cladoptosis. A condition in trees that's characterized by the premature dropping of twigs (figure A). Cladoptosis is most often seen during the summer months, and it's brought on by heat and drought. Some trees are more susceptible that others--in particular maples and birches--but it can strike just about any tree anywhere.Thankfully, cladoptosis rarely causes any lasting problems. In fact, it's often a sort of survival mechanism--a tree's response to the stress caused by extreme heat and lack of water. Once temperatures moderate and rain becomes more plentiful, the condition disappears.
But cladoptosis can also appear as a result of a tree being poorly located, such as a shade-loving dogwood or Japanese maple being planted in full blazing sun. And trees that are planted in compacted soils may also show symptoms of cladoptosis, which is why it pays to plant trees--as well as all other plants--in their preferred soil types.