chrisben said:... some old cuts of the trunk...
This is where many trees begin to decline. Once the trunk is damaged it's difficult for the plant to stay healthy. I agree with J.C. Seek on-site consultation.
Other possible contacts include; an arborist, a knowledgeable tree service or your local Master Gardeners group. I had one of our local Master Gardeners out to check our pines and there was no fee involved.
Welcome to ATP, Chris, and good luck with your tree.