The holes appear to be emergence holes from wood-boring insects, which could include beetles, moths, or sawflies. This means that at least one generation has completed development into adulthood inside the wood, and has exited to breed and start a new generation. Many species of wood-boring insects prefer to attack trees already under stress from environmental conditions or injury, though we cannot clearly see any problems in the photo of the overall tree. (Symptoms of stress can take surprisingly long to manifest, however.) It's also possible these are holes from a woodpecker attempting to access these insects to eat them, but in either case, it strongly suggests that at least some wood damage has occurred. Some borers predominantly damage sapwood, which is vital tissue located just under the bark, while others tunnel into heartwood instead, causing minimal damage to live wood. (Heartwood is naturally dead wood at the core of the trunk and branches.) Differentiating between the two insect groups isn't always possible from exit hole appearance alone.

Due to the size of the tree and the greater ease of diagnosis by an in-person assessment, we suggest you have the tree evaluated by a certified arborist. They may not have any effective treatments for a pest which has become established or already caused concerning damage, but they may be able to prevent further infestation or to ease the tree's stress through other means. Fortunately, borer damage does not necessarily doom a tree. You can search for an arborist via this tool provided by the accrediting organization: https://www.treesaregood.org/findanarborist/arboristsearch

Miri