree.
