Nothing is constant. We must recognize that no matter how much work we put into these systems or how well they might be working today, eventually all things come to pass; but from their ashes rises something new. Letting ourselves get distressed and depressed when things change is of no help; instead, look at it as an opportunity to design something new. Perhaps a large, fruitful tree falls in a storm. Cut it up and use the logs/chips to grow mushrooms, then plant sun-loving fruits and vegetables in the area that used to be shaded by the tree. Maybe your neighbor puts on a new addition to their house that shades out the vegetable garden, take it as an opportunity to grow more shade-loving species like pawpaws, or turn it into an outdoor mushroom yard for shiitakes or oysters.