pear tree

from The Arbor Centre:
Pears do not ripen on the tree. They mature, then fall off and ripen on the ground. Pick the fruit when it looks mature, and put it in a cool place, indoors. Pears will soften for eating within a few days or a few weeks, depending on variety, but do not continue to store them once they have softened.
September-ripening kinds, such as ‘William’s Bon Chretien’ ripen after a week or so off the tree. ‘Conference’ matures later and can take a few weeks to soften. If pears are picked too soon, they tend to simply dry up and wither without softening. If they are picked too late, the fruit softens quite quickly but soon develops brown mushy flesh at the centre.