Top of large Ponderosa tree is dead.
A large Ponderosa Pine is dying at the top. Could you tell us what may be the cause?
The rest of tree and needles seem to be healthy. Tree is in Sisters, OR and a tree
we can see in the distance began that way and now the whole tree is brown.
Deschutes County Oregon
Pine engraver beetle (also known as IPS beetle) is known to attack trees from the top and work their way down. They usually infest trees that are already stressed for some other reason. The trees don't always die, but often do because these trees are already stressed and this attack can be the final straw.
Even with our great snow pack from last winter, our pine trees are still coming out of the stress of the prior three years' drought. Too many trees competing for sun and water can also cause stress and make trees susceptible to bark beetles.
The best thing you can do to prevent these beetles are to help make the tree as vigorous as possible. That means protecting the root system, ensuring space to grow and get sun (thinning trees if necessary), and not pruning trees during the growing season. Deep watering once a month will also help pine trees in our yards.
I recommend this fact sheet from the US Forest Service for more information on these beetles. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5187526.pdf
Hope this helps! Nicole