According to the American Society for the Prevention of Cruelty to Animals, dogs should not be allowed to eat wood. Animals that ingest non-food items suffer from a condition know as "pica," the ASPCA explains.
The ASPCA identifies several reasons why dogs eat wood and other unusual objects. Puppies do this while exploring their world, but this behavior typically ends by 6 months of age. Some dogs have a compulsive disorder; on occasion, medical conditions, such as systemic disorders, parasitic infections, nutritional deficiencies or poisoning, drive dogs to pica. The ASPCA also mentions that some dogs swallow pieces of objects while they are engaged in destructive chewing, but this is not pica. Whatever the cause, WebMD reports that eating wood is potentially dangerous, because splinters sometimes become stuck in the gastrointestinal track, leading to bowel obstruction or infection.