My dog suffocated in foliage of a tree

I was walking in forest with my tamed wolf. At some moment I found out my wolf suffocating in the foliage. I dont know how it came there. The place were I found it is shown by arrows on screenshot. I removed foliage, but it was too late. Wolf died. I don't know exactly how it happened. And I dont know whether it suffocated in foliage or it came into trunk of the tree.