Bark falling off trunk of Linden Tree
We refer to this as bark blasting. What is causing it determines whether it is a major problem or not; however, it is not a good sign and a tree typically continues to decline once it begins to lose bark. There is not much you can do but maintain good growing conditions for the tree and hope for the best. (Use organic mulch around the base, water during dry periods without overwatering; avoid nitrogen fertilization, especially if the tree is growing in a lawn that is already fertilized). We are seeing this in a number of trees across Nebraska. In most cases, it is likely due to extremes in weather (i.e. November 2014 sudden cold spell and/or our wide swings in temperatures this past winter - some could even still relate back to the heat/drought stress year of 2012 - one stress after the other). During these times, the cambium layer beneath the bark is injured; hence the bark falls off. Some trees become infected with canker diseases, others with root rots...... Good luck with your tree.