Fruits and Nuts: just bragging on my pear tree, 1 by Echo4u

Echo4u wrote:
Your pear trees are beautiful and I am jealous!!! Please look at this approx. 40 yo pear tree...and help me figure out what to do with it! It blooms every year, sets plenty of fruit. Some years the fruit splits open and we lose it to insects. Moreover, the tree itself looks as if it could topple over at any moment. Is it a fire blight, black rot??? Note the "ringed" (for lack of a better term) twigs...AND it looks like the lichen is eating the bark away...is that possible? HELP! Two more pics coming.