Falling Tree Leaves: Leaf Abscission

Trees loose their leaves by design. When leaves become inefficient and unable to produce food and growth regulators, a process of shutting-down and sealing-off begins. Trees shed many parts besides leaves, including fruit, flowers, bud scales, trichomes,

The link address is: http://warnell.forestry.uga.edu/service/library/for99-025/for99-025.pdf