Question
There is a Blenheim apricot tree, close to one hundred years old, in my yard.  Today a visitor was swinging from one and then another of its largest branches.  I noticed that the entire branch moved as she swung on it, as well as some smaller branches nearby.  Is this a danger to the tree?  The woman weighs about 160 pounds.  I thought that each branch might be weakened by her grasping it, lifting her feet off the ground, and allowing her entire weight to be born by the branch.

Answer
Bonnie,

I seriously doubt that the tree was weakened by swinging on the branches.  In fact I would not be surprised if the branches weighed 2-3 times more than your swinger did.  

If you are concerned, and I would rely on my evaluation since I have not physically seen the tree, I would consult with a CERTIFIED arborist.  Only this way can you be absolutely certain of the trees condition.

Good luck

Gary