I have a straight row of holes poked in my nice oak tree by woodpeckers and it is dying. Do they only peck trees that have a problem to start with anyway?
Yes. They're looking to harvest the insects that are under the bark. The insects are there because the tree has a problem.
What thonotorose said; I understand woodpeckers aren't interested in boring holes in healthy wood.
Could have been a lightning strike. That can be a long, slow death.
While most woodpeckers in our area will not damage healthy trees, there is an exception. The yellow-bellied sapsucker does drill holes into healthy trunks and branches - rather than looking for borers under the bark, they're drilling holes to drink the sap and eat insects that are attracted to the wounds. Sapsucker damage can be recognized by the neat, nearly horizontal rows of holes. When you say you have a "straight row" of holes, that sounds like sapsuckers - the others tend to make very irregular, fairly random holes as they dig for woodboring insects.
However, a tree that's otherwise healthy will generally tolerate some sapsucker damage without serious effects. Unless you've got a tree that's been really heavily damaged (which I have seen rarely, with nearly the entire trunk riddled with many rows of holes), the tree's problems are probably not due to sapsuckers.
Here is a link that might be useful: Yellow-bellied sapsucker
My hubby thought the tree was dying. It's just losing its leaves because it's fall. The garden guru, our horticultural expert from church, confirmed that it is a yellow bellied sapsucker attacking our tree and that it should live. Phew! I'm so glad. It's our favorite shade tree.