At a closer vantage point, it resembles the Spanish Moss of the deep south,
and it looks a lot like a bird's nest. It is not harmful to the tree.
It feeds on the air, not the tree. Here's a link to one of many pages on the subject. Just Google the term ball moss and you will find a lot of results. Ball Moss is a nitrogen fixer. That is, it is able to convert atmospheric nitrogen (which is unusable to plants) into a form that plants can use. With the exception of the beans and peas, most plants cannot do this. So when ball moss falls to the ground and decomposes, it provides fertilizers for other plants.
It doesn't take a lot of imagination to think of some of the uses native people might have had for this plant. They didn't have an abundance of things to use for padding, so they used it for lining their baby baskets, beds if sufficient furs were not available, hygene, and more.
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